Effects of Vibrations on Gastrocnemius Medialis Tissue Oxygenation

COZA, A., B. M. NIGG, and J. F. DUNN. Effects of Vibrations on Gastrocnemius Medialis Tissue Oxygenation. Med. Sci. Sports Exerc., Vol. 43, No. 3, pp. 509-515, 2011. Purpose: Whole-body vibrations are known to affect muscle activity and tissue oxygenation, but some energetic aspects are still poorly understood. This study investigates the effects of whole-body vibration on gastrocnemius muscle oxygen utilization rate and tissue oxygenation dynamics during exercise. Methods: The effects of vibration on gastrocnemius medialis muscle oxygenation were investigated during a dynamic exercise on a sample of 16 active male subjects (age = 26.3 +/- 5.1 yr, mass = 71.2 +/- 4.8 kg (mean +/- SD)). Both arterially occluded (AO) and nonoccluded (N/O) conditions were investigated. Tissue oxygenation was monitored with a near-infrared spectrometer. Oxygen utilization rate and tissue oxygenation recovery were computed as the slopes of the regression line of the oxygenation decay and recovery, respectively. A fast Fourier transform (FFT) was used to determine the frequency spectrum of the oxygen saturation data. EMG activity was monitored using bipolar EMG electrodes. A windowed root mean square analysis was used to monitor the amplitude of the EMG signal. Results: A statistically significant increase of 15% (P < 0.05) in oxygen utilization rate was found for the vibration condition in the AO leg but not in the N/O leg. The oxygenation recovery rate for the vibration condition was 34% higher (P < 0.05) than that for the control condition. A low-frequency periodic oscillation (T approximate to 10 s) in the tissue oxygenation data was determined from the FFT spectrum. A statistically significant decrease in the oscillation frequency was noticed for the vibration condition compared with the control. Conclusions: Vibrations increased the oxygen utilization rate during a dynamic exercise. The oxygenation recovery rate increased with vibrations. The low-frequency oscillation of the oxygenation was attributed to the periodic changes in tissue blood flow, and this seems to be influenced by vibrations.