THE 30-15 INTERMITTENT FITNESS TEST ACCURACY
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THE 30-15 INTERMITTENT FITNESS TEST: ACCURACY FOR INDIVIDUALIZING INTERVAL TRAINING OF YOUNG INTERMITTENT SPORT PLAYERS MARTIN BUCHHEIT Institute of Physiology, Faculty of Medicine, Strasbourg, France and APS and Motor Patterns: Adaptations-Rehabilitation, Sport Science Department, Picardie Jules Verne University, Amiens, France
ABSTRACT
INTRODUCTION
The objective of this study was to gather evidence supporting the accuracy of the 30-15 Intermittent Fitness Test (30-15IFT) for individualizing interval training of young intermittent sport players. In 59 young intermittent sport players (age, 16.2 6 2.3 years), we observed the relationships between the maximal running speed (MRS) reached at the end of the 30-15IFT (MRS30-15IFT) and physiological variables elicited by shuttle intermittent runs, including maximal oxygen uptake, explosive power of lower limbs, and the ability to repeat intense exercise bouts through cardiorespiratory recovery kinetics during exercise. To observe the capacity of the 30-15IFT to prescribe suitable running intensities for interval training sessions, we compared heart rates (HRs) reached during 3 series of intermittent runs, where distances were set according to the MRS30-15IFT and to MRS reached with 2 popular continuous field tests: the University of Montreal track test and the 20-m shuttle run test. The results show that the MRS30-15IFT is significantly correlated with all physiological variables elicited by shuttle intermittent runs (P , 0.05). Although mean HR were not different among the 3 series of intermittent runs, HR recorded during the runs based on MRS30-15IFT presented significantly less interindividual variation than when the continuously determined MRS were used as reference speeds. In conclusion, we can say that the 30-15IFT leads to an MRS that simultaneously takes into account various physiological qualities elicited when performing shuttle intermittent runs. For scheduling interval training sessions, the MRS30-15IFT appears to be an accurate reference speed for getting players with different physiological profiles to a similar level of cardiorespiratory demand and thus for standardizing training content.
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KEY WORDS reference maximal running speed, maximal oxygen uptake, explosive strength, quickness, heart rate recovery Address correspondence to Martin Buchheit, martin.buchheit@ u-picardie.fr. 22(2)/365–374 Journal of Strength and Conditioning Research Ó 2008 National Strength and Conditioning Association
ith the exception of track and field or other endurance activities (e.g., rowing, triathlon, cycling, swimming), the nature of most sport exercise is intermittent (2,6,21,38). Performance in intermittent sports has been related more to speed, agility, strength, explosive power, and the ability to repeat brief supramaximal exercise bouts than to the capacity to maintain continuous steady submaximal mechanical work (5,6). Thus, from a strength and conditioning approach, intermittent sport coaches’ priorities are to increase and maintain those physiological variables predictive of performance during intermittent sports through athletic drills and maximal strength programs (17,27). High-intensity anaerobic interval training is also regularly planned in the majority of team sports (20,27) to _ 2max) and enhance the develop maximal oxygen uptake (Vo ability to repeat intense exercise bouts (23,41). Although a direct _ 2max and repeated sprint ability is still relationship between Vo not well established (4,10,24), it has been shown that high aerobic capacity might have a beneficial effect on recovery kinetics during high-intensity intermittent exercise (41) and that _ 2max may influence game performance and total highVo intensity running distance during a soccer match (26,29). Until now, running intensities of such intense interval training sessions have been set according to individual maximal aerobic speed (MAS, determined by gas exchange _ 2max) analysis, is the lowest running speed that elicits Vo (7,8,20). These exercises are often composed of shuttle runs so as to introduce accelerations, decelerations and changes of direction, which are, on the one hand, running patterns specific to intermittent sports, and, on the other, more adapted for short anaerobic interval training sessions aimed at preferentially enhancing peripheral components of cardiorespiratory function (7,27). In the past 2 decades, numerous field tests have been proposed to determine MAS and consequently indirectly _ 2max of athletes (31–33). These famous tests are based on Vo continuous linear runs (31) or shuttle runs (32,34), and the maximal running speeds (MRSs) reached at the end of the tests (which are not far from the MASs) are obtained through an effort different from that of intermittent sports and the way VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization interval training sessions are programmed. Using these MRSs in the field may be the first objective way to individualize highintensity intermittent runs (7,8,20), but certain physiological determinants of performance during intermittent and shuttle efforts are not evaluated by these field tests. How do subjects adapt to the intermittency of the runs? How do they tolerate changes in direction when running at supramaximal speeds? Since shuttle speeds (32,34) are lower compared to linear ones (1), coaches have to convert them to get more appropriate reference speeds. Such conversion tables are based on theoretical data that do not provide for individual adjustment. Sometimes to get different players to reach a similar internal load, a distinct percentage of the continuous MRS is used (external load), depending on how each athlete adapts to the intermittency of a run and on how each tolerates the changes in direction. Unfortunately, these empirical manipulations diminish the precision of a training prescription. In view of these field test defects, a protocol that includes intermittent and shuttle runs simultaneously appeared necessary. A few intermittent field tests already exist, for example, the yo-yo test (29) and the Intermittent Shuttle Run Test (ISRT) (35), but they provide only an index of intermittent aerobic performance (22,30). They do not give an MRS that can be used as a reference speed for training purposes. We have thus been led to develop the 30-15 Intermittent Fitness Test (30-15IFT) (12,13), the reliability of which has already been shown (13), as an alternative to these other tests. Being both intermittent and shuttle, its main interest is that it involves physiological variables similar to those solicited during shuttle interval training sessions (i.e., explosive power of lower limbs when changing direction, aerobic qualities, and ability to recover between exercise bouts). It allows players reach a final MRS (MRS30-15IFT) that we hypothesize to be more accurate for scheduling shuttle interval training sessions than a usual continuously determined MRS. The aims of this work are (a) to show the capacity of the 30-15IFT to determine a particular speed (MRS30-15IFT) reflecting the multiple physiological qualities elicited when performing shuttle intermittent runs and (b) to illustrate the accuracy of the MRS30-15IFT for individualizing high-intensity anaerobic interval training. We propose that the first merit of the 30-15IFT lies in its ability to assess various physiological variables related to performance during intermittent runs instead of just a single specific quality [usual continuous tests _ 2max, which is used to examine (31–33) estimate only Vo criterion validity]. We also suggest that the accuracy of the MRS30-15IFT to individualize interval training sessions will be demonstrated if cardiorespiratory responses during intermittent runs based on the MRS30-15IFT present little interindividual dispersion. This would indeed help offer a similar training load to all athletes of a team by standardizing training contents.
Subjects
Participants were 59 young athletes (27 women, 32 men; age, 16.2 6 2.3 years; weight, 62.4 6 7.5 kg; height, 169.7 6 10.1 cm; Tanner stages 4 and 5). Their sexual development was determined by the usual recommendations (39) from values assigned to each maturity indicator on a scale of 1, representing immaturity, to 5, indicating full maturity. The youths were randomly selected from 2 competitive basketball and handball training camps that worked out at the same gymnasium and benefited from similar medical and testing conditions. Participants were involved in 7.2 6 1.1 hours of physical training per week plus a match each weekend (usually at a regional level). The athletes underwent medical screening and did not present any contraindications for vigorous exercise. Subjects and their parents were informed about the study and gave their consent to participate. The study protocol, which was approved by the CNIL (French National Committee for Informatics and Liberties) and the local ethics committee (Consultative Committee for Human Protection in Biomedical Research), conforms to the Declaration of Helsinki. Testing Procedures
Although the 59 subjects all performed a laboratory-graded continuous running test on an electronic treadmill and jumping and sprinting tests (see below), we had to divide them into 2 groups for field testing because of methodological constraints. The first group (group 1) included 34 athletes _ 2max taken randomly who performed explosive tests, Vo testing, and the 30-15IFT plus the UM-TT. They thus performed intermittent runs on the basis of the MRS30-15IFT and the MRSUM-TT. The 25 others constituted the group 2. They _ 2max testing, and the 30-15IFT performed explosive tests, Vo together with the 20mSRT. They had their training sessions scheduled with the MRS30-15IFT and the MRS20mSRT. The 30-15 Intermittent Fitness Test
METHODS Experimental Approach to the Problem
We first examined the associations between the MRS30-15IFT and certain physiological abilities elicited when performing
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shuttle intermittent runs, such as explosive power of lower limbs (estimated by 10-m sprint and counter movement jump _ 2max and cardiorespiratory recovery ability (evaltests), Vo uated via short-term heart rate (HR) recovery kinetics during exercise). In order to judge the accuracy of the 30-15IFT as training prescription for intermittent sport athletes, we observed the variability of cardiorespiratory responses (internal load, inferred from the percentage of HR reserve, %HRres) elicited by 3 series of short intermittent runs. The running distances (similar relative external load) were set at fixed percentages of the MRS30-15IFT and of the MRS reached at the end of 2 popular continuous tests, the University of Montreal track test (UM-TT) (31) and the 20-m shuttle run test (20mSRT) (32). A low variability (i.e., coefficient of variation ,5%) of %HRres is taken as evidence of accuracy.
