Body Fat Content Does Not Affect Body's Maximal Muscle Strength

Abstract

We investigated that the relationship between body fat content and maximal muscle strength when skeletal muscle mass was matched. Muscle mass was measured from 140 preliminary selected people, and 30 males were finally selected and divided into one of four experimental groups: low body fat (group 1, ≤11.9%), low-moderate fat (group 2, 12.0%−16.9%), moderate-high fat (group 3, 17.0%−22.9%), high fat (group 4, ≥23.0%). All subjects undertook one repetition maximum (1RM) test of abdominal and back upper body's and lower body's, and bench press, squat, and back strength dynamometer was used. Repeated oneway analysis of variance and Tukey's post-hoc test was adopted to specify mean differences among groups. Statistical significance level was set at α=0.05. 1RM of bench press was not different among groups (p＞0.05) even though values from group 2 was marginally higher (15.9%) than group 1 values (p=0.091). 1RM of squat was higher in group 4 compared to group 2 and group 3 (p＜0.05), and maximal back muscular strength was higher in group 1 and group 3 than group 2 (p＜0.05). However, total 1RM values, sum of 1RM obtained from different exercises, did not reveal any statistical differences. No notable correlation was found between percent body fat (%BF) and maximal muscular strength. Interestingly, negative correlation of muscular strength was observed between %BF and relative (per kilogram) body mass (p＜0.001), but not with between %BF and relative skeletal muscle mass. Therefore, it was concluded that maximal muscular strength is influenced not by fat mass but by skeletal muscle mass.