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Quantifying Added Drag in Swimming With Parachutes: Implications for Resisted Swimming Training
Vittorio Coloretti1, Silvia Fantozzi2,3, Giorgio Gatta1
1Department for Life Quality Studies, University of Bologna, Bologna, Italy.
Journal of Strength and Conditioning Research
|April 23, 2025
Summary
This study quantifies the drag of swimming parachutes, finding resistance changes when a swimmer is present. Coaches can use this data to better estimate training loads with parachutes.
Area of Science:
- Sports Science
- Hydrodynamics
- Biomechanics
Background:
- Swimming parachutes are common training tools for resistance.
- The actual added drag and hydrodynamic effects of a swimmer using parachutes are not well understood.
Purpose of the Study:
- To quantify the drag coefficient (k) of commercial swimming parachutes.
- To investigate how a swimmer's presence (passive or active) affects parachute drag.
- To provide data for coaches to accurately assess training loads.
Main Methods:
- Measured drag coefficient (k) for four parachute sizes under three conditions: towed alone, pulled by a passive swimmer, and pulled by an active swimmer.
- Used an electromechanical device and residual thrust methods for drag assessment.
- Tested at various velocities to determine drag at different speeds.
Main Results:
- Drag coefficients (kpara) for parachutes (400-1,600 cm²) ranged from 15.4 to 73.9 N·s²·m⁻².
- Parachute resistance decreased by ~21% when pulled by a passive swimmer.
- Resistance increased by ~15% when pulled by an actively propelling swimmer.
Conclusions:
- Swimmer interaction significantly alters parachute drag, with drafting and added mass effects playing roles.
- The findings allow for more precise quantification of added load during resisted swimming training.
- Coaches can now better estimate training intensity based on parachute size and swimming velocity.
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