Calf circumference positively correlates with calf muscle thickness and negatively correlates with calf subcutaneous fat thickness and percent body fat in non-obese healthy young adults

BACKGROUND: Calf circumference is measured for assessing sarcopenia, nutrition status, percent body fat or obesity. However, there has been no study that investigated the relationship between calf circumference and calf subcutaneous fat tissue thickness. Therefore, the aim of this study was to investigate the relationship between calf circumference, calf muscle thickness, and calf subcutaneous fat tissue thickness in non-obese healthy young adults. METHODS: The study participants were non-obese 22 women (20.1 +/- 0.8 years) and 21 men (20.0 +/- 0.8 years). The right calf circumference was measured in prone position at the point where the circumference was maximal by visual recognition using a measuring tape. Then, thickness of calf subcutaneous fat tissue and calf muscles were measured with an ultrasonic diagnostic equipment. RESULTS: There was a positive relationship between calf circumference and calf muscle thickness both in women (r=0.58, P<0.01) and men (r=0.46, P<0.05), negative relationship between calf circumference and calf subcutaneous fat tissue thickness both in women (r=-0.43, P<0.05) and men (r=-0.67, P<0.001), no correlation between calf circumference and percent body fat both in women (r=0.04, P=0.87) and men (r=0.41, P=0.06), and a negative relationship between calf subcutaneous fat tissue thickness and percent body fat both in women (r=-0.48, P<0.05) and men (r=0.46, P<0.05) CONCLUSIONS: The present study showed that a larger calf indicated larger calf muscle thickness, and largely different from previous studies, a lower calf subcutaneous fat tissue thickness. That is because when the calf circumference increases, calf subcutaneous fat tissue thickness should be thinner to keep the percent body fat equal in non-obese healthy young adults. The finding will help to get a better understanding of the nature of the calf.