PDF(Pubmed)
Abstract：
Quadriceps rate of torque development (RTD) and torque steadiness are valuable metrics for assessing explosive strength and the ability to control force over a sustained period of time, which can inform clinical assessments of knee function. Despite their widespread use, there is a significant gap in standardized methodology for measuring these metrics, which limits their utility in comparing outcomes across different studies and populations. To address these gaps, we evaluated the influence of sampling rates, signal filtering, and torque onset detection on RTD and torque steadiness. Twenty-seven participants with a history of a primary anterior cruciate ligament reconstruction (N = 27 (11 male/16 female), age = 23 ± 8 years, body mass index = 26 ± 4 kg/m2) and thirty-two control participants (N = 32 (13 male/19 female), age = 23 ± 7 years, body mass index = 23 ± 3 kg/m2) underwent isometric quadriceps strength testing, with data collected at 2222 Hz on an isokinetic dynamometer. The torque-time signal was downsampled to approximately 100 and 1000 Hz and processed using a low-pass, zero-lag Butterworth filter with a range of cutoff frequencies spanning 10-200 Hz. The thresholds used to detect torque onset were defined as 0.1 Nm, 1 Nm, and 5 Nm. RTD between 0 and 100 ms, 0 and 200 ms, and 40-160 ms was computed, as well as absolute and relative torque steadiness. Relative differences were computed by comparing all outcomes to the \"gold standard\" values computed, with a sampling rate of 2222 Hz, a cutoff frequency in the low-pass filter of 150 Hz, and torque onset of 1 Nm, and compared utilizing linear mixed models. While all combinations of signal collection and processing parameters reached statistical significance (p < 0.05), these differences were consistent between injured and control limbs. Additionally, clinically relevant differences (+/-10%) were primarily observed through torque onset detection methods and primarily affected RTD between 0 and 100 ms. Although measurements of RTD and torque steadiness were generally robust against diverse signal collection and processing parameters, the selection of torque onset should be carefully considered, especially in early RTD assessments that have shorter time epochs.
摘要：
股四头肌扭矩发展率（RTD）和扭矩稳定性是评估爆炸强度和在持续一段时间内控制力的能力的有价值的指标。这可以为膝关节功能的临床评估提供信息。尽管它们广泛使用，衡量这些指标的标准化方法存在显著差距，这限制了它们在比较不同研究和人群结果方面的效用。为了弥补这些差距,我们评估了采样率的影响，信号滤波,以及RTD的转矩起始检测和转矩稳定。27名具有原发性前交叉韧带重建病史的参与者（N=27（11男/16女），年龄=23±8岁，体重指数=26±4kg/m2）和32名对照参与者（N=32（13男/19女），年龄=23±7岁，身体质量指数=23±3kg/m2）进行了等轴测股四头肌强度测试，在等速测功机上以2222Hz的频率收集数据。扭矩时间信号被下采样到大约100和1000Hz，并使用低通处理，零滞后巴特沃斯滤波器的截止频率范围跨越10-200赫兹。用于检测扭矩开始的阈值定义为0.1Nm，1Nm,5nm。RTD在0到100ms之间，0和200ms，计算了40-160毫秒，以及绝对和相对转矩的稳定性。通过将所有结果与计算的“黄金标准”值进行比较来计算相对差异，采样率为2222Hz，低通滤波器的截止频率为150Hz，和1Nm的扭矩开始，并利用线性混合模型进行比较。而所有信号收集和处理参数的组合达到了统计学意义(p<0.05),这些差异在受伤和控制肢体之间是一致的。此外,临床相关差异(+/-10%)主要通过扭矩开始检测方法观察到,并且主要在0-100ms之间影响RTD.尽管RTD和扭矩稳定性的测量通常对不同的信号收集和处理参数具有鲁棒性，扭矩起始的选择应仔细考虑，尤其是在早期RTD评估中，时间较短。
