Background: The human chair-rise ability reduces according to various factors such as; Age, Incidents, diseases and etc. The Sit-to-Stand (STS) movement strategy modification is a way chosen to compensate the STS inabilities.
Objective: Musculoskeletal evaluation of the effects of standing up strategy modification is beneficial for correct selection. The aim of this study is to compute, compare, and classify the biomechanical effects of each STS movement strategy.
Methods: A full-body human who stands up from seat with three various strategies are modeled and simulated with commercial musculoskeletal simulation software, AnyBody (Anybody Technology, Aalborg, Denmark). A specific algorithm is employed to compute time-histories of the reaction forces between body and seat.
Results: Time-histories of joint moments, joint loads and muscles forces are computed and compared between strategies. Two statistical analyses (Pearson product-moment correlation and paired-samples t-test) are also employed to compare the effects of strategy modification in various aspects. The major finding is that the body joints and muscles reactions to strategy modification are different or even antithetical to each other.
Conclusion: A table is derived which depicts the sequences of the body joints and muscles affected from strategy modification from the most to the least. This table could be practical for therapists, physicians, and rehabilitation devices experts.
Keywords: AnyBody; Sit-to-Stand strategy; biomechanics; chair-rise pattern; modeling; musculoskeletal; rehabilitation; simulation.