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Hermassi S.,University of Sfax | Chelly M.S.,University of Sfax | Chelly M.S.,Manouba University | Tabka Z.,University of Sfax | And 3 more authors.
Journal of Strength and Conditioning Research | Year: 2011

Hermassi, S, Chelly,MS, Tabka,Z, Shephard, RJ, andChamari, K. Effects of 8-week in-season upper and lower limb heavy resistance training on the peak power, throwing velocity, and sprint performance of elite male handball players. J Strength Cond Res 25(9): 2424-2433, 2011-The aims of this study were to test the potential of in-season heavy upper and lower limb strength training to enhance peak power output (W peak), vertical jump, and h ndball related field performance in elite male handball players who were apparently already well trained, and to assess any adverse effects on sprint velocity. Twentyfour competitors were divided randomly between a heavy resistance (HR) group (age 2060.7 years) and a control group (C; age 20 ± 0.1 years). Resistance training sessions were performed twice a week for 8 weeks. Performance was assessed before and after conditioning. Peak power (W peak) was determined by cycle ergometer; vertical squat jump (SJ) and countermovement jump (CMJ); video analyses assessed velocities during the first step (V 1S), the first 5 m (V 5m), and between 25 and 30 m (V peak) of a 30-m sprint. Upper limb bench press and pull-over exercises and lower limb back halfsquats were performed to 1-repetition maximum (1RM). Upperlimb, leg, and thigh muscle volumes and mean thigh crossse ctional area (CSA) were assessed by anthropometry. W peak (W) for both limbs (p < 0.001), vertical jump height (p < 0.01 for both SJ and CMJ), 1RM (p,0.001 for both upper and lower limbs) and sprint velocities (p < 0.01 for V 1S and V 5m; p < 0.001 for V peak) improved in the HR group. Upper body, leg, and thigh muscle volumes and thigh CSA also increased significantly after stre gth training. We conclude that in-season biweekly heavy back half-squat, pull-over, and bench-press exercises can be commended to elite male handball players as improving many m asures of handball-related performance without adverse effects upon speed of movement. © 2011 National Strength and Conditioning Association.


Souissi N.,Research Laboratory Sports Performance Optimization | Souissi N.,Manouba University | Chtourou H.,Research Laboratory Sports Performance Optimization | Chtourou H.,University of Sfax | And 5 more authors.
Journal of Strength and Conditioning Research | Year: 2013

Souissi, N, Chtourou, H, Aloui, A, Hammouda, O, Dogui, M, Chaouachi, A, and Chamari, K. Effects of time-of-day and partial sleep deprivation on short-term maximal performances of judo competitors. J Strength Cond Res 27(9): 2473-2480, 2013-This study assessed the effects of partial sleep deprivation on short-term maximal performances of judokas in the morning and afternoon of the following day. In a randomized design, 12 judokas completed the maximal voluntary contraction, the handgrip, and the Wingate tests before and after a judo combat. Measurements were performed at 09:00 and 16:00 hours after a reference-normal sleep night and 2 conditions of 4-hour partial sleep deprivation timed at the beginning (SDB) or at the end of the night (SDE). The results showed that muscle power and strength were significantly higher at 16:00 than 09:00 hours (p < 0.05). These diurnal variations disappeared after SDB and SDE and after the combat. In addition, SDE resulted in significant decreases of short-term maximal performance in the afternoon (p <0.01). In conclusion, SDE decreased muscle strength and power at 16:00 hours and, therefore, might have blunted the diurnal variations of short-term maximal exercise. Thus, early rising is more detrimental than late bedtime to muscle strength and power for judo athletes when competitions are scheduled in the afternoon hours. © 2013 National Strength and Conditioning Association.


