Activity Identification, Classification, and Representation of Wheelchair Sport Court Tasks: A Method Proposal

Abstract

Background: Monitoring player mobility in wheelchair sports is crucial for helping coaches understand activity dynamics and optimize training programs. However, the lack of data from monitoring tools, combined with a lack of standardized processing approaches and ineffective data presentation, limits their usability outside of research teams. To address these issues, this study aimed to propose a simple and efficient algorithm for identifying locomotor tasks (static, forward/backward propulsion, pivot/tight/wide rotation) during wheelchair movements, utilizing kinematic data from standard wheelchair mobility tests.

Methods: Each participant's wheelchair was equipped with inertial measurement units-two on the wheel axes and one on the frame. A total of 36 wheelchair tennis and badminton players completed at least one of three proposed tests: the star test, the figure-of-eight test, and the forward/backward test. Locomotor tasks were identified using a five-step procedure involving data reduction, symbolic approximation, and logical pattern searching.

Results: This method successfully identified 99% of locomotor tasks for the star test, 95% for the figure-of-eight test, and 100% for the forward/backward test.

Conclusion: The proposed method offers a valuable tool for the simple and clear identification and representation of locomotor tasks over extended periods. Future research should focus on applying this method to wheelchair court sports matches and daily life scenarios.

Keywords: monitoring; paralympic; performance; symbolic aggregate approximation.

Figure 1

Overview of the methodology presented in this study to identify and represent the locomotor tasks performed during manual wheelchair locomotion [33].

Figure 2

Identification of locomotor tasks and representation of trajectories (on the right) from the three field tests conducted ((A) forward/backward test; (B) star test; (C) figure-of-eight-test). Each color is associated with locomotor tasks (green: forward propulsion; yellow: backward propulsion; red: static phase; blue: wide rotation). On the left side, colors are overlaid on the yaw angular velocity signals of the wheelchair. In the graph representing the locomotor tasks of the figure-of-eight test, the frame composed of dashed lines is used to represent left turns (positive values), and the frame composed of dots is used to represent right turns (negative values).

Figure 3

Representation of the locomotor tasks detected using the SAX algorithm for the athlete with asynchronous propulsion during the figure-of-eight test. The colors are overlaid on the yaw angular velocity signals of the wheelchair that exhibit alternance of positive and negative values, meaning that the turning direction changed during the full recognized wide rotation task.