Investigation of Trunk and Pelvis Muscle Activity during Sprinting using T2-Weighted Magnetic Resonance Imaging
(Takaya Yoshimoto, Yoshihiro Chiba, Hayato Ohnuma, Norihide Sugisaki)

There are few studies that clarify the level of muscle activity in the trunk and pelvis muscles during sprinting. This study aimed to investigate muscle activity in the trunk and pelvis muscles during sprinting using T2-weighted magnetic resonance imaging (MRI). The pre- and post-test designs were employed by measuring trunk and pelvis muscle activity using T2-weighted MRI before and after 60-m round-trip sprints. Ten male sprinters (N = 10, age, 23.3 ± 6.7 years; body height, 175.1 ± 3.6 cm; body mass, 66.8 ± 4.3 kg; 100-m personal record, 11.18 ± 0.48 s, means ± standard deviations [SDs]) performed three sets of three 60-m round-trip sprints. Before and after the round-trip sprints, 3T MRI scans were performed to obtain the T2 values of the trunk and pelvis muscles. After the 60-m roundtrip sprints, the T2 values of lateral abdominal, psoas major, erector spinae, gluteus maximus, gluteus medius, rectus femoris, tensor fasciae latae, sartorius and pectineus muscles increased significantly. There were intermuscular differences in the rate of change of T2 values before and after the 60-m round-trip sprints, with significantly higher levels of muscle activity in lateral abdominals, psoas major, erector spinae, gluteus maximus, and pectineus. In sprinting, the trunk and pelvis muscles were found to be specifically activated.