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Protocol. All 59 subjects did the 30-15IFT, which consists of 30-second shuttle runs interspersed with 15-second passive recovery periods. Velocity was set at 8 kmh21 for the first 30-second run and was increased by 0.5 kmh21 every
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Journal of Strength and Conditioning Research 45-second stage thereafter. Calculation of targeted distances to run during each 30-second period took into account the fact that the effort to turn is increased when running speed is increased. We subtracted an empirical value of 0.7 second from the 30-second running periods for each change of direction. For example, at 11.5 kmh21, one would cover 96 m in a 30-second straight line run, but covering the same distance over a 40-m shuttle distance requires 2 direction changes taking 2 3 0.7 seconds, which brings the corrected distance run to 91.6 m. The subjects had to run back and forth between two lines set 40 m apart at a pace governed by a prerecorded beep at appropriate intervals that helped them adjust their running speed by entering into 3-m zones at each extremity and in the middle of the field while the short beep sounds (Figure 1). During the 15-second recovery period, the subjects walked in the forward direction to join the closest line (at the middle or at one end of the running area, depending on where the previous run stopped) from where they started the next run stage. Subjects were instructed to complete as many stages as possible. The test ended when a subject could no longer maintain the imposed running speed or when he or she was unable to reach a 3-m zone around each line at the moment of the audio signal consecutively 3 times. The velocity attained during the last completed stage is taken as the MRS30-15IFT. Physiological Basis of Exercise/Recovery Pattern. The respective durations of exercise and recovery periods were chosen (a) with regard to most intermittent sports characteristics (2,6,21,38) and (b) according to various physiological
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considerations. Concerning exercise periods, 30 seconds is close to the time of cardiorespiratory on-response kinetics at the beginning of exercise (16,19) and is also the time in which HbO2 resources have been shown to be consumed at intense exercise (36). Since the half-time for recovery of phosphocreatine stores has been reported to be 20–30 seconds (25), the 15 seconds of recovery would allow sufficient but incomplete recovery of energy substrates as during intermittent games (6,21,38). Finally, compared to the ISRT (35), the choice of longer shuttle distances (40 m vs. 20 m) is intended to diminish muscular lactacidemia (1) and perceived exercise painfulness in the lower limbs, which helps reach a supramaximal MRS (higher than MAS). Reliability of the 30-15 Intermittent Fitness Test. The reliability of the test has been described elsewhere (12,13). We previously reported that test-retest yielded similar results in 19 subjects (9 women, 10 men; age, 19.4 6 1.8 years) with intraclass correlation coefficient (ICC) r = 0.96 for the MRS30-15IFT. The mean MRS30-15IFT was similar (20.1 6 0.7 vs. 20.2 6 0.9 kmh21). Physiological parameters were also not different: maximal HR: 196 6 2.3 vs. 195 6 3.1 bmin21; blood lactate 3 minutes after the test: 11.8 6 1.3 vs. 12.0 6 1.9 mmolL21. The University of Montreal Track Test
The UM-TT was conducted on a 400-m outdoor track according to the recommendations of Leger and Boucher (31) on 34 subjects. Pylons were placed at every 50 m of the track. The 34 subjects ran continuously and were paced with a sound signal emitted at specific intervals from a prerecorded tape. The velocity was set initially at 8 kmh21. Thereafter, it was increased by 1 kmh21 every 2 minutes. The subjects were instructed to complete as many stages as possible, and the test was stopped when the subjects were at least 5 m behind the appropriate pylon at the sound signal 2 successive times or when they felt they could not complete the stage. Although we believe that the test leads to MAS, with no gas analysis data, we prefer to note the final velocity as MRSUM-TT. The reliability of this test has already been investigated (ICC r = 0.94; n = 60) (31). The 20-Meter Shuttle Run Test
Figure 1. Area prepared for the 30-15 Intermittent Fitness Test (30-15IFT) and example of 2 intermittent runs. For the run at 8.5 kmh21 (about 69.2 m in 30 seconds), subjects start at line A, run to line C crossing line B, and then return. After crossing line B again, they stop after 8.5 m and walk to line A during the 15-second recovery to be ready for the next stage. For the run at 11.5 kmh21 (about 91.2 m in 30 seconds), subjects start at line A, make one complete round trip, stop after 9.5 m when going toward line B, and then walk to line B during the 15- second of recovery for the next start. Note that calculation of targeted distances takes into account the time needed for the direction changes.
The 20mSRT was performed as formulated by Leger and Lambert (32) by 25 subjects. It involves continuous running between 2 lines set 20 m apart on a nonsliding surface at running speeds governed by a prerecorded beep at appropriate intervals. Velocity was set at 8 kmh21 for the first minute, increasing by 0.5 kmh21 every minute thereafter. Subjects were instructed to complete as many stages as possible, and the test was stopped when a subject was unable 3 consecutive times to reach a 3-m zone situated ahead of each 20-m line at the moment of the audio signal. We believe that the test leads to MAS, but without gas analysis data, we prefer to note the final velocity as MRS20mSRT. The reliability of this test has already been investigated (ICC r = 0.98; n = 50) (32). VOLUME 22 | NUMBER 2 | MARCH 2008 |
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TABLE 1. Physiological capacities elicited when performing intermittent runs and maximal running speeds reached at the end of each of 3 field tests. MRS Subjects
_ 2max Vo
MAS
Treadmill
30-15IFT
UM-TT
20mSRT
10 m
CMJ
HRRE
Total (N = 59) 45.8 (5.8) 14.1 (0.9)* 14.7 (1.9)* 18.2 (1.6) –– –– 1.98 (0.14) 42.5 (7.7) 6.6 (1.3) Group 1 (n = 34) 49.2 (4.2) 14.8 (1.1)* 15.1 (1.7)* 18.6 (2.1) 14.9 (1.9)* –– 1.90 (0.09) 47.2 (5.3) 6.5 (1.5) Group 2 (n = 25) 41.9 (3.6) 13.2 (1.4)* 13.9 (1.2)* 16.9 (1.2) –– 11.5 (0.9)* 2.09 (0.10) 36.7 (4.9) 6.8 (1.9) _ 2max, mLmin21kg21), maximal aerobic speed (MAS), maximal running speed Mean values (SD) of maximal oxygen uptake (Vo (MRS, kmh21) reached at the end of each test (treadmill for the laboratory exercise test, 30-15 Intermittent Fitness Test [30-15IFT], University of Montreal track test [UM-TT], and 20-m shuttle run test [20mSRT]), explosive power of lower limbs (10-m sprint time [10 m], in seconds; countermovement jump [CMJ], in centimeters), and heart rate recovery index (HRRE) measured during the 30-15IFT. Group 1 = subjects who performed the 30-15IFT and the UM-TT; group 2 = subjects who performed the 30-15IFT and the 20mSRT. *Significant difference (P , 0.001) vs. MRS30-15IFT.
Series of Intermittent Runs
Here the aim was to bring all players to a similar level of metabolic demand during each of 3 series of intermittent runs, using in each series 1 of the 3 MRSs as the reference running intensity. Each series consisted of repeated runs for 15
seconds at high intensity alternated with 15 seconds of passive recovery lasting 10 minutes. The targeted running distance of each intermittent run was calculated as a given percentage of each MRS. Awareness of MRS differences among the 3 tests [Table 1; MRS30-15IFT is higher than MRSUM-TT (by 20%)
Figure 2. Zero-order linear regressions between the maximal running speed (MRS) reached at the end of the 30-15 Intermittent Fitness Test (MRS30-15IFT) and _ 2max), explosive power of lower limbs physiological qualities elicited when performing shuttle intermittent runs in the 59 subjects. Maximal oxygen uptake (Vo (10-m sprint time [10 m] and countermovement jump [CMJ]) and heart rate recovery index (HRRE).
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TABLE 2. Targeted distance and heart rate reserve observed during 10-minute intermittent runs.
Subjects
Reference speed
Total (N = 59) Group 1 (n = 34)
MRS30-15IFT MRS30-15IFT MRSUM-TT MRS30-15IFT MRS20mSRT
Group 2 (n = 25)
HR
Targeted distance (m) for 15-s runs 69.5 72.4 69.9 66.6 66.5
(7.2) (6.1) (12.2) (4.7) (10.5)
CV (%)
%HRres 91.2 92.4 89.1 91.7 89.5
(87.9–94.1; (88.1–93.6; (78.3–96.1; (87.9–94.1; (77.8–95.9;
2.8) 2.1) 8.3)* 2.7) 9.5)†
3.1 2.3 9.2 2.9 10.6
Mean values (SD) of targeted distance runs and mean percentage (range; SD) of heart rate reserve (%HRres) reached during each series of intermittent runs (15-second exercise/15-second rest) based on the maximal running speed (MRS) of each test [MRS30-15 IFT = MRS reached with the 30-15IFT = 30-15 Intermittent Fitness Test, MRSUM-TT for the University of Montreal track test, and MRS20mSRT for the 20-m shuttle run test (kmh21)]. CV = coefficient of variation; Group 1 = subjects who performed both the 30-15IFT and the UM-TT; Group 2 = subjects who performed both the 30-15IFT and the 20mSRT. *Six subjects (18%) were not able to finish the 10-minute intermittent runs based on the UM-TT. †Four subjects (16%) were not able to finish the 10-minute intermittent runs based on the 20mSRT.
