Effects of whole-body vibration training on bone-free lean body mass and muscle strength in young adults

Abstract

Resistance training with whole-body vibration (WBV) is becoming increasingly popular as an alternative to conventional resistance training or as supplementary training. Despite its growing popularity, the specific effects of WBV training on muscle morphology, strength, and endurance are not well understood, particularly in young adults. The aim of this study was to determine the effects of WBV training on bone-free lean body mass (BFLBM), and maximal muscle strength and endurance in healthy, untrained, young individuals. Eighteen healthy men and women (21-39 years) were randomly assigned to either a body-weight exercise with WBV (VT) group or a control exercise group without WBV (CON). Participants performed eight exercises per 40- min session on a vibration platform (VT group, frequency = 30-40 Hz; amplitude = 2 mm) twice weekly for 12 weeks. Anthropometry, total and regional BFLBM (trunks, legs, and arms) measured by dual- energy X-ray absorptiometry, and muscle strength and endurance measured by maximal isometric lumbar extension strength, maximal isokinetic knee extension and flexion strength, and the number of sit- ups performed were recorded and compared. Two-way repeated-measures ANOVA revealed no significant changes between the groups in any of the measured variables. We conclude that 12 weeks of body weight vibration exercise compared to body weight exercise alone does not provide meaningful changes to BFLBM or muscle performance in healthy young adults. Key pointsA randomized controlled trial was conducted to investigate the effects of body-weight exercise combined with whole-body vibration on bone-free lean body mass and maximal muscle strength and endurance in healthy young individuals.Body-weight exercises for lower extremities and trunk muscles were performed twice weekly for 12 weeks.Participants in the exercise with whole-body vibration group increased the vibration frequency from 30, 35, to 40 Hz at a constant amplitude of 2 mm during the trial.A 12-week body-weight exercise program with whole-body vibration did not significantly increase bone-free lean body mass in healthy young individuals, and no additional increases in maximal muscle strength and endurance were observed.

Keywords: exercise; lean body mass; untrained; vibration; young.

Figure 1.

The 8 body-weight exercises of the 12-week training program used in the present study. The top images show the four lower extremity exercises, while the bottom images show the four trunk exercises. The lower extremity and trunk exercises were performed twice weekly for 30 sec/set on the WBV platform with intermittent rest periods of 60 sec. Each exercise was performed for 3 sets, except for lower extremity exercise 4 and trunk exercise 4, which were performed for 2 sets on each limb. In static exercises, the knee and hip joints were in the following positions during the four lower-body exercises: exercise 1, knee angle, 60 degrees knee extension (full extension = 0 degree), and hip angle, 60 degrees hip joint flexion (static position); exercise 2, knee angle, 90 degrees knee extension, and hip angle, 90 degrees hip joint flexion; exercise 3, knee angle, 90 degrees knee flexion, and hip angle, 90 degrees hip joint flexion; and exercise 4, knee angle, 90 degrees knee extension (static position). Only trunk exercise 2 was performed statically throughout the trial. During the dynamic exercises, participants went to the static position, and then returned to the relaxed position. During trunk exercise 3, participants were instructed to lean their upper body backward with their arms straight, and investigators often touched participants’ lower back muscles to ascertain the muscles were contracted properly. In dynamic exercises, participants moved their upper body forward to backward

Figure 2.

The flow of participants through the trial. VT, vibration training; CON, control; WBV, whole-body vibration