The Relationship Between Thigh Muscle Size and 1RM Squat Strength Among Bodybuilders, Powerlifters, and Olympic Weightlifters

The purpose of this study was to determine if a significant difference exists in the relationship between measures of muscle size and strength among elite bodybuilders, powerlifters, and Olympic weightlifters. Fifteen male subjects between the ages of 16 and 48 years participated in the study. All three subject groups, Olympic weightlifters (OWL, n=5), powerlifters (PL, n=5), and bodybuilders (BB, n=5), were highly trained and currently involved in competition training. All test subjects were of similar body weight and weighed between 76-96 kilograms. Measures of body weight, body composition (bioelectrical impedence), shoulder width, thigh circumference (proximal, distal, and mid-thigh), and thigh skinfold thickness were performed on all three subject groups. The barbell back squat exercise was used to measure one repetition maximum (1RM) squat strength. Stance width, bar placement, and squat depth were controlled so that all subjects performed the exercise in a similar manner. All measures of thigh size were compared to measures of 1RM squat strength. Comparisons among the groups were performed using ANOVA with significant omnibus results followed by Tukey\u27s HSD post-hoe. Pearson Product Moment Correlations were performed to determine if a correlation existed between measures of thigh muscle size and 1RM squat strength. Statistical analysis showed no significant differences in thigh muscle area (TMA) (p=.44) or for any measure of thigh circumference among the groups. The PL (205.45 ± 17.27 kg) and OWL (200.18 ± 25.16 kg) groups had significantly greater 1RM squat strength than the BB group (159.99 ± 16.82 kg). Significance was p=.01 and p=.02 for PL and OWL respectively. No significant difference in 1RM squat strength was found between the PL and OWL groups. The PL group (2.91 ± .34 kg/kg FFM) had significantly (p=.02) greater strength per kg fat free mass (FFM) than the BB group (2.15 ± .32 kg/kg FFM). No significant difference was found in strength per kg FFM between the OWL and BB groups or between the PL and OWL groups. The PL (.0904 ± .0099 kg/cm2) (p=.003) and OWL (.0831 ± .0119 kg/cm2) (p=.02) groups demonstrated significantly greater 1RM squat strength per unit TMA than the BB group (.0636 ± .0062 kg/cm2). No significant difference existed between the OWL and PL groups in strength per unit TMA. There was no significant correlation among the groups for any measure of thigh muscle size with any measure of strength. The correlation between mid-thigh circumference (MTC) and 1RM squat strength was r=.20. It was concluded that thigh size among highly trained BB, PL, and OWL of similar body weight was not significantly different. Powerlifters and OWL are significantly stronger than BB in the 1RM squat lift. Differences in strength among the groups were not due to differences in absolute muscle size. The relationship between muscle hypertrophy and strength is different in highly trained individuals than that of untrained or lessor-trained individuals