Characteristics of Surface Electromyography During Strength Training of 12 weeks

12주 근력강화훈련 동안 표면근전도 신호의 특성

  • Shin, Hwa-Kyung (Dept. of Rehabilitation Therapy, The Graduate School, Yonsei University) ;
  • Cho, Sang-Hyun (Dept. of Physical Therapy, College of Health Science, Yonsei University, Institute of Health Science, Yonsei University) ;
  • Cha, Kwang-Suk (Dept. of Sport Science, College of Natural Science, Konkuk University)
  • 신화경 (연세대학교 대학원 재활학과) ;
  • 조상현 (연세대학교 보건과학대학 물리치료학과 및 보건과학연구소) ;
  • 차광석 (건국대학교 자연과학대학 스포츠과학부)
  • Published : 2003.02.19

Abstract

This study tested whether repeated measurement of median frequency (MDF)-related variables could express the muscle power changes during a 12-week DeLome strengthening program, by using consecutive overlapping FFT (Fast Fourier transformation) and integrated EMG (IEMG) from surface EMG data for isometric and isotonic exercise. To evaluate the effect of training, the following were recorded every 3 weeks for the elbow flexors and knee extensors of 5 healthy male volunteers: MVC, lRM, limb circumference, and surface EMG during isometric MVC or isotonic contraction at 10RM load. From the EMG data, IEMG and variables from a regression analysis between MDF and time were obtained. MVC, lRM, IEMG, and initial MDF increased linearly over the training period. The fatigue index and slope of the regression line increased temporarily until the 6th week and decreased thereafter. From these results, there appeared to be enhanced neural recruitment of fast twitch fibers in the first 6 weeks and continued enhancement in the recruitment and hypertrophy of fast twitch fibers, which led to increased fatigue resistance, over the last 6 weeks. Accordingly, the MDF and IEMG analysis technique could demonstrate the effect of the program detected significant changes in both isometric and isotonic contractions. EMG analysis methods can be used to estimate the electrophysiological and histological changes in skeletal muscles during a strengthening program.

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