The Effect of Whole Body Vibration Training on Bone and Muscle Function in Children With Osteogenesis Imperfecta.

CONTEXT: Osteogenesis imperfecta (OI) is associated with reduced muscle size, dynamic muscle function, and mobility.

OBJECTIVE

To assess the effect of whole body vibration (WBV) on bone density and geometry, muscle size and function, mobility, and balance in children with OI.

DESIGN

Randomized controlled pilot trial.

SETTING

Tertiary pediatric research center.

PARTICIPANTS

Twenty-four children (5 to 16 years) with OI types 1, 4, and limited mobility [Child Health Assessment Questionnaire (CHAQ) score ≥ 0.13] recruited in sex- and pubertal stage-matched pairs. Incident fractures in two boys (WBV arm) led to exclusion of two prepubertal pairs.

INTERVENTION: Five months of WBV training (3 × 3 minutes twice daily) or regular care.

MAIN OUTCOME MEASURES: Bone and muscle variables measured by dual-energy X-ray absorptiometry (spine, hip, total body) and peripheral quantitative computed tomography (tibia). Mobility assessed by 6-minute walk tests and CHAQ; dynamic muscle function by mechanography.

RESULTS

All participants had reduced walking distances and muscle function (P < 0.001). Body mass index z score was associated with higher CHAQ scores (ρ + 0.552; P = 0.005) and lower walking and two-leg jumping performance (ρ - 0.405 to -0.654, P < 0.05). The WBV and control groups did not differ in the 5-month changes in bone. Total lean mass increased more in the WBV group [+1119 g (+224 to +1744)] compared with controls [+635 g (-951 to +1006)], P = 0.01, without improving mobility, muscle function, or balance.

CONCLUSIONS

The increase in lean mass without changes in muscle function or bone mass suggests reduced biomechanical responsiveness of the muscle-bone unit in children with OI.