Mohamed Souhaiel Chelly

Effects of 8-week in-season plyometric training on upper and lower limb performance of elite adolescent handball players.

Abstract Chelly, MS, Hermassi, S, Aouadi, R, and Shephard, RJ. Effects of 8-week in-season plyometric training on upper and lower limb performance of elite adolescent handball players. J Strength Cond Res 28(5): 1401–1410, 2014—We hypothesized that replacement of a part of the normal in-season regimen of top-level adolescent handball players by an 8-week biweekly course of lower and upper limb plyometric training would enhance characteristics important to competition, including peak power output (Wpeak), jump performance, muscle volume, and ball throwing velocity. Study participants (23 men, age: 17.4 ± 0.5 years, body mass: 79.9 ± 11.5 kg, height: 1.79 ± 6.19 m, body fat: 13.8 ± 2.1%) were randomly assigned between controls (C; n = 11) and an experimental group (E, n = 12). Measures preintervention and postintervention included force-velocity ergometer tests for upper (Wupper peak) and lower limbs (Wlower peak), force platform determinations of squat jump (SJ) and countermovement jump (CMJ) characteristics (jump height, maximal force, initial velocity, and average power), video filming of sprint velocities (first step [V1S], first 5 m [V5m], and 25–30 m [Vmax]), and anthropometric estimates of leg muscle volume. E showed gains relative to C in Wupper peak and Wlower peak (p < 0.01 and p < 0.001), SJ (height p < 0.01; force p ⩽ 0.05), CMJ (height p < 0.01; force p < 0.01 and relative power p ⩽ 0.05), and sprint velocities (p < 0.001 for V1S, V5m, and Vmax). E also showed increases in leg and thigh muscle volumes (p < 0.001), but arm muscle volumes did not differ from control. We conclude that introduction of biweekly plyometric training into the standard regimen improved components important to handball performance, particularly explosive actions, such as sprinting, jumping, and ball throwing velocity.

Test-retest reliability, criterion-related validity, and minimal detectable change of score on an abbreviated Wingate test for field sport participants.

Abstract Hachana, Y, Attia, A, Nassib, S, Shephard, RJ, and Chelly, MS. Test-retest reliability, criterion-related validity, and minimal detectable change of score on an abbreviated Wingate test for field sport participants. J Strength Cond Res 26(5): 1324–1330, 2012—Repeat measurements in 69 young adults were performed to assess the test-retest reliability and the 95% confidence interval of the difference in score between paired observations (MDC95) of a Wingate test as abbreviated for field sport participants (test of a 15-second duration [15-secT]). Test-retest reliability was excellent for peak power output (PPO) and mean power output (MPO), independently of their mode of expression and was moderate for the fatigue index (FI). The standard errors of measurement (SEM) for absolute, relative, and derived PPO and MPO values ranged from 2.6 to 3.7%, all being smaller than the corresponding smallest worthwhile change (SWC). In contrast, FI values were rated as “marginal,” with an SEM (9.6%) greater than the SWC (1.7). The range of MDC95 values for PPO and MPO were 9.9–10.4 and 7.37–7.42%, respectively. The absolute MPO showed the highest test-retest reliability and was the most effective in detecting real change. A second phase of the study evaluated the criterion-related validity of the 15-secT in 43 young men who performed 15-secT and standard 30-second Wingate anaerobic test (30-secT) in random order, on 2 separate occasions. There were no significant intertest differences in absolute, relative, or derived PPO. However, the FI for the 30-secT was greater than that for the 15-secT. Intertest correlations were highly significant for both MPOs and FIs. These findings suggest that the abbreviated Wingate test offers a reliable and valid tool for the evaluation of PPO and MPO, at least in young physical education students.

