Purpose: Applying a backstroke ledge (BSL) during the backstroke start reportedly enhances starting performance; however, whether different BSL heights improve start performance remains unclear. We aimed to examine the effect of different BSL heights on flight distance, entry posture, and time to reach 5 m during backstroke start. Methods: Eleven male backstroke swimmers performed a 15-m backstroke under 3 different starting conditions, with BSL heights set at +0.04 m (High), 0 m (Medium), and -0.04 m (Low) trials relative to the water surface. One 60-Hz and two 120-Hz video cameras were used to analyze whole-body kinematics, including center-of-mass (CM) height and horizontal velocity at takeoff, flight distance, whole-body posture, and time to reach 5 m. Results: The high trial significantly reduced the time to reach 5 m compared with that of the Low trial (P = .013). Additionally, CM height (P < .001) and horizontal velocity (P = .042) at takeoff were higher in the High trial than in the Low trial; hence, the flight distance was extended (P = .032). While upper-body water-entry posture improved with higher BSL (P < .043), whole-body posture did not differ significantly (P > .090). Conclusion: Setting a BSL higher than the water surface enhances flight distance by increasing CM vertical position and horizontal velocity at takeoff, thereby improving backstroke start performance. Athletes are encouraged to familiarize themselves with higher BSL settings to enhance their start performance.
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