Purpose: This study aimed to evaluate the effects of three different crank lengths (165 mm, 170 mm, and 175 mm) on cycling efficiency, sprint performance, and perceived fatigue in high-level amateur road cyclists. Methods: A single-blind, randomized crossover design was employed, involving 28 trained male cyclists who completed three trials, each using a different crank length. Performance metrics, cycling economy (CE) including 20-min cycling under 60 % VO2MAX, peak and average power during a 6s sprint, cadence, heart rate, and perceived exertion, were measured using validated ergometers and metabolic analyzers. Results: The results indicated significant differences in 60 %VO2MAXRPE were observed between the 165 mm and 175 mm cranks (p 0.34). Conclusion: For high-level amateur road cyclists, using a 165 mm or 170 mm crank reduces subjective fatigue compared to a 175 mm crank, influencing affecting cycling efficiency or sprint performance. These findings help refine crank length recommendations to optimize performance, reduce injury risk, and improve comfort for high-level amateur road cyclists.