and higher than MRS20mSRT (by 35%)] and based on previous experimentation (14), we used the following percentages that are intended to represent equivalent metabolic demands: 110% of MRSUM-TT (group 1, n = 34), 140% of MRS20mSRT (group 2, n = 25) and 95% of MRS30-15IFT (pooled, N = 59). For example, for one subject displaying typical MRS values (MRSUM-TT = 16.5 kmh21 and MRS30-15IFT = 19.0 kmh21), running at 95% of an MRS30-15IFT consisting of covering [(19/3.6) 3 0.95] 3 (15 2 0.7) = 71.7 m in 15 seconds and running at 110% of an MRSUM-TT consisting of covering [(16.5/3.6) 3 1.10) 3 (15 2 0.7) = 72.0 m in 15 seconds, which are quite similar distances. Instrumentation
Maximal Oxygen Uptake. A maximal graded continuous running test was performed on an electronic treadmill (Cardiovit _ 2max was determined. 100; Schiller, Baar, Switzerland) where Vo All athletes performed a standardized 5-minute warm-up, and the test began at a running speed of 8 kmh21, which was increased by 1 kmh21 every 2 minutes until exhaustion. The treadmill grade was set to 1%. After a standard calibration procedure of all apparatus, HR and gas exchange parameters _ 2, CO2 output) were continuously (minute ventilation, Vo recorded with a commercially available system (Breath-by-Breath Metabolic Measurement; Sensor Medic MSE, Rungis, _ 2max was determined by the criteria of Taylor et al. France). Vo _ 2 despite an increase in running speed and (40): a plateau in Vo HR .90% of the predicted maximal value. The velocity _ 2max (MAS) was the lowest running speed associated with Vo _ 2max (9) and represented _ 2 value equal to Vo that elicited a Vo 92.2% of the MRS reached during the treadmill test. Explosive Power of Lower Limbs
After a supervised warm-up, muscular explosive power of lower limbs was assessed by jumping and sprinting abilities
(18). Following Bosco et al. (11), jump testing consisted of a vertical countermovement jump (CMJ; in centimeters) on a Bosco jumping mat (Ergojump; Globus Italia, Codogne, Italy) that calculates jumping height from flying times. Since this method of assessment can have a methodological bias (notably landing with leg flexion), an experienced investigator validated each trial visually. Sprint abilities were evaluated by a 10-m standing-start run (10 m; in seconds) (18) recorded with photoelectric cells (Wireless Timing-Radio Controlled, Brower Timing System; Matsport, St. Ismier, France). Both tests were performed 3 times, separated by 45 seconds of passive recovery. Only the best performance was retained. Heart Rate
After applying conductive gel, an electrode transmitter belt (T61; Polar Electro, Kempele, Finland) was fitted to the chest of each subject as prescribed by the manufacturer. Heart rate was measured during quiet wakefulness in the morning (15) in the supine position for 10 minutes (HRrest). During all the tests, HR was recorded at 5-second intervals using a HR monitor (S610; Polar Electro, Kempele, Finland). When recorded data displayed aberrant values, HR was corrected by interpolation from adjacent values. Maximal HR (HRmax) was recorded in all field tests so as to verify that the subject performed at maximal effort. During field tests, data from the subject presenting at exhaustion an HR ,90% of HRmax recorded during the maximal graded continuous running was rejected (n = 1). Heart Rate Analysis
The HR recovery index (HRRE) (12,13) was used to evaluate cardiorespiratory recovery capacities. The HR recovery index was calculated, during the 30-15IFT only, as the sum of all differences between maximal and minimal HRs registered during each 15-second recovery period divided by the total number of beats during the entire test. Mean individual HR VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization recorded during the 3 series of intermittent runs are reported as a percentage of HRres as proposed by Karvonen et al. (28). In order to evaluate the %HRres disparity among athletes, we calculated the difference between the mean %HRres reached by all the subjects and the individual %HRres:DHRres = abs (mean %HRres 2 %HRres individual). The coefficient of variation (CV; in percentage) (3) was also calculated for %HRres. Statistical Analyses
Statistical analyses were carried out using Minitab 13.2 Software (Minitab Inc., Paris, France). Descriptive statistics were computed as means and SD. As data were normally
distributed, parametric tests were used. To avoid any gender, age, or body mass effect (all known to influence endurance, power, and speed), we adjusted data on these possible confounding factors by introducing them as variables in the analyses. A multiple linear regression model was first used to establish the link between MRS30-15IFT and all the intermittent sport-specific physiological capacities tested in the 59 subjects. A minimal sample size of 59 subjects was determined based on the work of Pedhazur (37), who suggested a subject-to-variable ratio of 15:1 for multiple regression analyses (15 3 4 = 60). Concerning HR responses during intermittent runs, DHRres calculated from each series were compared with a one-way analysis of variance with a post hoc test (Tukey). Significance was set at P # 0.05; a tendency was assumed for P , 0.10.
RESULTS Maximum Heart Rate at the End of Each Field Test
The HRmax reached at the end of the 30-15IFT was not different from those measured at the end of the other tests [respectively, 193.8 6 4.8 vs. 192.1 6 6.0 bmin21 for 30-15IFT vs. treadmill (N = 59), 193.3 6 5.5 vs. 191.8 6 5.4 bmin21 for 30-15IFT vs UM-TT (n = 34) and 195.6 6 5.4 vs. 193.9 6 6.8 bmin21 for 30-15IFT vs 20mSRT (n = 25)].
Physiological Qualities and Maximal Running Speeds Reached Within Each Field Test
_ 2max, Mean (6SD) values of Vo MAS, MRS, explosive power of lower limbs, and HRRE are presented in Table 1. Whatever the subgroup considered, the was signifiMRS30-15IFT cantly higher than the MAS, MRSUM-TT, and MRS20mSRT (P , 0.001). Relationships Between MRS3015IFT
and Physiological
Qualities Elicited When Figure 3. Individual HR reserve (%HRres) profiles during intermittent runs in 3 subjects. The exercise consisted of running 15 seconds at 110% of the maximal running speed (MRS) reached with the University of Montreal track test (MRSUM-TT, upper plots) and at 95% of the MRS reached with the 30-15 Intermittent Fitness Test (MRS30-15IFT, lower plots) intersected with 15 seconds of passive recovery during 10 minutes.
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Performing Shuttle Intermittent Runs
For the 59 subjects, the MRS30-15IFT was significantly
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Cardiorespiratory Demands During Intermittent Runs Based on Each Maximal Running Speed
Table 2 presents mean values of targeted distances and the corresponding %HRres observed for subjects performing intermittent runs at a similar relative intensity (at a similar percentage of a given MRS). The results show that the mean %HRres reached by the subjects did not depend on the reference MRS used. Nonetheless, when scheduling intermittent runs based on a given percentage of a continuously obtained MRS, 6 and 4 subjects of the groups using, respectively, the MRSUM-TT and MRS20mSRT as reference speeds could not finish the 10-minute series, and 7 of these subjects presented an HRres ,80%. The %HRres range of values showed more disparity with the 2 continuous tests than with the 30-15IFT, and the CV of the %HRres was lower for the series based on the 30-15IFT than those based on the 2 continuous tests (Table 2). Individual differences from the mean %HRres were significantly lower in the series based on the 30-15IFT than in the series based on the UM-TT (DHRres = 2.8 6 1.2 vs. Figure 4. Individual heart rate reserve (%HRres) profiles as a function of running speed for 2 subjects presenting 9.5 6 2.1 bmin21, P , 0.05) or significantly different maximal running speeds (MRSs) determined with the University of Montreal track test (MRSUM21 , upper) but quite similar MRSs obtained with the 30-15 Intermittent Fitness Test (30-15IFT) on the 20mSRT (DHRres = 2.6 TT of 15 vs. 18 kmh (MRS30-15 IFT of 19.5 vs. 20 kmh21, lower). 6 1.8 vs. 8.1 6 2.9 bmin21, P , 0.05). Figure 3 illustrates data for 3 representative athletes correlated with all physiological variables elicited when who did not display comparable %HRres during 2 series performing shuttle intermittent runs and can be summarized when distances were planned based on the MRSUM-TT or the by the following regression: MRS30-15IFT = 14.6 + 0.06 MRS30-15IFT. _ 2max 2 1.34 10 m + 0.02 CMJ + 0.43 HRRE 2 1.20 G 2 Vo DISCUSSION 0.10 W + 0.11 A (r = 0.87 and P , 0.001 for the relationship), 21 _ where Vo2max is expressed in mLminkg , 10 m in seconds, The present study shows that the 30-15IFT (12,13) leads to an CMJ in centimeters, HRRE with no units, G stands for gender MRS that is significantly associated with physiological (1 = male, 2 = female), W for weight (kilograms), and A for qualities elicited when performing shuttle intermittent runs, age (years). Zero-order linear regression analyses made i.e., explosive muscular power of lower limbs, aerobic power, _ 2max, explosive power of lower between MRS30-15IFT and Vo and cardiovascular recovery capacity. In addition, the results limbs, and HRRE kinetics index were all significant (P , 0.05). show that using the MRS30-15FT as a reference speed for These 4 relationships are illustrated in Figure 2. determining intermittent run distances enables reaching VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization a requested level of metabolic demand with lower interindividual differences than when using continuously determined running speeds. This possibility to easily provide all members on a team a similar exercise load and especially to individuals with distinct aerobic or anaerobic capacities illustrates the good accuracy of the 30-15IFT for individualizing interval training sessions. The significant relationships between MRS30-15IFT and _ 2max, and HRRE exemplifies the CMJ, 10-m sprint time, Vo merit of the 30-15IFT. The relationship between an MRS reached after a graded exercise test and anaerobic capacities has not been investigated before. In the present study, the physiological qualities elicited when performing shuttle intermittent runs accounted for 75% of the variance of the MRS30-15IFT (r = 0.87). These results for adolescents suggest that MRS30-15IFT is a unique speed that takes into account several physiological variables simultaneously. The present results also illustrate the accuracy of the 3015IFT when testing intermittent sports players with different physiological profiles. Figure 4 illustrates the fact previously reported (5,10) that physiological capacities other than _ 2max (i.e., explosive power and the ability to recover Vo between efforts) condition shuttle intermittent performance. Here, 2 subjects with different continuous linear MRSs reached with the UM-TT (18 and 15 kmh21) presented quite similar performances on the 30-15IFT (20 and 19.5 kmh21). Their individual physiological profiles can explain these running speed differences. Compared to MRSUM-TT, athlete A with a clearly ‘‘aerobic profile’’ together with poor explosive _ 2max: 63.4 mLminkg21, CMJ: 44 cm, 10 m: strength (Vo 1.94 seconds, HRRE: 9.7) has increased his MRS by 2 kmh21 with the 30-15IFT. Athlete B with an ‘‘anaerobic profile,’’ _ 2max (54.5 mLminkg21) but with greater despite a lower Vo explosive power (CMJ: 69 cm, 10 m: 1.81 seconds) and higher cardiovascular recovery capacity (HRRE: 11.6) was able to run 4.5 kmh21 faster during the 30-15IFT. In other words, compared to athlete A, athlete B tolerated the changes of direction better and derived more benefit from the intermittency of the runs. This point should be considered when programming interval training sessions, especially for athletes with different physiological profiles, as in team sports. Finally, the results demonstrate the capacity of the 30-15IFT to prescribe proper running intensities for interval training sessions. We have made the assumption that the MRS30-15IFT helps get players with different physiological profiles to reach similar cardiorespiratory levels and that interindividual differences become less important when using the MRS30-15IFT compared to continuously determined MRSs for prescribing the intensity of interval training sessions. When scheduling intermittent runs based on a given percentage of the MRS obtained with the two continuous tests, 17.5 and 16% of the subjects could not finish the 10-minute series, whereas many of them presented low HRres values (,80% HRres) (Table 2).
