Biewener, AndrewLai, Adrian K.M.Wakeling, James M.2019-07-242019-05-24Lai, Adrian K.M., Andrew M. Biewener, and James M. Wakeling. 2019. "Muscle-specific Indices to Characterise the Functional Behaviour of Human Lower-limb Muscles during Locomotion." Journal of Biomechanics 89 (2019): 134-38.0021-9290http://nrs.harvard.edu/urn-3:HUL.InstRepos:40999588The mechanical output of a muscle may be characterised by having distinct functional behaviours, which can shift to satisfy the varying demands of movement, and may vary relative to a proximo-distal gradient in the muscle-tendon architecture (MTU) among lower-limb muscles in humans and other terrestrial vertebrates. We adapted a previous joint-level approach to develop a muscle-specific index-based approach to characterise the functional behaviours of human lower-limb muscles during movement tasks. Using muscle mechanical power and work outputs derived from experimental data and computational simulations of human walking and running, our index-based approach differentiated known distinct functional behaviours with varying mechanical demands, such as greater spring-like function during running compared with walking; with anatomical location, such as greater motor-like function in proximal compared with the distal lower-limb muscles; and with MTU architecture, such as greater strut-like muscles fibre function compared with the MTU in the ankle plantarflexors. The functional indices developed in this study provide distinct quantitative measures of muscle function in the human lower-limb muscles during dynamic movement tasks, which may be beneficial towards tuning the design and control strategies of physiologically-inspired robotic and assistive devices.en-USBiophysicsRehabilitationOrthopedics and Sports MedicineBiomedical EngineeringJournal Article2019-07-2410.1016/j.jbiomech.2019.04.027