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Graja, A, Kacem, M, Hammouda, O, Borji, R, Bouzid, MA, Souissi, N, and Rebai, H. Physical, biochemical, and neuromuscular responses to repeated sprint exercise in eumenorrheic female handball players: effect of menstrual cycle phases. J Strength Cond Res 36(8): 2268-2276, 2022-Very few studies have been interested in the relationship between ovarian hormones and physiological function in female athletes. The aim of this study was to assess the effect of menstrual phases (MP) on physical, neuromuscular, and biochemical responses after repeated sprint exercise (RSE) in female handball players. Ten eumenorrheic athletes (22.5 ± 1.5 years, 1.70 ± 0.04 m) participated in 3 study visits (follicular phase [FP], luteal phase [LP], and premenstrual phase [PMP]). During each MP, they performed 20 × 5-second cycle sprints interspersed with 25 seconds of rest. Maximal voluntary contraction (MVC) tests of the knee extensor muscles at 90° of knee flexion were performed before and after RSE. Peak force and electromyography (EMG) signals were measured during the MVC tests. Blood samples were collected before and 3 minutes after each session. The percentage of decrement in peak power output over the 20 × 5-second cycle test (i.e., fatigue index) calculated between sprints 1 and 20 decreased significantly during PMP (-43.3% ± 5.7%) but not in LP (-39.2% ± 7.7%) compared with FP (-32.44% ± 6.3%) ( p0.05). Moreover, no significant difference was found between MP in all frequency components of EMG before RSE ( p0.05). Maximal voluntary contraction, neuromuscular efficiency, and median frequency values of vastus lateralis and rectus femoris were significantly decreased in PMP compared with FP and LP ( p0.05). Creatine kinase (CK) levels were significantly higher in PMP compared with FP and LP after RSE ( p0.05). These findings suggest that RSE induces more peripheral fatigue associated with muscle damage in PMP. This might be attributable to hormonal variation across MP. Therefore, FP seems to be the right time for intense training to improve strength performance.

Fathi, A, Hammami, R, Moran, J, Borji, R, Sahli, S, and Rebai, H. Effect of a 16-week combined strength and plyometric training program followed by a detraining period on athletic performance in pubertal volleyball players. J Strength Cond Res 33(8): 2117-2127, 2019-The purpose of this study was to determine the effects of 16 weeks of combined strength and plyometric training or plyometric training alone and how a detraining program can modify adaptations in response to the training stimulus. Sixty male volleyball players (circa peak-height-velocity [PHV]: -1 to +1 year from PHV) were assigned to a combined training group (CTG) (n = 20), a plyometric training group (PTG) (n = 20), or a control group (n = 20). The experimental groups (CTG and PTG) participated in training twice weekly for 16 weeks. Thigh muscle volume, body fat, flexibility, sprint, jump height, and medicine ball throw were measured before and after the intervention and after the period of detraining. Respectively, the CTG and PTG showed increases in thigh muscle volume (effect size: 0.71 and 0.42) and decreases in body fat (-0.42 and -0.34), as well as improvements in 5-m sprint (-0.69 and -0.46), 10-m sprint (-0.31 and -0.3), lower-body muscle power (0.44 and 0.36), and upper-body muscle power (1.32 and 0.7). After the detraining period, all groups maintained previously attained muscle power (6.79-9.87%; p < 0.001). In conclusion, combined strength and plyometric training provided better improvements than plyometric training only. The combination of strength and plyometric training is a time-effective training modality that confers improvements in physical performance measures, muscle size, and body fat. A temporary period of detraining may not undermine performance gains in pubertal volleyball players.