The Effects of Whole-Body-Vibration on the Musculoskeletal System in Female Rats

Whole-body-vibration training has been promoted as an efficient and safe alternative for resistance and exercise training, even if performed to exhaustion; the increases in heart rate, blood pressure, and oxygen uptake during whole-body-vibration are mild, so that cardiovascular risks from whole-body-vibration in older adults are negligible. PURPOSE: To evaluate the effects of whole-body-vibration on the musculoskeletal system of 6-month old female rats. METHODS: Twenty 6-month old female 344 Fischer rats were randomized by weight into two groups (vibration n = 10 or control n = 10). Rats in the vibration group (n = 10) were placed inside individual 5″× 11″ × 6″ compartments attached to a Pneu-Vibe vibration platform (Pneumex, Sandpoint, ID). This group received 36 minutes of high amplitude (10mm peak to peak) vibration per day five days per week for 13 weeks. The vibration intervention consisted of 6 five minute cycles. Each minute consisted of 35 seconds at 30Hz, 25 seconds at 40Hz, and five seconds at 50Hz. Each five minute cycle was followed by a one minute rest interval. A one-way analysis of variance was conducted to evaluate between-subjects effects for body composition and bone mass. RESULTS: Whole-body-vibration resulted in significant body composition differences between the whole-body-vibration and body-weight-matched control group. Dual x-ray absorptiometry (DXA) whole body scans revealed that the whole-body-vibration group weighed approximately 10% less [222 (g) vs. 207 (g), p. ≤ .03] and had less body fat [26.8 (g) vs. 20.6 (g), p. ≤.02] and a lower percent body fat [10.2% vs. 12%, p. ≤ .05] than the age matched controls. No differences were observed for total lean mass, total body BMC or BMD. Regional high resolution DXA scans of the lumbar spine (L1-4) revealed that the whole-body-vibration group had significantly greater BMC [.33 (g) vs .26 (g) p. ≤.01] and BMD [.21 (g/cm2) vs .19 (g/cm2), p. ≤ .01] than the control group. Additionally, no differences were observed in the amount of food consumed by either group each week [88 (g) vs. 84 (g), p ≥ .05]. CONCLUSION: These findings suggest that whole-body-vibration training may have potential beneficial effects on body composition and BMD at the spine.