Durability in Junior Cyclists After Work Above Critical Power: Implications for Talent Identification

Background : Durability, defined as the ability to sustain performance following efforts above critical power (CP), is a critical determinant of elite cycling performance, yet its role in junior cyclists remains underexplored despite its relevance for talent identification. Objective : This study aimed to compare physiological profiles and high-intensity durability between an international-level group (ILG) and a national-level group (NLG) of junior cyclists, establishing normative values for talent detection. Methods : Forty-six male junior cyclists (ILG, n = 20; NLG, n = 26) were evaluated over a full season. CP, maximal aerobic power, and power-output decay (percentage of decay) after energy expenditures above CP (25–200 kJ) were measured using field-derived data across 6 durations (5 s to 30 min). Independent t tests and linear mixed models assessed group differences ( P < .05). Results : ILG demonstrated higher CP (383 vs 341 W, P = .003), maximal aerobic power (ILG 434 54 W vs NLG 391 44 W, P = .004), and minutes above CP (137 vs 113 min, P = .022) than NLG. NLG exhibited lower percentage of decay at 1 minute (−4.37%, P = .016), suggesting greater durability in short efforts. However, ILG showed lower percentage of decay at 5 to 30 minutes (eg, 1.7% at 5 min, P = .001), reflecting endurance capacity. Interindividual variability in percentage of decay (36%) underscored diverse fatigue responses among cyclists. Conclusion : ILG’s aerobic advantage and durability in prolonged efforts, contrasted with NLG’s resilience in short efforts, highlight durability after work above CP as a talent marker. Normative percentage-of-decay values provide benchmarks for junior talent identification.