Research on long-term athlete development indicates that performance progression in youth and adolescent sport is often nonlinear, influenced by maturation, training exposure, recovery, and context rather than occurring as steady, predictable improvement (Lloyd et al., 2015). In practical terms, many athletes experience periods of rapid gains alongside periods of plateau or temporary regression during growth and training transitions.
Growth and maturation research also describes how changes in body size and proportions, along with neuromuscular development, can affect coordination and technique. During these periods, sport performance may not immediately track with training effort or underlying physiological changes (Malina et al., 2015).
Training science and periodization literature further support that adaptation and performance expression can be time-shifted; improvements in fitness markers and technical consistency may occur before measurable changes in competition outcomes, particularly when training load or emphasis changes (Issurin, 2010). Swimming-focused performance literature describes variability in how training adaptation presents in race results across cycles and seasons (Pyne & Sharp, 2014).