肌束力长关系是骨骼肌的主要基本力学特性之一,随后影响运动力学。虽然通过超快超声成像越来越多地描述力-长度特性,他们的测试-重测可靠性仍然未知。使用超快超声波,和不同脚踝角度的电诱发收缩,对腓肠肌中肌束力-长度关系进行了两次评估,相隔几天,16名参与者。所得束力-长度关系关键参数的测试-重测可靠性-即,最大力(Fmax),和最佳束长(L0)-考虑(i)在每个踝关节处获得的所有试验和(ii)在每个测试角度处获得的两个试验的平均值进行评估。考虑到所有的考验,L0表示\'高\'测试-重测可靠性,类内相关系数(ICC)为0.89,Fmax为“中等”可靠性(ICC=0.71),而当平均两次试验时,L0可靠性是“非常高”(ICC=0.91),和Fmax可靠性“中等”(ICC=0.73)。变异系数和测量标准误差的所有值都很低,即,L0≤7.7%且≤0.35cm,Fmax≤3.4N,分别。L0的绝对可靠性高于Fmax,在每个角度平均两次试验时具有更好的可靠性。所有这些参数,根据协议的限制,证明了L0和Fmax重测可靠性是可以接受的,特别是当平均在给定角度获得的多个点时。有趣的是,束力-长度关系的形状变化更大。因此,L0和Fmax可用于比较干预后的天数效应,而分束操作长度的比较可能需要更多的预防措施。
Fascicle force-length relationship is one major basic mechanical property of skeletal muscle, subsequently influencing movement mechanics. While force-length properties are increasingly described through ultrafast ultrasound imaging, their test-retest reliability remains unknown. Using ultrafast ultrasound, and electrically evoked contractions at various ankle angles, gastrocnemius medialis fascicle force-length relationship was assessed twice, few days apart, in sixteen participants. The test-retest reliability of the resulting fascicle force-length relationship key parameters - i.e., maximal force (Fmax), and optimal fascicle length (L0) - was evaluated considering (i) all the trials obtained at each ankle joint and (ii) the mean of the two trials obtained at each tested angle. Considering all trials, L0 indicated a \'high\' test-retest reliability, with intra-class correlation coefficients (ICC) of 0.89 and Fmax a \'moderate\' reliability (ICC = 0.71), while when averaging the two trials L0 reliability was \'very-high\' (ICC = 0.91), and Fmax reliability \'moderate\' (ICC = 0.73). All values of coefficient of variation and standard error of measurement were low, i.e., ≤7.7 % and ≤0.35 cm for L0 and ≤3.4 N for Fmax, respectively. Higher absolute reliability was reported for L0 than Fmax, with better reliability when averaging the two trials at each angle. All these parameters, in accordance with the limit of agreement, demonstrated that L0 and Fmax test-retest reliability is acceptable, particularly when averaging multiple points obtained at a given angle. Interestingly, the shape of the fascicle force-length relationship is more variable. Therefore, L0 and Fmax can be used to compare between days-effects following an intervention, while a comparison of fascicle operating lengths may require more precautions.