Effects of Eccentric Contractions Induced Electrical Stimulation Training System on Quadriceps Femoris Muscle

Abstract

We developed an eccentric contraction induced electrical stimulation (ES) training system. The purpose of this study was to investigate whether the eccentric contraction induced ES enhance the knee extension torque compared with typical ES. Twenty-two young untrained men (age: 23 ± 3 years) in the acute response trial (single training) and seven untrained men in the long period training trial (for 6 weeks) were studied. We measured muscle thickness and knee extension torque evoked by ES with eccentric contraction training system (ES + ECC) or ES alone for the quadriceps muscle of men. The levels of pain and discomfort were evaluated using numeric rating scale (NRS) and heart rate variability. The knee extension torque of ES + ECC was higher than that of ES alone in the acute response trial. There were no significant differences in the levels of pain and discomfort between ES and ES + ECC. Additionally, ES + ECC training for 6 weeks was effective on the quadriceps muscle thickness and knee extension torque. In contrast, the ES alone training failed to increase muscle thickness and knee extension torque. These results suggest that eccentric contraction induced ES would have the potential to become an effective intervention to promote muscle strengthening.

The effect of neuromuscular electrical stimulation on muscle EMG activity and the initial phase rate of force development during tetanic contractions in the knee extensor muscles of healthy adult males

“…In addition, the practical level has not been studied. NMES should be used carefully so as not to cause pain 20,21 ) . Our previous study suggested that the levels of pain caused by NMES depend on the intervention intensity, and NMES at 20% of MVIC torque level caused less pain 21 ) .…”

“…NMES should be used carefully so as not to cause pain 20,21 ) . Our previous study suggested that the levels of pain caused by NMES depend on the intervention intensity, and NMES at 20% of MVIC torque level caused less pain 21 ) . Therefore, the optimal strength to improve RFD should be investigated at or below NMES of 20% of MVIC torque level so that everyone can tolerate the pain.…”