2015 Volume 22 Issue 1 Pages 22-29
The purpose of this study was to clarify the effect of transcutaneous electrical nerve stimulation (TENS) on muscular viscoelasticity utilizing muscle hardness (MH), pressure pain threshold (PPT), change of the straight leg raising (SLR) angle. These evaluation indexes were measured just before (T1) and immediately after TENS (T2), and at 10 minutes after the stimulation (T3). For the measurements, the difference values based on T1 were calculated as S1 (S1＝T−T1) and S2 (S2＝T3−T1). 40 healthy males were randomly allocated into four groups; placebo, low frequency (3 pps), mid frequency (30 pps), and high frequency (100 pps) groups and TENS was applied for 20 minutes. As a result, the S1 values for MH in the TENS groups were significantly higher than the placebo group (p＜0.01). The S1 and S2 values of both PPT and SLR angle in the TENS groups were significantly higher than the placebo group (p＜0.01). The relationship between PPT and SLR angle at S1 shows a positive correlation (r＝0.599, p＜0.01). The relationship between MH and SLR angle at S1 shows no significant correlation. This study suggests that TENS reduces the muscular viscoelasticity. However, it is considered that the reduction of muscular viscoelasticity is induced by the secondary effects of TENS, such as changes in inhibitory pain control and increases in peripheral circulation. The results of this study suggested that the PPT elevation is directly involved with the increase of SLR angle.
