Effect of electro-motor stimulation on the power production of a maximally stretched muscle

Abstract

The effect of electro-motor stimulation (EMS) upon the increase in power production of the tibialis anterior muscle (TA) of healthy individuals in both the maximally stretched (ST group) and shortened (SH group) positions was investigated. The effect of cross-education upon the contralateral muscle was also examined. EMS with a frequency of 50 hertz, a duration of 0.2 milliseconds, and a rectangular wave was applied for ten seconds with a ten second interval and repeated ten times per day for six weeks. The ST group gained significantly 9.4%, 15.5%, and 16.4% after two, four, and six weeks of stimulation, respectively, while the SH group also showed a significant gain of 5.1%, 8.3%, and 3.0%. When comparing the two groups at the end of the six-week period the ST group's gain was significantly greater. The increase of power production of the unstimulated TA was 5.5%, 8.0%, and 4.3% in the ST group, which was significant at the end of the second and fourth week of stimulation. The SH group, however, registered a non-significant increase of -2.7%, 1.8%, and -1.5%. Comparison between the two groups showed a significant increase in the power production of the unstimulated TA in the ST group commencing the second week. Conclusion: EMS of the TA in the maximally stretched position is a more effective way to gain strength.