Estimating Active Drag Based on Full and Semi-Tethered Swimming Tests

Area of Science:

• Sports Science
• Biomechanics
• Fluid Dynamics

Background:

• Hydrodynamic resistance is a key factor in swimming performance.
• Estimating active drag (drag experienced during swimming) is crucial for understanding and improving technique.
• Previous methods for estimating active drag can be complex or require specialized equipment.

Purpose of the Study:

• To investigate the feasibility of using a "residual thrust method" to estimate active drag in swimming.
• To compare active drag values obtained from the "residual thrust method" with passive drag and active drag estimated by the "planimetric method".
• To determine the relationship between active and passive drag in human swimming.

Main Methods:

• Conducted full and semi-tethered swimming tests at various intensities (35-100% of individual propulsive force).
• Calculated active drag using the "residual thrust method" (propulsive force minus force exerted on tether).
• Measured passive drag through towing tests and estimated active drag using the "planimetric method" (Da × 1.5).

Main Results:

• Active drag was consistently higher than passive drag, with speed-specific drag coefficients (ka) approximately 1.5 times greater than passive drag coefficients (kp).
• The "residual thrust method" provided a viable way to estimate active drag.
• Active drag was found to be approximately 1.5 times larger than passive drag in human swimming.

Conclusions:

• Active drag in human swimming is significantly greater than passive drag.
• The "residual thrust method" offers a practical and accessible approach to estimate active drag in a swimming pool setting.
• This method utilizes basic equipment and simple calculations, making it suitable for ecological research and performance analysis.