The limitations of the present study should be discussed. First, the study period was relatively short (6 months). Long-term exercise is needed to reduce the lifetime risk of falls and fall-related fractures. Second, the number of study subjects was too small to obtain significant results regarding the incidence of falls, even though statistically significant results regarding physical function were obtained. Third, we did not evaluate vitamin D insufficiency/deficiency by measuring serum 25(OH)D levels, and we did not provide calcium/vitamin D supplements to the subjects. In Japan, vitamin D supplementation is uncommon, and measurement of serum 25(OH)D levels is not covered by health insurance. Because low serum levels of 25(OH)D are correlated with an increased risk of falls and vitamin D supplementation reduces the incidence of falls in elderly adults,20–22 evaluating vitamin D status is important. Fourth, because there was no control group in which participants performed either WBV exercise or squat training, the effect of WBV exercise alone on physical function remains unclear. Fifth, because of the open-label nature of this study, physical function was not assessed in a blinded manner, so its outcome might have