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  • Author: Helmi Chaabene x
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Helmi Chaabene and Yassine Negra

Purpose:

To assess and compare the effects of 8 wk of in-season (2 sessions/wk) low- and high-volume plyometric training (PT) on measures of physical fitness in prepubertal male soccer players.

Methods:

A total of 25 soccer players were randomly assigned to a low-volume PT group (LPT; n = 13, age 12.68 ± 0.23 y, age at peak height velocity [APHV] 14.25 ± 0.29 y, maturity offset –1.57 ± 0.29 y) or a high-volume PT group (HPT; n = 12, age 12.72 ± 0.27 y, APHV 14.33 ± 0.77 y, maturity offset –1.61 ± 0.76 y). A linear-sprint test (5-m, 10-m, 20-m, and 30-m), change-of-direction (CoD) test, and vertical- (squat-jump [SJ]), countermovement- (CMJ), and horizontal-jump (standing long jump [SLJ]) test were carried out before and after 8 wk of PT.

Results:

There was a significant main effect of time for sprint outcomes (5-m, P = .005, ES = 0.86; 10-m, P = .006, ES = 0.85; 20-m, P = .03, ES = 0.64, and 30-m, P = .05, ES = 0.57), CoD (P = .002, ES = 0.96), SJ (P = .008, ES = 0.81; CMJ, P = .01, ES = 0.73), and SLJ ability (P = .007, ES = 0.83). There were no significant training group × time interactions in any measured outcomes.

Conclusions:

After 8 wk of training, results showed similar performance improvement on measures of sprint time, CoD, and jumping ability between LPT and HPT groups. From a time-efficiency perspective, it is recommended to use LPT in prepubertal male soccer players to improve their proxies of athletic performance.

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Maamer Slimani, Helmi Chaabene, Bianca Miarka and Karim Chamari

Purpose:

To determine the performance aspects (time–motion and technical-tactical analysis) of top-level low-kick kickboxers according to gender, weight category, combat round, and match outcome.

Methods:

Seventy-two kickboxers (44 male, 28 female) were studied. Thirty-six bouts (male = 61, female = 41 rounds) were analyzed using a time–motion system. Time structure was classified into 3 phases: preparatory-activity time (PT), fighting time (FT), and stoppage time (ST).

Results:

Referee decisions caused an overall effort:pause ratio (E:P) of ~1:1.5, with a significant difference between weight categories (light and middleweights = 1:1.5, heavyweight = 1:1). This ratio was ~1:6 when high-intensity actions–to-pause activities were considered. Significant differences were also observed between rounds (all P < .001), with 1st-, 2nd-, and 3rd-round E:Ps of 1:1, 1:1.5, and ~1:2, respectively. The relative times of FT and PT, total attacking actions, upper-limb actions, number of technical actions performed on the head, and the number of high-intensity actions were higher in males than females (all P = .05). Males performed more jab-cross actions and fewer low kicks than females (P < .001). Males used upper-limb (63.4%) more than lower-limb techniques (36.6%), targeting the head (56.9%) more than the body/leg (43.1%), with no significant difference from females (P > .05). E:P was similar between winners and losers. However, the numbers of technical actions performed on the head, counterattack actions, jab-cross technique, and total punches were higher in winners than losers (all P < .05).

Conclusions:

Training programs need to be adapted to the specific requirements of kickboxers’ weight categories and gender to develop the technical-tactical abilities that improve athletes’ chances of winning.

