Modifications in Wheelchair Propulsion Technique with Speed.

Area of Science:

• Biomechanics
• Rehabilitation Engineering
• Musculoskeletal Health

Background:

• Manual wheelchair (WC) propulsion (WCP) involves repetitive upper limb loading, often leading to shoulder pain and reduced quality of life in individuals with paraplegia.
• Understanding how users adapt their propulsion mechanics to increased speeds is crucial for preventing shoulder injuries.

Purpose of the Study:

• To investigate how manual wheelchair users with paraplegia adjust their propulsion mechanics when increasing their speed.
• To determine how these adjustments accommodate the higher reaction forces (RFs) at the pushrim.

Main Methods:

• Measured upper extremity kinematics and pushrim RFs in 40 experienced manual WC users with paraplegia.
• Compared propulsion mechanics at self-selected free and fast speeds using a stationary ergometer.
• Analyzed within-subject kinematic and kinetic differences between speeds.

Main Results:

• Higher propulsion speeds correlated with increased RF magnitude and shoulder net joint moment (NJM), and shorter pushrim contact duration.
• 27% of participants altered their WCP mechanics by adjusting RF orientation relative to upper extremity segments at faster speeds.

Conclusions:

• Reorienting RFs is an effective strategy for manual wheelchair users to reduce shoulder NJM demands during faster propulsion.
• Identifying adaptive propulsion strategies is key to preserving shoulder health and enhancing the quality of life for manual WC users.