The effects of external load-based circuit training on endurance performance in long-distance runners

Abstract

This study aimed to analyze the effect of external load-based circuit training on muscular endurance performance in long-distance runners from the Indonesian Athletics Association (PASI) Balikpapan. A quasi-experimental one-group pretest-posttest design was used. The sample included seven senior male athletes aged 21–28 years who competed in the 5000-meter and 10,000-meter events. The training intervention lasted eight months and consisted of 66 sessions, held 2–3 times per week. Athletes performed circuit-based resistance exercises using 40%–60% of one-repetition maximum (1RM), with 6–9 sets, 8–12 repetitions, and 15–30 seconds of rest between stations. The results indicated a statistically significant improvement (p=0.002) between pre- and post-training scores. The average performance increased by 18%, and the N-Gain score was 0.42, categorized as moderate effectiveness. The greatest improvements were observed in lower body strength endurance (squat test). Although direct race performance data were not collected, the functional tests used reflect the physiological demands of long-distance running, particularly in the 5000m and 10,000m events. In conclusion, circuit training with moderate external loads had a positive effect on enhancing muscular endurance among long-distance runners. Future studies should adopt randomized controlled designs with larger and more diverse athlete populations to validate these findings.