CAJ | 학술논문

背景：人体关节力量输出主要取决于关节周围主动肌与拮抗肌的激活效果，而拮抗肌通过共激活形式参与肢体活动，从而协助维持关节稳定性。但是肌肉不同收缩模式下拮抗肌共激活的不同中枢策略的报道较少。目的：观察健康受试者膝关节伸肌在最大和次最大等速运动至疲劳过程中主动肌与拮抗肌表面肌电信号的特征与差别。方法：对16名在校学生使用Biodex等速训练仪诱发下肢右侧膝关节伸肌等速屈伸运动直至疲劳，同时使用表面肌电仪采集单侧股内侧肌、股外侧肌以及股二头肌的表面肌电信号。分析时域指标均方根振幅百分比以及频域指标平均频率的变化规律。结果与结论：在膝关节最大等速屈伸运动中峰值力矩下降了40.3%(P <0.05)，主动肌活动先增加后下降(P <0.05)，而拮抗肌电活动保持不变。在次最大等速运动中峰值力矩平均下降了40.0%(P <0.05)，主动肌肌电活动逐渐增加(P<0.05)，而拮抗肌电活动先增加随后又降低。在指定的交互收缩屈伸运动中作为拮抗肌的股内和股外侧肌的均方根振幅和平均频率没有显著变化(P >0.05)。结果提示，在不同强度的等速疲劳运动中中枢神经系统对主动肌和拮抗肌采取了不同神经支配策略。
배경：인체관절역량수출주요취결우관절주위주동기여길항기적격활효과，이길항기통과공격활형식삼여지체활동，종이협조유지관절은정성。단시기육불동수축모식하길항기공격활적불동중추책략적보도교소。목적：관찰건강수시자슬관절신기재최대화차최대등속운동지피로과정중주동기여길항기표면기전신호적특정여차별。방법：대16명재교학생사용Biodex등속훈련의유발하지우측슬관절신기등속굴신운동직지피로，동시사용표면기전의채집단측고내측기、고외측기이급고이두기적표면기전신호。분석시역지표균방근진폭백분비이급빈역지표평균빈솔적변화규률。결과여결론：재슬관절최대등속굴신운동중봉치력구하강료40.3%(P <0.05)，주동기활동선증가후하강(P <0.05)，이길항기전활동보지불변。재차최대등속운동중봉치력구평균하강료40.0%(P <0.05)，주동기기전활동축점증가(P<0.05)，이길항기전활동선증가수후우강저。재지정적교호수축굴신운동중작위길항기적고내화고외측기적균방근진폭화평균빈솔몰유현저변화(P >0.05)。결과제시，재불동강도적등속피로운동중중추신경계통대주동기화길항기채취료불동신경지배책략。
BACKGROUND:The power output of the human joints depends on the activation of agonists and antagonist muscles around the joints, and the antagonist muscle is involved in physical activity in a co-activated manner, thereby helping to maintain joint stability. But there are less reports on the central nervous system strategies of antagonist co-activation under different muscle contraction modes. OBJECTIVE:To observe the characteristics and differences of surface electromyography (sEMG) of agonists and antagonist muscles of the knee joints during maximal and submaximal isokinetic exercises until fatigue. METHODS:Sixteen students were enroled, who developed the right knee joint fatigue induced by the Biodex isokinetic equipment, and simultaneously sEMG activities of vastus medialis, vastus lateralis and biceps femoris were recorded by the myoelectrical equipment. The RMS (%) and mean frequency were selected to analyze sEMG characteristics. RESULTS AND CONCLUSION:In the maximal isokinetic fatigue, the peak torque was decreased by 40.3% (P < 0.05) and the sEMG activity of agonists gradualy increased and then declined, but the sEMG activity of antagonists kept constant. In the submaximal isokinetic fatigue, the peak torque was decreased by 40.0% (P < 0.05), the sEMG activity of agonists gradualy increased (P < 0.05), and however the sEMG activity of the antagonists initialy increased and then decreased. The RMS and mean frequency of vastus medialis and lateralis as antagonists at selected reciprocal contractions showed no significant changes (P > 0.05). These results suggest that in the different intensities of isokinetic fatigue, the central nervous system employs different neural strategies on agonists and antagonists.