UNIPEDAL POSTURAL BALANCE AND COUNTERMOVEMENT JUMPS AFTER A WARM-UP AND PLYOMETRIC TRAINING SESSION: A RANDOMIZED CONTROLLED TRIAL

Romero-Franco, N and Jimenez- Reyes, P. Unipedal postural balance and countermovement jumps after a warm-up and plyometric training session: A randomized controlled trial. J Strength Cond Res 29( 11): 3216-3222, 2015- The purpose of this study was to analyze the immediate effects of a plyometric training protocol on unipedal postural balance and countermovement jumps. In addition, we analyzed the effects of a warm-up on these parameters. Thirty-two amateur male sprinters ( 24.9 +/- 4.1 years; 72.3 +/- 10.7 kg; 1.78 +/- 0.05 m; 22.6 +/- 3.3 kg. m-2) were randomly sorted into a control group ( n = 16) ( they did not perform any physical activity) and a plyometric training group ( n = 16) ( they performed a 15-minute warm-up and a high-intensity plyometric protocol consisting of 10 sets of 15 vertical jumps). Before and after the warm-up, and immediately after and 5 minutes after the plyometric protocol, all athletes indicated the perceived exertion on calf and quad regions on a scale from 0 ( no exertion) to 10 ( maximum exertion). They also carried out a maximum countermovement jump and a unipedal postural balance test ( athletes would remain as still as possible for 15 seconds in a left leg and right leg support stance). Results showed that, in the plyometric group, length and velocity of center-of- pressure movement in right leg support stance increased compared with baseline ( p = 0.001 and p = 0.004, respectively) and to the control group ( p = 0.035 and p = 0.029, respectively) immediately after the plyometric protocol. In addition, the countermovement jump height decreased right after the plyometric protocol ( p, 0.001). The perceived exertion on calf and quad regions increased after the plyometry ( p, 0.001). Five minutes later, these parameters remained deteriorated despite a slight recovery ( length: p = 0.044; velocity: p = 0.05; countermovement jump height: p, 0.001; local exertion: p, 0.001). Data also showed that countermovement jump height improved after the warm- up ( p = 0.021), but unipedal postural balance remained unaltered. As a conclusion, high-intensity plyometric exercises blunt unipedal postural balance and countermovement jump performance. The deterioration lasts at least 5 minutes, which may influence future exercises in the training session. Coaches should plan the training routine according to the immediate effects of plyometry on postural balance and vertical jumps, which play a role in injury prevention and sports performance.