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Front-Crawl Instantaneous Velocity Estimation Using a Wearable Inertial Measurement Unit
Laboratory of Movement Analysis and Measurement, École Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland
Institute of Sport Sciences, University of Lausanne, 1015 Lausanne, Switzerland
* Author to whom correspondence should be addressed.
Received: 31 July 2012; in revised form: 17 September 2012 / Accepted: 17 September 2012 / Published: 25 September 2012
Abstract: Monitoring the performance is a crucial task for elite sports during both training and competition. Velocity is the key parameter of performance in swimming, but swimming performance evaluation remains immature due to the complexities of measurements in water. The purpose of this study is to use a single inertial measurement unit (IMU) to estimate front crawl velocity. Thirty swimmers, equipped with an IMU on the sacrum, each performed four different velocity trials of 25 m in ascending order. A tethered speedometer was used as the velocity measurement reference. Deployment of biomechanical constraints of front crawl locomotion and change detection framework on acceleration signal paved the way for a drift-free integration of forward acceleration using IMU to estimate the swimmers velocity. A difference of 0.6 ± 5.4 cm·s−1 on mean cycle velocity and an RMS difference of 11.3 cm·s−1 in instantaneous velocity estimation were observed between IMU and the reference. The most important contribution of the study is a new practical tool for objective evaluation of swimming performance. A single body-worn IMU provides timely feedback for coaches and sport scientists without any complicated setup or restraining the swimmer’s natural technique.
Keywords: accelerometer; gyroscope; biomechanical constraint; strap-down integration; swimming velocity
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Dadashi, F.; Crettenand, F.; Millet, G.P.; Aminian, K. Front-Crawl Instantaneous Velocity Estimation Using a Wearable Inertial Measurement Unit. Sensors 2012, 12, 12927-12939.
Dadashi F, Crettenand F, Millet GP, Aminian K. Front-Crawl Instantaneous Velocity Estimation Using a Wearable Inertial Measurement Unit. Sensors. 2012; 12(10):12927-12939.
Dadashi, Farzin; Crettenand, Florent; Millet, Grégoire P.; Aminian, Kamiar. 2012. "Front-Crawl Instantaneous Velocity Estimation Using a Wearable Inertial Measurement Unit." Sensors 12, no. 10: 12927-12939.