Nicholson Gareth, Walker Josh, Brogden Chris, Alt Tobias
Carnegie School of Sport, Leeds Beckett University, Leeds, UK.
School of Health, Leeds Beckett University, Leeds, UK.
Scand J Med Sci Sports. 2025 Apr;35(4):e70049. doi: 10.1111/sms.70049.
Most measurements of isokinetic hamstring:quadriceps (H:Q) strength ratios are conducted using concurrent repetitions, whereby active knee extension is immediately followed by active knee flexion. To reduce the influence of the stretch-shortening cycle and limit axis misalignment, isolated repetitions have been recommended, whereby extension and flexion are completed separately. To inform screening protocols, this study examined the effect of concurrent and isolated trials on discrete and angle-specific H:Q ratios. Fifteen males (age: 27 ± 4 years; height: 184 ± 9 cm; body mass: 80 ± 9 kg) performed isokinetic tests of the knee flexors and extensors (60°/s) using concurrent and isolated trials while sagittal kinematics were captured (100 Hz). Statistical parametric mapping enabled the effects of protocol type (concurrent vs. isolated) and axis misalignment (uncorrected vs. corrected) to be compared. Uncorrected data resulted in an underestimation of discrete conventional (-10.17%, p < 0.001) and functional (-9.21%, p < 0.05) ratios, with differences being observed for all angle-specific ratios (p < 0.001). The use of concurrent repetitions resulted in a significant overestimation of the conventional H:Q ratio (+7.41%, p < 0.05) with the differences being most prevalent at more extended (24°-45° knee flexion, p < 0.05) knee joint positions. Dynamometer users should be aware that concurrent repetitions increase the likelihood of "false-negative" injury risk categorization. Nevertheless, the common practice of using uncorrected data from concurrent repetitions does not lead to significant differences in discrete or angle-specific H:Q ratios when compared with corrected data obtained from isolated repetitions.
大多数等速腘绳肌与股四头肌（H:Q）力量比的测量是通过同时进行屈伸重复动作来完成的，即主动伸膝后紧接着主动屈膝。为了减少拉长-缩短周期的影响并限制轴不对准，有人建议采用单独重复动作，即伸膝和屈膝分别完成。为了为筛查方案提供依据，本研究考察了同时和单独试验对离散和特定角度的H:Q比值的影响。15名男性（年龄：27±4岁；身高：184±9厘米；体重：80±9千克）在进行膝关节屈伸肌（60°/秒）等速测试时，分别采用同时和单独试验，同时采集矢状面运动学数据（100赫兹）。统计参数映射能够比较试验类型（同时与单独）和轴不对准（未校正与校正）的影响。未校正的数据导致离散传统比值（-10.17%，p<0.001）和功能比值（-9.21%，p<0.05）被低估，所有特定角度比值均存在差异（p<0.001）。同时进行屈伸重复动作会导致传统H:Q比值显著高估（+7.41%，p<0.05），这种差异在膝关节更伸展（屈膝24°-45°，p<0.05）的位置最为普遍。测力计使用者应意识到，同时进行屈伸重复动作会增加“假阴性”损伤风险分类的可能性。然而，与从单独重复动作获得的校正数据相比，使用同时重复动作的未校正数据在离散或特定角度的H:Q比值上不会导致显著差异。