Abedelmalek S.,University of Sfax | Chtourou H.,Research Laboratory Sports Performance Optimization | Aloui A.,Research Laboratory Sports Performance Optimization | Souissi N.,Research Laboratory Sports Performance Optimization | Souissi N.,Manouba University
European Journal of Applied Physiology | Year: 2013

The present study was designed to evaluate the effect of time of day and partial sleep deprivation (PSD) on short-term maximal performance and level of interleukin-6 (IL-6) in trained subjects. In a randomized order, 12 football players were asked to perform a 30-s Wingate test during which we measured the peak (PP) and mean (MP) powers. Measurements were performed at 0800 and 1800 hours, after two nocturnal regimens: (1) a reference normal sleep night (RN) and (2) 4 h of PSD caused by an early awakening. Plasma IL-6 concentrations were measured before (P1), immediately after (P2), and 60 min after the exercise (P3). PP and MP improved significantly from the morning to the afternoon after RN (P < 0.05) and from the afternoon to the morning after PSD (P < 0.05). Compared to RN, PP and MP were not affected by PSD the following morning. However, there was a significant decrease in PP and MP (P < 0.001) after the PSD at 1800 hours. In all conditions, IL-6 and resting core temperature were significantly higher (P < 0.05) in the afternoon than in the morning. In all sessions, IL-6 levels increased significantly from P1 to P2 (P < 0.01) and remained elevated in the afternoon during the recovery period after PSD (P < 0.05). However, no significant difference was observed in IL-6 between P1 and P3 during RN and PSD at 0800 hours. In conclusion, a short-term high-intensity exercise may increase the IL-6 concentrations in the morning and the afternoon. Moreover, IL-6 remained elevated during the recovery period in the afternoon after the PSD at the end of the night. © 2012 Springer-Verlag.


Chtourou H.,Research Laboratory Sports Performance Optimization | Chtourou H.,University of Sfax | Souissi N.,Research Laboratory Sports Performance Optimization | Souissi N.,Manouba University
Journal of Strength and Conditioning Research | Year: 2012

This article focuses on physical performances after training at a specific time of day. To date, although the effect of time of day on aerobic performances appears to be equivocal, during anaerobic exercises, the effect of time of day has been well established with early morning nadirs and peak performances in the late afternoon. These diurnal rhythms can be influenced by several factors such as the regular training at a specific time of day. Indeed, regular training in the morning hours may increase the lower morning performances to the same or even higher level as their normal diurnal peak typically observed in the late afternoon by a greater increase of performance in the evening. However, regular training in the evening hours may increase the morning-evening (i.e., amplitude of the rhythm) difference by a greater increase of performance in the late afternoon. Therefore, adaptations to training are greater at the time of day at which training is regularly performed than at other times. Nevertheless, although modifications in resting hormones concentrations could explain this time-of-day specific adaptations, precise information on the underlying mechanisms is lacking. © 2012 National Strength and Conditioning Association.


Chtourou H.,Research Laboratory Sports Performance Optimization | Chtourou H.,University of Sfax | Hammouda O.,Research Laboratory Sports Performance Optimization | Chaouachi A.,University of Sfax | And 4 more authors.
International Journal of Sports Medicine | Year: 2012

This study was designed to assess the effects of Ramadan-intermittent- fasting (RIF) and time-of-day on muscle power and fatigue during the Wingate test. In a randomized design, 10 football players completed a Wingate test at 07:00 and 17:00h on 3 different occasions: one week before Ramadan (BR), the second week of Ramadan (SWR) and the fourth week of Ramadan (ER). There was an interval of 36-h between any 2 successive tests. During the Wingate test, peak power (PP), mean power (MP) and the fatigue index (FI) were recorded. While PP, MP and FI were greater in the evening than in the morning during BR (p<0.001), these diurnal variations in muscle power disappeared during the month of Ramadan (i.e., SWR and ER) due to a significant decrease in PP and MP in the evening (p<0.001). However, the diurnal variation in FI when measured at 17:00h increased during this month (p<0.001). In addition, ratings of perceived exertion and fatigue were higher in the evening during Ramadan in comparison with BR. These results suggest that Ramadan might modify the circadian rhythm of muscle power and fatigue during the Wingate test by decreasing power output and increasing muscle fatigue at the time of the acrophase. © Georg Thieme Verlag KG • Stuttgart New York.


