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 PHV:-1 to +1 years from PHV) were assigned to a Combined Training group (CTG) (n=20), a Plyometric Training group (PTG) (n=20) or a control group (CG) (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 at pre-training, post-training and 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% to 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.

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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 18:00 h. 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 06:00 h 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.

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BackgroundThe present study aimed to investigate the concomitant effects of Ramadan intermittent fast (RIF) and muscle fatigue on neuromuscular performances and reaction times in young trained athletes.MethodsEight karate players (17.2 ± 0.5 years) were tested on three sessions: during a control period (S1: one week before Ramadan), and during the first (S2) and the fourth week of RIF (S3). Dietary intake and anthropometric measurements were assessed before each session. During each test session, participants performed maximal voluntary isometric contractions (MVC) and a submaximal contraction at 75 % MVC until exhaustion (Tlim) of the right elbow flexors. Surface electromyography was recorded from biceps brachii muscle during MVC and Tlim. Simple (SRT) and choice (CRT) reaction times were evaluated at rest and just after Tlim in a random order.ResultsThe total daily energy (S2: +19.5 %, p < 0.05; S3: +27.4 %, p < 0.01) and water (S2: +26.8 %, p < 0.01; S3: +23.2 %, p < 0.05) intake were significantly increased during RIF. However, neither body mass nor body mass index was altered by RIF (F(2,14) = 0.80, p = 0.47 and F(2,14) = 0.78, p = 0.48, respectively). In addition, Tlim (F(2,14) = 2.53, p = 0.12), MVC (F(2,14) = 0.51, p = 0.61) and associated electrical activity (F(2,14) = 0.13, p = 0.88) as well as neuromuscular efficiency (F(2,14) = 0.27, p = 0.76) were maintained during RIF. Moreover, neither SRT nor CRT was affected by RIF (F(2,14) = 1.82, p = 0.19 and F(2,14) = 0.26, p = 0.78, respectively) or neuromuscular fatigue (F(1,7) = 0.0002, p = 0.98 and F(1,7) = 3.78, p = 0.09, respectively).ConclusionsThe present results showed that RIF did not adversely affect the neuromuscular performances and anthropometric parameters of elite karate athletes who were undertaking their usual training schedule. In addition, neither RIF nor neuromuscular fatigue poorly affects reaction times in elite karate athletes.

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