The Relationship between Independent Transfer Skills and Upper Limb Kinetics in Wheelchair Users

Transfers are one of the most physically demanding wheelchair activities. The purpose of this study was to determine if using proper transfer skills as measured by the Transfer Assessment Instrument (TAI) is associated with reduced loading on the upper extremities. Twenty-three wheelchair users performed transfers to a level-height bench while a series of forces plates, load cells, and a motion capture system recorded the biomechanics of their natural transferring techniques. Their transfer skills were simultaneously evaluated by two study clinicians using the TAI. Logistic regression and multiple linear regression models were used to determine the relationships between TAI scores and the kinetic variables on both arms across all joints. The results showed that the TAI measured transfer skills were closely associated with the magnitude and timing of joint moments ( < .02, model R 2 values ranged from 0.27 to 0.79). Proper completion of the skills which targeted the trailing arm was associated with lower average resultant moments and rates of rise of resultant moments at the trailing shoulder and/or elbow. Some skills involving the leading side had the effect of increasing the magnitude or rate loading on the leading side. Knowledge of the kinetic outcomes associated with each skill may help users to achieve the best load-relieving effects for their upper extremities

Assessment of Muscle Activation of Caregivers Performing Dependent Transfers With a Novel Robotic-Assisted Transfer Device Compared With the Hoyer Advance

OBJECTIVE: The purpose of this study was to compare muscle activity in caregivers while using a novel robotic assistive transfer device (Strong Arm) to a clinical standard of care (Hoyer Advance). DESIGN: A Quasi-Experimental design was used in which twenty caregivers (33±15 years old) performed transfers with three surfaces (toilet, bench and shower chair) with the Strong Arm and Hoyer Advance. Transfer completion time (sec), peak percentage surface electromyography (EMG) and integrated EMG of the bilateral erector spinae, latissimus dorsi, pectoralis major and anterior deltoid were measured. RESULTS: Caregivers required less transfer time when transferring from wheelchair to surface using the Hoyer Advance (p=.011, f=.39). Lower back: significantly lower pEMG were found using Strong Arm in 50% and for the iEMG in 25% of the cases, with the remaining cases showing no significant differences. Shoulder: significantly lower pEMG were found using Strong Arm in 19% of transfers and lower iEMG was found in 25% of transfers when using the Hoyer Advance, with the remaining cases showing no significant differences. CONCLUSION: While back muscle activation during Strong Arm transfers is statistically, but not clinically, lower, additional features that couple with significantly lower muscle activation make it an alternative to the clinical standard for further research and possible clinical applicability