Date Presented

Spring 5-1-2023

Document Type



Computer Science

First Advisor

Sean Collins, PhD

Second Advisor

Jeffrey Herrick, PhD

Third Advisor

Price Blair, PhD


The 200 and 400-yard individual medley (IM; 200 IM and 400 IM, respectively) are two swimming events that challenge swimmers' versatility. Each of these events has different physiological requirements, where the 200 IM is viewed as an anaerobic event and the 400 IM as an aerobic event. Additionally, the IMs require performance in all four competitive stroke disciplines in a specific order (butterfly, backstroke, breaststroke, and freestyle), with each stroke requiring a different magnitude of intensity, efficiency, and speed. Purpose: To study the different pacing strategies and corresponding blood lactate response during the 200 IM and 400 IM in National Collegiate Athletic Association (NCAA) Division III swimmers. Methods: 10 NCAA Division III swimmers (age: 19.7 ± 0.95yrs, height: 169.0 ± 6.4cm, weight: 71.8 ± 0.95kg) performed a simulated time trials of the 200 IM and 400 IM during the competitive season. Blood lactate (BLA) was measured prior to warm up, prior to racing, and at the completion of the time trial. Change in blood lactate (ΔBLA) was calculated from the pre and post BLA. Splits were taken for each lap (50 yard) of each stroke, and segment (50,100 yard) velocities were calculated. Additionally, percents of the total time each stroke took were also calculated. Multiple repeated measures ANOVAs were used to determine significant differences. Results: No significant differences (p>0.05) were reported between the BLA Post 200 IM (8.9±3.2 mmol/L) and BLA Post 400 IM (8.87±2.4 mmol/L), nor in ΔBLA2IM (7.56±3.25 mmol/L) and ΔBLA4IM (6.11±2.82 mmol/L). Rate of perceived exertion (RPE) was found to be significantly (p<0.01) greater following the 400 IM (9.1±0.88) versus the 200 IM (7.4±0.84). Significant interactions were found (p<0.05) between the stroke velocities and stroke percentage of total time for the 200 IM and 400 IM. Conclusion: Measurement of BLA showed that there was an equivalent amount of anaerobic involvement between the 200 IM and 400 IM but the pacing strategies were different.