Data from elite professional sports players provide a valuable source of information on human performance and ageing. Functional declines in performance have been investigated across a wide range of sporting disciplines that vary in their need for physical strength, endurance, cognitive ability and motor skills, but researchers do not always consider other sources of heterogeneity that can exist between individuals. Using information on all male bowlers to have played Test match cricket since the early 1970s, this study separated age-dependent variation in bowling performance at the population-level into within-individual and between-individual (age-class) changes. There was little evidence for senescence in bowling performance as measured via economy rate or wicket-taking ability, irrespective of the style of the bowler (fast or slow). Instead, analyses detected strong between-individual contributions to bowling performance as higher quality bowlers were able to compete at the elite level for longer, and were therefore over-represented in older age classes: how they accomplish this alongside the physical demands of Test cricket remains unresolved. Bowlers also experienced a deterioration in the last year of their Test careers. Lastly, multivariate models identified a negative correlation between slow bowlers in their economy rate and their wicket-taking ability, suggesting that in general, the most economical slow bowlers in the modern era of Test match cricket have also taken wickets at the fastest rate. The same is not true for fast bowlers, which is perhaps partly because bowling at high speed compromises accuracy and thus increases scoring opportunities for batters.