Consistency as the Primary Driver of Performance in Amateur Half-Marathon Runners: An Applied Coaching Analysis

Training consistency is widely advocated in endurance coaching, yet its relative importance compared with training volume remains underexplored in applied, non-elite settings. This retrospective observational study examined the relationship between training consistency, weekly volume, and half-marathon performance outcomes in 18 amateur runners completing a minimum 16-week preparation cycle. Runners were classified into three consistency groups (High: uninterrupted training; Medium: one to two breaks of 7-14 days; Low: multiple interruptions), based on coaching logs and TrainingPeaks records. Performance outcomes were assessed by personal best (PB) achievement and mean improvement in finish time. Runners in the High and Medium consistency groups achieved personal bests in 83% of cases, with mean improvements of 15.8 and 11.8 minutes respectively. Runners classified as Low consistency recorded no PB achievements and a marginal mean decline of 0.6 minutes. A clear threshold effect was observed: without training continuity, volume alone did not produce performance gains. These findings support consistency as the primary prerequisite for improvement in amateur endurance runners, with weekly volume acting as a secondary amplifier. Implications for coaching practice and athlete self-management are discussed.