Acute exercise affects dual‐energy X‐ray absorptiometry body composition estimates but not standardised ultrasound measurements of subcutaneous adipose tissue

Abstract

Ultrasound has been demonstrated to be a highly accurate and reliable tool for measuring subcutaneous adipose tissue thickness and is robust against changes in hydration status or acute food or fluid intake. However, the effect of prior acute exercise is unexamined. This study examined the impact of an acute endurance exercise and resistance exercise session on standardised brightness‐mode ultrasound measurements of subcutaneous adipose tissue thickness compared to skinfolds and dual‐energy X‐ray absorptiometry body composition estimates. In a randomised cross‐over design, 30 active adults (24.2 ± 4.9 years) undertook physique assessment via standardised brightness‐mode ultrasound, skinfolds and dual‐energy X‐ray absorptiometry before, immediately and 45 min after an acute endurance or resistance exercise session. The mean sum of eight subcutaneous adipose tissue thickness measured via standardised brightness‐mode ultrasound increased (0.6 mm, p = 0.04) immediately postendurance exercise but was not meaningful when evaluated against the technical error of measurement of the investigator. A significant (p = 0.01) but not meaningful decrease in the sum of eight skinfolds occurred immediately (−1.1 ± 0.4 mm) and 45 min (−1.3 ± 0.4 mm) postresistance exercise. Comparatively, endurance exercise elicited a meaningful decrease of total mass (460 ± 30 g) and trunk lean mass (680 ± 90 g) dual‐energy X‐ray absorptiometry estimates. Findings from this study indicate standardised client presentation may be unnecessary when employing either standardised brightness‐mode ultrasound or skinfolds for body composition assessment unlike dual‐energy X‐ray absorptiometry.