The effects of whole‐body vibration training and vitamin D supplementation on muscle strength, muscle mass, and bone density in institutionalized elderly women: A 6‐month randomized, controlled trial

Randomized controlled trial in institutionalized, postmenopausal elderly women over 70 years of age in the Leuven, Belgium area. Four active groups were compared: WBV plus 1600 IU/day vitamin D3 (n=26), no WBV plus 1600 IU/day (n=28), WBV plus 880 IU/day (n=29), and no WBV plus 880 IU/day (n=28).

Participants received oral vitamin D3 (cholecalciferol) for 6 months at either 1600 IU/day or 880 IU/day, with the vitamin D regimen tested with or without whole-body vibration training. All groups also received calcium 1000 mg/day.

Whole-body vibration added no additional musculoskeletal benefit over vitamin D supplementation alone, and the higher vitamin D dose increased circulating 25(OH)D more but did not improve muscle strength or hip BMD further. In the WBV plus 1600 IU/day group, within-group changes over 6 months included isometric muscle strength +4.48%, dynamic muscle strength +7.94%, muscle mass -0.26%, hip BMD +0.75%, and serum vitamin D +171.27%. However, between WBV and no-WBV groups there were no significant differences for isometric strength (+3.86%, 95% CI -1.32 to 9.05; p=.182), dynamic strength (+1.50%, -4.79 to 7.78; p=.881), muscle mass (-0.14%, -1.35 to 1.06; p=.706), hip BMD (-0.14%, -0.99 to 0.72; p=.949), or serum vitamin D (-6.56%, -84.60 to 71.46; p=.628). Overall, dynamic strength, hip BMD, and serum vitamin D improved over time, but the intervention comparisons were not superior for WBV or high-dose vitamin D.

Modest per-arm sample sizes and a 6-month follow-up limit power to detect group differences and long-term effects. The population was restricted to frail institutionalized elderly women in one Belgian setting, which limits generalizability. All groups received calcium and active intervention, so the independent effects of vitamin D dose versus WBV are only partially separable.