Intramuscular pressure (IMP) shows promise for estimating individual muscle tension in vivo. However, previous pressure measurements show high variability during isometric contraction and poor correlation with tension during dynamic contraction. We hypothesized that enhanced sensor anchoring/orientation would improve tension estimation and thus developed a novel pressure sensor with a barbed housing. Sensors were inserted into the tibialis anterior (TA) of New Zealand White rabbits (N = 8) both parallel and perpendicular to the fiber orientation. We measured muscle stress and IMP during both isometric and dynamic contractions. Passive stress showed good agreement for both insertion directions across muscle lengths (ICC > 0.8). Active stress and IMP agreement were good (ICC = 0.87 ± 0.04) for perpendicular insertions but poor (ICC = 0.21 ± 0.22) for parallel insertions across both dynamic contractions and isometric contractions within the muscle’s range of motion. These findings support use of IMP measurements to estimate muscle tension across a range of contraction conditions.

肌内压 (IMP) 有望用于估计体内个体肌肉张力。然而，之前的压力测量显示等长收缩过程中的变异性较高，而动态收缩过程中与张力的相关性较差。我们假设增强的传感器锚定/方向将改善张力估计，因此开发了一种带有倒刺外壳的新型压力传感器。将传感器平行和垂直于纤维方向插入新西兰白兔（ N = 8）的胫骨前肌（TA）中。我们测量了等长收缩和动态收缩期间的肌肉压力和 IMP。被动应力在跨肌肉长度的两个插入方向上表现出良好的一致性（ICC > 0.8）。对于垂直插入，主动应力和 IMP 一致性良好（ICC = 0.87 ± 0.04），但对于肌肉运动范围内的动态收缩和等长收缩的平行插入，主动应力和 IMP 一致性较差（ICC = 0.21 ± 0.22）。这些发现支持使用 IMP 测量来估计一系列收缩条件下的肌肉张力。