Effect of transcutaneous electrical acupoint stimulation on fatigue recovery of the quadriceps.

The aim of this study was to evaluate the effect of transcutaneous electrical acupoint stimulation (TEAS) at selected acupoints on enhancing the rate of muscle force recovery after strenuous knee extension/flexion exercise. Ten male and seven female healthy young adults participated in this study in which they performed isokinetic knee fatigue exercise on the Biodex System 3 ergometer on three separate days. After the familiarization trial on day 1, subjects underwent 15 min of either TEAS or pseudo-TEAS recovery treatment after the isokinetic exercise in the following two trials on days 2 and 3, respectively. The TEAS treatment was applied on four selected acupoints [Zusanli (ST36), Chenshan (BL57), Yanglingquan (GB34) and Sanyinjiao (SP6)] while the pseudo-TEAS treatment was applied to the points away from the true acupoints. Isometric knee extension peak torque was measured before and immediately after the test exercise, and again during the 15-min recovery period at 5-min intervals. Blood lactate and median power frequency (MF) of the vastus medialis, vastus lateralis and rectus femoris were also measured at the same time points. The results indicated that the TEAS treatment was significantly more effective than the pseudo-TEAS treatment in enhancing the rate of muscle force recovery (knee extension peak torque recovery after 15 min, from 155 to 195 Nm in TEAS group and from 155 to 182 Nm in the pseudo-TEAS group), but had no effect on lactate removal and MF restitution rate. It is proposed that pain control is a plausible mechanism to explain the benefit of TEAS treatment. As TEAS is a non-invasive and simple treatment, it is feasible to apply it during and immediately after training.