Swimming Phase-Based Performance Evaluation Using a Single IMU in Main Swimming Techniques.

Area of Science:

• Sports Science
• Biomechanics
• Performance Analysis

Background:

• Optimizing swimming training requires comprehensive performance monitoring.
• Swimmers progress through distinct phases: wall push-off, glide, stroke preparation, and swimming.
• Coaches aim to enhance swimmer performance in each specific phase.

Purpose of the Study:

• To evaluate the utility of a sacrum-worn inertial measurement unit (IMU) for assessing elite swimmer performance.
• To analyze performance across four key swimming techniques: front crawl, breaststroke, butterfly, and backstroke.
• To determine the IMU's potential in evaluating specific swimming phases.

Main Methods:

• Nineteen elite swimmers performed 25m trials in four techniques wearing a sacrum IMU.
• Data from the IMU were correlated with reference systems (tethered speedometer, cameras).
• Kinematic variables from the IMU were extracted for each swimming phase and used to estimate performance metrics via regression analysis.

Main Results:

• The study identified relevant kinematic variables from the IMU for each swimming phase.
• A linear regression model using selected IMU variables achieved R² > 0.75 and relative RMSE < 10% for most metrics.
• The selected variables offered interpretable insights into phase-specific motion characteristics.

Conclusions:

• A single sacrum-worn IMU is a viable tool for comprehensive swimming performance evaluation.
• The IMU can provide a broad spectrum of performance-related kinematic data across major swimming styles.
• This technology aids coaches in optimizing training by offering detailed insights into swimmer performance.