| Whole Body Vibration (WBV) is becoming increasingly popular for bone maintenance and muscle strengthening applications. Low-magnitude WBV (<1 G) has shown evidence for increasing bone density, bone formation rate, as well as bone strength. High- magnitude WBV (>1 G) has also been found to increase muscle size, strength, and reaction time. Our study is the first to examine the biomechanical effects of both low-magnitude and high-magnitude WBV on tendons and ligaments. It was hypothesized that both low vibration (0.3 G) and high vibration (2 G) would strengthen ligament and tendon but that low vibration would be more effective because high vibration may be near the threshold of tissue overloading. A total of 36 rats were divided into three groups: control, low-vibration (0.3 G), high-vibration (2 G). Experimental groups were vibrated 20 minutes a day, 5 days a week, over 5 weeks with a 30 Hz sinusoidal stimulus. Tensile testing and histological examination were carried out on the rats' Achilles tendons, patellar tendons, anterior cruciate ligaments, and medial collateral ligaments. Differences in biomechanical data and histology of the high-vibration group suggest that high-magnitude vibration may be harmful to ligaments and tendons. No significant differences in the biomechanical properties were observed with the low-vibration group relative to the control suggesting that little effect exists or that a longer duration or higher-magnitude stimulus may be required to observe significant effects. |
