ULTRASONOGRAPHIC COMPARISON OF ABDOMINAL MUSCLE THICKNESS BETWEEN ELITE SPRINTERS AND DISTANCE RUNNERS

Abstract

The objective of the study is to compare the effects of high level sprinting and distance running on the abdominal muscles of respective athletes. Participants were 18 elite male runners selected without randomization, aged 18-22 (19.4 ± 1.3). The number of runners was nine in both running groups. Athletes had been running competitively for at least two years. Abdominal muscles anteroposterior (AP) thickness measurements were performed using a clinical ultrasonography (US) device, furnished with a curvilinear probe, emitting 7.5 MHz ultrasonic waves. Athletes were supine and still throughout the test. The probe was placed on two points on the left side of the abdomen, which are standard in abdominal muscle still image taking US. Statistically, AP thicknesses of all abdominal muscles were significantly different for the two groups of runners. The rectus abdominis (RA), the internal and external obliques (IO and EO) were thicker in sprinters; in contrast, the transversus abdominis (TA) was thicker in distance runners (p<0.05). These results may suggest that running training differences can influence muscle development and current morphology. Clearly, the TA muscle displayed greater AP thickness in distance runners. This phenomenon may be indicative that the increased activity of this muscle results from the cost effective strategy distance runners use to maintain performance. Besides, the difference might be due to respiratory function differences in the two groups. Furthermore, the combination of the obliques and RA might work together to facilitate forward leaning during sprinting, so that greater hypertrophy of these muscles is observed in the latter group.