Reliability and Validity of a 20-s Alternative to the Wingate Anaerobic Test in Team Sport Male Athletes

The intent of this study was to evaluate relative and absolute reliability of the 20-s anaerobic test (WAnT20) versus the WAnT30 and to verify how far the various indices of the 30-s Wingate anaerobic test (WAnT30) could be predicted from the WAnT20 data in male athletes. The participants were Exercise Science majors (age: 21.5±1.6 yrs, stature: 0.183±0.08 m, body mass: 81.2±10.9 kg) who participated regularly in team sports. In Phase I, 41 participants performed duplicate WAnT20 and WAnT30 tests to assess reliability. In Phase II, 31 participants performed one trial each of the WAnT20 and WAnT30 to determine the ability of the WAnT20 to predict components of the WAnT30. In Phase III, 31 participants were used to cross-validate the prediction equations developed in Phase II. Respective intra-class correlation coefficients (ICC) for peak power output (PPO) (ICCu200a=u200a0.98 and 0.95) and mean power output (MPO) (ICC 0.98 and 0.90) did not differ significantly between WAnT20 and WAnT30. ICCs for minimal power output (POmin) and fatigue index (FI) were poor for both tests (range 0.53 to 0.76). Standard errors of the means (SEM) for PPO and MPO were less than their smallest worthwhile changes (SWC) in both tests; however, POmin and FI values were “marginal,” with SEM values greater than their respective SWCs for both tests values. Stepwise regression analysis showed that MPO had the highest coefficient of predictability (Ru200a=u200a0.97), with POmin and FI considerable lower (Ru200a=u200a0.71 and 0.41 respectively). Cross-validation showed insignificant bias with limits of agreement of 0.99±1.04, 6.5±92.7 W, and 1.6±9.8% between measured and predicted MPO, POmin, and FI, respectively. WAnT20 offers a reliable and valid test of leg anaerobic power in male athletes and could replace the classic WAnT30.

Effects of In-Season Short-term Plyometric Training Program on Sprint and Jump Performance of Young Male Track Athletes

Abstract Chelly, MS, Hermassi, S, and Shephard, RJ. Effects of in-season short-term plyometric training program on sprint and jump performance of young male track athletes. J Strength Cond Res 29(8): 2128–2136, 2015—We studied the effect of supplementing normal in-season training by a 10-week lower limb plyometric training program (hurdle and depth jumping), examining measures of competitive potential (peak power output [PP], sprint running velocity, squat jump [SJ], countermovement jump [CMJ], drop jump [DJ], and lower limb muscle volume). The subjects (27 male track athletes, aged 11.9 ± 1.0 years; body mass: 39.1 ± 6.1 kg; height: 1.56 ± 0.02 m; body fat: 12.8 ± 4.4%) were randomly assigned between a control (normal training) group (C; n = 13) and an experimental group (E; n = 14) who also performed plyometric training 3 times per week. A force-velocity ergometer test determined PP and SJ, and an Optojump apparatus evaluated CMJ height and DJ (height and power). A multiple-5-bound test assessed horizontal jumping, and video-camera analyses over a 40-m sprint yielded velocities for the first step (VS), the first 5 m (V5m), and between 35 and 40 m (Vmax). Leg muscle volume was estimated anthropometrically. Experimental group showed gains relative to C in SJ height (p < 0.001); CMJ height (p < 0.01); DJ height and power relative to body mass (p < 0.01 for both); and all sprint velocities (p < 0.01 for VS and V5m, p ⩽ 0.05 for Vmax). There was also a significant increase (p < 0.01) in thigh muscle volume, but leg muscle volume, thigh cross-sectional area, and PP remained unchanged. We conclude that adding plyometric training improved important components of athletic performance relative to standard in-season training in young runners.

Effects of an in-season plyometric training program on repeated change of direction and sprint performance in the junior soccer player.