Chtourou H.,Research Laboratory Sports Performance Optimization | Chtourou H.,Institute Superieur Of Sport Et Of Leducation Physique | Driss T.,Paris West University Nanterre La Défense | Souissi S.,Institute Superieur Of Sport Et Of Leducation Physique | And 3 more authors.
Journal of Strength and Conditioning Research | Year: 2012

The aim of this study was to examine the effects of training at the same time of the day on the diurnal variations of anaerobic performances to provide some recommendations to adjust training hours with the time of the day of competitive events. Thirty participants underwent 8 weeks of lower-extremity progressive resistance training performed 3 times per week designed to promote muscular strength and power. These subjects were randomly assigned to a morning training group (MTG, 07:00-08:00 hours, n = 10), an evening training group (ETG, 17:00-18:00 hours, n = 10), and a control group (CG, completed all tests but did not train, n = 10). Performance in the squat jump, the countermovement jump, the Wingate and 1 repetition maximum (1RM) during leg extension, leg curl, and squat tests was recorded just before and 2 weeks after an 8-week course of regular training. For all the subjects, the morning and evening tests were scheduled at the same time of the day as for the morning and evening training sessions. Before training, the results indicated a significant increase in performance from morning to evening tests (ca. 2.84-17.55% for all tests) for all groups. After training, the diurnal variations in anaerobic performances were blunted in the MTG. In fact, there was no significant difference in muscular power or strength between morning and evening tests. However, these intradaily variations in anaerobic performances persisted in the ETG and CG. From a practical point of view, adaptation to strength training is greater at the time of the day at which training was scheduled than at other times. © 2012 National Strength and Conditioning Association.


Zarrouk N.,Service Route | Chtourou H.,Research Laboratory Sports Performance Optimization | Rebai H.,Unite de Recherche | Hammouda O.,Research Laboratory Sports Performance Optimization | And 3 more authors.
International Journal of Sports Medicine | Year: 2012

The present study aimed at investigating the effects of time-of-day on muscle power and associated electromyographic (EMG) activity level of 4 thigh muscles during a repeated pedalling sprint exercise. After a familiarization session, 12 male subjects were asked to perform the repeated sprint ability test during 2 experimental sessions (randomized order), which were set up either at 06:00 or 18:00h. For each sprint, peak power output, percentage of peak power decrement and total work were calculated. EMG activity of vastus lateralis, rectus femoris, vastus medialis and biceps femoris muscles was recorded throughout the test and analyzed for each sprint. Total work and percentage of peak power decrement were higher in the evening than in the morning (p<0.01 and p<0.05, respectively). Likewise, peak power was significantly higher at 18:00 than 06:00h during the first 3 sprints (p<0.01 for sprint 1 and p<0.05 for sprint 2 and 3). There was no time-of-day effect for EMG activity level. The neuromuscular efficiency decreased significantly over the repeated sprint ability test at the 2 times of testing (p<0.01). Despite diurnal fluctuation in muscular power and neuromuscular fatigue during the repeated sprint ability test, EMG activity of major thigh muscles was not time-of-day dependent. © Georg Thieme Verlag KG Stuttgart . New York.


Chaouachi A.,Research Laboratory Sports Performance Optimization | Manzi V.,University of Rome Tor Vergata | Wong D.P.,The Hong Kong Institute of Education | Chaalali A.,Research Laboratory Sports Performance Optimization | And 3 more authors.
Journal of Strength and Conditioning Research | Year: 2010

The ability to perform highintensity intermittent exercise (i.e., Yo-Yo Intermittent Recovery Test [Yo-Yo IR1]) and to repeat sprints with relatively short recovery times (i.e., 20-to 30-seconds, relatively short time interval [repeated sprint ability (RSA)]) has been shown to be relevant fitness variables in soccer. However, though they potentially share common features, it is not known whether these 2 abilities are associated. The aim of this study was to examine the relationships between Yo-Yo IR1 and RSA performances in elite soccer players. Twenty-three soccer players (age 19 ± 1 years, height 181 ± 5.7 cm, body mass 73. 2 ± 4.1 kg, %body fat 11 ± 2.4) performed the Yo-Yo IR1 and a test for RSA (7 × 30 m with 25-second recovery). Results were 2,289 ± 409 m, 31.21 ± 1.13 seconds, and 4 ± 2. 1% for Yo-Yo IR1, total sprint time, and sprint decrement, respectively. Yo-Yo IR1 showed a significant and moderate relationship with sprint decrement (r = 20.44, p = 0.04). Splitting the sample into Best and Worst Yo-Yo IR1 performers according to median score (2,320 m), the Best group showed lower RSA total time (30.69 ± 0.99 vs. 31.79 ± 1.06, p < 0.05) and speed decrement (2.90 ± 0.86 vs. 5.09 6 2.42, p < 0.01) compared to the Worst group. Sprint-time deterioration over 30 m occurred earlier (from the second sprint on) in the Yo-Yo Worst compared with in the Yo-Yo Best group (from the fourth sprint on, p < 0.001). Intermittent high-intensity endurance is poorly associated with RSA performance (r 2 = 0.19). Consequently, coaches and strength and conditioning professionals should consider both Yo-Yo IR1 and RSA in their testing batteries. A Yo-Yo IR1 performance ≥2,320 m could be considered as a reasonable indicator of physical fitness in elite soccer. Relatively short time interval test protocols similar to the present study should consist of at least 5 sprint bouts. © 2010 National Strength and Conditioning Association.


