The purposes of this study were to clarify if force fluctuations during steady multi-muscle contractions have a temporal correlation with a low-frequency component of rectified surface EMG (rEMG) in the involved muscles and collection of that component across muscles allows for the reconstruction of force fluctuations across a wide range of contraction intensities. Healthy young men (n = 15) exerted steady isometric plantarflexion force at 5–60% of maximal force. Surface EMG was recorded from the medial and lateral gastrocnemii, soleus, peroneus longus, abductor hallucis, and tibialis anterior muscles. The cross-correlation function (CCF) between plantarflexion force fluctuations and low-pass filtered rEMG in each muscle was calculated for 8 s. To reconstruct force fluctuations from rEMGs, the product of rEMG and an identified constant factor were summed across muscles with time-lag compensation for electro-mechanical delay. A distinct peak of the CCF was found between plantarflexion force fluctuations and rEMG in most cases except for the tibialis anterior. The CCF peak was greatest in the medial gastrocnemius and soleus. Reconstructed force from rEMGs was temporally correlated with measured force fluctuations across contraction intensities (average CCF peak: r = 0.65). The results indicate that individual surface rEMG has a low-frequency component that is temporally correlated with net force fluctuations during steady multi-muscle contractions and contributes to the reconstruction of force fluctuations across a wide range of contraction intensities. It suggests a potential applicability of individual surface EMGs for identifying the contributing muscles to controlling or disturbing isometric steady force in multi-muscle contractions.

这项研究的目的是弄清楚稳定的多肌收缩过程中的力波动是否与受累肌肉中整流表面肌电图（rEMG）的低频分量具有时间相关性，跨肌肉集合该分量可以重建收缩力在很大范围内波动。健康年轻男性（ñ = 15）在最大力的5–60％处施加稳定的等角plant屈力。从内侧和外侧腓肠肌，比目鱼，长骨腓骨，外展幻觉和胫骨前肌记录表面肌电图。计算每个肌肉中plant屈力波动和低通滤波后的rEMG之间的互相关函数（CCF），持续8 s。为了重建来自rEMG的力波动，将rEMG的乘积和一个确定的常数因子相加，并在整个肌肉之间进行时延补偿，以实现机电延迟。在大多数情况下，除了胫前肌外，在plant屈力波动和rEMG之间发现了一个明显的CCF峰值。CCF峰值在腓肠肌内侧和比目鱼肌中最大。r  = 0.65）。结果表明，单个表面rEMG具有低频成分，该频率成分在稳定的多肌收缩过程中与净力波动在时间上相关，并有助于在较大范围的收缩强度中重建力波动。它暗示了单个表面肌电图在识别多肌收缩中控制或干扰等距稳定力的贡献肌肉方面的潜在适用性。