Novel Strength Training Using Electrical Stimulation
【Supercategory：7. DESCENTE SPORTS SCIENCE Subcategory：7.37 Vol.37】
ABSTRACT
Muscle fatigue is a major limiting factor in the use of functional electrical stimulation (FES) for strength training. FES induces rapid muscle fatigue because muscle fibres have to be activated at unnaturally high frequencies to generate functional contractions. To overcome this weakness, we have proposed a unique method called Spatially Distributed Sequential Stimulation (SDSS), and tested its advantage in isometric contractions for major leg muscles. The purpose of this project was to test if SDSS was capable of reducing fatigue for isokinetic knee extension. Eleven healthy volunteers participated. Intermittent stimulation (0.3-s on : 0.7-s off; 120-s total) was delivered to the knee-extensors using the conventional method (Single-Electrode-Stimulation; SES)(1 active electrode; 40 Hz) and SDSS (4 active electrodes, each stimulated at 10 Hz; composite 40 Hz stimulation) in separate trials, to generate isometric (0 ﾟ/s) and isokinetic (180 ﾟ/s) torque. Measures of fatigability included fatigue index (FI, average peak torque of last 10 contractions ÷ average peak torque of initial 10 contractions) and torque peak mean (TPM, average peak torque of all 120 contractions ÷ average peak torque of initial 10 contractions). FIs were significantly higher for SDSS than SES during isometric (SES = 0.616 ± 0.092; SDSS = 0.761± 0.165; p = 0.002) and isokinetic (SES = 0.645 ± 0.147; SDSS = 0.800 ± 0.175; p = 0.002) contractions. TPM values were significantly higher for SDSS than SES during isometric (SES = 0.781 ± 0.068; SDSS = 0.846 ± 0.108; p = 0.022) and isokinetic (SES = 0.788 ± 0.103; SDSS = 0.883 ± 0.075; p = 0.014) contractions. We have reproduced previous findings that SDSS reduces fatigability of isometric contractions compared to similar sized contractions generated by SES. Further, we have extended these findings to isokinetic conditions. The present findings are important for facilitating the utility of FES for use in strength training.
DESCENTE SPORTS SCIENCE Vol.37/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
Muscle fatigue is a major limiting factor in the use of functional electrical stimulation (FES) for strength training. FES induces rapid muscle fatigue because muscle fibres have to be activated at unnaturally high frequencies to generate functional contractions. To overcome this weakness, we have proposed a unique method called Spatially Distributed Sequential Stimulation (SDSS), and tested its advantage in isometric contractions for major leg muscles. The purpose of this project was to test if SDSS was capable of reducing fatigue for isokinetic knee extension. Eleven healthy volunteers participated. Intermittent stimulation (0.3-s on : 0.7-s off; 120-s total) was delivered to the knee-extensors using the conventional method (Single-Electrode-Stimulation; SES)(1 active electrode; 40 Hz) and SDSS (4 active electrodes, each stimulated at 10 Hz; composite 40 Hz stimulation) in separate trials, to generate isometric (0 ﾟ/s) and isokinetic (180 ﾟ/s) torque. Measures of fatigability included fatigue index (FI, average peak torque of last 10 contractions ÷ average peak torque of initial 10 contractions) and torque peak mean (TPM, average peak torque of all 120 contractions ÷ average peak torque of initial 10 contractions). FIs were significantly higher for SDSS than SES during isometric (SES = 0.616 ± 0.092; SDSS = 0.761± 0.165; p = 0.002) and isokinetic (SES = 0.645 ± 0.147; SDSS = 0.800 ± 0.175; p = 0.002) contractions. TPM values were significantly higher for SDSS than SES during isometric (SES = 0.781 ± 0.068; SDSS = 0.846 ± 0.108; p = 0.022) and isokinetic (SES = 0.788 ± 0.103; SDSS = 0.883 ± 0.075; p = 0.014) contractions. We have reproduced previous findings that SDSS reduces fatigability of isometric contractions compared to similar sized contractions generated by SES. Further, we have extended these findings to isokinetic conditions. The present findings are important for facilitating the utility of FES for use in strength training.
DESCENTE SPORTS SCIENCE Vol.37/THE DESCENTE AND ISHIMOTO MEMORIAL FOUNDATION FOR THE PROMOTION SPORTS SCIENCE
| Researcher | Kei Masani |
|---|---|
| University or institution | Rehabilitation Engineering Laboratory, Toronto Rehabilitation Institute - University Health Network Rehabilitation Engineering Laboratory, Institute of Biomaterials and Biomedical Engineering, University of Toronto |
Keywords
Electrical Stimulation, Strength Training, Muscle Fatigue, Lower Limb, Human