Data from: Neuromechanical coupling within the human triceps surae and its consequence on individual force sharing strategies

Little is known about the factors that influence the coordination of
synergist muscles that act across the same joint, even during single-joint
isometric tasks. The overall aim of this study was to determine the nature
of the relationship between the distribution of activation and the
distribution of force-generating capacity among the three heads of the
triceps surae (soleus [SOL], gastrocnemius medialis [GM] and lateralis
[GL]). Twenty volunteers performed isometric plantarflexions during which
the activation of GM, GL and SOL was estimated using electromyography
(EMG). Functional muscle physiological cross-sectional area (PCSA) was
estimated using imaging techniques and was considered as an index of
muscle-force generating capacity. The distribution of activation and PCSA
among the three muscles varied greatly between participants. A significant
positive correlation between the distribution of activation and the
distribution of PCSA was observed when considering the two bi-articular
muscles at intensities ≤50% of the maximal contraction (0.51