Long-Term Whole-Body Vibration on Knee Extensor Function: A Randomized Clinical Trial

Introduction. The whole-body vibration platform (WBV) has shown positive effects on muscle aspects of strength and power due to the tonic vibration reflex. However, there is still disagreement about the parameters to be used.Objective. To investigate the effect of two WBV frequencies (30 and 45 Hz) on maximum isometric and resistance torques of the knee extensors, and power in two jumping modalities, Squat Jump (SJ) and Counter-Movement Jump (CMJ).Methods. Randomized clinical trial, composed of 40 healthy young adults of both sexes, aged between 18 and 30 years, not practicing systematic physical activities and randomized into three interventions according to the frequency of WBV: 30 Hz (F30), 45 Hz (F45) and sham (SG). The outcomes evaluated were the maximum isometric torque and quadriceps resistance measured by a traction dynamometer, and the quadriceps power obtained in two jumping modalities: squat and countermovement jump. The WBV intervention lasted 12 weeks, 2x weekly. After a familiarization session the outcomes were measured before and after the interventions. For statistical analysis the percentage of change between pre and post measures was used (Delta percentage).Results. No statistical differences were observed in the percentage deltas for any of the outcomes evaluated.Conclusions. WBV, regardless of the frequency adopted, did not influence the aspects of muscle function.