Lloyd & Oliver 2012, the Youth Physical Development model

Framework paper proposing the Youth Physical Development (YPD) model for long-term athletic development (Lloyd RS, Oliver JL, Strength and Conditioning Journal 2012;34(3):61-72, DOI 10.1519/SSC.0b013e31825760ea). It argues that earlier models, organised by chronological age, are too crude, and instead maps the trainability of fitness qualities onto biological maturation, centred on peak height velocity. It describes children’s greater reliance on aerobic and oxidative metabolism with limited anaerobic/glycolytic capacity, a smaller trainable VO2max response than adults, and the case for emphasising broad athletic skill and varied physical development across childhood rather than narrow early specialisation. A widely cited conceptual model; synthesises developmental physiology rather than reporting a single trial.