【Research Review】Hydrodynamics of the Flip Turn and the Effect of Underwater Dolphin Kicking in the Pool: Latest Academic Literature Review and Training Practice (Article 714)

Source Reference: Sports Biomechanics • International Research Findings Review Series

This article explores the hydrodynamic characteristics of glide distance and dolphin kick effects in the pool flip turn.

Mechanical Phase Breakdown of the Flip Turn

The flip turn can be broken down into four mechanical phases: the final stroke approaching the wall, the somersault rotation, the explosive power output at the moment of wall push-off, and the underwater glide with dolphin kick transition after push-off. Among these, the explosive power at push-off and the gliding posture are the keys to maintaining speed after the turn—the faster the initial push-off velocity and the better the body’s streamline, the longer the high-speed distance that can be maintained during the underwater glide.

Underwater Glide Depth and Dolphin Kick Initiation Timing

There is an optimal range for underwater glide depth after push-off: too shallow (near the surface) is affected by wave drag, while too deep incurs additional distance and time costs for ascending. Most studies recommend an optimal glide depth in the 0.5–0.9 m range. The timing of dolphin kick initiation is equally critical—kicking while the glide speed is still faster than cruise pace will actually slow overall speed due to the drag created by the kicking motion itself; the high-frequency, low-amplitude dolphin kick should be initiated only after the glide speed drops to near normal pace to sustain underwater momentum.

Time Allocation Across Turn Phases (Schematic)

Core Research Conclusions and Practical Recommendations

• Push-off strength training: Land-based lower-body explosive power training (e.g., jump training) helps improve initial velocity at the moment of push-off
• Streamline posture practice: Body posture during the underwater glide phase (arms pressed against ears, body extended) directly affects glide drag and warrants dedicated technical training sets
• Individualized glide distance: Longer glide distance is not always better; the optimal transition point depends on individual push-off strength and dolphin kick ability—overextending the glide causes excessive speed decay
• Integrating turn rhythm into pace training: Long-distance training sets should include actual turn practice rather than only straight swimming; the cumulative effect of turn quality is considerable in long-distance events

Common Research Q&A (FAQ)

Q: Is a longer underwater glide always better?

A: No. Glide speed continuously decays with distance, and gliding too long actually lowers average speed. The key is finding the critical point where “gliding is still faster than pace” to transition into the dolphin kick.

Q: Do amateur swimmers also need to practice flip turn technique?

A: Yes. Even for amateur-level long-distance swimmers, the cumulative time benefit of optimized turn technique across an entire race or training session is significant and worth dedicating specific practice time to.

References and Academic Citations

1. Sports Biomechanics — Research directions related to mechanical phase analysis of swimming turns.
2. Journal of Sports Sciences — Literature related to quantitative research on underwater glide depth and dolphin kick efficiency.

Related Reading

• 【Research Review】Hydrodynamics of the Flip Turn and the Effect of Underwater Dolphin Kicking in the Pool: Latest Academic Literature Review and Training Practice (Article 516)
• 【Research Review】Hydrodynamics of the Flip Turn and the Effect of Underwater Dolphin Kicking in the Pool: Latest Academic Literature Review and Training Practice (Article 627)
• 【Research Review】Hydrodynamics of the Flip Turn and the Effect of Underwater Dolphin Kicking in the Pool: Latest Academic Literature Review and Training Practice (Article 879)
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