Comparison Of Marker-based And Markerless Motion Capture During Single And Double Leg Jumping

Abstract

Markerless motion capture (MMC) is a newer technology that utilizes advanced computer vision and machine learning algorithms to evaluate human movement. Traditional marker-based motion capture (MBC) systems can be time consuming for both participant and researcher and setup can often take more time than collection. Further, MMC allows athletes to perform in a more familiar environment without the potential error introduced by the laboratory environment. However, it is imperative to examine its accuracy in comparison to the gold-standard of conventional MBC. PURPOSE: To determine interrater reliability between a marker-based and markerless motion capture systems. METHODS: 15 collegiate basketball players (8 females, height: 180.8 ± 14.0 cm, mass: 80.8 ± 19.0 kg) participated in this study. 3 double leg drop vertical jumps (DVJ) and 3 maximum single leg vertical countermovement hops on each limb were performed. Limb dominance (Dom vs NDom) was self-reported through survey. Standard MBC techniques were utilized to track markers throughout the execution of each task. A MMC system collected data concurrently and used advanced computer vision and machine learning algorithms to estimate the pose of individuals during dynamic movements without the need of markers. Hip joint centers were estimated from each system and used to determine the lowest and highest vertical displacement during each trial. Intraclass correlation coefficient (ICC[3,1]) was used to determine the interrater reliability between systems. ICC and 95% confidence interval were used for interpretation. RESULTS: Interrater reliability between MMC and MBC was excellent for DOM side single leg jumps (MMC 47.8 ± 10.6 cm, MBC 47.1 ± 10.8 cm, ICC = 0.986 [95 CI 0.966, 0.994]), NDom side single leg jumps (MMC 48.4 ± 10.3 cm, MBC 47.2 ± 10.7 cm, ICC = 0.983 [95 CI 0.958, 0.993]), and double leg drop vertical jumps (MMC 67.7 ± 11.1 cm, MBC 66.9 ± 12.1 cm, ICC = 0.982 [95 CI 0.956, 0.993]). The root mean square error between systems was less than 2.3 cm (Dom: 1.8 cm, NDom: 2.2 cm, DVJ: 2.3 cm). CONCLUSIONS: Markerless motion capture techniques to calculate vertical jump displacement had excellent agreement to marker-based motion capture during both single leg and double leg tasks. Future studies should compare additional kinematic and kinetic variables between systems.