RESUMO
BACKGROUND: Measured physical activity and percent body fat obtained by bioelectrical impedance analysis have been used as indicators of cardiorespiratory fitness in middle-aged women and children. However, the relationship between subcutaneous fat thickness in various regions of the thigh determined by ultrasonography and cardiorespiratory fitness has not been previously reported. METHODS: We measured subcutaneous fat thickness in the frontal, lateral, and medial regions of both thighs using ultrasonography, and also determined peak VO2 and percent body fat in 13 healthy and generally well female college students. RESULTS: There were significant negative correlations found between peak VO2 and the 3 frontal portions of the thigh, as well as the vastus lateralis (both sides), while correlations were not seen with the right and left medial regions 15 cm above the medial epicondyle. CONCLUSIONS: Our results suggest that increases in peak VO2 are reflected by decreases in subcutaneous fat thickness in the frontal and lateral regions of the thigh, but not in decreases in that in both sides of the medial region of the thigh. In addition, subcutaneous fat thickness may indicate partial or segmental activation of the frontal and lateral regions of the legs, such as that obtained by cycling. We concluded that measurement of subcutaneous fat thickness in the region above the muscle mass of the thigh such as the rectus femoris or lateral vastus using ultrasonography may reasonably represent physical activity. Further study is needed to be done with larger groups of subjects and to evaluate the effects of training on activation of regions of the thigh.
