O032 - MUSCLE MASS ISN’T ENOUGH: OBESITY AND METABOLIC DISEASE WEAKENS THE MASS-STRENGTH RELATIONSHIP

O032

MUSCLE MASS ISN’T ENOUGH: OBESITY AND METABOLIC DISEASE WEAKENS THE MASS-STRENGTH RELATIONSHIP

J. Bennett¹, Y. E. Liu¹, N. Kelly¹, C. Prado^2,*, S. Heymsfield³, J. Shepherd¹

¹University of Hawaii Cancer Center, Honolulu, United States, ²University of Alberta, Edmonton, Canada, ³Pennington Biomedical Research Center, Baton Rouge, United States

Rationale: Obesity and cardiometabolic disease are associated with reduced quality of life and early mortality, but their impact on muscle mass and its relationship with muscle strength is less understood. This study investigates the mass-strength relationship and how cardiometabolic comorbidities affect it.

Methods: Adults (≥18 years) from the Shape Up! Adults study underwent dual-energy X-ray absorptiometry to assess appendicular lean soft tissue, indexed for height (ALSTI, kg/m²), and strength testing (isokinetic leg extension and handgrip in Newton-meters [Nm]). Associations between ALSTI and strength were adjusted for age and sex. The mass-strength relationship was compared across individuals with or without overweight (BMI ≥ 25 kg/m²), central obesity (elevated waist circumference), and Metabolic Syndrome (MetS, defined as ≥3 of: elevated blood pressure, triglycerides, glucose, waist circumference, or low HDL cholesterol) using multiple regression.

Results: Among 516 adults, ALSTI was moderately correlated with leg (r=0.63) and arm (r=0.72) strength. The association between ALSTI and strength was weaker in individuals with overweight, elevated waist circumference, or MetS (p < 0.05). These conditions were also independently associated with lower absolute strength. Compared to unaffected individuals, those with obesity, MetS, or elevated waist circumference had 13.5–22.5 Nm lower leg strength (mean: 110.6 ± 56.1 Nm) and 2.8–6.0 Nm lower grip strength (mean: 32.6 ± 13.0 Nm).

Conclusion: Overweight, central obesity, and MetS weaken the relationship between muscle mass and strength, suggesting reduced muscle quality. These conditions may contribute to earlier functional decline and frailty risk, even when muscle mass is preserved. Findings underscore the need to identify and target mechanisms through which clinical conditions impair muscle quality and performance to inform effective interventions.

Disclosure of Interest: J. Bennett: None declared, Y. Liu: None declared, N. Kelly: None declared, C. Prado: None declared, S. Heymsfield Grant / Research Support from: Funding for this study was part of the Shape Up! Adults (NIH R01 DK109008) study, J. Shepherd Grant / Research Support from: Funding for this study was part of the Shape Up! Adults (NIH R01 DK109008) study