优秀乒乓球运动员肘关节等动屈伸运动时拮抗肌共激活现象研究

目的:研究优秀乒乓球运动员和普通在校大学生肘关节拮抗肌活动在等动屈伸过程中的差异。方法:以8名优秀乒乓球运动员和8名普通高校大学生为研究对象,利用Biodex等动测试仪和Noraxon表面肌电仪记录上肢肘关节等动屈伸过程中作为拮抗肌的肱二头肌和肱三头肌的力量特征和表面肌电信号特征。肘关节伸肌和屈肌分别在最大等长收缩、15°/s、30°/s、60°/s、120°/s、180°/s、240°/s条件下进行3次最大等动离心屈伸运动。以标准化的均方根振幅(RMS)和标准化的峰值力矩作为评价指标。结果:对于大学生和优秀乒乓球运动员来说,随着肘关节速度的增加,两组受试者的屈伸肌力矩都呈下降趋势,大学生表现为速度大于60°/s时伸肌力矩大于屈肌力矩(P<0.05),优秀乒乓球运动员表现为伸肌力矩低于屈肌力矩,但没有统计学差别(P>0.05)。大学生和优秀乒乓球运动员都表现为在向心收缩时不同速度下随着主动肌力矩下降,拮抗肌激活水平表现为逐渐增高,且所有线性拟合系数r2>0.7。优秀乒乓球运动员拮抗肌肱三头肌的激活水平(在MVC时:10.1%±5.2%,240°/s时:15.1%±6.6%)要显著低于普通高校大学生(MVC时:29.3%±8.8%,240°/s时:38.0%±15.1%)。而作为拮抗肌的肱二头肌激活水平在普通大学生和优秀乒乓球运动员之间没有统计学差异(P>0.05)。优秀乒乓球运动员拮抗肌/主动肌肌电活动比要显著低于普通大学生(P<0.05)。结论:与普通大学生相比,优秀乒乓球运动员肘关节拮抗肌肱三头肌的激活水平要更低,这可能是优秀乒乓球运动员对肘关节周围肌肉进行长期训练的结果。而两者拮抗肌肱二头肌激活水平没有统计学差异,其原因可能是由于两者在日常活动中肱二头肌作为拮抗肌经常为了克服地心引力受到同样的刺激造成的。

Analysis on Coactivation of the Antagonist in Elbow during Isokinetic Flexion and Extension Movement for Elite Table Tennis Players

Objective:The aim of this study was to examine whether the amount of antagonist activation of biceps brachii and triceps brachii is different between table tennis players and students during maximal isokinetic contractions.Methods:By using Biodex and Noraxon,8 young healthy men and 8 male table tennis players participated in the study,the surface electromyographic signals(SEMG) were recorded from the biceps brachii and triceps brachii muscles as antagonist during three maximal voluntary isometric contractions(MVC) of elbow flexors and extensors and a set of three maximal elbow flexions and extensions at all angular velocities.Normalized Root Mean Square(RMS) of SEMG and normalized peak torque was calculated.Results:As for students and elite table tennis players,with the increase of elbow velocity the peak torque of flexor and extensor in elbow both decreased.When the angular velocity is higher than 60°/s,there was a significance higher for the extensors torque than the flexors torque in students,but the flexors torque was lower than the extensors torque in elite table tennis players(P>0.05).The RMSantagonist(%)of the antagonistic muscles gradually increased with the peak torque of the agonists decline in both students and elite table tennis players at all velocities.Antagonist activation level of triceps brachii was significantly lower in elite table tennis players(10.1%±5.2% at MVC and 15.1%±6.6% at 240°/s),with respect to students(29.3%±8.8% at MVC and 38.0%±15.1% at 240°/s,at different angular velocities.In contrary to students,table tennis players did not indicate any difference in antagonist activation.Conclusion:Table tennis players,learn how to reduce coactivation of muscles involved in the control of this joint,with a frequent practice in controlling the elbow movement,so as to optimally perform technique.But there was no significant difference in the biceps brachii as antagonist activation,perhaps since the biceps brachii is usually in the same stimulation induced by the effects of gravity.