The effect of seasonal changes in training load on mood, neuromuscular function, and measures of physical power were examined in 12 collegiate women swimmers. These subjects were studied at three training stages during a competitive swim season: baseline (5,000 m.d-1), peak training (8,300 m.d-1), and taper (2,300 m.d-1). Mood was evaluated with the Profile of Mood States. Neuromuscular function was measured via the soleus Hoffmann-reflex (H-reflex). Anaerobic swimming power was assessed with a 30-s tethered swim test, and maximal aerobic power was determined following a maximal 378-m swim. Repeated measures ANOVA revealed that at peak training H-reflex and peak anaerobic swimming power were reduced (P < 0.05) below baseline values by 8.6% and 9.4%, respectively, and total mood disturbance was elevated above baseline (P < 0.01). These variables returned to baseline values at the taper assessment. H-reflex values were correlated with peak (r = 0.52, P < 0.01) and mean (r = 0.39, P < 0.05) anaerobic swimming power. Total mood disturbance was correlated (r = -0.34, P < 0.05) with mean swimming power. The results suggest that neurological mechanisms play a role in the adaptations that result from periodized training.