Search Results

You are looking at 1 - 3 of 3 items for :

  • Author: Tarak Driss x
  • Sport and Exercise Science/Kinesiology x
  • International Journal of Sports Physiology and Performance x
  • Refine by Access: All Content x
Clear All Modify Search
Restricted access

Hamdi Jaafar, Majdi Rouis, Elvis Attiogbé, Henry Vandewalle, and Tarak Driss

Purpose:

To verify the hypothesis that the peak power (PP) of a Wingate test (WT) is an underestimation of maximal power (Pmax) computed from the force–velocity test (FVT), to examine possible fatigue effect on Pmax, and to investigate the effect of load on mean power (MP) and fatigue index (FI) during a WT in trained and recreational men.

Methods:

Ten recreational (22.9 ± 1.7 y, 1.81 ± 0.06 m, 73.3 ± 10.4 kg) and 10 highly trained subjects (22.7 ± 1.4 y, 1.85 ± 0.05 m, 78.9 ± 6.6 kg) performed 2 WTs with 2 loads (8.7% and 11% of body mass [BM]) and an FVT on the same cycle ergometer, in randomized order.

Results:

Optimal load was equal to 10% BM in recreational participants. Given the quadratic relationship between load and power, the underestimation of Pmax was lower than 10% for the average values of trained and recreational participants with both loads. However, PP with a load equal to 8.7% BM was a large underestimation (~30%) of Pmax in the most powerful individuals. In addition, PP was not greater than Pmax of FVT for the same load. FI was independent of the load only if it was expressed relative to PP. The optimal load for MP during WT was close to the optimal load for PP.

Conclusions:

The optimal load for WT performance should be approximately equal to 10% BM in recreational subjects. In powerful subjects, the FVT appears to be more appropriate in assessing maximal power, and loads higher than 11% BM should be verified for the WT.

Restricted access

Mohamed Romdhani, Nizar Souissi, Yassine Chaabouni, Kacem Mahdouani, Tarak Driss, Karim Chamari, and Omar Hammouda

Purpose: To investigate the effects of napping after partial sleep deprivation (PSD) on reaction time, mood, and biochemical response to repeated-sprint exercise in athletes. Methods: Nine male judokas performed 4 test sessions in a counterbalanced and randomized order. Participants accomplished 1 control session after a normal sleep night (NSN) and 3 after PSD with (1) no nap, (2) ∼20-min nap (N20), and (3) ∼90-min nap (N90) opportunities. Test sessions included the running-based anaerobic sprint test, reaction time, Hooper index, and Epworth Sleepiness Scale. Muscle-damage biomarkers and antioxidant status were evaluated before and after exercise. Results: PSD decreased maximum (P < .001, d = 1.12), mean (P < .001, d = 1.33), and minimum (P < .001, d = 1.15) powers compared with NSN. However, N20 and N90 enhanced maximum power compared with PSD (P < .05, d = 0.54; P < .001, d = 1.06, respectively). Minimum power and mean power increased only after N90 (P < .001, d = 1.63; P < .001, d = 1.16, respectively). Epworth Sleepiness Scale increased after PSD (P < .001, d = 0.86) and decreased after N20 (P < .001, d = 1.36) and N90 (P < .001, d = 2.07). N20 reduced multiple-choice reaction time (P < .001, d = 0.61). Despite performance decrement, PSD increased postexercise aspartate aminotransferase (P < .001, d = 4.16) and decreased glutathione peroxidase (P < .001, d = 4.02) compared with NSN. However, the highest performances after N90 were accompanied with lesser aspartate aminotransferase (P < .001, d = 1.74) and higher glutathione peroxidase (P < .001, d = 0.86) compared with PSD. Conclusions: Napping could be preventive against performance degradation caused by sleep loss. A short nap opportunity could be more beneficial when the subsequent effort is brief and requires frequent decision making. However, a longer nap opportunity could be preventive against muscle and oxidative damage, even for higher performances.

Restricted access

Mohamed Romdhani, Nizar Souissi, Imen Moussa-Chamari, Yassine Chaabouni, Kacem Mahdouani, Zouheir Sahnoun, Tarak Driss, Karim Chamari, and Omar Hammouda

Purpose: To compare the effect of a 20-minute nap opportunity (N20), a moderate dose of caffeine (CAF; 5 mg·kg−1), or a moderate dose of caffeine before N20 (CAF+N) as possible countermeasures to the decreased performance and the partial sleep deprivation–induced muscle damage. Methods: Nine male, highly trained judokas were randomly assigned to either baseline normal sleep night, placebo, N20, CAF, or CAF+N. Test sessions included the running-based anaerobic sprint test, from which the maximum (P max), mean (P mean), and minimum (P min) powers were calculated. Biomarkers of muscle, hepatic, and cardiac damage and of enzymatic and nonenzymatic antioxidants were measured at rest and after the exercise. Results: N20 increased P max compared with placebo (P < .01, d = 0.75). CAF+N increased P max (P < .001, d = 1.5; d = 0.94), P min (P < .001, d = 2.79; d = 2.6), and P mean (P < .001, d = 1.93; d = 1.79) compared with placebo and CAF, respectively. Postexercise creatine kinase increased whenever caffeine was added, that is, after CAF (P < .001, d = 1.19) and CAF+N (P < .001, d = 1.36). Postexercise uric acid increased whenever participants napped, that is, after N20 (P < .001, d = 2.19) and CAF+N (P < .001, d = 2.50) and decreased after CAF (P < .001, d = 2.96). Conclusion: Napping improved repeated-sprint performance and antioxidant defense after partial sleep deprivation. Contrarily, caffeine increased muscle damage without improving performance. For sleep-deprived athletes, caffeine before a short nap opportunity would be more beneficial for repeated sprint performance than each treatment alone.