Department of Sports Medicine, Medical Clinic, University of Tuebingen , Germany.
J Sports Sci Med. 2013 Sep 1;12(3):439-46. eCollection 2013.
The intention of this study was to systematically analyze the impact of biomechanical variables in terms of different vibration frequencies, amplitudes and knee angles on quadriceps femoris and hamstring activity during exposure to whole-body vibration (WBV). 51 healthy men and women (age 55 ± 8 years) voluntary participated in the study and were randomly allocated to five different vibration-frequency groups. Each subject performed 9 static squat positions (3 amplitudes x 3 knee angles) on a side alternating vibration platform. Surface electromyography (EMG) was used to record the neuromuscular activity of the quadriceps femoris and hamstring muscles. Maximal voluntary contractions (MVCs) were performed prior to the measurements to normalize the EMG signals. A three-way mixed ANOVA was performed to analyze the different effects of the biomechanical variables on muscle activity. Depending on the biomechanical variables, EMG muscle activity ranged between 18.2 and 74.1 % MVC in the quadriceps femoris and between 5.2 and 27. 3 % MVC in the hamstrings during WBV. The highest levels of muscle activation were found at high frequencies and large amplitudes. Especially in the quadriceps femoris muscle, a WBV frequency of 30 Hz led to a significant increase in muscle activity compared to the other tested frequencies. However, it seems that knee angle is only relevant for the quadriceps femoris muscle. The results of this study should give more information for developing individual training protocols for WBV treatment in different practical applications. Key PointsWBV leads to a higher muscle activity of the quadriceps femoris than of the hamstrings.The maximum levels of muscle activity were significantly reached at high amplitude and high frequency.The knee angle only significantly affects the quadriceps femoris.Certain combinations of the biomechanical variables have similar effects on the level of muscle activity.
本研究旨在系统分析不同振动频率、振幅和膝关节角度等生物力学变量对全身振动（WBV）下股四头肌和腘绳肌活动的影响。51 名健康男性和女性（年龄 55±8 岁）自愿参加了这项研究，并被随机分配到五个不同的振动频率组。每位受试者在交替振动平台上完成 9 个静态深蹲姿势（3 个振幅 x 3 个膝关节角度）。表面肌电图（EMG）用于记录股四头肌和腘绳肌的神经肌肉活动。在测量前进行最大自主收缩（MVC）以对 EMG 信号进行归一化。采用三因素混合方差分析来分析生物力学变量对肌肉活动的不同影响。根据生物力学变量的不同，股四头肌的 EMG 肌肉活动在 WBV 期间范围为 18.2%至 74.1%MVC，而腘绳肌的 EMG 肌肉活动范围为 5.2%至 27.3%MVC。在 WBV 中，肌肉激活水平最高的是高频和大振幅。特别是在股四头肌中，与其他测试频率相比，30Hz 的 WBV 频率导致肌肉活动显著增加。然而，似乎膝关节角度仅与股四头肌有关。本研究的结果应为不同实际应用中开发针对 WBV 治疗的个体训练方案提供更多信息。关键点：WBV 会导致股四头肌的肌肉活动高于腘绳肌。肌肉活动的最高水平在高振幅和高频率时显著达到。膝关节角度仅显著影响股四头肌。某些生物力学变量的组合对肌肉活动水平具有相似的影响。