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Olaf Prieske, Helmi Chaabene, Christian Puta, David G. Behm, Dirk Büsch and Urs Granacher

Purpose: To examine the effects of drop height on drop-jump (DJ) performance and on associations between DJ and horizontal-jump/sprint performances in adolescent athletes. Methods: Male (n = 119, 2.5 [0.6] y post-peak-height velocity) and female (n = 120, 2.5 [0.5] y post-peak-height velocity) adolescent handball players (national level) performed DJs in randomized order using 3 drop heights (20, 35, and 50 cm). DJ performance (jump height, reactive strength index [RSI]) was analyzed using the Optojump Next system. In addition, correlations were computed between DJ height and RSI with standing-long-jump and 20-m linear-sprint performances. Results: Statistical analyses revealed medium-size main effects of drop height for DJ height and RSI (P < .001, 0.63 ≤ d ≤ 0.71). Post hoc tests indicated larger DJ heights from 20 to 35 and 35 to 50 cm (P ≤ .031, 0.33 ≤ d ≤ 0.71) and better RSI from 20- to 35-cm drop height (P < .001, d = 0.77). No significant difference was found for RSI between 35- and 50-cm drop height. Irrespective of drop height, associations of DJ height and RSI were small with 5-m-split time (−.27 ≤ r ≤ .05), medium with 10-m-split time (−.44 ≤ r ≤ .14), and medium to large with 20-m sprint time and standing-long-jump distance (−.57 ≤ r ≤ .22). Conclusions: The present findings indicate that, irrespective of sex, 35-cm drop heights are best suited to induce rapid and powerful DJ performance (ie, RSI) during reactive strength training in elite adolescent handball players. Moreover, training-related gains in DJ performance may at least partly translate to gains in horizontal jump and longer sprint distances (ie, ≥20-m) and/or vice versa in male and female elite adolescent athletes, irrespective of drop height.

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Helmi Chaabène, Emerson Franchini, Bianca Miarka, Mohamed Amin Selmi, Bessem Mkaouer and Karim Chamari

Purpose:

The aim of this study was to measure and compare physiological and time–motion variables during karate fighting and to assess eventual differences between winners and defeated elite karatekas in an ecologically valid environment.

Methods:

Fourteen elite male karatekas who regularly participated in national and international events took part in a national-level competition.

Results:

There were no significant differences between winners and defeated karatekas regarding all the studied variables. Karatekas used more upper-limb (76.19%) than lower-limb techniques (23.80%). The kisami-zuki represented the most frequent technique, with 29.1% of all used techniques. The duration of each fighting activity ranged from <1 s to 5 s, with 83.8% ± 12.0% of the actions lasting less than 2 s. Karatekas executed 17 ± 7 high-intensity actions per fight, which corresponded to ~6 high-intensity actions per min. Action-to-rest ratio was about 1:1.5, and high-intensityaction- to-rest ratio was ~1:10. The mean blood lactate response at 3 min postcombat (Lapost) elicited during karate fighting was 11.18 ± 2.21 mmol/L (difference between Lapre and Lapost = 10.01 ± 1.81 mmol/L). Mean heart rate (HR) was 177 ± 14 beats/min (91% ± 5% of HRpeak). Karatekas spent 65% of the time exercising at HR >90% of the individual HRpeak.

Conclusion:

Karatekas predominantly use upper-limb karate techniques. Karate’s nature is intermittent, with fighting activities representing ~6% of total combat’s duration and ~84% of actions lasting less than 2 s, with ~21-s mean time interval in between. Kumite combat sessions induced high La and near-maximal cardiovascular strain. Other key success factors should be investigated to properly discriminate winners and defeated athletes.

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Senda Sammoud, Alan Michael Nevill, Yassine Negra, Raja Bouguezzi, Helmi Chaabene and Younés Hachana

