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Interpreting the Projected Frontal Area in Front Crawl: Determining the Projected Frontal Area of Each Body Segment
Sohei Washino1, Akihiko Murai1, Tomoya Kadi
1Human Augmentation Research Center, National Institute of Advanced Industrial Science and Technology, Kashiwa, Chiba, JAPAN.
Medicine and Science in Sports and Exercise
|October 1, 2024
Summary
Calculating projected frontal area (PFA) for swimming segments needs to include horizontal velocity. Ignoring velocity overestimates upper limb contribution to pressure drag in front crawl.
Area of Science:
- Biomechanics of swimming
- Fluid dynamics in sports
- Human motion analysis
Background:
- Projected frontal area (PFA) is crucial for estimating drag in swimming.
- Previous methods may not fully account for dynamic body segment movement.
- Accurate drag calculation is essential for performance optimization.
Purpose of the Study:
- To develop and validate a method for calculating PFA of individual body segments in front crawl.
- To compare pressure drag calculations with and without considering horizontal velocity.
- To provide evidence for interpreting PFA in front crawl biomechanics.
Main Methods:
- Developed digital human models from 3D body scans of competitive swimmers.
- Reconstructed 3D swimming motion using inverse kinematics and underwater motion capture.
- Calculated PFA for eight body segments and compared pressure drag index under static (PFA only) and dynamic (PFA + horizontal velocity) conditions.
Main Results:
- The pressure drag index was significantly higher for the humerus, ulna, and hand segments under the static condition compared to the dynamic condition (P < 0.001).
- This indicates that PFA alone overestimates the contribution of these segments to pressure drag.
Conclusions:
- The projected frontal area of upper limb segments overestimates their contribution to pressure drag during front crawl when horizontal velocity is not considered.
- Dynamic calculation of PFA, incorporating horizontal velocity, provides a more accurate assessment of pressure drag in swimming.
- This methodology enhances the understanding of biomechanical forces in front crawl.
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