ELECTRICAL STIMULATION IS VASTLY SUPERIOR TO ACTIVE EXERCISE AS A RECOVERY TREATMENT FOLLOWING ACUTE MUSCLE FATIGUE
Lu, P.-T., & Tsai, M.-W. (2014). Effects of active recovery and electrical stimulation on muscle fatigue recovery. Medicine & Science in Sports & Exercise, 46(5), Supplement abstract number 1460.
“Muscle fatigue limits a person’s ability to maintain at high exercise and/or training level. Active recovery and electrical stimulation are two common clinical interventions used to help fatigue recovery. Both interventions are based on the mechanism that increase blood flow and circulation to speed up the recovery process. Up to date, however, it is still under debate which intervention can better help the recovery of muscle fatigue.”
This investigation compared the effects of active recovery and low-frequency electrical stimulation on muscle-fatigue recovery. Ss (N = 6) were randomly assigned to one of two active-recovery groups, i) active-exercise recovery, and ii) electrical stimulation. Ss were asked to perform repetitive voluntary contractions (7 x 10-repetition sets: a repetition consisted of 10 seconds of contraction and two seconds of relaxation) to fatigue with the biceps brachii of the non-dominant arm. Immediately after the fatigue protocol, Ss in the active recovery group received an elbow flexion exercise (6 seconds of contraction and 2 seconds of relaxation) for 20 minutes. The electrical stimulation group received 20 minutes of low-frequency electrical stimulation (5Hz, motor level, 6 seconds on – 2 seconds off). Maximal voluntary contraction and a visual analogue scale for pain were evaluated before and after the fatiguing exercise, after the recovery period (post-intervention), and a follow-up at 5, 10, and 30 minutes after the recovery period.
Average force recovery was 21.6% in the active recovery and 66.5% in the electrical stimulation treatments. Thirty minutes after the recovery period, the muscle forces in the electrical stimulation group returned to almost the same as before fatigue (97.9%), while there was only 27.3% of recovery in the active-exercise recovery group. The visual analogue scale for pain was 5.4 after the fatiguing exercise and 2.3 at 30 minutes of the follow-up in both groups.
Implication. Electrical stimulation as a recovery treatment is vastly superior to active-exercise after acute muscle fatigue.