Comparisons of ultrasound-estimated intramuscular fat with fitness and health indicators.

ABSTRACT

INTRODUCTION: We examined ultrasound-estimated intramuscular fat of 4 muscles rectus femoris (RF), biceps femoris (BF), tibialis anterior (TA), and medial gastrocnemius (MG), and compared the results with other health measures. METHODS: Forty-two participants were tested. Muscle echo intensity was quantified into percent intramuscular fat using previously published equations. RESULTS: Strong correlations were found in percent intramuscular fat in the 4 muscles (r ≥ 0.8). Weak to moderate correlations were found between intramuscular fat and body mass index (r ≥ 0.2), waist/hip ratio (r ≥ 0.2), muscle thickness (r = -0.5 in RF, r = -0.4 in TA, r = -0.7 in MG), and muscle strength (leg extension r = 0.4; leg flexion r = -0.5). A relationship between intramuscular fat in RF and MG and physical activity was also observed (P < 0.05). CONCLUSION: Ultrasound-estimated intramuscular fat was associated with other health measures and may provide physiological insight into the health consequences of obesity. Muscle Nerve 54 743-749, 2016.