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Our results show that there is significantly more disparity among cardiorespiratory responses (inferred by higher CVand DHRres) during intermittent runs targeted based on the MRSUM-TT or the MRS20mSRT than when programmed with the MRS30-15IFT as the reference speed (Table 2, P , 0.05). The findings illustrate that the metabolic demand can be different from one subject to another, even at a similar percentage of a continuously determined MRSs (similar relative external load). These data are illustrated in Figure 3. When using MRSUM-TT as the reference running speed to calculate individual intermittent run distances, cardiorespiratory demands were clearly different for each athlete (Figure 3, top; %HRres = 95.8, 82.8, and 91.1% for athletes C, D, and E, respectively). However, when using MRS30-15IFT as the reference speed, %HRres for the 3 athletes were similar (Figure 3, bottom; %HRres = 92.9, 94.2, and 93.1% for athletes C, D, and E, respectively). Note that since MRS30-15IFT is 20% higher than MRSUM-TT, we used a distinct percentage of each MRS (95% MRS30-15IFT and 110% MRSUM-TT). Previous investigations have indicated that physiological demands are quite similar to these percentages (14). When using a continuously determined MRS, players with different cardiovascular responses may be led to produce efforts with disproportionate intensities that may have different physiological impacts and unexpected consequences on their health, fitness, or fatigue. Finally, we postulate that it is because the MRS30-15IFT is a speed taking into account various qualities solicited during shuttle intermittent runs that it brings athletes with different physiological profiles to a similar level of cardiorespiratory demand. We can thus propose that the 30-15IFT is an accurate tool for individualizing aerobic training since it permits programming a similar workout load for each athlete.
PRACTICAL APPLICATIONS Coaches and trainers can use the 30-15IFT examined in this study because it leads to a particular MRS that takes into account various qualities solicited during shuttle intermittent runs, i.e., explosive power of lower limbs, aerobic qualities, and the ability to recover between exercise bouts. The 3015IFT has been shown to be accurate for individualizing short intermittent run distances in subjects presenting different aerobic or anaerobic profiles. Using the MRS30-15FT as a reference speed for determining intermittent run distances enables a given level of cardiorespiratory demand with lower interindividual differences to be reached than when using continuously determined MRSs. This result has its importance in team sports since a coach can be certain that a similar training load will be offered to all the athletes. Although further study is still needed to determine at which percentage of the MRS30-15IFT players have to train to improve one or another physical capacity, our present results already show that the accuracy of the test for a training prescription is high.
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Journal of Strength and Conditioning Research Involving the main intermittent sport-specific physiological determinants and not just one component such as aerobic or anaerobic power, the 30-15IFT could also be used as a single tool for evaluating seasonal changes in an athlete’s overall fitness and performance. In that case, it would be important to standardize test conditions as much as possible (i.e., controlling food consumption and training load before the test and exercising in comparable weather and field conditions if testing outdoors).
ACKNOWLEDGMENTS The author thanks Mathieu Puzenat for technical assistance and data treatment and the coaches and athletes for their participation. The author declares no conflict of interest. A compact disc on the 30-15IFT (with instruction booklet) is available free of charge from the author upon request.
REFERENCES 1. Ahmaidi, S, Collomp, K, and Prefaut, C. The effect of shuttle test protocol and the resulting lactacidaemia on maximal velocity and maximal oxygen uptake during the shuttle exercise test. Eur J Appl Physiol Occup Physiol 65: 475–479, 1992. 2. Apostolidis, N, Nassis, GP, Bolatoglou, T, and Geladas, ND. Physiological and technical characteristics of elite young basketball players. J Sports Med Phys Fitness 44: 157–163, 2004. 3. Atkinson, G and Nevill, AM. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med 26: 217–238, 1998. 4. Aziz, AR, Chia, M, and Teh, KC. The relationship between maximal oxygen uptake and repeated sprint performance indices in field hockey and soccer players. J Sports Med Phys Fitness 40: 195–200, 2000. 5. Bangsbo, J. Fitness Training in Football: A Scientific Approach. Bagsvaerd, Denmark: Storm, 1994. 6. Bangsbo, J, Norregaard, L, and Thorso, F. Activity profile of competition soccer. Can J Sport Sci 16: 110–116, 1991. 7. Billat, LV. Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part II: anaerobic interval training. Sports Med 31: 75–90, 2001. 8. Billat, LV. Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part I: aerobic interval training. Sports Med 1: 13–31, 2001. 9. Billat, LV and Koralsztein, JP. Significance of the velocity at VO2max and time to exhaustion at this velocity. Sports Med 22: 90–108, 1996. 10. Bishop, D and Spencer, M. Determinants of repeated-sprint ability in well-trained team-sport athletes and endurance-trained athletes. J Sports Med Phys Fitness 44: 1–7, 2004. 11. Bosco, C, Luhtanen, P, and Komi, PV. A simple method for measurement of mechanical power in jumping. Eur J Appl Physiol Occup Physiol 2: 273–282, 1983. 12. Buchheit, M. [The 30-15 Intermittent Fitness Test: a new intermittent running field test for intermittent sport players—part 1]. Approches Handball. 87: 27–34, 2005. 13. Buchheit, M. The 30-15 intermittent fitness test: reliability and implication for interval training of intermittent sport players. In: ECSS Proceedings. Belgrade: 2005. 14. Buchheit, M. [Illustration of interval-training prescription on the basis of an appropriate intermittent maximal running speed - the 30-15 intermittent fitness test—part 2]. Approches Handball. 88: 36–46, 2005. 15. Buchheit, M, Simon, C, Piquard, F, Ehrhart, J, and Brandenberger, G. Effect of increased training load on vagal-related indexes of heart
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rate variability: a novel sleep approach. Am J Physiol Heart Circ Physiol 287: H2813–H2818, 2004. 16. Cerretelli, P and Di Prampero, PE. Kinetics of respiratory gas exchange and cardiac output at the onset of exercise. Scand J Respir Dis Suppl 77: 35a–35g, 1971. 17. Christopher, W, Lee, E, and Geoff, W. Development of speed, agility, and quickness for the female soccer athlete. Strength Cond J 22: 9–12, 2000. 18. Cometti, G, Maffiuletti, NA, Pousson, M, Chatard, JC, and Maffulli, N. Isokinetic strength and anaerobic power of elite, subelite and amateur French soccer players. Int J Sports Med 22: 45–51, 2001. 19. Davies, CT, Di Prampero, PE, and Cerretelli, P. Kinetics of cardiac output and respiratory gas exchange during exercise and recovery. J Appl Physiol 32: 618–625, 1972. 20. Dupont, G, Akakpo, K, and Berthoin, S. The effect of in-season, high-intensity interval training in soccer players. J Strength Cond Res 18: 584–589, 2004. 21. Duthie, G, Pyne, D, and Hooper, S. Applied physiology and game analysis of rugby union. Sports Med 13: 973–991, 2003. 22. Elferink-Gemser, MT, Visscher, C, Lemmink, KA, and Mulder, TW. Relation between multidimensional performance characteristics and level of performance in talented youth field hockey players. J Sports Sci 22: 1053–1063, 2004. 23. Gaitanos, GC, Williams, C, Boobis, LH, and Brooks, S. Human muscle metabolism during intermittent maximal exercise. J Appl Physiol 75: 712–719, 1993. 24. Glaister, M. Multiple sprint work: physiological responses, mechanisms of fatigue and the influence of aerobic fitness. Sports Med 35: 757–777, 2005. 25. Harris, RC, Edwards, RH, Hultman, E, Nordesjo, LO, Nylind, B, and Sahlin, K. The time course of phosphorylcreatine resynthesis during recovery of the quadriceps muscle in man. Pflugers Arch 367: 137–142, 1976. 26. Helgerud, J, Engen, LC, Wisloff, U, and Hoff, J. Aerobic endurance training improves soccer performance. Med Sci Sports Exerc 33: 1925–1931, 2001. 27. Hoff, J and Helgerud, J. Endurance and strength training for soccer players: physiological considerations. Sports Med 3: 165–180, 2004. 28. Karvonen, MJ, Kentala, E, and Mustala, O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 35: 307–315, 1957. 29. Krustrup, P, Mohr, M, Amstrup, T, Rysgaard, T, Johansen, J, Steensberg, A, Pedersen, PK, and Bangsbo, J. The yo-yo intermittent recovery test: physiological response, reliability, and validity. Med Sci Sports Exerc 35: 697–705, 2003. 30. Krustrup, P, Mohr, M, Ellingsgaard, H, and Bangsbo, J. Physical demands during an elite female soccer game: importance of training status. Med Sci Sports Exerc 37: 1242–1248, 2005. 31. Leger, LA and Boucher, R. An indirect continuous running multistage field test: the Universite de Montreal track test. Can J Appl Sport Sci 5: 77–84, 1980. 32. Leger, LA and Lambert, J. A maximal multistage 20-m shuttle run test to predict VO2 max. Eur J Appl Physiol Occup Physiol 49: 1–12, 1982. 33. Leger, LA, Lambert, J, Goulet, A, Rowan, C, and Dinelle, Y. Aerobic capacity of 6 to 17-year-old Quebecois—20 meter shuttle run test with 1 minute stages. Can J Appl Sport Sci 9: 64–69, 1984. 34. Leger LA, Mercier, D, Gadoury, C, and Lambert, J. The multistage 20 metre shuttle run test for aerobic fitness. J Sports Sci 6: 93–101, 1988. 35. Lemmink, KA, Visscher, C, Lambert, MI, and Lamberts, RP. The interval shuttle run test for intermittent sport players: evaluation of reliability. J Strength Cond Res 18: 821–827, 2004. VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization 36. McCully, KK, Iotti, S, Kendrick, K, Wang, Z, Posner, JD, Leigh, J, Jr, and Chance, B. Simultaneous in vivo measurements of HbO2 saturation and PCr kinetics after exercise in normal humans. J Appl Physiol 77: 5–10, 1994. 37. Pedhazur, EJ. Multiple Regression in Behavioral Research: Explanation and Prediction. Fort Worth: Harcourt Brace College Publishers, 1997. 38. Rannou, F, Prioux, J, Zouhal, H, Gratas-Delamarche, A, and Delamarche, P. Physiological profile of handball players. J Sports Med Phys Fitness 41: 349–353, 2001.
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39. Sun, SS, Schubert, CM, Chumlea, WC, Roche, AF, Kulin, HE, Lee, PA, Himes, JH, and Ryan, AS. National estimates of the timing of sexual maturation and racial differences among US children. Pediatrics 110: 911–919, 2002. 40. Taylor, H, Buskirk, E, and Henschel, A. Maximal oxygen uptake as an objective measure of cardiorespiratory performance. J Appl Physiol 8: 73–80, 1955. 41. Tomlin, DL and Wenger, HA. The relationships between aerobic fitness, power maintenance and oxygen consumption during intense intermittent exercise. J Sci Med Sport 5: 194–203, 2002.
