Biomechanical inter-relationships between physical and motor features in maximal effort locomotion.

This paper summarises research on the biomechanical inter-relationships between motor and physical features in maximal-effort locomotion. It first addresses separately conducted motion analyses and physical measurements, and then discusses their integration. In running single-leg jump, the human-specific, highest jumping mode, movements induced by actions other than lower-limb extension, such as stance-leg pivoting and pelvic elevation, generate more than half of the effective energy directly contributing to centre-of-mass height, highlighting the relevance of human-specific morphological features. Some effective energy generation by non-extensor movements is common to other locomotion modes, such as sprinting and cutting. These non-extensor contributions to propulsion during maximal-effort locomotion suggest that the way locomotion is executed reflects general human morphological and mechanical properties. Among morphological and mechanical properties, this paper emphasises those passively related to motor execution, in particular, inertial properties and tendon stiffness, as potential determinants of individually optimised motor solutions. These passive properties exhibit substantial inter-individual variability even within a single population; for example, the highest recorded lower-limb moment of inertia was 1.7 times the lowest. Meanwhile, studies combining motion and mechanical/morphological measurements remain limited. The integration of different areas within biomechanics is suggested as a key to unlocking the principles underlying human motor performance.