This study aimed to determine how the speed–distance relationship, described by critical speed (CS) and distance prime (D′), is altered with aging.
Official race data from the past eight World Masters Athletics Indoor Track and Field World Championships were used for this study. CS and D′ were calculated for female and male athletes (35–90 yr of age) who registered times for the 800-, 1500-, and 3000-m runs during a single championship to determine the relationship between age and CS and D′. Twenty-six athletes completed sufficient races in multiple championships to retrospectively assess the change in CS and D′ over time.
Cross-sectional data indicated that CS continuously decreases after age 35 yr in a curvilinear manner with advancing age (R2 = 0.73, P < 0.001, n = 187), with even greater decreases in CS occurring after ~70 yr of age. D′ also changed in a curvilinear manner with age (R2 = 0.45, P < 0.001, n = 103), such that decreases were observed between 35 and 70 yr, followed by an increase in D′ thereafter. Retrospective, longitudinal data, with an average follow-up of 6.38 ± 1.73 yr, support these findings, indicating that the annual decrease in CS grows with advancing age (e.g., ~1% vs ~3% annual decrease in CS at age 55 vs 80 yr, respectively) and that D′ shifts from an annual decrease (e.g., ~2.5% annual decrease at 55 yr) to an annual increase (e.g., ~2.5% annual increase at 80 yr) around 70 yr of age. Importantly, the relationship between CS and race pace was unaffected by age, supporting the relevance of CS throughout aging.
Even among world-class athletes, CS decreases and D′ changes with aging. These adaptations may contribute to the diminished exercise ability associated with aging.