ABSTRACT
INTRODUCTION
The objective of this study was to gather evidence supporting the accuracy of the 30-15 Intermittent Fitness Test (30-15IFT) for individualizing interval training of young intermittent sport players. In 59 young intermittent sport players (age, 16.2 6 2.3 years), we observed the relationships between the maximal running speed (MRS) reached at the end of the 30-15IFT (MRS30-15IFT) and physiological variables elicited by shuttle intermittent runs, including maximal oxygen uptake, explosive power of lower limbs, and the ability to repeat intense exercise bouts through cardiorespiratory recovery kinetics during exercise. To observe the capacity of the 30-15IFT to prescribe suitable running intensities for interval training sessions, we compared heart rates (HRs) reached during 3 series of intermittent runs, where distances were set according to the MRS30-15IFT and to MRS reached with 2 popular continuous field tests: the University of Montreal track test and the 20-m shuttle run test. The results show that the MRS30-15IFT is significantly correlated with all physiological variables elicited by shuttle intermittent runs (P , 0.05). Although mean HR were not different among the 3 series of intermittent runs, HR recorded during the runs based on MRS30-15IFT presented significantly less interindividual variation than when the continuously determined MRS were used as reference speeds. In conclusion, we can say that the 30-15IFT leads to an MRS that simultaneously takes into account various physiological qualities elicited when performing shuttle intermittent runs. For scheduling interval training sessions, the MRS30-15IFT appears to be an accurate reference speed for getting players with different physiological profiles to a similar level of cardiorespiratory demand and thus for standardizing training content.
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KEY WORDS reference maximal running speed, maximal oxygen uptake, explosive strength, quickness, heart rate recovery Address correspondence to Martin Buchheit, martin.buchheit@ u-picardie.fr. 22(2)/365–374 Journal of Strength and Conditioning Research Ó 2008 National Strength and Conditioning Association
ith the exception of track and field or other endurance activities (e.g., rowing, triathlon, cycling, swimming), the nature of most sport exercise is intermittent (2,6,21,38). Performance in intermittent sports has been related more to speed, agility, strength, explosive power, and the ability to repeat brief supramaximal exercise bouts than to the capacity to maintain continuous steady submaximal mechanical work (5,6). Thus, from a strength and conditioning approach, intermittent sport coaches’ priorities are to increase and maintain those physiological variables predictive of performance during intermittent sports through athletic drills and maximal strength programs (17,27). High-intensity anaerobic interval training is also regularly planned in the majority of team sports (20,27) to _ 2max) and enhance the develop maximal oxygen uptake (Vo ability to repeat intense exercise bouts (23,41). Although a direct _ 2max and repeated sprint ability is still relationship between Vo not well established (4,10,24), it has been shown that high aerobic capacity might have a beneficial effect on recovery kinetics during high-intensity intermittent exercise (41) and that _ 2max may influence game performance and total highVo intensity running distance during a soccer match (26,29). Until now, running intensities of such intense interval training sessions have been set according to individual maximal aerobic speed (MAS, determined by gas exchange _ 2max) analysis, is the lowest running speed that elicits Vo (7,8,20). These exercises are often composed of shuttle runs so as to introduce accelerations, decelerations and changes of direction, which are, on the one hand, running patterns specific to intermittent sports, and, on the other, more adapted for short anaerobic interval training sessions aimed at preferentially enhancing peripheral components of cardiorespiratory function (7,27). In the past 2 decades, numerous field tests have been proposed to determine MAS and consequently indirectly _ 2max of athletes (31–33). These famous tests are based on Vo continuous linear runs (31) or shuttle runs (32,34), and the maximal running speeds (MRSs) reached at the end of the tests (which are not far from the MASs) are obtained through an effort different from that of intermittent sports and the way VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization interval training sessions are programmed. Using these MRSs in the field may be the first objective way to individualize highintensity intermittent runs (7,8,20), but certain physiological determinants of performance during intermittent and shuttle efforts are not evaluated by these field tests. How do subjects adapt to the intermittency of the runs? How do they tolerate changes in direction when running at supramaximal speeds? Since shuttle speeds (32,34) are lower compared to linear ones (1), coaches have to convert them to get more appropriate reference speeds. Such conversion tables are based on theoretical data that do not provide for individual adjustment. Sometimes to get different players to reach a similar internal load, a distinct percentage of the continuous MRS is used (external load), depending on how each athlete adapts to the intermittency of a run and on how each tolerates the changes in direction. Unfortunately, these empirical manipulations diminish the precision of a training prescription. In view of these field test defects, a protocol that includes intermittent and shuttle runs simultaneously appeared necessary. A few intermittent field tests already exist, for example, the yo-yo test (29) and the Intermittent Shuttle Run Test (ISRT) (35), but they provide only an index of intermittent aerobic performance (22,30). They do not give an MRS that can be used as a reference speed for training purposes. We have thus been led to develop the 30-15 Intermittent Fitness Test (30-15IFT) (12,13), the reliability of which has already been shown (13), as an alternative to these other tests. Being both intermittent and shuttle, its main interest is that it involves physiological variables similar to those solicited during shuttle interval training sessions (i.e., explosive power of lower limbs when changing direction, aerobic qualities, and ability to recover between exercise bouts). It allows players reach a final MRS (MRS30-15IFT) that we hypothesize to be more accurate for scheduling shuttle interval training sessions than a usual continuously determined MRS. The aims of this work are (a) to show the capacity of the 30-15IFT to determine a particular speed (MRS30-15IFT) reflecting the multiple physiological qualities elicited when performing shuttle intermittent runs and (b) to illustrate the accuracy of the MRS30-15IFT for individualizing high-intensity anaerobic interval training. We propose that the first merit of the 30-15IFT lies in its ability to assess various physiological variables related to performance during intermittent runs instead of just a single specific quality [usual continuous tests _ 2max, which is used to examine (31–33) estimate only Vo criterion validity]. We also suggest that the accuracy of the MRS30-15IFT to individualize interval training sessions will be demonstrated if cardiorespiratory responses during intermittent runs based on the MRS30-15IFT present little interindividual dispersion. This would indeed help offer a similar training load to all athletes of a team by standardizing training contents.
Subjects
Participants were 59 young athletes (27 women, 32 men; age, 16.2 6 2.3 years; weight, 62.4 6 7.5 kg; height, 169.7 6 10.1 cm; Tanner stages 4 and 5). Their sexual development was determined by the usual recommendations (39) from values assigned to each maturity indicator on a scale of 1, representing immaturity, to 5, indicating full maturity. The youths were randomly selected from 2 competitive basketball and handball training camps that worked out at the same gymnasium and benefited from similar medical and testing conditions. Participants were involved in 7.2 6 1.1 hours of physical training per week plus a match each weekend (usually at a regional level). The athletes underwent medical screening and did not present any contraindications for vigorous exercise. Subjects and their parents were informed about the study and gave their consent to participate. The study protocol, which was approved by the CNIL (French National Committee for Informatics and Liberties) and the local ethics committee (Consultative Committee for Human Protection in Biomedical Research), conforms to the Declaration of Helsinki. Testing Procedures
Although the 59 subjects all performed a laboratory-graded continuous running test on an electronic treadmill and jumping and sprinting tests (see below), we had to divide them into 2 groups for field testing because of methodological constraints. The first group (group 1) included 34 athletes _ 2max taken randomly who performed explosive tests, Vo testing, and the 30-15IFT plus the UM-TT. They thus performed intermittent runs on the basis of the MRS30-15IFT and the MRSUM-TT. The 25 others constituted the group 2. They _ 2max testing, and the 30-15IFT performed explosive tests, Vo together with the 20mSRT. They had their training sessions scheduled with the MRS30-15IFT and the MRS20mSRT. The 30-15 Intermittent Fitness Test
METHODS Experimental Approach to the Problem
We first examined the associations between the MRS30-15IFT and certain physiological abilities elicited when performing
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shuttle intermittent runs, such as explosive power of lower limbs (estimated by 10-m sprint and counter movement jump _ 2max and cardiorespiratory recovery ability (evaltests), Vo uated via short-term heart rate (HR) recovery kinetics during exercise). In order to judge the accuracy of the 30-15IFT as training prescription for intermittent sport athletes, we observed the variability of cardiorespiratory responses (internal load, inferred from the percentage of HR reserve, %HRres) elicited by 3 series of short intermittent runs. The running distances (similar relative external load) were set at fixed percentages of the MRS30-15IFT and of the MRS reached at the end of 2 popular continuous tests, the University of Montreal track test (UM-TT) (31) and the 20-m shuttle run test (20mSRT) (32). A low variability (i.e., coefficient of variation ,5%) of %HRres is taken as evidence of accuracy.
