The Effects of Varying Degrees of Backrest on Abdominal Muscles and Back Extensor Activation During Lower Extremity Exercise

하지운동 시 등받이의 각도가 복근과 요부 신전근의 활성도에 미치는 영향

  • Cynn, Won-Suk (Dept. of Physical Therapy, The Graduate School, Hanseo University) ;
  • Lee, Young-Rok (Dept. of Physical Therapy, The Graduate School, Hanseo University) ;
  • Chang, Young-Jin (Dept. of Physical Therapy, The Graduate School, Hanseo University) ;
  • Choi, In-Yong (Dept. of Physical Therapy, The Graduate School, Hanseo University)
  • 신원석 (한서대학교 대학원 물리치료학과) ;
  • 이영록 (한서대학교 대학원 물리치료학과) ;
  • 장영진 (한서대학교 대학원 물리치료학과) ;
  • 최인용 (한서대학교 대학원 물리치료학과)
  • Published : 2004.02.19

Abstract

The purpose of this study was to investigate the effects of backrests of varying degrees ($90^{\circ}$, $100^{\circ}$, $110^{\circ}$) on three abdominal muscles (upper rectus abdominis, external oblique, internal oblique) and back extensor activation during lower extremity exercise. The three different conditions during bilateral knee extention exercise were: (1) leaning on a chair with a $90^{\circ}$ backrest, (2) leaning on a chair with a $100^{\circ}$ backrest, (3) leaning on a chair with a $110^{\circ}$ backrest. Fifteen healthy muscle subjects (mean age=24.2 years [SD=2.96], mean height=175.6 cm [SD=7.46], mean weight=69.1 kg [SD=7.36]) with no history of neuromusculoskeletal disease voluntarily participated in this study. Electromyography was used to collect muscle activation, and the muscle activation was expressed as a percentage of maximal voluntary isometric contraction (%MVIC). Repeated one-way analysis of variance (ANOVA) was used to determine the statistical significance. The results were as follows: (1) upper rectus abdominis, external oblique, internal oblique activation measured significantly lower. (2) measured significantly lower when lower degree.

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