151. A Comparison of Computational Methods to Determine Intrastroke Velocity in Swimming Using IMUs
- Author
-
Rebecca Pahl, Peter Milburn, David V. Thiel, and Matthew T. O. Worsey
- Subjects
Heading (navigation) ,020208 electrical & electronic engineering ,Significant difference ,030229 sport sciences ,02 engineering and technology ,Rotation ,Geodesy ,03 medical and health sciences ,Acceleration ,0302 clinical medicine ,Inertial measurement unit ,0202 electrical engineering, electronic engineering, information engineering ,Breaststroke ,Electrical and Electronic Engineering ,Robust analysis ,Instrumentation ,Mathematics - Abstract
Sacrum located IMU sensors were used to monitor three-axis acceleration and three-axis rotation from elite swimmers in competition conditions. The intrastroke velocity was determined for each swimmer using their preferred swim stroke (freestyle, backstroke, and breaststroke) using three different calculation techniquesdual-axis acceleration, dual-axis acceleration eliminating the static gravity constant, and altitude and heading reference system. The mean intrastroke velocity variation (averaged over one 50-m lap) in freestyle swimming was less than 0.6 in all cases. This resulted in a timing under-estimate of less than 0.60ms for freestyle, 4.0ms for breaststroke, and a timing overestimate of less than 6.2ms for backstroke. The difference was less than 5 over the complete stroke (one way ANOVA p > 0.05), indicating no significant difference in the velocity profiles. These simple, robust analysis techniques can be used to quantify variations in every stroke as the swimmer fatigues, providing significant information to coaching staff and athletes.
- Published
- 2018