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Protocol. All 59 subjects did the 30-15IFT, which consists of 30-second shuttle runs interspersed with 15-second passive recovery periods. Velocity was set at 8 kmh21 for the first 30-second run and was increased by 0.5 kmh21 every
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Journal of Strength and Conditioning Research 45-second stage thereafter. Calculation of targeted distances to run during each 30-second period took into account the fact that the effort to turn is increased when running speed is increased. We subtracted an empirical value of 0.7 second from the 30-second running periods for each change of direction. For example, at 11.5 kmh21, one would cover 96 m in a 30-second straight line run, but covering the same distance over a 40-m shuttle distance requires 2 direction changes taking 2 3 0.7 seconds, which brings the corrected distance run to 91.6 m. The subjects had to run back and forth between two lines set 40 m apart at a pace governed by a prerecorded beep at appropriate intervals that helped them adjust their running speed by entering into 3-m zones at each extremity and in the middle of the field while the short beep sounds (Figure 1). During the 15-second recovery period, the subjects walked in the forward direction to join the closest line (at the middle or at one end of the running area, depending on where the previous run stopped) from where they started the next run stage. Subjects were instructed to complete as many stages as possible. The test ended when a subject could no longer maintain the imposed running speed or when he or she was unable to reach a 3-m zone around each line at the moment of the audio signal consecutively 3 times. The velocity attained during the last completed stage is taken as the MRS30-15IFT. Physiological Basis of Exercise/Recovery Pattern. The respective durations of exercise and recovery periods were chosen (a) with regard to most intermittent sports characteristics (2,6,21,38) and (b) according to various physiological
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considerations. Concerning exercise periods, 30 seconds is close to the time of cardiorespiratory on-response kinetics at the beginning of exercise (16,19) and is also the time in which HbO2 resources have been shown to be consumed at intense exercise (36). Since the half-time for recovery of phosphocreatine stores has been reported to be 20–30 seconds (25), the 15 seconds of recovery would allow sufficient but incomplete recovery of energy substrates as during intermittent games (6,21,38). Finally, compared to the ISRT (35), the choice of longer shuttle distances (40 m vs. 20 m) is intended to diminish muscular lactacidemia (1) and perceived exercise painfulness in the lower limbs, which helps reach a supramaximal MRS (higher than MAS). Reliability of the 30-15 Intermittent Fitness Test. The reliability of the test has been described elsewhere (12,13). We previously reported that test-retest yielded similar results in 19 subjects (9 women, 10 men; age, 19.4 6 1.8 years) with intraclass correlation coefficient (ICC) r = 0.96 for the MRS30-15IFT. The mean MRS30-15IFT was similar (20.1 6 0.7 vs. 20.2 6 0.9 kmh21). Physiological parameters were also not different: maximal HR: 196 6 2.3 vs. 195 6 3.1 bmin21; blood lactate 3 minutes after the test: 11.8 6 1.3 vs. 12.0 6 1.9 mmolL21. The University of Montreal Track Test
The UM-TT was conducted on a 400-m outdoor track according to the recommendations of Leger and Boucher (31) on 34 subjects. Pylons were placed at every 50 m of the track. The 34 subjects ran continuously and were paced with a sound signal emitted at specific intervals from a prerecorded tape. The velocity was set initially at 8 kmh21. Thereafter, it was increased by 1 kmh21 every 2 minutes. The subjects were instructed to complete as many stages as possible, and the test was stopped when the subjects were at least 5 m behind the appropriate pylon at the sound signal 2 successive times or when they felt they could not complete the stage. Although we believe that the test leads to MAS, with no gas analysis data, we prefer to note the final velocity as MRSUM-TT. The reliability of this test has already been investigated (ICC r = 0.94; n = 60) (31). The 20-Meter Shuttle Run Test
Figure 1. Area prepared for the 30-15 Intermittent Fitness Test (30-15IFT) and example of 2 intermittent runs. For the run at 8.5 kmh21 (about 69.2 m in 30 seconds), subjects start at line A, run to line C crossing line B, and then return. After crossing line B again, they stop after 8.5 m and walk to line A during the 15-second recovery to be ready for the next stage. For the run at 11.5 kmh21 (about 91.2 m in 30 seconds), subjects start at line A, make one complete round trip, stop after 9.5 m when going toward line B, and then walk to line B during the 15- second of recovery for the next start. Note that calculation of targeted distances takes into account the time needed for the direction changes.
The 20mSRT was performed as formulated by Leger and Lambert (32) by 25 subjects. It involves continuous running between 2 lines set 20 m apart on a nonsliding surface at running speeds governed by a prerecorded beep at appropriate intervals. Velocity was set at 8 kmh21 for the first minute, increasing by 0.5 kmh21 every minute thereafter. Subjects were instructed to complete as many stages as possible, and the test was stopped when a subject was unable 3 consecutive times to reach a 3-m zone situated ahead of each 20-m line at the moment of the audio signal. We believe that the test leads to MAS, but without gas analysis data, we prefer to note the final velocity as MRS20mSRT. The reliability of this test has already been investigated (ICC r = 0.98; n = 50) (32). VOLUME 22 | NUMBER 2 | MARCH 2008 |
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TABLE 1. Physiological capacities elicited when performing intermittent runs and maximal running speeds reached at the end of each of 3 field tests. MRS Subjects
_ 2max Vo
MAS
Treadmill
30-15IFT
UM-TT
20mSRT
10 m
CMJ
HRRE
Total (N = 59) 45.8 (5.8) 14.1 (0.9)* 14.7 (1.9)* 18.2 (1.6) –– –– 1.98 (0.14) 42.5 (7.7) 6.6 (1.3) Group 1 (n = 34) 49.2 (4.2) 14.8 (1.1)* 15.1 (1.7)* 18.6 (2.1) 14.9 (1.9)* –– 1.90 (0.09) 47.2 (5.3) 6.5 (1.5) Group 2 (n = 25) 41.9 (3.6) 13.2 (1.4)* 13.9 (1.2)* 16.9 (1.2) –– 11.5 (0.9)* 2.09 (0.10) 36.7 (4.9) 6.8 (1.9) _ 2max, mLmin21kg21), maximal aerobic speed (MAS), maximal running speed Mean values (SD) of maximal oxygen uptake (Vo (MRS, kmh21) reached at the end of each test (treadmill for the laboratory exercise test, 30-15 Intermittent Fitness Test [30-15IFT], University of Montreal track test [UM-TT], and 20-m shuttle run test [20mSRT]), explosive power of lower limbs (10-m sprint time [10 m], in seconds; countermovement jump [CMJ], in centimeters), and heart rate recovery index (HRRE) measured during the 30-15IFT. Group 1 = subjects who performed the 30-15IFT and the UM-TT; group 2 = subjects who performed the 30-15IFT and the 20mSRT. *Significant difference (P , 0.001) vs. MRS30-15IFT.
Series of Intermittent Runs
Here the aim was to bring all players to a similar level of metabolic demand during each of 3 series of intermittent runs, using in each series 1 of the 3 MRSs as the reference running intensity. Each series consisted of repeated runs for 15
seconds at high intensity alternated with 15 seconds of passive recovery lasting 10 minutes. The targeted running distance of each intermittent run was calculated as a given percentage of each MRS. Awareness of MRS differences among the 3 tests [Table 1; MRS30-15IFT is higher than MRSUM-TT (by 20%)
Figure 2. Zero-order linear regressions between the maximal running speed (MRS) reached at the end of the 30-15 Intermittent Fitness Test (MRS30-15IFT) and _ 2max), explosive power of lower limbs physiological qualities elicited when performing shuttle intermittent runs in the 59 subjects. Maximal oxygen uptake (Vo (10-m sprint time [10 m] and countermovement jump [CMJ]) and heart rate recovery index (HRRE).
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TABLE 2. Targeted distance and heart rate reserve observed during 10-minute intermittent runs.
Subjects
Reference speed
Total (N = 59) Group 1 (n = 34)
MRS30-15IFT MRS30-15IFT MRSUM-TT MRS30-15IFT MRS20mSRT
Group 2 (n = 25)
HR
Targeted distance (m) for 15-s runs 69.5 72.4 69.9 66.6 66.5
(7.2) (6.1) (12.2) (4.7) (10.5)
CV (%)
%HRres 91.2 92.4 89.1 91.7 89.5
(87.9–94.1; (88.1–93.6; (78.3–96.1; (87.9–94.1; (77.8–95.9;
2.8) 2.1) 8.3)* 2.7) 9.5)†
3.1 2.3 9.2 2.9 10.6
Mean values (SD) of targeted distance runs and mean percentage (range; SD) of heart rate reserve (%HRres) reached during each series of intermittent runs (15-second exercise/15-second rest) based on the maximal running speed (MRS) of each test [MRS30-15 IFT = MRS reached with the 30-15IFT = 30-15 Intermittent Fitness Test, MRSUM-TT for the University of Montreal track test, and MRS20mSRT for the 20-m shuttle run test (kmh21)]. CV = coefficient of variation; Group 1 = subjects who performed both the 30-15IFT and the UM-TT; Group 2 = subjects who performed both the 30-15IFT and the 20mSRT. *Six subjects (18%) were not able to finish the 10-minute intermittent runs based on the UM-TT. †Four subjects (16%) were not able to finish the 10-minute intermittent runs based on the 20mSRT.
and higher than MRS20mSRT (by 35%)] and based on previous experimentation (14), we used the following percentages that are intended to represent equivalent metabolic demands: 110% of MRSUM-TT (group 1, n = 34), 140% of MRS20mSRT (group 2, n = 25) and 95% of MRS30-15IFT (pooled, N = 59). For example, for one subject displaying typical MRS values (MRSUM-TT = 16.5 kmh21 and MRS30-15IFT = 19.0 kmh21), running at 95% of an MRS30-15IFT consisting of covering [(19/3.6) 3 0.95] 3 (15 2 0.7) = 71.7 m in 15 seconds and running at 110% of an MRSUM-TT consisting of covering [(16.5/3.6) 3 1.10) 3 (15 2 0.7) = 72.0 m in 15 seconds, which are quite similar distances. Instrumentation
Maximal Oxygen Uptake. A maximal graded continuous running test was performed on an electronic treadmill (Cardiovit _ 2max was determined. 100; Schiller, Baar, Switzerland) where Vo All athletes performed a standardized 5-minute warm-up, and the test began at a running speed of 8 kmh21, which was increased by 1 kmh21 every 2 minutes until exhaustion. The treadmill grade was set to 1%. After a standard calibration procedure of all apparatus, HR and gas exchange parameters _ 2, CO2 output) were continuously (minute ventilation, Vo recorded with a commercially available system (Breath-by-Breath Metabolic Measurement; Sensor Medic MSE, Rungis, _ 2max was determined by the criteria of Taylor et al. France). Vo _ 2 despite an increase in running speed and (40): a plateau in Vo HR .90% of the predicted maximal value. The velocity _ 2max (MAS) was the lowest running speed associated with Vo _ 2max (9) and represented _ 2 value equal to Vo that elicited a Vo 92.2% of the MRS reached during the treadmill test. Explosive Power of Lower Limbs
After a supervised warm-up, muscular explosive power of lower limbs was assessed by jumping and sprinting abilities
(18). Following Bosco et al. (11), jump testing consisted of a vertical countermovement jump (CMJ; in centimeters) on a Bosco jumping mat (Ergojump; Globus Italia, Codogne, Italy) that calculates jumping height from flying times. Since this method of assessment can have a methodological bias (notably landing with leg flexion), an experienced investigator validated each trial visually. Sprint abilities were evaluated by a 10-m standing-start run (10 m; in seconds) (18) recorded with photoelectric cells (Wireless Timing-Radio Controlled, Brower Timing System; Matsport, St. Ismier, France). Both tests were performed 3 times, separated by 45 seconds of passive recovery. Only the best performance was retained. Heart Rate
After applying conductive gel, an electrode transmitter belt (T61; Polar Electro, Kempele, Finland) was fitted to the chest of each subject as prescribed by the manufacturer. Heart rate was measured during quiet wakefulness in the morning (15) in the supine position for 10 minutes (HRrest). During all the tests, HR was recorded at 5-second intervals using a HR monitor (S610; Polar Electro, Kempele, Finland). When recorded data displayed aberrant values, HR was corrected by interpolation from adjacent values. Maximal HR (HRmax) was recorded in all field tests so as to verify that the subject performed at maximal effort. During field tests, data from the subject presenting at exhaustion an HR ,90% of HRmax recorded during the maximal graded continuous running was rejected (n = 1). Heart Rate Analysis
The HR recovery index (HRRE) (12,13) was used to evaluate cardiorespiratory recovery capacities. The HR recovery index was calculated, during the 30-15IFT only, as the sum of all differences between maximal and minimal HRs registered during each 15-second recovery period divided by the total number of beats during the entire test. Mean individual HR VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization recorded during the 3 series of intermittent runs are reported as a percentage of HRres as proposed by Karvonen et al. (28). In order to evaluate the %HRres disparity among athletes, we calculated the difference between the mean %HRres reached by all the subjects and the individual %HRres:DHRres = abs (mean %HRres 2 %HRres individual). The coefficient of variation (CV; in percentage) (3) was also calculated for %HRres. Statistical Analyses
Statistical analyses were carried out using Minitab 13.2 Software (Minitab Inc., Paris, France). Descriptive statistics were computed as means and SD. As data were normally
distributed, parametric tests were used. To avoid any gender, age, or body mass effect (all known to influence endurance, power, and speed), we adjusted data on these possible confounding factors by introducing them as variables in the analyses. A multiple linear regression model was first used to establish the link between MRS30-15IFT and all the intermittent sport-specific physiological capacities tested in the 59 subjects. A minimal sample size of 59 subjects was determined based on the work of Pedhazur (37), who suggested a subject-to-variable ratio of 15:1 for multiple regression analyses (15 3 4 = 60). Concerning HR responses during intermittent runs, DHRres calculated from each series were compared with a one-way analysis of variance with a post hoc test (Tukey). Significance was set at P # 0.05; a tendency was assumed for P , 0.10.
