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THE EFFECTS OF GRADED PROTEIN INTAKE IN CONJUNCTION WITH RESISTANCE TRAINING ON SKELETAL MUSCLE OUTCOMES IN OLDER ADULTS

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title
THE EFFECTS OF GRADED PROTEIN INTAKE IN CONJUNCTION WITH RESISTANCE TRAINING ON SKELETAL MUSCLE OUTCOMES IN OLDER ADULTS
author
Michel, John Max
abstract
Background: The aging process is associated with a decline in skeletal muscle size and quality1,2. This process can lead to increases in comorbidities such as obesity, and can factor into survival rates in disease3–5. There is a need for pragmatic interventions to attenuate the typical age-related loss of skeletal muscle, and as such resistance training (RT)6,7 and protein intake modification interventions8 have received much attention. Objective: To examine the effects of graded protein intake with a conjunctive RT intervention on body composition, strength measures, and vastus lateralis thickness in older adults. Methods: A cohort of older adults (n=18; age=69.72±8.23 years; 11 females) were randomly assigned to either a graded protein (GP) intake or constant protein (CP) intake for 10 weeks. During this time, both groups underwent the same RT intervention. Dual energy x-ray absorptiometry (DXA) derived lean/soft tissue mass, isokinetic dynamometry derived peak torque, ultrasonography derived vastus lateralis tissue thickness, and muscle quality scores (peak torque/leg lean mass) were assessed at baseline and post-intervention, with peak torque additionally assessed at midpoint (week 5). Results: The RT intervention had adherence of 96% as assessed by session attendance, the CP group adhered to prescribed protein intake levels for all 10 weeks, and the GP group demonstrated no more than 5.5% variance from prescribed protein intake after week 2 of the intervention. Appendicular lean/soft tissue mass increased over time regardless of group (mean increase=0.269 kg; P=0.028). Similarly, muscle quality scores improved regardless of protein intake group at 60 degrees/s (mean increase=1.011 N*m/kg; P=0.001) and 120 degrees/s (mean increase=0.568 N*m/kg; P=0.015). Increases in absolute strength were only observed for knee flexion peak torque at 60 degrees/s (mean increase= 6.167 N*m; P=0.027) with no other peak torque value increasing over time (P>0.05). No other changes were observed, and no group*time interactions were observed for any measure. Conclusion: Ten weeks of RT, regardless of either a constant or graded protein intake structure, significantly improved muscle quality and appendicular lean/soft tissue mass in older adults. Results suggest that RT increases appendicular lean/soft tissue mass and muscle quality score, while protein intake level did not influence these adaptations to a significant degree.
subject
Hypertrophy
Older Adults
Protein
Resistance Training
Skeletal Muscle
contributor
Miller, Gary D (committee chair)
Brubaker, Peter H (committee member)
Berry, Michael J (committee member)
date
2022-05-24T08:36:11Z (accessioned)
2022-05-24T08:36:11Z (available)
2022 (issued)
degree
Health and Exercise Science (discipline)
identifier
http://hdl.handle.net/10339/100770 (uri)
language
en (iso)
publisher
Wake Forest University
type
Thesis

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