网球拍线材质对持拍前臂冲击载荷的影响及前臂表面肌电分析

目的:测试不同材质的网球拍线对底线击球表现和持拍前臂冲击载荷的影响,分析被试持拍前臂肌肉在击球过程中的表面肌电特征。方法:15名网球运动员使用相同线径、不同材质(聚酯与尼龙仿肠)拍线的网球拍进行底线击球测试,通过雷达测速仪和ITN网球技能评价标准测量底线击球速度和控制性,运用加速度测试系统、应力应变测试仪及无线表面肌电测试系统记录分析被试击球时球拍的振动频率、加速度峰值和应力应变峰值,以及持拍前臂表面肌电的变化特征。结果:聚酯线与尼龙仿肠线条件下被试的击球速度与控制性无显著性差异(P>0.05),但聚酯线的总体趋势要高于尼龙仿肠线;网球拍线材质对球拍的振动频率、加速度和应力应变无显著影响(P>0.05);聚酯线对被试持拍前臂表面肌电峰值、均方根振幅和放电时程的影响趋势高于尼龙仿肠线,其中肱桡肌肌电峰值、旋前圆肌均方根振幅(RMS)存在显著性差异(P<0.05)。结论:网球拍线材质对底线击球表现无显著影响,但聚酯材质比尼龙仿肠材质的网球拍线表现出较高的影响趋势;网球拍线材质会对持拍前臂造成一定程度的影响,聚酯材质的网球拍线对持拍前臂产生更大的冲击载荷,其中对伸肌群中的肱...

The Effect of Tennis String Material on Shock Load of Racket-hold Forearm and its Surface Electromyography

ObjectiveTo examine the effect of tennis strings of different material on the groundstroke performance and shock load of racket-holding forearms,whose surface electromyography(sEMG)characteristics was also analyzed.MethodsFifteen tennis players using tennis rackets with the same diameter but different string material(polyester and nylon imitated catgut) played groundstrokes on the baseline,and their speed,accuracy and control of balls were measured using the radar chronograph and international tennis number(ITN). Besides,YSV system and stress strain tester were applied to examine the vibration frequency, acceleration and stress strain of tennis rackets. TrignoTM wireless sEMG system was employed to collect and analyze the sEMG characteristics of subjects’ forearms holding the racquet when playing the groundstrokes.ResultsNo significant differences were found in the speed and control when playing with tennis rackets of polyester and nylon imitated catgut strings(P>0.05), but there was a higher tendency of polyester string’ influence on the groundstroke. Different tennis string material had no significant effect on the vibration frequency, acceleration and stress strain of rackets(P>0.05). The influence of polyester strings on the sEMG peak,root-mean-square amplitude and discharge duration of subjects’ forearm was greater than the nylon imitated catgut,and significant differences were founded in the sEMG peak of the brachioradialis and root-mean-square amplitude of teres anterior rotation(P<0.05).ConclusionThe tennis string material has no significant effect on groundstroke performance,but the polyester string has more effects on performance than the nylon imitated cargut. Tennis string material has some influence on racket-holding forearms when the ball impacts the tennis racket,as it can produce more shock load transmitting to subjects’ forearm holding rackets,among which the brachioradialis is most affected.