RESULTS Maximum Heart Rate at the End of Each Field Test
The HRmax reached at the end of the 30-15IFT was not different from those measured at the end of the other tests [respectively, 193.8 6 4.8 vs. 192.1 6 6.0 bmin21 for 30-15IFT vs. treadmill (N = 59), 193.3 6 5.5 vs. 191.8 6 5.4 bmin21 for 30-15IFT vs UM-TT (n = 34) and 195.6 6 5.4 vs. 193.9 6 6.8 bmin21 for 30-15IFT vs 20mSRT (n = 25)].
Physiological Qualities and Maximal Running Speeds Reached Within Each Field Test
_ 2max, Mean (6SD) values of Vo MAS, MRS, explosive power of lower limbs, and HRRE are presented in Table 1. Whatever the subgroup considered, the was signifiMRS30-15IFT cantly higher than the MAS, MRSUM-TT, and MRS20mSRT (P , 0.001). Relationships Between MRS3015IFT
and Physiological
Qualities Elicited When Figure 3. Individual HR reserve (%HRres) profiles during intermittent runs in 3 subjects. The exercise consisted of running 15 seconds at 110% of the maximal running speed (MRS) reached with the University of Montreal track test (MRSUM-TT, upper plots) and at 95% of the MRS reached with the 30-15 Intermittent Fitness Test (MRS30-15IFT, lower plots) intersected with 15 seconds of passive recovery during 10 minutes.
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Performing Shuttle Intermittent Runs
For the 59 subjects, the MRS30-15IFT was significantly
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Cardiorespiratory Demands During Intermittent Runs Based on Each Maximal Running Speed
Table 2 presents mean values of targeted distances and the corresponding %HRres observed for subjects performing intermittent runs at a similar relative intensity (at a similar percentage of a given MRS). The results show that the mean %HRres reached by the subjects did not depend on the reference MRS used. Nonetheless, when scheduling intermittent runs based on a given percentage of a continuously obtained MRS, 6 and 4 subjects of the groups using, respectively, the MRSUM-TT and MRS20mSRT as reference speeds could not finish the 10-minute series, and 7 of these subjects presented an HRres ,80%. The %HRres range of values showed more disparity with the 2 continuous tests than with the 30-15IFT, and the CV of the %HRres was lower for the series based on the 30-15IFT than those based on the 2 continuous tests (Table 2). Individual differences from the mean %HRres were significantly lower in the series based on the 30-15IFT than in the series based on the UM-TT (DHRres = 2.8 6 1.2 vs. Figure 4. Individual heart rate reserve (%HRres) profiles as a function of running speed for 2 subjects presenting 9.5 6 2.1 bmin21, P , 0.05) or significantly different maximal running speeds (MRSs) determined with the University of Montreal track test (MRSUM21 , upper) but quite similar MRSs obtained with the 30-15 Intermittent Fitness Test (30-15IFT) on the 20mSRT (DHRres = 2.6 TT of 15 vs. 18 kmh (MRS30-15 IFT of 19.5 vs. 20 kmh21, lower). 6 1.8 vs. 8.1 6 2.9 bmin21, P , 0.05). Figure 3 illustrates data for 3 representative athletes correlated with all physiological variables elicited when who did not display comparable %HRres during 2 series performing shuttle intermittent runs and can be summarized when distances were planned based on the MRSUM-TT or the by the following regression: MRS30-15IFT = 14.6 + 0.06 MRS30-15IFT. _ 2max 2 1.34 10 m + 0.02 CMJ + 0.43 HRRE 2 1.20 G 2 Vo DISCUSSION 0.10 W + 0.11 A (r = 0.87 and P , 0.001 for the relationship), 21 _ where Vo2max is expressed in mLminkg , 10 m in seconds, The present study shows that the 30-15IFT (12,13) leads to an CMJ in centimeters, HRRE with no units, G stands for gender MRS that is significantly associated with physiological (1 = male, 2 = female), W for weight (kilograms), and A for qualities elicited when performing shuttle intermittent runs, age (years). Zero-order linear regression analyses made i.e., explosive muscular power of lower limbs, aerobic power, _ 2max, explosive power of lower between MRS30-15IFT and Vo and cardiovascular recovery capacity. In addition, the results limbs, and HRRE kinetics index were all significant (P , 0.05). show that using the MRS30-15FT as a reference speed for These 4 relationships are illustrated in Figure 2. determining intermittent run distances enables reaching VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization a requested level of metabolic demand with lower interindividual differences than when using continuously determined running speeds. This possibility to easily provide all members on a team a similar exercise load and especially to individuals with distinct aerobic or anaerobic capacities illustrates the good accuracy of the 30-15IFT for individualizing interval training sessions. The significant relationships between MRS30-15IFT and _ 2max, and HRRE exemplifies the CMJ, 10-m sprint time, Vo merit of the 30-15IFT. The relationship between an MRS reached after a graded exercise test and anaerobic capacities has not been investigated before. In the present study, the physiological qualities elicited when performing shuttle intermittent runs accounted for 75% of the variance of the MRS30-15IFT (r = 0.87). These results for adolescents suggest that MRS30-15IFT is a unique speed that takes into account several physiological variables simultaneously. The present results also illustrate the accuracy of the 3015IFT when testing intermittent sports players with different physiological profiles. Figure 4 illustrates the fact previously reported (5,10) that physiological capacities other than _ 2max (i.e., explosive power and the ability to recover Vo between efforts) condition shuttle intermittent performance. Here, 2 subjects with different continuous linear MRSs reached with the UM-TT (18 and 15 kmh21) presented quite similar performances on the 30-15IFT (20 and 19.5 kmh21). Their individual physiological profiles can explain these running speed differences. Compared to MRSUM-TT, athlete A with a clearly ‘‘aerobic profile’’ together with poor explosive _ 2max: 63.4 mLminkg21, CMJ: 44 cm, 10 m: strength (Vo 1.94 seconds, HRRE: 9.7) has increased his MRS by 2 kmh21 with the 30-15IFT. Athlete B with an ‘‘anaerobic profile,’’ _ 2max (54.5 mLminkg21) but with greater despite a lower Vo explosive power (CMJ: 69 cm, 10 m: 1.81 seconds) and higher cardiovascular recovery capacity (HRRE: 11.6) was able to run 4.5 kmh21 faster during the 30-15IFT. In other words, compared to athlete A, athlete B tolerated the changes of direction better and derived more benefit from the intermittency of the runs. This point should be considered when programming interval training sessions, especially for athletes with different physiological profiles, as in team sports. Finally, the results demonstrate the capacity of the 30-15IFT to prescribe proper running intensities for interval training sessions. We have made the assumption that the MRS30-15IFT helps get players with different physiological profiles to reach similar cardiorespiratory levels and that interindividual differences become less important when using the MRS30-15IFT compared to continuously determined MRSs for prescribing the intensity of interval training sessions. When scheduling intermittent runs based on a given percentage of the MRS obtained with the two continuous tests, 17.5 and 16% of the subjects could not finish the 10-minute series, whereas many of them presented low HRres values (,80% HRres) (Table 2).
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Our results show that there is significantly more disparity among cardiorespiratory responses (inferred by higher CVand DHRres) during intermittent runs targeted based on the MRSUM-TT or the MRS20mSRT than when programmed with the MRS30-15IFT as the reference speed (Table 2, P , 0.05). The findings illustrate that the metabolic demand can be different from one subject to another, even at a similar percentage of a continuously determined MRSs (similar relative external load). These data are illustrated in Figure 3. When using MRSUM-TT as the reference running speed to calculate individual intermittent run distances, cardiorespiratory demands were clearly different for each athlete (Figure 3, top; %HRres = 95.8, 82.8, and 91.1% for athletes C, D, and E, respectively). However, when using MRS30-15IFT as the reference speed, %HRres for the 3 athletes were similar (Figure 3, bottom; %HRres = 92.9, 94.2, and 93.1% for athletes C, D, and E, respectively). Note that since MRS30-15IFT is 20% higher than MRSUM-TT, we used a distinct percentage of each MRS (95% MRS30-15IFT and 110% MRSUM-TT). Previous investigations have indicated that physiological demands are quite similar to these percentages (14). When using a continuously determined MRS, players with different cardiovascular responses may be led to produce efforts with disproportionate intensities that may have different physiological impacts and unexpected consequences on their health, fitness, or fatigue. Finally, we postulate that it is because the MRS30-15IFT is a speed taking into account various qualities solicited during shuttle intermittent runs that it brings athletes with different physiological profiles to a similar level of cardiorespiratory demand. We can thus propose that the 30-15IFT is an accurate tool for individualizing aerobic training since it permits programming a similar workout load for each athlete.
