Analyzing Intra-Cycle Velocity Profile and Trunk Inclination during Wheelchair Racing Propulsion

Area of Science:

• Biomechanics
• Sports Science
• Rehabilitation Engineering

Background:

• Trunk inertia significantly impacts manual wheelchair (MWC) propulsion biomechanics.
• Maximal wheelchair velocity often occurs post-handrim release in daily and sports propulsion.
• Understanding propulsion dynamics is crucial for optimizing wheelchair athlete performance.

Purpose of the Study:

• To analyze linear velocity and trunk kinematics in elite wheelchair racers during stabilized speed propulsion.
• To investigate the factors contributing to velocity peaks within a single propulsion cycle.
• To differentiate propulsion patterns among athletes with varying impairment levels.

Main Methods:

• Monitored MWC and trunk kinematics of eight wheelchair racers (7 elite, 1 intermediate; T54, T53, T52 classifications) using inertial measurement units.
• Recorded data during 400 m races at stabilized speeds.
• Computed an average propulsion cycle for each athlete to analyze intra-cycle velocity profiles.

Main Results:

• Observed distinct propulsion patterns among athletes, characterized by 1, 2, or 3 peaks in their intra-cycle velocity profiles.
• A second velocity peak, often attributed to trunk inertia, was present.
• For athletes with minimal trunk motion, a second peak may stem from arm inertia or specific propulsion techniques.

Conclusions:

• Wheelchair propulsion patterns are diverse, even among elite athletes.
• The origin of secondary velocity peaks can be attributed to trunk inertia, arm inertia, or propulsion technique, particularly in athletes with limited trunk mobility.
• Further research is needed to fully elucidate the complex interplay of factors influencing wheelchair propulsion efficiency.