Achraf Ammar

Temporal specificity of training: intra-day effects on biochemical responses and Olympic-Weightlifting performances

Abstract The aim of this study was to investigate the performance of an Olympic-Weightlifting session training at three times of the day on the performance related to biochemical responses. Nine weightlifters (21 ± 0.5 years) performed, in randomised order, on three Olympic-Weightlifting training (snatch, clean and jerk) sessions (08:00 a.m., 02:00 p. m., 06:00 p. m.). Blood samples were collected: before, 3 min and 48 h after each training session. Haematological parameters and markers of muscle injury were assessed. Resting oral temperature and rating of perceived exertion (RPE) were also assessed during each session. ANOVA showed that the performance was better (P < 0.001) at 02:00 p. m. with a less RPE (P < 0.01) compared to the morning and the evening sessions while there was higher (P < 0.05) oral temperature at 06:00 p. m. versus 08:00 a.m. and 02:00 p. m. Muscle damage changed immediately (without significant effect after 48 h) after the training sessions with lower values in the evening compared to the morning. In conclusion, the afternoon training is more effective than morning or evening sessions for weightlifters. Therefore, coaches and weightlifters should be advised to schedule their training session in the afternoon hour.

Pomegranate Supplementation Accelerates Recovery of Muscle Damage and Soreness and Inflammatory Markers after a Weightlifting Training Session.

Purpose The aim of this study was to investigate the effect of natural Pomegranate juice supplementation on performance and acute and delayed responses of muscle soreness and biomarkers of muscle damage after a weightlifting training session. Methods Nine elite weightlifters (21±0.5 years) performed two Olympic-Weightlifting-sessions after either placebo (PLA) or natural pomegranate juice (POMj) supplementations. Heart rate, blood pressure and blood samples (hematological parameters, muscle damage and C-reactive protein (CRP)) were collected at rest, 3min and 48h after each session. Weightlifting performance, RPE, and DOMS were also assessed after each training session. Results T-test showed higher performance (+8.30%) and lower RPE values (-4.37%) using POMj supplementation (p<0.05) in comparison with PLA. For the DOMS values, a significant improvement (13.4%) was shown only for the knee extensors (p<0.01) using the POMj. Compared to PLA condition, POMj attenuated the acute (i.e., 3min) increase of systolic blood pressure (SBP), HR, CK and LDH (p<0.05; -4.46%, -1.81%, -8.75%, -1.64%, respectively) and blunted the significant increase of ASAT, PAL and CRP (p>0.05). Additionally, during the 48h following the training session, POMj improved the recovery kinetic of SBP (p<0.01, 7.97%), CK (p<0.001, 11.34%), LDH (p<0.05, 7.30%) and ASAT (p<0.05, 6.77%). Indeed, the present study showed that 48h of recovery associated to natural POMj supplementation was sufficient to reach the resting values of the selected muscle damage markers after intensive training session. Conclusion Natural POMj seems to ameliorate the capacity to adhere to an intensive training program. Therefore, elite weightlifters are advised to use natural POMj during intensive training program and competition to accelerate muscle recovery. Trial Registration ClinicalTrials.gov NCT02697903

Acute and delayed responses of C-reactive protein, malondialdehyde and antioxidant markers after resistance training session in elite weightlifters: Effect of time of day.

The aim of this study was to investigate the effect of an Olympic-Weightlifting-session followed by 48-h recovery period on the oxidative and antioxidant parameters’ diurnal variation. Nine weightlifters (21 ± 0.5 years) performed, in randomized order, three Olympic-Weightlifting-sessions at 08 h:00, 14 h:00 and 18 h:00. Blood samples were collected: at rest and 3 min and 48 h after each session. C-reactive protein (CRP), rate of lipid peroxidation and antioxidant activities were assessed. At rest, analysis of variance showed a significant time of day (TOD) effect (p < 0.05) for uric acid, catalase and glutathione peroxidase with higher values at 14 h:00 and 18 h:00 compared with 08 h:00. However, no significant TOD effect for malondialdehyde, total bilirubin and CRP was observed. Given the profound changes (p < 0.001) in the post-training session values, these diurnal variations have been altered immediately and even 48 h after the training sessions. Despite the significant decreases in the post-training values after the 48-h recovery period (p < 0.05), levels of lipid peroxidation and enzymatic defense remained elevated (p < 0.05) 48 h after the morning training session. However, after the afternoon and evening sessions, the same period was sufficient to return values to the baseline levels. In conclusion, the morning session seems to generate the most important acute and delayed lipid peroxidation responses. Therefore, weightlifting coaches should avoid scheduling their training sessions in the morning-hours.

