Development of an automated method to detect sitting pivot transfer phases using biomechanical variables: toward a standardized method

Thirty-five individuals with a spinal cord injury performed two SPTs between seats of similar height using their usual SPT technique. Kinematics and kinetics were recorded using an instrumented transfer assessment system. Based on kinetic and kinematic measurements, a relative threshold-based algorithm was developed to identify four distinct phases: pre-lift, upper arm loading, lift-pivot and post-lift phases. To determine the stability of the algorithm between the two SPTs, Student t-tests for dependent samples were performed on the absolute duration of each phase.The mean total duration of the SPT was 2.00 ± 0.49 s. The mean duration of the pre-lift, upper arm loading, lift-pivot and post-lift phases were 0.74 ± 0.29 s, 0.28 ± 0.13 s, 0.72 ± 0.24 s, 0.27 ± 0.14 s whereas their relative contributions represented approximately 35%, 15%, 35% and 15% of the overall SPT cycle, respectively. No significant differences were found between the trials (p = 0.480-0.891).The relative threshold-based algorithm used to automatically detect the four distinct phases of the SPT, is rapid, accurate and repeatable. A quantitative and thorough description of the precise phases of the SPT is prerequisite to better interpret biomechanical findings and measure task performance. The algorithm could also become clinically useful to refine the assessment and training of SPTs.The large number of sitting pivot transfers (SPTs) performed daily by individuals with a spinal cord injury, along with the excessive physical strains acting on the wrist, elbow and shoulder joints while carrying out this functional task likely contributes to the development or perpetuation of secondary upper extremity musculoskeletal impairments over time in this population [1]. Such a potentially damaging cycle deserves attention given the relevance of preserving U/E integrity and optimizing performance in this population. Comprehensive biomechanical assessments of SPTs have been shown to be a useful approach to gain