Data from: Tuning of feedforward control enables stable muscle force-length dynamics after loss of autogenic proprioceptive feedback

Animals must integrate feedforward, feedback and intrinsic mechanical
control mechanisms to maintain stable locomotion. Recent studies of guinea
fowl (Numida meleagris) revealed that the distal leg muscles rapidly
modulate force and work output to minimize perturbations in uneven
terrain. Here we probe the role of reflexes in the rapid perturbation
responses of muscle by studying the effects of proprioceptive loss. We
induced bilateral loss of autogenic proprioception in the lateral
gastrocnemius muscle (LG) using self-reinnervation. We compared in vivo
muscle dynamics and ankle kinematics in birds with reinnervated and intact
LG. Reinnervated and intact LG exhibit similar steady state mechanical
function and similar work modulation in response to obstacle encounters.
Reinnervated LG exhibits 23ms earlier steady-state activation, consistent
with feedforward tuning of activation phase to compensate for lost
proprioception. Modulation of activity duration is impaired in rLG,
confirming the role of reflex feedback in regulating force duration in
intact muscle.