Sit-to-stand biomechanics : a systematic review
Objective: This review focuses on studies that enhance our knowledge of the biomechanics of the sit-to-stand (STS) quantitatively. The questions asked and the methods of study have led to the partitioning of the STS into components, or phases. Our goal is to summarize the methodological approaches and define the phases of a STS transfer in order to provide a standard practice for STS.
Data Sources: Electronic database searches were conducted in PubMed and Google Scholar from inception to February 2021. Study Selection: Articles with a combination of the keywords “sit-to-stand”, “biomechanics”, “stability” and “postural control” were searched. Only the articles that provided quantitative biomechanical insights of the STS movement were included. Data Extraction: We categorized the studies by the questions posed, the measurement techniques used, and the definition of phases. Data Synthesis: Seventy-two papers published between 1976 and 2021 that provided quantitative biomechanical insights of the STS movement itself were included in this review. Among the studies that qualified for this review, research interest in the STS may be parsed into the following categories: a) how the movement is performed, b) use of the STS to understand postural stability, and c) use of the STS to understand clinical differences in performance. Conclusion: Definitions of events in the STS that define phases are inconsistent. The major reason identified is due to differences in the purpose of the studies or equipment used. Four studies dividing STS into 2 phases, eight studies divided STS into 3 phases, and 2 studies divided STS into 4 phases and 2 studies divided STS into 5 phases. At a minimum, the STS is typically deconstructed into two phases, with seat-off being the demarcation of transition between phases. This is based on the characteristics of muscle power or on select kinematic events. However, 10 different ways in which the event of ‘seat-off’ has been defined shows the impact of differences in measurement technique. These differences between studies result in contradictory definitions of the same event. These findings reveal a need for standardization of event definition and recommendations on measurement techniques.