Abstract Hammami, M, Negra, Y, Aouadi, R, Shephard, RJ, and Chelly, MS. Effects of an in-season plyometric training program on repeated change of direction and sprint performance in the junior soccer player. J Strength Cond Res 30(12): 3312–3320, 2016—We aimed to determine the gains in explosive movements of male junior soccer players induced by incorporating an 8-week plyometric training program (PTP) into a standard soccer conditioning regimen 5 months after the beginning of the competitive season. Our hypothesis was that PTP would enhance explosive movements, and thus sprint running, repeated shuttle sprint ability (RSSA), agility and the ability to make repeated changes of direction (RCOD). A group of junior soccer players were randomly divided into 2 groups: an experimental group (E, n = 15, age 15.7 ± 0.2 years) and a control group (C, n = 13, age 15.8 ± 0.2 years). The participants in E and C performed training exercises and matches together, but for an 8-week period in the latter part of the season, the experimental group replaced a part of the normal regimen (the tactical session) by a biweekly course of PTP (hurdle and drop jumps). Two familiarization sessions were held 2 weeks before definitive testing. The ability of the players was assessed by 3 agility tests (a sprint test with 180° turns, a 9-3-6-3-9 m sprint with backward and forward running, and a four 5-m sprint test with turns); 2 repeated sprint tests (RSSA and RCOD); and running times over 5-, 10-, 20-, 30-, and 40-m distances. Participants in E showed gains relative to C in sprint times (p ⩽ 0.05 for 5, 10, and 20 m), and 2 of 3 the RCOD parameters (RCOD best, p ⩽ 0.001; RCOD total, p ⩽ 0.05). However, with the pattern of plyometric training that we adopted, and perhaps because participants were in good initial physical condition, the agility and RSSA test scores remained unchanged. Nevertheless, we conclude that our PTP can be commended to junior soccer players as a means of improving important components of their physical performance.

Effectiveness and time-course adaptation of resistance training vs. plyometric training in prepubertal soccer players

Purpose This study aimed to assess the effectiveness and time course for improvements in explosive actions through resistance training (RT) vs. plyometric training (PT) in prepubertal soccer players. Methods Thirty-four male subjects were assigned to: a control group (n = 11); an RT group (5 regular soccer training sessions per week, n = 12); a PT group (3 soccer training sessions and 2 RT sessions per week, n = 11). The outcome measures included tests for the assessment of muscle strength (e.g., 1 repetition maximum half-squat test), jump ability (e.g., countermovement jump, squat jump, standing long jump, and multiple 5 bounds test), linear speed (e.g., 20u2009m sprint test), and change of direction (e.g., Illinois change of direction test). Results The RTG showed an improvement in the half-squat (Δu2009=u200913.2%; du2009=u20091.3, pu2009<u20090.001) and countermovement jump (Δu2009=u20099.4%; du2009=u20092.4, pu2009<u20090.001) at Week 4, whereas improvements in the 20-m sprint (Δu2009=u20094.2%; du2009=u20091.1, pu2009<u20090.01); change of direction (CoD) (Δu2009=u20093.8%; du2009=u20092.1, pu2009<u20090.01); multiple 5 bounds (Δu2009=u20095.1%; du2009=u20091.5, pu2009<u20090.05); standing long jump (Δu2009=u20097.2%; du2009=u20091.2, pu2009<u20090.01); squat jump (Δu2009=u200919.6%; du2009=u20091.5, pu2009<u20090.01); were evident at Week 8. The PTG showed improvements in CoD (Δu2009=u20092.1%; du2009=u20091.3, pu2009<u20090.05); standing long jump (Δu2009=u20099.3%; du2009=u20091.1, pu2009<u20090.01); countermovement jump (Δu2009=u200916.1%; du2009=u20091.2, pu2009<u20090.01); and squat jump (Δu2009=u200916.7%; du2009=u20091.4, pu2009<u20090.01); at Week 8 whereas improvements in the 20-m sprint (Δu2009=u20094.1%; du2009=u20091.3, pu2009<u20090.01); and multiple 5 bounds (Δu2009=u20097.4%; du2009=u20092.4, pu2009<u20090.001); were evident only after Week. The RT and PT groups showed improvements in all sprint, CoD, and jump tests (pu2009<u20090.05) and in half-squat performance, for which improvement was only shown within the RTG (pu2009<u20090.001). Conclusion RT and PT conducted in combination with regular soccer training are safe and feasible interventions for prepubertal soccer players. In addition, these interventions were shown to be effective training tools to improve explosive actions with different time courses of improvements, which manifested earlier in the RTG than in the PTG. These outcomes may help coaches and fitness trainers set out clear and concise goals of training according to the specific time course of improvement difference between RT and PT on proxies of athletic performance of prepubertal soccer players.

