R. Haj Sassi

Effect of between-set recovery durations on repeated sprint ability in young soccer players

The purposes of this study were to examine the effect of between-set recovery duration on physiological responses (heart rate and blood lactate), rating of perceived exertion (RPE) and performance indices of repeated sprint sets (RSS) and to investigate their relationship with aerobic power. Twenty-four young male soccer players (age: 17.4 ± 0.32 years) performed three randomized RSS protocols consisting of 2 sets of 5x20 m with 15 s recovery between sprints and 1 min (RSS1), 2 min (RSS2) and 4 min (RSS4) between sets, and a multi-stage aerobic track test to estimate VO2max. Results showed that in contrast to RSS2 and RSS4, RSS1 leads to a large decline in performance expressed as the sum of sprint times (34.0±1.0 s, 34.0±1.1s and 34.6±1.1s, respectively) and a significant increase of both mean heart rate (124.0±9.7 bpm, 112.5±6.7 bpm and 137.3±12.4, respectively) and RPE (3.2±1.5, 3.4±1.2 and 6.3±1.4, respectively) with no change in blood lactate and peak HR between the three rest conditions. No significant correlations were obtained between estimated VO2max and any of the indices of the three RSS protocols. In conclusion, 1 min of recovery between sets is sufficient to ensure a significant decrease in performance in the second set, while 2 min and 4 min of recovery were long enough to provide maintenance of high intensity work in the second set. These findings would be useful for coaches and sport scientists when attempting to assess repeated sprint abilities, allowing coaches to accurately define the intended training goals in young soccer players.

Do maximal aerobic power and blood lactate concentration affect Specific Judo Fitness Test performance in female judo athletes

The Special Judo Fitness Test (SJFT) has become the test most widely used by coaches and physical trainers for assessment of competitors’ judo-specific physical aptitude and training programme prescription. The aim of this study was to investigate the relationship between the SJFT performance indices and both maximal aerobic power and the level of blood lactate concentrations in female judo athletes. Seventeen female judokas (age: 21.9±1.6 years, body mass: 74.6±27.4 kg, height: 164.5±8.6 cm; BMI: 27.1±8.0 kg · m-2) took part in this study. All participants performed the SJFT, 20 m multi-stage shuttle run test (MSRT), and 30 m straight sprint test (SST), from which we calculated both acceleration (10 m) and the maximal anaerobic speed (MAnS: flying 20 m sprint). A blood sample was taken 3 min after the SJFT. The number of throws was significantly correlated with estimated VO2max (r=0.795, p=0.0001) and both acceleration (r=0.63, p =0.006) and MAnS (r=0.76, p=0.0004). Peak blood lactate recorded after the SJFT was 13.90±1.39 mmol · l-1. No significant correlation was found between blood lactate concentration and the SJFT performance indices. The lack of significant correlation between blood lactate and SJFT performance suggests that lactic anaerobic metabolism has no effect on this type of judo-specific supra-maximal exercise. The observed results can provide coaches and strength and conditioning professionals with relevant information for the interpretation of SJFT performance and the prescription of specific training programmes for female judo athletes.