Lead author Dr. Janneke Schwaner has recently published a new paper in Journal of Experimental Biology, comparing in vivo operating ranges of the guinea fowl lateral gastrocnemius to the force-length and force-velocity properties measured in situ. We found that the muscle operates at shorter than optimal lengths in steady walking and running. We hypothesize that this provides the safety of additional force reserve for locomotion in uneven terrain or otherwise unpredictable conditions.
Schwaner, M. J., Mayfield, D. L., Azizi, E., & Daley, M. A. (2024). Linking in vivo muscle dynamics to in situ force-length and force-velocity reveals that guinea fowl lateral gastrocnemius operates at shorter than optimal lengths. Journal of Experimental Biology, jeb-246879.