Journal of Digital Convergence (디지털융복합연구)

The Society of Digital Policy and Management (한국디지털정책학회)
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The Effect of Knee Muscle Imbalance on Motion of Back Squat

무릎 근력의 불균형이 백 스쿼트 동작에 미치는 영향

  • Sohn, Jee-Hoon (Department of Physical Education, Jeonju University)
  • 손지훈 (전주대학교 생활체육학과)
  • Received : 2019.01.04
  • Accepted : 2019.03.20
  • Published : 2019.03.28
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Abstract

The purpose of this study was to investigate the effect of muscle imbalance on motion of back squat. The isokinetic muscle strength of the 8 subjects was recorded for the knee flexion/extension by the cybex 770 dynamometer. Each subject performed 3 back squats with the long barbell with an intensity of 25% body weight(BW), 50%BW, 100%BW, 125%BW. During the back squat through the recorded kinematic data the subjects' maximum flexion and extension knee angle, center of mass displacement and V-COP were calculated for evaluation of the stability of the movement. For the statistical analysis independent t-test was used. Knee flexion angle and COM displacement are dominated by the reciprocal muscle ratio. V-COP factor was dominated by bilateral extension deficit. Based on the results we can know that as the intensity of the squat increased to a level control was difficult because the muscles' imbalance influenced the movement.

본 연구는 무릎 근력의 불균형이 백 스쿼트 시 인체 움직임의 제한 요인으로 작용하는지를 확인하는 것에 목적이 있다. 백 스쿼트 유경험자로 최근 2년간 부상이 없는 서울시 소재 S대학교 학생 8명을 연구 대상자로 선정하였다. Cybex 770으로 무릎관절의 등속성 근력을 측정한 후, 동측 주작용근과 대항근의 근력 불균형 정도와 좌 우 같은 근 군의 결손율에 따라 그룹을 나눈 후, 개인별 몸무게의 25%, 50%, 100%, 125%의 중량과 같은 바벨을 백 스쿼트로 들게 하였다. 무릎 굽힘 각도, 신체중심의 수직 변위, V-COP의 측정 구간 내 평균 위치로부터 매 순간 V-COP 까지의 거리 합 변인들에 대한 집단별 차이를 검증하기 위해 독립표본 T 검정을 실시하였다. 125%BW 조건에서 무릎관절 근력의 동측 불균형은 쭈그려 앉는 자세의 제한 요인으로, 좌 우측 폄 근력의 불균형은 평형성 유지의 제한 요인으로 작용하였다. 근력의 불균형이 인체 움직임의 제한 요인으로 작용할 수 있음을 확인하였으므로, 차후 임상에서는 근력 불균형에 대한 검사법과 함께 교정 및 재활 운동 방법 또한 발전시켜 나갈 필요가 있다.

Keywords

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Fig. 1. Experimental equipments

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Fig. 2. Event definition(In case of 25%BW)

DJTJBT_2019_v17n3_463_f0003.png 이미지

Fig. 3. Right knee flexion angle(Down to Up)

DJTJBT_2019_v17n3_463_f0004.png 이미지

Fig. 4. Right knee flexion angle graph(Down to Up)

DJTJBT_2019_v17n3_463_f0005.png 이미지

Fig. 5. Left knee flexion angle(Down to Up)

DJTJBT_2019_v17n3_463_f0006.png 이미지

Fig. 6. Left knee flexion angle graph(Down to Up)

DJTJBT_2019_v17n3_463_f0007.png 이미지

Fig. 7. COM displacement(Down to Squat Min)

DJTJBT_2019_v17n3_463_f0008.png 이미지

Fig. 8. V-COP Summation(Down to Squat Min)

Table 1. Subjects

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Table 2. Isokinetic muscle strength

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Table 3. Grouping by reciprocal muscle imbalance

DJTJBT_2019_v17n3_463_t0003.png 이미지

Table 4. Grouping by bilateral muscle imbalance (deficit)

DJTJBT_2019_v17n3_463_t0004.png 이미지

Table 5. Right knee flexion angle

DJTJBT_2019_v17n3_463_t0005.png 이미지

Table 6. Left knee flexion angle

DJTJBT_2019_v17n3_463_t0006.png 이미지

Table 7. COM Z axis displacement

DJTJBT_2019_v17n3_463_t0007.png 이미지

Table 8. V-COP summation

DJTJBT_2019_v17n3_463_t0008.png 이미지

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