Purpose We aimed to compare the effects of warm-up exercises with dynamic stretching and total-resistance exercise (TRX) suspension for enhancing core body temperature and the metabolic equivalents of task of body extremities on Crawl stroke speed in young athlete swimmers with different body mass index (BMI) classifications. Methods The sample comprised 32 young athlete swimmers (age 13.74 ± 1.03 years, BMI 19.91 ± 3.34 kg/m2) who had been involved in organized competitive swimming. BMI was divided into 3 classifications. After a conventional warm-up and 10-mins rested, the intervention group were received the TRX warm-up protocol, while the control group performed with dynamic stretching. They then performed a 50-meters and a 100-meters crawl-stroke for speed. Before completing the testing, swimmers had a one-day rest period for their own activities. Results Warm-ups with dynamic stretching affect the core body temperature, heart rate, and metabolic equivalent of task (METs rate), and enhance crawl-stroke speed performance in young athlete swimmers. While swimmers in BMI class 2 have shown the best crawl-stroke speed, warm-ups with TRX suspension required lower energy expenditures (METs rate) than warm-ups with dynamic stretching (P<0.01). Male swimmers were found to have faster crawl-stroke speed performances than female swimmers in warm-ups with TRX suspension and dynamic stretching. Conclusion Energy expenditure, body temperature, and heart rate in the warm-up protocol have correlations with swimming performance.