Moderate to vigorous physical activity, leucine, and protein intake contributions to muscle health in middle age

Original Article

J Frailty Sarcopenia Falls 2022 Sep; 7(3):123-132 Copied!

10.22540/JFSF-07-123 Copied!

Kara A. Stone¹, Allison M. Barry², Christopher J. Kotarsky³, Nathan D. Dicks⁴, Sherri N. Stastny⁵, Wonwoo Byun⁶, Steven Mitchell^5,7, Ryan McGrath⁵, Kyle J. Hackney⁵

Department of Kinesiology and Health Studies, University of Central Oklahoma, Edmond, OK, USA
Health, Human Performance, and Recreation Department, Pittsburg State University, Pittsburg, KS, USA
Department of Health and Human Physiological Sciences, Skidmore College, Saratoga Springs, NY, USA
Nutrition, Dietetics, and Exercise Science Department, Concordia College, Moorhead, MN, USA
Department of Health, Nutrition, and Exercise Sciences, North Dakota State University, Fargo, ND, USA
Department of Health, Kinesiology, and Recreation, The University of Utah, Salt Lake City, UT, USA
Department of Radiology, Sanford Health, Fargo, ND, USA

Keywords:

Abstract

Objective

Identify contributors to differences in the muscle size and strength of sedentary and active young and middle-aged adults.

Methods

This cross-sectional study included 98 participants aged 20-65 years. Participants were categorized based on age and self-reported physical activity (PA) habits. Participants completed a strength assessment of knee extensors (KEPT), knee flexors (KFPT), plantar flexors (PFPT), and dorsiflexors (DFPT), a 3-day dietary intake log, 7-day accelerometry, and a magnetic resonance imaging (MRI) scan for muscle cross-sectional area analysis of the right quadriceps (CSAq).

Results

There were significant age and activity-related group effects for relative protein intake (p<0.001), relative energy intake (p=0.04), KEPT (p=0.01), CSAq (p=0.002), PFPT (p=0.004) and DFPT (p=0.003). Moderate, moderate-to-vigorous, and vigorous PA were positively associated with CSAq (R²=0.69- 0.71; p<0.05), KEPT (R²=0.61-0.63; p<0.05), and PFPT (R²=0.31-0.36; p<0.05). Relative protein intake and daily leucine intake were significantly and positively associated with CSAq (R²=0.70 and 0.67 respectively; p<0.05), KEPT (R²=0.62 and 0.65 respectively; p<0.05), and PFPT (R²=0.29 and 0.28 respectively; p<0.05).

Conclusion

Muscle size and strength were lower in middle age relative to younger age, but increased PA, protein intake, and leucine intake was associated with the preservation of muscle size and strength in larger muscle groups of the lower body.