This study aimed to estimate the optimal body size, limb segment length, and girth or breadth ratios of 100-m breaststroke performance in youth swimmers. In total, 59 swimmers [male: n = 39, age = 11.5 (1.3) y; female: n = 20, age = 12.0 (1.0) y] participated in this study. To identify size/shape characteristics associated with 100-m breaststroke swimming performance, we computed a multiplicative allometric log-linear regression model, which was refined using backward elimination. Results showed that the 100-m breaststroke performance revealed a significant negative association with fat mass and a significant positive association with the segment length ratio (arm ratio = hand length/forearm length) and limb girth ratio (girth ratio = forearm girth/wrist girth). In addition, leg length, biacromial breadth, and biiliocristal breadth revealed significant positive associations with the 100-m breaststroke performance. However, height and body mass did not contribute to the model, suggesting that the advantage of longer levers was limb-specific rather than a general whole-body advantage. In fact, it is only by adopting multiplicative allometric models that the previously mentioned ratios could have been derived. These results highlighted the importance of considering anthropometric characteristics of youth breaststroke swimmers for talent identification and/or athlete monitoring purposes. In addition, these findings may assist orienting swimmers to the appropriate stroke based on their anthropometric characteristics.

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Montassar Tabben, Jeremy Coquart, Helmi Chaabène, Emerson Franchini, Karim Chamari and Claire Tourny

Purpose:

This study determined the validity and reliability of a new specific field test that was based on the scientific data from the latest research.

Methods:

Seventeen international-level karatekas participated in the study: 14 men (age 24.1 ± 4.6 y, body mass 65.7 ± 10.8 kg) and 3 women (age 19 ± 3.6 y, body mass 54.1 ± 0.9 kg). All performed the new karate-specific test (KST) 2 times (test and retest sessions were carried out on separated occasions 1 wk apart). Thirteen men also performed a laboratory test to assess maximal oxygen uptake (VO2max).

Results:

Test–retest results showed the KST to be reliable. Peak oxygen uptake (VO2peak), peak heart rate (HRpeak), blood lactate concentration, rating of perceived exertion, and time to exhaustion (TE) did not display a difference between the test and the retest. The SEM and ICC for relative and absolute VO2peak and TE were <5% and >.90, respectively. Significant correlations were found between VO2peak (mL · kg−1 · min−1) and TE measured from the KST (r = .71, 95%CI 0.35–0.88, P < .0001). There was also no significant difference between VO2peak measured from the KST and VO2max recorded from the cycle-ergometer laboratory test (55.1 ± 4.8 vs 53.2 ± 6.6 mL · kg−1 · min−1, respectively; t = –1.85, df = 12, P = .08, dz = 0.51 [small]). The Bland and Altman analyses reported a mean difference (bias) ± the 95% limits of agreement of 1.9 ± 7.35 mL · kg−1 · min−1.

Conclusions:

This study showed that the new KST test, with effort patterns replicating real karate combat sessions, can be considered a valid and reliable karate-specific field test for assessing karatekas’ endurance fitness.

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Simone Ciaccioni, Laura Capranica, Roberta Forte, Helmi Chaabene, Caterina Pesce and Giancarlo Condello

This study aimed to investigate the effects of a 4-month judo training (1 hr session, biweekly) on physical and mental health of older adults (69.7 ± 4.2 years). Participants (N = 30) were assigned to a judo novice practitioners group (n = 16) or a control group (n = 14), which did not receive any training. Before and after the program, they underwent anthropometric (body mass index and waist and hip circumferences); functional fitness (upper and lower body flexibility and strength, coordination); and psychological assessments (perceived physical and mental health, body image, and fear of falling). The judo group showed reductions of waist circumference (Δ = −1%, d = 0.2) and improvements for lower and upper body flexibility (Δ = +69%, d = 0.4 and Δ = +126%, d = 0.5, respectively) and strength (Δ = +12%, d = 0.6 and Δ = +31%, d = 1.6, respectively). The control group showed a decline in lower body strength (Δ = −12%, d = 0.8). Psychological variables did not reveal statistically significant effects. Judo seems beneficial for improving anthropometric and functional fitness variables, relevant aspects of successful aging.

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Helmi Chaabene, Yassine Negra, Jason Moran, Olaf Prieske, Senda Sammoud, Rodrigo Ramirez-Campillo and Urs Granacher

Purpose:

This study examined the effects of an 8-week Nordic-hamstring exercise (NHE) training on components of physical performance in young female handball players.

