(30) RELATIONSHIP BETWEEN FAT MASS-TO-FAT-FREE MASS RATIO AND PUSH-UPS PERFORMANCE

Introduction: Fat mass (FM) and fat-free mass (FFM) are two body composition metrics associated with muscular performance. However, the association these metrics have with performance is not independent. To account for this, the FM to FFM ratio (FM:FFM) is an emerging body composition marker that may be associated with performance above and beyond their standalone values.

Purpose: The purpose of this study was to determine if push-ups to failure was more strongly related to the FM:FFM compared to FM and FFM alone in a sample of healthy adult men and women.

Methods: Participants (n=145, 51% female, 24.2±7.8 years, 172.4±9.9 cm, 74.4±16.0 kg) completed a single visit to the Exercise Physiology Laboratory at the University of Alabama. Self-reported age and gender were collected for each participant. Standing height was measured to the nearest 0.1 cm using a stadiometer (SECA 213, Seca Ltd., Hamburg, Germany). Body mass was measured to the nearest 0.1 kg using a calibrated digital scale (Tanita BWB-800, Tanita Corporation, Tokyo, Japan). Dual Energy X-Ray Absorptiometry (DXA) was used to determine FM and FFM. Then, FM was divided by FFM to give the FM:FFM ratio. Participants then completed a maximal-rep push-up test. Based on self-reported gender, females were required to perform push-ups on their knees and males were required to not use their knees to standardize form based on established strength differences between genders. Pearson’s r correlations were used to measure the association between FM, FFM, FM:FFM and muscular performance. The strength of each r value was qualitatively described as weak, moderate, and strong (r=0.2, 0.5, and 0.8, respectively). In addition, Fisher’s r to z transformation was used to determine if the strength of the observed correlations were statistically different from each other. Data are reported as the mean±standard deviation unless otherwise indicated. Statistical significance was considered as p< 0.05.

Results: FM values ranged from 7.7 to 55.8 kg (20.0±9.1 kg), whereas FFM ranged from 33.0 to 88.4 kg (54.4±12.8 kg). FM:FFM ratio ranged from 0.11 to 0.95 (0.39±0.18), and maximal push-ups ranged from 3 to 91 repetitions (32.8±15.6 repetitions). FM (r=-0.46, p< 0.001), FFM (r=0.31, p< 0.001) and FM:FFM (r=-0.56, p< 0.001) were all moderately associated with muscular performance. However, the observed correlation between FM:FFM and muscular performance was stronger the correlation between FM and muscular performance (p< 0.001) and the correlation between FFM and muscular performance (p< 0.001).

Conclusion: The results of the study indicate that FM, FFM, and FM:FFM are all associated with muscular performance, however FM:FFM provided the strongest correlation.

PRACTICAL APPLICATION: Based on these results, practitioners should consider accounting for both FM and FFM codependently when relating body composition to muscular performance. Additionally, more research should confirm these findings, as well as compare these body composition metrics to other muscular performance assessments.

Acknowledgements: None