Indicator analysis of the footwork in the world's top badminton athletes based on markerless motion measurement.

Introduction: This study aimed to quantitatively compare the footwork characteristics of world-class badminton players and high school athletes using a markerless motion measurement technique, and to clarify the effects of rally length on movement speed and speed variability. Methods: Positional data of players were automatically extracted from match footage, and multiple performance indicators, including movement speed, the coefficient of variation (CV) of speed, and the frequency of acceleration and deceleration - were calculated. Additionally, rallies were categorized into segments, and changes in footwork characteristics across these segments were analyzed. Results: The results revealed high speed variability accompanied by rapid acceleration and deceleration in the early stages of rallies, particularly pronounced in top-level players who exhibited large speed fluctuations over short periods. As rallies progressed, both average speed and speed variability gradually decreased, suggesting that players may efficiently regulate their pace to maintain performance. In high school athletes, maintaining speed variability during later rally stages was more challenging, likely reflecting limitations in physical capacity and technical skills. Discussion: These findings highlight not only the quantitative assessment of footwork but also the importance of qualitative aspects such as pace-control ability. The results provide valuable insights for designing training programs aimed at improving competitive performance.