Hamstra-Wright Karrie L, Swanik C Buz, Sitler Michael R, Swanik Kathleen A, Ferber Reed, Ridenour Marcella, Huxel Kellie C
Biomechanics Laboratory, Department of Movement Sciences, University of Illinois at Chicago, Chicago, IL 60608, USA.
Clin J Sport Med. 2006 Jan;16(1):56-62. doi: 10.1097/01.jsm.0000179232.10261.65.
To assess differences in neuromuscular dynamic restraint between high-skilled and low-skilled prepubescent girls and boys. To determine the contribution of sport experience and physical characteristics to motor skill.
Nineteen girls and 17 boys (8.89-9.40 y) participated.
Isometric hamstring and quadriceps muscle strength was assessed. Subjects performed 3 landing trials for measurement of preparatory EMG and vertical leg stiffness. Motor skill was assessed through analysis of 12 fundamental tasks. Sport experience was reported as hours per week and total years in organized and nonorganized activity.
Dynamic restraint variables of isometric strength, preparatory EMG activity, and vertical leg stiffness were measured between groups. The contributions of time in sport, type of sport, and physical characteristics on skill were analyzed.
No significant gender or skill differences were found in quadriceps strength (P = 0.73), hamstring strength (P = 0.96), hamstring-to-quadriceps ratio (P = 0.71), or vertical leg stiffness (P = 0.38). Low-skilled children exhibited significantly greater (47.8%) preparatory hamstring-quadriceps coactivation than high-skilled subjects (P = 0.03). Participation in organized and nonorganized sport accounted for 29% of the variance in motor skill.
Neuromuscular differences between genders were not observed, but dynamic restraint EMG measures differed between skill levels. The factors predisposing females to noncontact injuries may develop prepuberty to postpuberty from a combination of variables. Greater coactivation in the low-skilled group appears consistent with immature feedforward neuromuscular control strategies. These unrefined motor skills are less economical, may compromise dynamic restraint, and appear partially determined by sport experience.
评估青春期前高技能和低技能女孩与男孩在神经肌肉动态约束方面的差异。确定运动经验和身体特征对运动技能的贡献。
19名女孩和17名男孩（8.89 - 9.40岁）参与。
评估等长腘绳肌和股四头肌力量。受试者进行3次着陆试验以测量预备肌电图和垂直腿部僵硬度。通过分析12项基本任务评估运动技能。运动经验以每周小时数以及有组织和无组织活动的总年数报告。
测量组间等长力量、预备肌电图活动和垂直腿部僵硬度的动态约束变量。分析运动时间、运动类型和身体特征对技能的贡献。
在股四头肌力量（P = 0.73）、腘绳肌力量（P = 0.96）、腘绳肌与股四头肌比率（P = 0.71）或垂直腿部僵硬度（P = 0.38）方面未发现显著的性别或技能差异。低技能儿童的预备腘绳肌 - 股四头肌共同激活明显高于高技能受试者（47.8%，P = 0.03）。参与有组织和无组织运动占运动技能方差的29%。
未观察到性别之间的神经肌肉差异，但技能水平之间的动态约束肌电图测量存在差异。使女性易发生非接触性损伤的因素可能在青春期前到青春期后由多种变量共同作用而形成。低技能组中更大的共同激活似乎与不成熟的前馈神经肌肉控制策略一致。这些未完善的运动技能效率较低，可能会损害动态约束，并且似乎部分由运动经验决定。
