Effects of different amplitudes (high vs. low) of whole-body vibration training in active adults.

The aim of this study was to evaluate the effects of two different amplitudes of whole-body vibrations on the development of strength, mechanical power of the lower limb, and body composition. Thirty-eight recreationally active participants took part in the study. Participants were divided in two experimental groups (low amplitude group [GL] = 2 mm; high amplitude group [GH] = 4 mm) and a control group. The experimental groups performed an incremental vibratory training, 2 days per week during 6 weeks. The frequency of vibration (50 Hz), time of work (60 seconds), and time of rest (60 seconds) were constant for GL and GH groups. All the participants were on the platform in a static semi-squat position. Maximum isokinetic strength, body composition, and performance in vertical jumps (squat and countermovement jumps) were evaluated at the beginning and at the end of the training cycle. A significant increase of isokinetic strength was observed in GL and GH at angular velocities of 60°.s(-1), 180°.s(-1) and 270°.s(-1). Total lean mass was significantly increased in GH (0.9 ± 1.0 kg). There were no significant changes in the total fat mass in any of the groups. Significant changes were not observed in different variables (height, peak power, and rate of force development) derived from the vertical jumps for any of the groups submitted to study. The vibration training, whatever the amplitude, produced significant improvements in isokinetic strength. However, high vibration amplitude training presents better adaptations for hypertrophy than the training with low vibration amplitude. In this sense, GH would be a better training if the practitioners want to develop both strength and hypertrophy of the lower limbs.