Using powerlifting athletes to determine strength adaptations across ages in males and females: a longitudinal growth modelling approach

Introduction: Several retrospective studies of strength sport athletes have reported strength adaptations over months to years; however, such adaptations are not linear. Methods: We explored changes in strength over time in a large, retrospective sample of powerlifting (PL) athletes. Specifically, we examined the rate and magnitude of strength adaptation based on age category and weight class for PL competition total, and the squat, bench press, and deadlift, respectively. Mixed effects growth modelling was performed for each operationalised performance outcome (squat, bench press, deadlift, and total) as the dependent variables, with outcomes presented on both the raw, untransformed time scale and on the common logarithmic scale. Additionally, the fitted values were rescaled as a percentage. Results: Collectively, the greatest strength gains were in the earliest phase of PL participation (~ 7.5–12.5% increase in the first year, and up to an ~ 20% increase after 10 years). Females tended to display faster progression, possibly because of lower baseline strength. Additionally, female Masters 3 and 4 athletes (> 59 years) still displayed ~ 2.5–5.0% strength improvement, but a slight strength loss was observed in Masters 4 (> 69 years) males (~ 0.35%/year). Conclusion: Although directly applicable to PL, these findings provide population-level support for the role of consistent and continued strength training to improve strength across the age span and, importantly, to mitigate, or at least largely attenuate age-related declines in strength compared to established general population norms. This information should be used to encourage participation in strength sports, resistance training more generally, and to support future public health messaging.