Miller, Michael F.van der Kruk, ElineSilverman, Anne K.2023-05-152023-05-15https://hdl.handle.net/11124/176889https://doi.org/10.25676/11124/176889Advisors and collaborators: Anne K. Silverman, Eline van der Kruk.Balance control and pain regulation require modulating muscle activity during movement. For example, adults with chronic ankle instability (CAI) had smaller ankle plantarflexor muscle activity and ankle joint moments during walking when compared to healthy participants. Additionally, greater peroneus longus activity has been hypothesized to modulate ankle loading at heel strike during walking for individuals with CAI. Dynamic muscle forces cannot be directly measured non-invasively, and few studies have investigated the effect of muscle recruitment on joint contact forces during dynamic rising tasks. The purpose of this study was to develop movement simulations to determine how ankle injury affects biomechanics during rising. Two participants, one healthy and one recovering from an ankle fracture, completed several rising trials. A musculoskeletal model was scaled to each participant and used to compare peak muscle and ankle joint contact forces between participants. The non-injured participant’s soleus produced 87% greater force and their peroneus longus produced 3.5 times greater force compared to the injured individual. Consistent with greater muscle forces, the healthy participant had 2.3 times greater resultant ankle joint contact force compared to the injured individual. An altered subtalar angle may have been chosen to reduce muscle force requirements and associated joint contact forces, protecting the injured joint, and mitigating pain. Offloading an injured ankle joint was achieved by an altered subtalar angle associated with larger muscle moment arms, which required smaller ankle muscle forces to successfully rise.presentation slidesengCopyright of the original work is retained by the author.Text