Relationship between motor and cognitive learning abilities among primary school-aged children

Abstract Background The relationship between motor and cognitive development has already been proven in young children. However, in relation to the academic achievement the association between motor and cognitive performance still not well established. Therefore, the aim of this study was to examine the levels of motor and cognitive learning abilities and their independent and combined associations among German primary school-children. Methods Participants were (n = 197) between the ages of six to eight. The German motor test (DMT), the cognitive abilities test (KFT), height, weight, and body mass index (BMI) were measured. Results ANOVA testing found that boys perform better in long jumping and in the six minutes running test while girls perform better in balancing backwards and in deductive thinking test (p < 0.05). With maturation from ages six to eight the achievement level of both populations showed a higher performance in motor and cognitive learning abilities (p < 0.001). Concerning the combined and independent associations between the tested abilities, a significant correlation was shown between total motor and total cognitive learning abilities (p < 0.001, r = 0.60) with higher contribution of balancing backwards, six minutes running and push-up levels (r = 0.63, r = 0.62, r = 0.60, respectively) in the performance of the cognitive learning abilities (i.e. mathematical thinking, r = 0.62 and language understanding, r = 0.59). Conclusions In conclusion, fostering the childrens’ physical fitness during the primary school age could enhance both motor and cognitive learning abilities related to the academic achievement.

Post-resistance training detraining: time-of-day effects on training and testing outcomes

The aim of this study was to examine the effects of 3 and 5 weeks of detraining after 14 weeks of resistance training at a specific time of day on performances during the squat jump (SJ) and the maximal voluntary contraction (MVC). Thirty-one healthy male physical education students (age: 23.1 ± 1.0 years; height: 176.1 ± 6.3 cm; weight: 74.9 ± 10.9 kg) were randomly assigned to either a morning training group (MTG, training between 07:00 and 08:00 h, n = 10), an evening training group (ETG, training between 17:00 and 18:00 h, n = 11) or a control group (CG, no training, n = 10). Participants then performed eight test sessions (twice per day, at 07:00 and 17:00 h) over the course of four phases: during pre-training, immediately post-training, and after 3 and 5 weeks of detraining. Before each test session, oral temperature was recorded. During the first 12 weeks of resistance training, participants performed 3 sets of 10 repetitions to failure (10-RM) for 4 exercises (squat, leg press, leg extension and leg curl, with 2 min of recovery between each exercise); during the last two weeks, training intensity increased to 8-RM with 3 min of recovery between each exercise. Oral temperature was significantly higher at 17:00 than 07:00 h during all test periods (p < 0.05). Likewise, SJ and MVC performances were significantly higher at 17:00 h than 07:00 h during all four test days in ETG and CG, and before training and 3 and 5 weeks after training in MTG (p < 0.05). For both training groups, most SJ and MVC performances (except MTG at 07:00 h and ETG at 17:00 h) returned to baseline values after 5, but not after 3, weeks of detraining. This study showed that 14 weeks of training at a specific time of day blunted the diurnal variation of MVC and SJ in the MTG. The improvement in performance brought about by resistance training was partially retained after 3 weeks of detraining (unless training had taken place at a non-habitual time of day) but was lost after 5 weeks of detraining. There was no effect of the time of training on core temperature.

