Physiological and Neuromuscular Responses to Warm-up and Racing in Competitive Swimmers: A Field-Based Case Series

This study examined acute physiological and neuromuscular responses of competitive swimmers across warm-up, prerace, and postrace time points during an official competition and explored associations with race performance.

Eighteen university-level swimmers (10 females and 8 males; 21.3 [2.4] y) competing in sprint (50-100 m) and middle-distance (200 m) events were assessed during the heats of a long-course meet. Heart rate, blood lactate ([La]), rating of perceived exertion (RPE), and countermovement jump (CMJ) height were measured post-warm-up, prerace, and postrace. Official race times were converted to AQUA points.

The transition between warm-up and race averaged 42 (9) minutes. [La] increased from 2.5 mmol·L-1 post-warm-up to 9.3 (2.2) mmol·L-1 postrace (P < .001). CMJ decreased modestly (∼2%-3% from prerace to postrace), while heart rate and RPE increased. Postrace [La] correlated strongly and negatively with AQUA points (r = -.77, P < .001), indicating lower [La] accumulation in higher performing swims. Changes in heart rate, RPE, and CMJ showed no clear associations with performance.

Swimmers experience a partial decline in physiological readiness during the transition from warm-up to race, followed by substantial metabolic and neuromuscular stress during competition. Higher performing swims showed lower metabolic strain (ie, smaller lactate accumulation). Individualized warm-up and re-warm-up strategies that sustain readiness during prolonged transitions may help optimize performance. Monitoring simple field markers such as [La], CMJ, and RPE provides a practical framework for individualizing competition preparation.