Correlation Between Muscle Strength and Cycling Speed Measured Using Motion Capture Camera in VR Environment

Research Objectives: To indirectly estimate the lower extremity strength, we developed a camera based VR cycling game. Because, strength is the most important element in physical rehabilitation, however, direct measure of strength is not possible when developing VR based rehabilitation contents using motion capture camera. Therefore, we studied the correlation between VR cycling speed and the peak knee torque measured using a Biodex isokinetic dynamometer to see if the maximum pedaling speed during VR cycling can indirectly represent lower limb muscle strength.

Design: A cross sectional correlational study. The subjects pedaled at a maximum speed for 15 seconds in VR environment. VR speedometer is programmed using the Unity engine, which counts number of revolutions whenever a trigger collider on the right ankle touches the trigger collider placed in the path of the right foot during cycling. Then the number of revolution acquired in 15 seconds was converted to revolutions per minute (RPM). Peak flexion/extension torques were measured using an isokinetic dynamometer to confirm the lower extremity muscle strength.

Setting: All measurements were obtained at the Experimental motor behavior laboratory in the University.

Participants: Thirty healthy adults without known medical, physical, and cognitive conditions that would interfere with the experimental procedure.

Interventions: Not applicable

Main Outcome Measures: Main outcome measures were the pedaling speed (RPM) obtained by VR speedometer and the peak knee flexion/extension torque measured using isokinetic dynamometer.

Results: The results of the Pearson correlation analysis revealed a significant moderate positive correlation between the pedaling speed of the VR cycling game and the peak torque of knee flexion (r=0.639) and extension (r=0.598).

Conclusions: This study suggests the potential of measuring the maximum pedaling speed using motion capture camera in a VR environment as an indirect assessment of muscle strength. However, technological improvements must be followed to obtain more accurate estimation of muscle strength from the VR cycling test.

Author(s) Disclosures: No conflict of interest existing.