Sport and Human Performance Research Centre, University of Limerick, Limerick, Ireland.
PLoS One. 2023 Jun 23;18(6):e0287431. doi: 10.1371/journal.pone.0287431. eCollection 2023.
The reliability of mechanical measures can be impacted by the protocol used, including factors such as joint angle and the sex of participants. This study aimed to determine the inter-day reliability of plantar flexor mechanical measures across ankle joint angles and contraction types and consider potential sex-specific effects. 14 physically-active individuals participated in two identical measurement sessions involving involuntary and voluntary plantar flexor contractions, at three ankle angles (10° plantarflexion (PF), 0° (anatomical zero (AZ)), and 10° dorsiflexion (DF)), while torque and surface EMG were recorded. The reliability of mechanical parameters of maximal voluntary torque (MVT), rate of torque development (RTD), electromechanical delay, and tendon stiffness were assessed using absolute and relative reliability measures. MVT measures were reliable across ankle angles. RTD measures showed good group level reliability and moderate reliability for an individual during the early phase of contraction across ankle angles. Explosive voluntary torque measures tended to be less reliable from 50 ms onward, with varied reliability across angles for late-phase RTD. Tendon stiffness demonstrated the best reliability at the DF angle. Sex-based differences in the reliability of tendon measures found that females had significantly different initial tendon length between testing sessions. Despite this, tendon excursion, force, and stiffness measures demonstrated similar reliability compared to males. Ankle angle changes influence the reliability of plantar flexor mechanical measurements across contraction types, particularly for voluntary contractions. These results highlight the importance of establishing potential protocol effects on measurement reliability prior to quantifying plantar flexor mechanical measures.
机械测量的可靠性可能会受到所使用的方案的影响，包括关节角度和参与者的性别等因素。本研究旨在确定在踝关节角度和收缩类型下，足底屈肌机械测量的日内可靠性，并考虑潜在的性别特异性影响。14 名体能活跃的个体参与了两次完全相同的测量过程，包括无意识和自愿的足底屈肌收缩，在三个踝关节角度（10°跖屈（PF）、0°（解剖学零位（AZ））和 10°背屈（DF）），同时记录扭矩和表面肌电图。使用绝对和相对可靠性指标评估最大自主扭矩（MVT）、扭矩发展速率（RTD）、机电延迟和肌腱刚度等机械参数的可靠性。MVT 测量在踝关节角度上具有可靠性。RTD 测量在组水平上具有良好的可靠性，在踝关节角度的收缩早期对个体也具有中度可靠性。爆发性自愿扭矩测量在 50 毫秒后趋于不太可靠，在各个角度的后期 RTD 具有不同的可靠性。在 DF 角度下，肌腱刚度表现出最佳的可靠性。基于性别的肌腱测量可靠性差异表明，女性在两次测试之间的初始肌腱长度存在显著差异。尽管如此，肌腱位移、力和刚度测量与男性相比具有相似的可靠性。踝关节角度的变化会影响不同收缩类型下的足底屈肌机械测量的可靠性，特别是对自愿收缩。这些结果强调了在量化足底屈肌机械测量之前，确定潜在方案对测量可靠性的影响的重要性。
