Biarticular energy transfer mechanisms of the gastrocnemii muscles are associated with managing body energy during hole negotiation gait

In this study, the energy transfer potential between the ankle and knee joints via the biarticular gastrocnemius medialis and lateralis muscles was investigated, as well as its association with changes in total centre of mass (CoM) energy during hole negotiation - a common task in daily life locomotion - and level walking. Whole-body kinematics and activation patterns of the gastrocnemii and vasti muscles were measured during the preparation, hole, and recovery steps in 18 participants. During hole negotiation, we found a significant (p < 0.001) increase in the peak-to-peak range of total CoM energy, providing evidence for an increased challenge in managing CoM energy. We observed significantly (p < 0.001) increased potential for energy transfer between the ankle and knee joints via the biarticular gastrocnemii muscles, accompanied by the gastrocnemii and vasti muscles being active during the energy transfer phases. Finally, we found that the increase in energy transfer potential from the ankle to the knee joint was associated with a decrease in total CoM energy, and the increase in energy transfer potential from the knee to the ankle joint was associated with an increase in total CoM energy. Our findings demonstrate increased involvement of biarticular mechanisms in the management of total CoM energy during hole negotiation compared to level walking.