Relationships Between the Yo-Yo Intermittent Recovery Test and Anaerobic Performance Tests in Adolescent Handball Players

Abstract The aim of the present study was to investigate relationships between a performance index derived from the Yo-Yo Intermittent Recovery Test level 1 (Yo-Yo IR1) and other measures of physical performance and skill in handball players. The other measures considered included peak muscular power of the lower limbs (Wpeak), jumping ability (squat and counter-movement jumps (SJ, CMJ), a handball skill test and the average sprinting velocities over the first step (VS) and the first 5 m (V5m). Test scores for 25 male national-level adolescent players (age: 17.2 ± 0.7 years) averaged 4.83 ± 0.34 m·s-1 (maximal velocity reached at the Yo-Yo IR1); 917 ± 105 Watt, 12.7 ± 3 W·kg-1 (Wpeak); 3.41 ± 0.5 m·s-1 and 6.03 ± 0.6 m·s-1 (sprint velocities for Vs and V5m respectively) and 10.3 ± 1 s (handball skill test). Yo-Yo IR1 test scores showed statistically significant correlations with all of the variables examined: Wpeak (W and W·kg-1) r = 0.80 and 0.65, respectively, p≤0.001); sprinting velocities (r = 0.73 and 0.71 for VS and V5m respectively; p≤0.001); jumping performance (SJ: r = 0.60, p≤0.001; CMJ: r= 0.66, p≤0.001) and the handball skill test (r = 0.71; p≤0.001). We concluded that the Yo-Yo test score showed a sufficient correlation with other potential means of assessing handball players, and that intra-individual changes of Yo-Yo IR1 score could provide a useful composite index of the response to training or rehabilitation, although correlations lack sufficient precision to help in players’ selection.

Effects of In-Season Explosive Strength Training on Maximal Leg Strength, Jumping, Sprinting, and Intermittent Aerobic Performance in Male Handball Athletes

Backgroundu2002Team handball is an intense ball sport with specific requirements on technical skills, tactical understanding, and physical performance. The ability of handball players to develop explosive efforts (e.u200ag. sprinting, jumping, changing direction) is crucial to success. Objectiveu2002The purpose of this pilot study was to examine the effects of an in-season high-intensity strength training program on the physical performance of elite handball players. Materials and methodsu2002Twenty-two handball players (a single national-level Tunisian team) were randomly assigned to a control group (CG; nu200a=u200a10) or a training group (TG; nu200a=u200a12). At the beginning of the pilot study, all subjects performed a battery of motor tests: one repetition maximum (1-RM) half-squat test, a repeated sprint test [6u200a× (2u200a×u200a15u200am) shuttle sprints], squat jumps, counter movement jumps (CMJ), and the Yo-Yo intermittent recovery test level 1. The TG additionally performed a maximal leg strength program twice a week for 10 weeks immediately before engaging in regular handball training. Each strength training session included half-squat exercises to strengthen the lower limbs (80u200a-u200a95u200a% of 1-RM, 1u200a-u200a3 repetitions, 3u200a-u200a6 sets, 3u200a-u200a4u200amin rest between sets). The control group underwent no additional strength training. The motor test battery was repeated at the end of the study interventions. Resultsu2002In the TG, 3 parameters (maximal strength of lower limb: η²u200a=u200a0.74; CMJ: η²u200a=u200a0.70, and RSA best time: η²u200a=u200a0.25) showed significant improvements, with large effect sizes (e.u200ag. CMJ: du200a=u200a3.77). A reduction in performance for these same 3 parameters was observed in the CG (du200a=u200a-0.24). Conclusionsu2002The results support our hypothesis that additional strength training twice a week enhances the maximal strength of the lower limbs and jumping or repeated sprinting performance. There was no evidence of shuttle sprints ahead of regular training compromising players speed and endurance capacities.