Castagna C.,University of Rome Tor Vergata | Impellizzeri F.M.,Schulthess Klinik | Chaouachi A.,Research laboratory Sports Performance Optimization | Bordon C.,Palermo Football Club | Manzi V.,University of Rome Tor Vergata
Journal of Strength and Conditioning Research | Year: 2011

Castagna, C, Impellizzeri, FM, Chaouachi, A, Bordon, C, and Manzi, V. Effect of training intensity distribution on aerobic fitness variables in elite soccer players: A case study. J Strength Cond Res 25(1): 66-71, 2011 - The aim of this article was to quantify the distribution of training intensities and its effect on aerobic fitness in professional elite soccer players. Fourteen professional soccer players were observed during the prechampionship training period (6 weeks). Treadmill running speed and heart rates (HRs) at 2 and 4 mmol · L -1 blood-lactate concentrations were assessed pre and posttraining. Training intensities were categorized using 3 HR zones: low intensity (


HR 4 mmol · L -1). Analysis of the 504 individual training sessions showed that 73 ± 2.5, 19 ± 2.8, and 8 ± 1.4% of the total training time was spent at low, moderate, and high intensity, respectively (p < 0.001). Speed at 2 and 4 mmol · L -1 significantly improved posttraining (5 and 7%, respectively, p < 0.01). Training spent at high intensity was significantly related to relative speed improvements at 2 mmol · L -1 (r = 0.84, p < 0.001;) and 4 mmol · L -1 (r = 0.65, p = 0.001). Players spent almost two-thirds of their training time at low intensities. However, only the time spent at high intensity (>90% of maximal HR) was related to changes in aerobic fitness. These results support the usefulness of the quantification of aerobic training load using HR. Furthermore, it stresses the effectiveness of the high-intensity training in soccer. © 2011 National Strength and Conditioning Association.


Souissi H.,Research Laboratory Sports Performance Optimization | Chtourou H.,Research Laboratory Sports Performance Optimization | Chaouachi A.,Research Laboratory Sports Performance Optimization | Dogui M.,Attention | And 3 more authors.
Pediatric Exercise Science | Year: 2012

The aim of this study was to assess the effect of time-of-day-specific training on the diurnal variations of short-term performances in boys. Twenty-four boys were randomized into a morning-training-group (07:00-08:00h; MTG), an eveningtraining- group (17:00-18:00h; ETG) and a control-group (CG). They performed four tests of strength and power (unilateral isometric maximal voluntary contraction of the knee extensor muscles, Squat-Jump, Counter-Movement-Jump and Wingate tests) at 07:00 and 17:00h just before (T0) and after 6 weeks of resistance training (T1). In T0, the results revealed that short-term performances improved and oral temperature increased significantly from morning to afternoon (amplitudes between 2.36 and 17.5% for both oral temperature and performances) for all subjects. In T1, the diurnal variations of performances were blunted in the MTG and persisted in the ETG and CG. Moreover, the training program increase muscle strength and power especially after training in the morning hours and the magnitude of gains was greater at the time-of-day-specific training than at other times. In conclusion, these results suggest that time-of-day-specific training increases the child's anaerobic performances specifically at this time-of-day. Moreover, the improvement of these performances was greater after morning than evening training. © 2012 Human Kinetics, Inc.

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