Kinetic and kinematic patterns during high intensity clean movement: searching for optimal load

ABSTRACT The aim of the present study was to investigate loading effects on kinematic and kinetic variables among elite-weightlifters in order to identify an optimal training load to maximize power production for clean-movement. Nine elite-weightlifter (age: 24 ± 4years, body-mass: 77 ± 6.5kg, height: 176 ± 6.1cm and 1RM clean: 170 ± 5kg) performed 2 separate repetitions of the clean using 85, 90, 95% and 100%, in a randomized order, while standing on a force platform and being recorded using 3D-capture-system. Differences in kinematics (barbell displacement, velocity and acceleration) and kinetics (power, vertical ground reaction force (vGRF), rate of force development (RFD), and work) across the loads were statistically assessed. Results revealed significant load effects for the majority of the studied parameters (p < 0.01) and showed that typical bar-displacement, greatest bar-velocity and peak-power were achieved at 85 and 90% 1RM (p < 0.001). Additionally greater average power was shown for 90 and 95% (p < 0.01) and greater work and vGRF were shown for 90, 95 and 100% than 85% 1RM (p < 0.05). Load had no significant effect on peak-vGRF and peak-RFD (p > 0.05). The results of this study, suggest 90% 1RM to be the most advantageous load to train explosive-force and to enhance power-outputs while maintaining technical efficiency in elite-weightlifters.

Effects of Pomegranate Juice Supplementation on Oxidative Stress Biomarkers Following Weightlifting Exercise

The aim of this study was to test the hypothesis that pomegranate juice supplementation would blunt acute and delayed oxidative stress responses after a weightlifting training session. Nine elite weightlifters (21.0 ± 1 years) performed two Olympic-Weightlifting sessions after ingesting either the placebo or pomegranate juice supplements. Venous blood samples were collected at rest and 3 min and 48 h after each session. Compared to the placebo condition, pomegranate juice supplementation attenuated the increase in malondialdehyde (−12.5%; p < 0.01) and enhanced the enzymatic (+8.6% for catalase and +6.8% for glutathione peroxidase; p < 0.05) and non-enzymatic (+12.6% for uric acid and +5.7% for total bilirubin; p < 0.01) antioxidant responses shortly (3 min) after completion of the training session. Additionally, during the 48 h recovery period, pomegranate juice supplementation accelerated (p < 0.05) the recovery kinetics of the malondialdehyde (5.6%) and the enzymatic antioxidant defenses compared to the placebo condition (9 to 10%). In conclusion, supplementation with pomegranate juice has the potential to attenuate oxidative stress by enhancing antioxidant responses assessed acutely and up to 48 h following an intensive weightlifting training session. Therefore, elite weightlifters might benefit from blunted oxidative stress responses following intensive weightlifting sessions, which could have implications for recovery between training sessions.

Diurnal variation of short-term repetitive maximal performance and psychological variables in elite judo athletes

Objectives: The aim of this study was to examine the effect of time of day on short-term repetitive maximal performance and psychological variables in elite judo athletes. Methods: Fourteen Tunisian elite male judokas (age: 21 ± 1 years, height:172 ± 7 cm, body-mass: 70.0 ± 8.1 kg) performed a repeated shuttle sprint and jump ability (RSSJA) test (6 m × 2 m × 12.5 m every 25-s incorporating one countermovement jump (CMJ) between sprints) in the morning (7:00 a.m.) and afternoon (5:00 p.m.). Psychological variables (Profile of mood states (POMS-f) and Hooper questionnaires) were assessed before and ratings of perceived exertion (RPE) immediately after the RSSJA. Results: Sprint times (p > 0.05) of the six repetition, fatigue index of sprints (p > 0.05) as well as mean (p > 0.05) jump height and fatigue index (p > 0.05) of CMJ did not differ between morning and afternoon. No differences were observed between the two times-of-day for anxiety, anger, confusion, depression, fatigue, interpersonal relationship, sleep, and muscle soreness (p > 0.05). Jump height in CMJ 3 and 4 (p < 0.05) and RPE (p < 0.05) and vigor (p < 0.01) scores were higher in the afternoon compared to the morning. Stress was higher in the morning compared to the afternoon (p < 0.01). Conclusion: In contrast to previous research, repeated sprint running performance and mood states of the tested elite athletes showed no-strong dependency of time-of-day of testing. A possible explanation can be the habituation of the judo athletes to work out early in the morning.