排序方式: 共有127条查询结果,搜索用时 15 毫秒
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Clayton L. Camic Attila J. Kovacs Trisha A. VanDusseldorp Ethan C. Hill Evan A. Enquist 《运动与健康科学(英文)》2020,9(6):628-633
PurposeThe purposes of the present study were: (1) to determine whether the physical working capacity at the fatigue threshold (PWCFT) model that has been used for estimating the onset of neuromuscular fatigue in the vastus lateralis (VL) during incremental treadmill running could also be applied to the vastus medialis (VM), biceps femoris (BF), and semitendinosus (ST) muscles; and (2) if applicable, to compare the running velocities associated with the PWCFT among these muscles.MethodsEleven subjects (age 21.7 ± 1.8 years) performed an incremental treadmill test to exhaustion with electromyographic signals recorded from the VL, VM, BF, and ST.ResultsThe results indicated there were no significant (p > 0.05) mean differences in the running velocities associated with the PWCFT for the VL (14.4 ± 2.0 km/h), VM (14.3 ± 1.9 km/h), BF (13.8 ± 1.8 km/h), and ST (14.7 ± 2.3 km/h). In addition, there were significant inter-correlations (r = 0.68–0.88) among running velocities associated with the PWCFT of each muscle. Individual results also indicated that 9 of the 11 subjects exhibited identical PWCFT values for at least 3 of the 4 muscles, but there were no uniform patterns for any intra-individual differences.ConclusionThe findings of the present study suggested that the PWCFT test is a viable method to identify neuromuscular fatigue in the quadriceps and hamstrings during incremental treadmill exercise and results in consistent PWCFT values among these muscles. 相似文献
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Activation of the hamstrings has been discussed as a measure for reducing strain on the ACL during jump landings in alpine skiing. The current study tested the hypothesis that hamstring and quadriceps activation can be voluntarily increased by the athlete. Specifically, two different instructions – to increase hamstring activation or to increase upper-leg co-contraction – were compared to normal landings. Eight members of the German national and junior national squad in freestyle skiing (age 19.6 ± 3.8 years; weight 66.1 ± 13.2 kg; height 172.2 ± 7.7 cm) performed 12 jump landings on a prepared run, 4 with no specific instruction, 4 with the instruction to generally activate the thigh muscles, and 4 with the instruction to specifically activate the hamstrings. Electromyographic (EMG) signals were recorded on the biceps femoris (BF), semitendinosus (ST), vastus lateralis (VL), rectus femoris (RF) and vastus medialis (VM). EMG activation levels were integrated over three landing phases and analysed with a repeated measures ANOVA. The instruction produced a significant main effect in ST (p = .026), VM (p = .032) and RF (p = .001). Contrary to previous research, the current study suggests that hamstring muscle activation levels can be voluntarily increased during jump landing, particularly in co-activation with its antagonists. 相似文献
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目的::探索老年人下楼梯过程踝关节和膝关节的关节活动度、地面反作用力以及肌肉表面肌电表现。方法:选择10名男性老年人,年龄(68.5±3.8)岁,身高(1.71±0.25)米,体重(70.2±13.5)千克,10名青年人,年龄(22.5±2.7)岁,身高(1.75±0.14)米,体重(65.9±11.3)千克。通过运动生物力学专业设备和软件,采集到老年人下楼梯行走过程的运动学、动力学和表面肌电信号。结果:老年人和青年人的运动学、动力学和表面肌电的曲线图变化趋势趋于一致;踝关节最大背屈角度、踝关节最大跖屈角度、地面反作用力垂直方向第1峰值、地面反作用力垂直方向第2峰值等指标方面,老年人和青年人之间差异具有显著性;在支撑阶段,老年人股外侧肌、腓肠肌外侧肌肉的激活水平都要略高于青年人。结论:老年人与青年人下楼梯过程的动作差异可能归因于肌肉力量的差异,因此,对于老年人来说,发展下肢肌肉力量对下楼梯行走的身体姿势稳定性具有重要的意义。 相似文献
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摘要:目的:本研究观察健康受试者在运动性肌肉疲劳过程中大脑中枢电信号与外周肌肉表面肌电电信号通讯之间的变化,为丰富运动性肌肉疲劳的中枢机制理论提供参考依据。方法:以15名健康受试者为研究对象,通过上肢间断性握力收缩诱发其指屈肌疲劳,观察疲劳过程中运动皮质区的β波段(15~30 Hz)脑电、指深屈肌肌电以及脑电与肌电相干性的变化。结果:在疲劳过程中位于FC1、FCz、FC2、C1电极位置的β波段标准化能量谱显著性下降(P < 0.05);指深屈肌sEMG的15~30 Hz标准化能量谱随着疲劳发生显著下降(P < 0.05)。FC1、FCz、FC2、C1以及Cz电极位置的β波段脑电-肌电相干性随着疲劳的加深加重显著性下降(P < 0.05)。结论:本研究发现在小强度运动诱发上肢肌肉疲劳的实验中,β波(15-30 Hz)频率带的EEG和EMG功率谱随着疲劳的加深加重而显著性降低,同时β波(15-30 Hz)频率带对应的EEG-EMG相干性显著性下降。 相似文献
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设置靶模具和信号灯,运用两台CASIO-EXFH25摄像机对两名国际级散打和泰拳选手后横踢动作进行同步拍摄,采用APAS系统(美国)进行三维视频图像解析,用Megwin Me6000表面肌电同步肌肉活动信号,对中泰横踢技术各运动环节支撑腿和进攻腿髋、膝、踝关节速度和角度变化特征,肌肉动员顺序、肌电特征进行对比分析,寻找差距,揭示技术动作内在规律,以期为鞭腿技术动作的教学、训练提供科学依据。 相似文献