【Research Review】Hydrodynamics of the Pool Flip Turn and the Effect of the Underwater Dolphin Kick: An International Scientific Literature Compilation and Review Report (No. 642)

Reference Journal Source: Sports Biomechanics • International Scientific Research Findings Review Series

This article examines the hydrodynamic characteristics of underwater glide length and the dolphin kick effect 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 somersaulting motion, 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 surface wave drag, while too deep requires additional distance and time costs to resurface. Most studies recommend an optimal glide depth in the 0.5–0.9 m range below the surface. The timing of dolphin kick initiation is equally critical—if you start kicking while the glide speed is still faster than your cruise pace, the drag from the kicking motion itself will actually slow you down overall; you should wait until the glide speed drops to near your normal pace before initiating high-frequency, low-amplitude dolphin kicks to sustain underwater momentum.

Time Allocation Comparison Across Turn Phases (Illustrative)

Core Research Conclusions and Practical Recommendations

• Push-off strength training: Dry-land training targeting lower-body explosive power (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 the ears, body extended) directly affects glide drag and deserves dedicated technical training sets
• Individualized glide distance: A longer glide 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-line swimming, as 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 will actually lower your average speed. The key is to find the critical point where “gliding is still faster than your pace” and 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 quite significant and deserves dedicated practice time.

References and Academic Citations

1. Sports Biomechanics — Research direction related to the mechanical phase analysis of swimming turn movements.
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 Pool Flip Turn and the Effect of the Underwater Dolphin Kick: An International Scientific Literature Compilation and Review Report (No. 474)
• 【Research Review】Hydrodynamics of the Pool Flip Turn and the Effect of the Underwater Dolphin Kick: An International Scientific Literature Compilation and Review Report (No. 906)
• 【Research Review】Hydrodynamics of the Pool Flip Turn and the Effect of the Underwater Dolphin Kick: An International Scientific Literature Compilation and Review Report (No. 864)
• 【Research Review】Hydrodynamics of the Pool Flip Turn and the Effect of the Underwater Dolphin Kick: An International Scientific Literature Compilation and Review Report (No. 1296)