Effects of static stretching for different durations on muscle oxygen saturation and muscle blood flow in the stretched muscles

Abstract

In this study, we examined the effects of static stretching (SST) for different durations on muscle oxygen saturation (StO₂) and muscle blood flow (BF_mus) in the stretched muscles during and after SST. Nine healthy male subjects received passive SST of the wrist flexors. SST was performed for 10, 30, and 60 s. The StO₂ and BF_mus in the forearm flexor muscles were measured by near-infrared spectroscopy. BF_mus was determined from the rate of increase in total hemoglobin during venous occlusion. StO₂ decreased immediately at the start of stretching, and thereafter kept decreasing until the end of SST. StO₂ replenished rapidly after completion of SST and remained above the resting level during the recovery period. For all 3 durations of SST, the peak value of StO₂ during the recovery period after SST showed a significant increase above the resting value (p<0.01) (10-s SST: 72.5±2.8%, 30-s SST: 72.5±1.8%, 60-s SST: 73.0±2.2%). There was no significant difference in the increase in the peak values of StO₂ after SST among the 3 SST durations. For all durations of SST, BF_mus after SST increased significantly above the resting level (p<0.01) (10-s SST: 2.6±1.2 fold, 30-s SST: 2.8±1.6 fold, 60-s SST: 2.9±1.0 fold), but there was no significant difference in the increase of BF_mus after SST among the 3 SST durations. These results show that SST of wrist flexors for 10 s, 30 s, and 60 s induced an increase in StO₂ and BF_mus after SST, but the increase in StO₂ and BF_mus was not affected by SST duration.