Effects of controlled whole-body vibration training on reducing risk of falls among young adults with obesity

Introduction: Among people with obesity, several factors increase the risk of falls: an abnormal body mass distribution, muscle weakness, and postural instability. Although standard exercise-based training could change these factors, a significant portion of people with obesity may be unable or unwilling to comply with long duration and high intensity training programs. Therefore, alternative training methods are highly demanded. Growing evidence supports that controlled whole-body vibration (CWBV) training can reduce risk of falls among older adults. No study has yet investigated the potential effect of CWBV training on reducing risk of falls among obese populations. The purpose of this study was to systematically investigate the overall effectiveness and feasibility of CWBV training on young obese populations. Focus was placed on the impact of a 6-week CWBV training on reducing body fat percentage, improving muscle strength, and enhancing dynamic gait stability. Methods: Eighteen young adults with obesity participated in the experiment and were randomized into two groups: training or control. Participants in the training group received CWBV training 3 days a week for 6-weeks while standing on a side-alternating vibration platform. Training consisted of 5-repetititions of 1-minute vibration followed by 1-minute rest. The vibration frequency was 25 Hz and an amplitude of 10.8 mm. The control group followed the same training procedure except for a 0-mm amplitude. Prior to (pre-training) and following (post-training) the 6-week training, participants were evaluated for their risk of falls in terms of body composition, muscle strength, and dynamic gait stability in response to an unannounced slip during gait. Results: All measurements were not different between groups at pre-training evaluation. The body composition parameters did not show any significant difference associated with the two main factors (i.e., group: training vs. control and time: pre-training vs. post-training) and their interaction (p \u3e 0.05 for all). For muscle strength, no significant main effect for time or group was detected, however a significant time × group interaction effect was seen for the knee extensor strength capacity (p \u3c 0.05). Dynamic gait stability in response to the slip demonstrated a significant time × group interaction (p \u3c 0.05) without significant main factors effect (p \u3e 0.05). The improved stability in the training group was resulted from the improved center of mass position and velocity (marginal time × group interaction effect for both center of mass position and velocity: p = 0.060 for position and p = 0.062 for velocity). A similar time × group interaction effect was also observed for the trunk angle after slip (p = 0.058). Discussion: A 6-week CWBV may not be effective to change the body composition among young individuals with obesity. The CWBV training could improve muscle strength, particularly knee extensor strength. The 6-week training course did increase the dynamic gait stability during the slip in the training group. The findings from this study could provide useful guidance to design effective fall prevention programs for people affected by obesity