Methods:

Participants were allocated to an experimental (EG; n=10; age: 15.9 ± 0.2 years) and a control group (CG; n=9; age: 15.9 ± 0.3 years). The EG performed NHE (2-3 sessions/week) in replacement of some handball-specific drills whereas the CG followed regular handball training. Pre- and post-training, tests were carried-out for the assessment of sprint speed (5 m, 10 m, 20 m), jump performance (countermovement jump [CMJ] height), change-of-direction (CoD [T-test]), and repeated-sprint-ability (RSA total-time [RSAtotal], RSA best-time [RSAbest], RSA fatigue-index [RSAFI]). Data were analyzed using magnitude-based inferences.

Results:

Within-group analyses for the EG showed moderate performance improvements for 5 m, 10 m, 20 m (effect-size [ES] = 0.68-0.82), T-test (ES=0.74), and CMJ (ES=0.85). Trivial-to-small improvements were observed for RSA (ES=-0.06-0.35). For the CG, within-group outcomes showed performance decrements with moderate (T-test [ES=0.71]), small (5 m [ES=0.46], and RSAbest [ES=0.20]), and trivial magnitude (10 m [ES=0.10], 20 m [ES=0.16] and RSAtotal [ES=0.00]). Further, trivial-to-small performance improvements were found for CMJ (ES=0.10) and RSAFI (ES=0.5). Between-group analyses revealed small-to-large effects in favor of EG for 5 m (ES=1.07), 10 m (ES=0.66), 20 m (ES=0.53), T-test (ES=1.38), and RSA (ES=0.68 to 0.78). A trivial between-group difference was demonstrated for CMJ (ES=-0.01).

Conclusions:

The NHE training intervention, in replacement of some handball-specific drills, was more effective than regular handball training in improving physical performance (i.e., linear sprint-time, jumping, CoD, and RSA) in young female handball players.

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Yassine Negra, Helmi Chaabene, Senda Sammoud, Olaf Prieske, Jason Moran, Rodrigo Ramirez-Campillo, Ali Nejmaoui and Urs Granacher

Purpose: To examine the effects of loaded (LPJT) versus unloaded plyometric jump training (UPJT) programs on measures of muscle power, speed, change of direction (CoD), and kicking-distance performance in prepubertal male soccer players. Methods: Participants (N = 29) were randomly assigned to a LPJT group (n = 13; age = 13.0 [0.7] y) using weighted vests or UPJT group (n = 16; age = 13.0 [0.5] y) using body mass only. Before and after the intervention, tests for the assessment of proxies of muscle power (ie, countermovement jump, standing long jump); speed (ie, 5-, 10-, and 20-m sprint); CoD (ie, Illinois CoD test, modified 505 agility test); and kicking-distance were conducted. Data were analyzed using magnitude-based inferences. Results: Within-group analyses for the LPJT group showed large and very large improvements for 10-m sprint time (effect size [ES] = 2.00) and modified 505 CoD (ES = 2.83) tests, respectively. For the same group, moderate improvements were observed for the Illinois CoD test (ES = 0.61), 5- and 20-m sprint time test (ES = 1.00 for both the tests), countermovement jump test (ES = 1.00), and the maximal kicking-distance test (ES = 0.90). Small enhancements in the standing long jump test (ES = 0.50) were apparent. Regarding the UPJT group, small improvements were observed for all tests (ES = 0.33–0.57), except 5- and 10-m sprint time (ES = 1.00 and 0.63, respectively). Between-group analyses favored the LPJT group for the modified 505 CoD (ES = 0.61), standing long jump (ES = 0.50), and maximal kicking-distance tests (ES = 0.57), but not for the 5-m sprint time test (ES = 1.00). Only trivial between-group differences were shown for the remaining tests (ES = 0.00–0.09). Conclusion: Overall, LPJT appears to be more effective than UPJT in improving measures of muscle power, speed, CoD, and kicking-distance performance in prepubertal male soccer players.