waist circumference, a clinical measurement for the activity of transversus abdominis

Objectives: improving the timing and endurance of the deep abdominal muscles, notably transversus abdominis (tra), is a known protocol for improving spinal stability. tra is the deepest abdominal muscle, and monitoring its activity is a difficult task. ultrasound and pressure biofeedback have been employed for monitoring the activity of tra; however, these methods are expensive, not always available in all clinical settings, and their application requires formal training. the purpose of this study was to examine the use of a broadly known method, i.e., changes in the waist circumference, to monitor the activity of tra. methods: the study was carried out on 14 subjects following a pilot study of 5 participants. the thickness of tra measured by ultrasound was considered the standard indicator for activity of tra and was compared with simultaneous measurement of waist circumference. results: a significant criterion validity between the thickness of tra and the waist circumference was established (pearson correlation=-0.71, p=0.001), indicating an inverse relationship between changes in the thickness of the transversus abdominis muscle and waist circumference. discussion: this result confirmed the hypothesis that changes in the waist circumference could be employed as a suitable indicator for the activity of tra.