【Research Review】Hydrodynamic Analysis of Flip Turns and Underwater Dolphin Kick Effects in Swimming Pools: A Biomechanical Quantification Experiment Report (Article 1407)

Reference Source: Sports Biomechanics • International Research Findings Review Series

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

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 key determinants of speed maintenance 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 at the water surface, 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 below the surface. The timing of dolphin kick initiation is equally critical—initiating the kick 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 only be initiated once the glide speed has dropped to near normal pace to sustain underwater momentum.

Time Allocation Across Turn Phases (Schematic)

Core Research Conclusions and Practical Recommendations

• Wall push-off strength training: Land-based lower-body explosive power training (e.g., jump training) helps improve initial push-off velocity
• Streamline posture practice: Body position during the underwater glide phase (arms pressed against ears, body extended) directly affects glide resistance 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—excessive gliding causes excessive speed decay
• Integrating turn rhythm into pace training: Long-distance training sets should incorporate actual turn practice rather than only straight-line swimming, as the cumulative effect of turn quality is substantial 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 average speed. The key is to find the critical point where “glide speed is still faster than pace” and transition into the dolphin kick.

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

A: Yes. Even for recreational-level long-distance swimmers, the cumulative time benefit of optimized turn technique across an entire race or training session is quite significant and warrants dedicated practice time.

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.

Further Reading

• 【Research Review】Hydrodynamic Analysis of Flip Turns and Underwater Dolphin Kick Effects in Swimming Pools: A Biomechanical Quantification Experiment Report (Article 1155)
• 【Research Review】Hydrodynamic Analysis of Flip Turns and Underwater Dolphin Kick Effects in Swimming Pools: Exploring the Relationship Between Clinical Medicine and Athletic Performance (Article 1479)
• 【Research Review】Hydrodynamic Analysis of Flip Turns and Underwater Dolphin Kick Effects in Swimming Pools: Frontiers in Exercise Physiology Research Progress (Article 1470)
• 【Research Review】Hydrodynamic Analysis of Flip Turns and Underwater Dolphin Kick Effects in Swimming Pools: A Study of Elite Athletes’ Physical Characteristics (Article 1371)