Department of Health and Human Performance, Texas State University, San Marcos, Texas, USA.
J Strength Cond Res. 2012 May;26(5):1257-64. doi: 10.1519/JSC.0b013e31824f2386.
The purpose of this study was to determine the effect of a weight-bearing free weight resistance training program alone on knee flexion, hip flexion, and knee valgus during unilateral and bilateral drop jump tasks. Twenty-nine young adult females with previous athletic experience were randomly divided into a control (n = 16) and a resistance training (n = 13) groups. The resistance training group completed 8 weeks of lower extremity, weight-bearing exercises using free weights, whereas the control group did not train. A pre- and posttest was conducted to measure knee valgus, knee flexion, and hip flexion during unilateral (30 cm) and bilateral (60 cm) vertical drop jumps for maximum height. Joint angles were determined using 3-dimensional electromagnetic tracking sensors (MotionMonitor; Innovative Sports Training, Inc., Chicago, IL, USA). Initial training intensity for the bilateral squat was 50% of the subject's 1 repetition maximum (RM), which increased 5% each week to 85% during the final week. Sets and repetitions ranged from 2 to 4 and from 4 to 12, respectively. The training loads for all other exercises (lunge, step-up, unilateral squat, and Romanian deadlift) increased from 15RM to 6RM from the initial to the final week. A repeated measures analysis of variance was used to determine differences in the hip and knee joint angles. No significant differences for knee valgus and hip flexion measures were found between the groups after training; however, knee flexion angle significantly increased in the training group from the pretest (77.2 ± 4.1°) to posttest (83.2 ± 3.7°) during the bilateral drop jump. No significant changes occurred during the unilateral drop jump. Bilateral measures for knee flexion, hip flexion, and knee valgus were significantly (p < 0.05) greater than the unilateral measures during the drop jump task, which indicate an increased risk for anterior cruciate ligament (ACL) injury during unilateral drop jumps. The data support that the strength and conditioning specialist can implement resistance training alone during a short-term training period to reduce the risk of ACL injury by increasing knee flexion during a bilateral drop jump task. Increased knee flexion angles after resistance training may indicate a reduced risk for knee injury from improved neuromuscular control, resulting in a softer landing.
本研究旨在确定单独进行负重自由重量抗阻训练计划对单侧和双侧跳落任务中膝关节屈曲、髋关节屈曲和膝关节外翻的影响。29 名有运动经验的年轻成年女性被随机分为对照组(n = 16)和抗阻训练组(n = 13)。抗阻训练组完成了 8 周的下肢负重运动,使用自由重量,而对照组没有进行训练。进行了预测试和后测试,以测量单侧(30 厘米)和双侧(60 厘米)垂直跳落时的最大高度的膝关节外翻、膝关节屈曲和髋关节屈曲。关节角度使用三维电磁跟踪传感器(MotionMonitor;创新运动训练公司,芝加哥,IL,美国)确定。双侧深蹲的初始训练强度为受试者 1 次重复最大值(RM)的 50%,每周增加 5%,最后一周增加到 85%。每组和每组的重复次数分别为 2 到 4 次和 4 到 12 次。所有其他练习(深蹲、跨步上提、单侧深蹲和罗马尼亚硬拉)的训练负荷从初始的 15RM 增加到最后一周的 6RM。使用重复测量方差分析来确定髋关节和膝关节角度的差异。训练后,两组之间的膝关节外翻和髋关节屈曲测量值没有显著差异;然而,训练组在双侧跳落测试中的膝关节屈曲角度从预测试(77.2 ± 4.1°)显著增加到后测试(83.2 ± 3.7°)。在单侧跳落测试中没有发生显著变化。双侧膝关节屈曲、髋关节屈曲和膝关节外翻测量值在跳落任务中显著(p < 0.05)大于单侧测量值,这表明单侧跳落时前交叉韧带(ACL)受伤的风险增加。数据支持力量和体能训练专家可以在短期训练期间单独进行抗阻训练,通过增加双侧跳落任务中的膝关节屈曲来降低 ACL 受伤的风险。抗阻训练后膝关节屈曲角度的增加可能表明通过改善神经肌肉控制降低了膝关节受伤的风险,从而实现更柔和的着陆。