The Effect of Standard Strength vs. Contrast Strength Training on the Development of Sprint, Agility, Repeated Change of Direction, and Jump in Junior Male Soccer Players

Abstract Hammami, M, Negra, Y, Shephard, RJ, and Chelly, MS. The effect of standard strength vs. contrast strength training on the development of sprint, agility, repeated change of direction, and jump in junior male soccer players. J Strength Cond Res 31(4): 901–912, 2017—The aim was to compare the impact of 2 differing strength training (ST) programs on the athletic performance of junior male soccer players at a critical phase during their competitive season. Participants aged 16.0 ± 0.5 years were randomly assigned between control (C, n = 12), standard ST (n = 16), and contrast strength training (CST, n = 16), each performed twice a week. Athletic performance was assessed before and after the intervention using 8 tests: 40-m sprint, 4 × 5-m sprint (S4 × 5), 9-3-6-3-9 m sprint with 180° turns (S180°), 9-3-6-3-9 m sprint with backward and forward running (SBF), repeated shuttle sprint ability (RSSA), repeated change of direction (RCOD), squat jump (SJ), and countermovement jump (CMJ). The control groups (CG) performance tended to improve in some tests and decrease in others, but these changes were not statistically significant. Both training programs enhanced all sprint performances relative to controls (p ⩽ 0.05). The strength training group (SG) and the CST group (CSG) increased significantly in S180°, SBF, and S4 × 5 relative to CG, although the S4 × 5 also increased in CSG relative to SG (p ⩽ 0.05). No intergroup difference of RSSA performance was observed. The RCOD parameters increased significantly in CSG relative to both SG and CG (p ⩽ 0.05). The SJ and CMJ height increased significantly in both experimental groups (p < 0.000). We conclude that during the competitive season, some measures of athletic performance in male soccer players were increased more by 8 weeks of CST than by ST.

Relationships Between Olympic Weightlifting Exercises, Peak Power of the Upper and Lower Limb, Muscle Volume and Throwing Ball Velocity in Elite Male Handball Players

BACKGROUNDnu2002This study aimed to investigate relationships between peak power (PP) as measured by upper limb (PPUL) and lower limb (PPLL) force velocity tests, maximal upper limb force assessed by clean and jerk (1RMCJ) and snatch (1RMSE) exercises, estimates of local muscle volume and throwing ball velocity.nnnMETHODSnu2002Thirty elite male handball players volunteered for the investigation (age: 20.3u200a±u200a2.1 years; body mass: 82.5u200a±u200a10.5u200akg; height: 1.85u200a±u200a0,07u200a%; body fat: 13.1u200a±u200a2.1u200a%). Lower and upper limb force velocity tests were performed on appropriately modified forms of a Monark cycle ergometer with measurement of PPUL and PPLL, and the corresponding respective maximal forces (F0UL and F0LL) and velocities (V0UL and V0LL). Snatched (SN) and clean and jerk (CJ) exercises were performed to one repetition maximum (1RM). Handball throwing velocity was measured with jump shot (JS) without run-up (TW) and 3 steps shot (T3 step). Muscle volumes of the upper and lower limbs were estimated with a standard anthropometric kit.nnnRESULTSnu2002The 1RM CJ proved to be the most important predictor for throwing velocity. All types of throwing showed a high correlation with this parameter (JS: ru200a=u200a0.75; TW: ru200a=u200a0.62; T3xa0step: ru200a=u200a0.66). The highest relation was detected between jump shot and 1RM snatch technique (ru200a=u200a0.82). The PPUL muscle volume correlated highly with PPUL absolute power (ru200a=u200a0.70). In contrast, we did not find any comparable relations for the lower limb (muscle volume vs. PPUL absolute power: ru200a=u200a0.07).nnnCONCLUSIONSnu2002Our results highlight the contribution of both lower and upper limbs to handball throwing velocity, suggesting the need for coaches to include upper and lower limb strength weightlifting exercises and power programs when improving the throwing velocity of handball players.