PRACTICAL APPLICATIONS Coaches and trainers can use the 30-15IFT examined in this study because it leads to a particular MRS that takes into account various qualities solicited during shuttle intermittent runs, i.e., explosive power of lower limbs, aerobic qualities, and the ability to recover between exercise bouts. The 3015IFT has been shown to be accurate for individualizing short intermittent run distances in subjects presenting different aerobic or anaerobic profiles. Using the MRS30-15FT as a reference speed for determining intermittent run distances enables a given level of cardiorespiratory demand with lower interindividual differences to be reached than when using continuously determined MRSs. This result has its importance in team sports since a coach can be certain that a similar training load will be offered to all the athletes. Although further study is still needed to determine at which percentage of the MRS30-15IFT players have to train to improve one or another physical capacity, our present results already show that the accuracy of the test for a training prescription is high.
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Journal of Strength and Conditioning Research Involving the main intermittent sport-specific physiological determinants and not just one component such as aerobic or anaerobic power, the 30-15IFT could also be used as a single tool for evaluating seasonal changes in an athlete’s overall fitness and performance. In that case, it would be important to standardize test conditions as much as possible (i.e., controlling food consumption and training load before the test and exercising in comparable weather and field conditions if testing outdoors).
ACKNOWLEDGMENTS The author thanks Mathieu Puzenat for technical assistance and data treatment and the coaches and athletes for their participation. The author declares no conflict of interest. A compact disc on the 30-15IFT (with instruction booklet) is available free of charge from the author upon request.
REFERENCES 1. Ahmaidi, S, Collomp, K, and Prefaut, C. The effect of shuttle test protocol and the resulting lactacidaemia on maximal velocity and maximal oxygen uptake during the shuttle exercise test. Eur J Appl Physiol Occup Physiol 65: 475–479, 1992. 2. Apostolidis, N, Nassis, GP, Bolatoglou, T, and Geladas, ND. Physiological and technical characteristics of elite young basketball players. J Sports Med Phys Fitness 44: 157–163, 2004. 3. Atkinson, G and Nevill, AM. Statistical methods for assessing measurement error (reliability) in variables relevant to sports medicine. Sports Med 26: 217–238, 1998. 4. Aziz, AR, Chia, M, and Teh, KC. The relationship between maximal oxygen uptake and repeated sprint performance indices in field hockey and soccer players. J Sports Med Phys Fitness 40: 195–200, 2000. 5. Bangsbo, J. Fitness Training in Football: A Scientific Approach. Bagsvaerd, Denmark: Storm, 1994. 6. Bangsbo, J, Norregaard, L, and Thorso, F. Activity profile of competition soccer. Can J Sport Sci 16: 110–116, 1991. 7. Billat, LV. Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part II: anaerobic interval training. Sports Med 31: 75–90, 2001. 8. Billat, LV. Interval training for performance: a scientific and empirical practice. Special recommendations for middle- and long-distance running. Part I: aerobic interval training. Sports Med 1: 13–31, 2001. 9. Billat, LV and Koralsztein, JP. Significance of the velocity at VO2max and time to exhaustion at this velocity. Sports Med 22: 90–108, 1996. 10. Bishop, D and Spencer, M. Determinants of repeated-sprint ability in well-trained team-sport athletes and endurance-trained athletes. J Sports Med Phys Fitness 44: 1–7, 2004. 11. Bosco, C, Luhtanen, P, and Komi, PV. A simple method for measurement of mechanical power in jumping. Eur J Appl Physiol Occup Physiol 2: 273–282, 1983. 12. Buchheit, M. [The 30-15 Intermittent Fitness Test: a new intermittent running field test for intermittent sport players—part 1]. Approches Handball. 87: 27–34, 2005. 13. Buchheit, M. The 30-15 intermittent fitness test: reliability and implication for interval training of intermittent sport players. In: ECSS Proceedings. Belgrade: 2005. 14. Buchheit, M. [Illustration of interval-training prescription on the basis of an appropriate intermittent maximal running speed - the 30-15 intermittent fitness test—part 2]. Approches Handball. 88: 36–46, 2005. 15. Buchheit, M, Simon, C, Piquard, F, Ehrhart, J, and Brandenberger, G. Effect of increased training load on vagal-related indexes of heart
| www.nsca-jscr.org
rate variability: a novel sleep approach. Am J Physiol Heart Circ Physiol 287: H2813–H2818, 2004. 16. Cerretelli, P and Di Prampero, PE. Kinetics of respiratory gas exchange and cardiac output at the onset of exercise. Scand J Respir Dis Suppl 77: 35a–35g, 1971. 17. Christopher, W, Lee, E, and Geoff, W. Development of speed, agility, and quickness for the female soccer athlete. Strength Cond J 22: 9–12, 2000. 18. Cometti, G, Maffiuletti, NA, Pousson, M, Chatard, JC, and Maffulli, N. Isokinetic strength and anaerobic power of elite, subelite and amateur French soccer players. Int J Sports Med 22: 45–51, 2001. 19. Davies, CT, Di Prampero, PE, and Cerretelli, P. Kinetics of cardiac output and respiratory gas exchange during exercise and recovery. J Appl Physiol 32: 618–625, 1972. 20. Dupont, G, Akakpo, K, and Berthoin, S. The effect of in-season, high-intensity interval training in soccer players. J Strength Cond Res 18: 584–589, 2004. 21. Duthie, G, Pyne, D, and Hooper, S. Applied physiology and game analysis of rugby union. Sports Med 13: 973–991, 2003. 22. Elferink-Gemser, MT, Visscher, C, Lemmink, KA, and Mulder, TW. Relation between multidimensional performance characteristics and level of performance in talented youth field hockey players. J Sports Sci 22: 1053–1063, 2004. 23. Gaitanos, GC, Williams, C, Boobis, LH, and Brooks, S. Human muscle metabolism during intermittent maximal exercise. J Appl Physiol 75: 712–719, 1993. 24. Glaister, M. Multiple sprint work: physiological responses, mechanisms of fatigue and the influence of aerobic fitness. Sports Med 35: 757–777, 2005. 25. Harris, RC, Edwards, RH, Hultman, E, Nordesjo, LO, Nylind, B, and Sahlin, K. The time course of phosphorylcreatine resynthesis during recovery of the quadriceps muscle in man. Pflugers Arch 367: 137–142, 1976. 26. Helgerud, J, Engen, LC, Wisloff, U, and Hoff, J. Aerobic endurance training improves soccer performance. Med Sci Sports Exerc 33: 1925–1931, 2001. 27. Hoff, J and Helgerud, J. Endurance and strength training for soccer players: physiological considerations. Sports Med 3: 165–180, 2004. 28. Karvonen, MJ, Kentala, E, and Mustala, O. The effects of training on heart rate; a longitudinal study. Ann Med Exp Biol Fenn 35: 307–315, 1957. 29. Krustrup, P, Mohr, M, Amstrup, T, Rysgaard, T, Johansen, J, Steensberg, A, Pedersen, PK, and Bangsbo, J. The yo-yo intermittent recovery test: physiological response, reliability, and validity. Med Sci Sports Exerc 35: 697–705, 2003. 30. Krustrup, P, Mohr, M, Ellingsgaard, H, and Bangsbo, J. Physical demands during an elite female soccer game: importance of training status. Med Sci Sports Exerc 37: 1242–1248, 2005. 31. Leger, LA and Boucher, R. An indirect continuous running multistage field test: the Universite de Montreal track test. Can J Appl Sport Sci 5: 77–84, 1980. 32. Leger, LA and Lambert, J. A maximal multistage 20-m shuttle run test to predict VO2 max. Eur J Appl Physiol Occup Physiol 49: 1–12, 1982. 33. Leger, LA, Lambert, J, Goulet, A, Rowan, C, and Dinelle, Y. Aerobic capacity of 6 to 17-year-old Quebecois—20 meter shuttle run test with 1 minute stages. Can J Appl Sport Sci 9: 64–69, 1984. 34. Leger LA, Mercier, D, Gadoury, C, and Lambert, J. The multistage 20 metre shuttle run test for aerobic fitness. J Sports Sci 6: 93–101, 1988. 35. Lemmink, KA, Visscher, C, Lambert, MI, and Lamberts, RP. The interval shuttle run test for intermittent sport players: evaluation of reliability. J Strength Cond Res 18: 821–827, 2004. VOLUME 22 | NUMBER 2 | MARCH 2008 |
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The 30-15 Intermittent Fitness Test for Interval Training Individualization 36. McCully, KK, Iotti, S, Kendrick, K, Wang, Z, Posner, JD, Leigh, J, Jr, and Chance, B. Simultaneous in vivo measurements of HbO2 saturation and PCr kinetics after exercise in normal humans. J Appl Physiol 77: 5–10, 1994. 37. Pedhazur, EJ. Multiple Regression in Behavioral Research: Explanation and Prediction. Fort Worth: Harcourt Brace College Publishers, 1997. 38. Rannou, F, Prioux, J, Zouhal, H, Gratas-Delamarche, A, and Delamarche, P. Physiological profile of handball players. J Sports Med Phys Fitness 41: 349–353, 2001.
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39. Sun, SS, Schubert, CM, Chumlea, WC, Roche, AF, Kulin, HE, Lee, PA, Himes, JH, and Ryan, AS. National estimates of the timing of sexual maturation and racial differences among US children. Pediatrics 110: 911–919, 2002. 40. Taylor, H, Buskirk, E, and Henschel, A. Maximal oxygen uptake as an objective measure of cardiorespiratory performance. J Appl Physiol 8: 73–80, 1955. 41. Tomlin, DL and Wenger, HA. The relationships between aerobic fitness, power maintenance and oxygen consumption during intense intermittent exercise. J Sci Med Sport 5: 194–203, 2002.
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