不同上肢预负荷对腰部肌肉自愿收缩力量的影响

Effect of Different Upper Limb Preload on Voluntary Contraction of Lumbar Muscle

目的:本研究探索不同上肢预负荷方式和强度对腰部肌肉最大自愿收缩力量的影响。方法:本研究共招募20名被试者,每名被试者以随机的顺序先后参加4组实验。在实验过程中,被试者保持中立正直坐姿,分别在无预负荷、举臂预负荷、手拉预负荷和手握预负荷方式下进行腰部和腹部力量全力共激活,每组预负荷方式的预负荷强度设置为20%和40%最大负荷力量,同时记录双侧腰部多裂肌和竖脊肌的肌电信号。结果:在双侧多裂肌中,举臂和手拉预负荷方式的均方根值(RMS)和积分肌电值(IEMG)均大于无预负荷组(P<0.05),手握预负荷方式和无预负荷组之间的RMS值和IEMG值无统计学差异(P>0.05);在双侧竖脊肌中,三种预负荷方式和无预负荷组之间的RMS值和IEMG值均无统计学差异(P>0.05)。在不同预负荷方式比较中,举臂和手拉预负荷方式的RMS值和IEMG值均大于手握预负荷方式(P<0.05),举臂预负荷的RMS值和IEMG值均大于手拉预负荷方式(P<0.05)。结论:举臂和手拉预负荷方式带来的肌肉预激活均可以有效提高腰部多裂肌的自愿收缩力量,预负荷强度越大,肌肉收缩力量可能也越大,且举臂预负荷方式具有更好的促进作用。

Objective:This study explores the effects of different upper limb preload methods and intensities on the maximum voluntary contraction force of lumbar muscles.Methods:20 subjects were recruited in this study,and each subject participated in 4 groups of experiments in random order.During the experiment,the subjects maintained in a neutral and upright sitting position,and were subjected to full force co-activation of the lumbar and abdominal muscles under no preload,arm lift preload,hand pull preload and hand grip preload,respectively.The preload intensity of each preload method was set at 20%and 40%of the maximum load force.At the same time,the electromyographic signals of the bilateral lumbar multifidus and erector spinalis muscles were recorded.Results:In bilateral multifidus muscles,the root mean square(RMS)and integrated electromyography(IEMG)values of the arm lift and hand pull preload methods were higher than those of the no preload group(P<0.05).There was no statistical difference in RMS and IEMG values between the hand grip preload method and the no preload group(P>0.05);There was no statistically significant difference in RMS and IEMG values between the three preload methods and the no preload group in the bilateral vertical spine muscles(P>0.05).In the comparison of different preload methods,the RMS and IEMG values of the arm lift and hand pull preload methods were higher than those of the hand grip preload method(P<0.05),and the RMS and IEMG values of arm lift preload method were higher than those of hand pull preload method(P<0.05).Conclusion:The muscle pre-activation brought about by arm lift and hand pull preload methods can effectively improve the voluntary contraction strength of the lumbar multifidus muscle.The greater the preload intensity,the greater the muscle contraction strength may also be,and the arm lift preload method has a better promoting effect.