Nonrestorative Sleep and Poor Self-Reported Physical and Mental Health among Middle-Aged Japanese Adults: A Cross-Sectional Study.

Athletic performance has traditionally been understood in physiological terms strength, endurance, speed, and technical skill (). Yet contemporary sports science treats elite performance as multidimensional, shaped not only by physical capacity but also by psychological and nutritional factors affecting athletes’ readiness, consistency, and long-term development (), particularly within organized sports settings that provide structured support (). The most studied psychological factors are motivation, competitive anxiety, mental resilience, and self-confidence. Intrinsically motivated athletes train more consistently and sustain effort under pressure (), whereas weak or external motivation predicts burnout and inconsistency. Pre-competition anxiety can disrupt concentration, decision-making, and motor execution (), although moderate arousal aids performance while excessive arousal impairs it the inverted-U relationship (). Regulating these states is central to applied sport psychology (). Mental resilience is a further correlate of performance, especially at higher competitive levels. Nutrition has a comparably prominent role, with dietary intake closely tied to physical output (). Beyond energy provision, the composition and timing of intake shape endurance, cognition, recovery, and training adaptation (). Yet many athletes show limited nutritional knowledge, and poor dietary habits are linked to reduced performance and greater injury risk ().