Human Performance Laboratory, UNESP, Rio Claro, SP , Brazil.
J Sports Sci Med. 2012 Sep 1;11(3):418-22. eCollection 2012.
Muscle strength imbalance can be an important factor in hamstrings muscle strain. A hamstrings/quadriceps (H/Q) strength ratio based on concentric peak torque values (Hcon:Qcon) has traditionally been used to describe the potential for knee-joint destabilization. Because certain standard actions in soccer are explosive, the analysis of the H/Q strength ratio based on the rate of torque development (Hrtd:Qrtd) might also be useful in the evaluation of joint stability. The objective of this study was to compare the Hrtd:Qrtd between professional soccer players with heterogeneous values of Hcon:Qcon. Thirty-nine professional soccer players took part in the following procedures on different days: 1) Familiarization session with the isokinetic dynamometer, and 2) Two maximal isometric actions and five maximal concentric actions at 60°·s(-1) for hamstrings (H) and quadriceps (Q). Participants were ranked according to their Hcon:Qcon ratio. The median third was excluded to form a high torque group (HTG), and a low torque group (LTG). Peak isometric (H) and concentric (H and Q) torques and rate of torque development (H) were significantly greater in the HTG group. Similarly, Hcon:Qcon (0.68 ± 0.02 vs. 0.52 ± 0.03) and Hrtd:Qrtd (0.54 ± 0.12 vs. 0.43 ± 0.16) were significantly greater in the HTG group than in the LTG group. There was no significant correlation between Hcon:Qcon and Hrtd:Qrtd. It can be concluded that Hcon:Qcon and Hrtd:Qrtd are determined, but not fully defined, by shared putative physiological mechanisms. Thus, the physiologic and clinical significance of Hcon:Qcon and Hrtd:Qrtd to an athlete's individual evaluation might be different. Key pointsSoccer players with high (0.66-0.70) and low (0.50-0.54) conventional concentric hamstrings:quadriceps ratios (Hcon:Qcon) tend to demonstrate similar profiles (i.e., high and low, respectively) in their rate of the torque development H/Q ratio (Hrtd:Qrtd).The lack of a significant relationship between Hcon:Qcon and Hrtd:Qrtd suggests that these ratios are determined, but not fully defined, by shared putative physiological mechanisms.Preseason screening programs that monitor hamstrings:quadriceps ratios should recognize that the physiologic and clinical significance of Hcon:Qcon and Hrfd:Qrfd to an athlete's individual evaluation might be different.
肌肉力量失衡可能是腘绳肌拉伤的一个重要因素。传统上，基于向心峰值扭矩值的腘绳肌/四头肌（H/Q）力量比（Hcon：Qcon）用于描述膝关节不稳定的潜在风险。由于足球中的某些标准动作具有爆发性，因此基于扭矩发展速率（Hrtd：Qrtd）分析 H/Q 力量比也可能有助于评估关节稳定性。本研究的目的是比较具有不同 Hcon：Qcon 值的职业足球运动员之间的 Hrtd：Qrtd。39 名职业足球运动员在不同的日子里进行了以下程序：1）使用等速测力计进行熟悉阶段，以及 2）在 60°·s（-1）下进行两次最大等长动作和五次最大向心动作，用于腘绳肌（H）和四头肌（Q）。参与者根据他们的 Hcon：Qcon 比值进行排名。中位数的三分之一被排除在外，形成高扭矩组（HTG）和低扭矩组（LTG）。HTG 组的峰值等长（H）和向心（H 和 Q）扭矩以及扭矩发展速率（H）显著更高。同样，HTG 组的 Hcon：Qcon（0.68 ± 0.02 比 0.52 ± 0.03）和 Hrtd：Qrtd（0.54 ± 0.12 比 0.43 ± 0.16）也显著高于 LTG 组。Hcon：Qcon 与 Hrtd：Qrtd 之间没有显著相关性。可以得出结论，Hcon：Qcon 和 Hrtd：Qrtd 由共同的假定生理机制决定，但不是完全定义的。因此，Hcon：Qcon 和 Hrtd：Qrtd 对运动员个体评估的生理和临床意义可能不同。关键点具有高（0.66-0.70）和低（0.50-0.54）传统向心腘绳肌：四头肌比值（Hcon：Qcon）的足球运动员往往在其扭矩发展 H/Q 比值（Hrtd：Qrtd）方面表现出相似的特征（即高和低）。Hcon：Qcon 与 Hrtd：Qrtd 之间缺乏显著关系表明，这些比值由共同的假定生理机制决定，但不是完全定义的。监测腘绳肌：四头肌比值的季前筛查计划应认识到，Hcon：Qcon 和 Hrfd：Qrfd 对运动员个体评估的生理和临床意义可能不同。
