The Effects of Graded Protein Intake in Conjunction with Progressive Resistance Training on Skeletal Muscle Outcomes in Older Adults: A Preliminary Trial.
Level 2 - randomized trial
Small preliminary controlled clinical trial.
PubMed 35807922 · doi:10.3390/nu14132739
What was done
Eighteen older adults completed a 10-week progressive whole-body resistance training (RT) program with advancing volume and intensity while following one of two dietary protocols: a constant protein diet (0.8–1.0 g/kg/day, no supplement) or a graded protein diet (progressing from 0.8 g/kg/day at week 1 to 2.2 g/kg/day at week 10 via whey protein supplementation). Outcomes included DXA-measured appendicular lean/soft tissue mass, ultrasound-measured muscle thickness, muscle quality scores (pre and post), and isokinetic dynamometry peak torque (pre, mid at week 5, and post).
What was found
Protocol adherence was high (96% RT attendance; constant protein remained in range; graded protein had a 7% deviation from prescription). Appendicular lean/soft tissue mass, muscle quality scores, and peak torque significantly increased over time across the cohort (p < 0.05). However, there were no significant group-by-time interaction effects or other main effects for any measured outcome. The abstract reports no exact numerical values or effect sizes for the physiological outcomes.
Why it matters
While progressive resistance training consistently improves muscle strength, quality, and lean mass in older adults, escalating protein intake beyond standard requirements up to 2.2 g/kg/day did not produce additional muscular adaptations over 10 weeks in this pilot study.
Limits
The sample size was extremely small (n = 18 total), making the trial underpowered to detect subtle interaction effects between dietary groups. The abstract does not provide exact point estimates, standard deviations, or confidence intervals for outcome measures. The 10-week duration was relatively brief, and long-term functional or clinical outcomes were not evaluated.
Cited by
- supports Individuals can gain muscle mass with a daily protein intake of 0.8 grams per kilogram of body weight when engaging in resistance training.