The influence of anxiety on sport performance was examined using the inverted-U hypothesis and Zone of Optimal Function (ZOF) theory. Sixty-seven collegiate track and field athletes completed versions of the State-Trait Anxiety Inventory (STAI) to determine baseline state anxiety, recalled best anxiety, and precompetition anxiety. Precompetition state anxiety was determined 1 h before competition in four meets. Three variants of the inverted-U hypothesis were examined: 1) task-specific anxiety, 2) individualized median precompetition anxiety, and 3) mean precompetition anxiety. For ZOF, optimal anxiety was established from anxiety scores based on recalled best performance. Subjects were grouped as either inside or outside of optimal anxiety levels according to inverted-U or ZOF criteria. Mean group performance was determined by transforming individual results using intra- and interindividual standards. ANOVA revealed that subjects possessing optimal anxiety according to inverted-U criteria performed no better (P > 0.05) than cases outside optimal. Subjects with precompetition anxiety values within their individual ZOF performed significantly (P < 0.05) better than cases with anxiety outside ZOF for all contrasts. The largest (P < 0.05) performance decrements resulted when anxiety was within a 1 SD range above or below ZOF. These results indicate that ZOF theory was more efficacious than the variants of the inverted-U hypothesis examined.