Distinct Sources of Supplementary Protein in the Resistance Exercise Training-induced Adaptations

Study Overview
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Brief Summary
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This is a randomized controlled trial aimed to investigate the effects of different supplementary protein sources on muscle adaptations to resistance exercise. Young, healthy, recreationally active participants consuming an omnivorous diet with protein intake within recommended dietary allowance (RDA) (i.e.; 0.8-1.0 g.kg-1. d-1) will be recruited to undergo a 12-wk supervised resistance training program in combination with the intake of three 15-g daily doses (45g. d-1 total) of either a mixed plant- (i.e.; soy and pea protein) or animal-based (i.e.; whey protein) protein in drink form as a supplementary source of protein to their main meals of the day (i.e.; breakfast, lunch, and dinner). Before (PRE) and after (POST) the 12-wk intervention, participants will be assessed for body composition by dual-energy X-ray absorptiometry (DXA), muscle cross-sectional area (ultrasound) and fiber cross-sectional area (muscle biopsy), and maximal isotonic strength (1RM). Training consists of a resistance training (RT) program individually supervised by a researcher blinded to treatment in a laboratorial setting. Assessments will also be conducted in a blinded fashion.

Official Title
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Mixed Plant- vs. Animal-based Supplementary Protein to Support Muscle Adaptations to Resistance Exercise: a Randomized Clinical Trial

Conditions
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Dietary Supplements, Diet Habit, Muscle Strength, Muscle, Skeletal, Resistance Training

Intervention / Treatment
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* Dietary Supplement: Animal protein
* Dietary Supplement: Plant Protein


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Physically active (according to the International Physical Activity Questionnaire (IPAQ) Absence of any chronic condition that could preclude participation in a RT program or physical testing Habitual protein consumption within RDA ≥ 0.8 ≤1.0 g.kg-1. d-1 Exclusion Criteria: Prior history of anabolic steroids use, current or previous (≤ 3 m) Use of ergogenic or protein-based supplements, current or previous (< 1 y) Engagement in energy-restricted diets

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: animal protein<br>Whey protein will be used as the active comparator for animal protein arm | Dietary Supplement: Animal protein<br>* Patients allocated to this arm will be submitted a supervised resistance training program in combination with the intake of three 15-g daily doses (45g. d- 1 total) animal-based protein (i.e.; whey protein) in drink form as a supplementary source of protein in their main meals of the day.<br>|
| Experimental: plant protein<br>A combination of pea and soy protein will be used as the experimental arm | Dietary Supplement: Plant Protein<br>* Patients allocated to this arm will be submitted a supervised resistance training program in combination with the intake of three 15-g daily doses (45g. d- 1 total) mixed plant protein (i.e.; soy and pea) in drink form as a supplementary source of protein in their main meals of the day.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| vastus lateralis muscle cross sectional area | the investigators used ultrasound measures of the vastus lateralis cross sectional area as the primary outcome | Ultrasound images will be obtained both at baseline (before the comencement of the study) and immediately after the 12-week intervention period | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| lean mass | total body and lower limb lean mass assessed by DXA | DXA scans will be taken both at baseline (before the comencement of the study) and immediately after the 12-week intervention period | 
| fiber cross sectional area | vastus lateralis fiber cross sectional area from muscle biopsy samples | Fiber cross sectional areas will be measured both at baseline (before the comencement of the study) and immediately after the 12-week intervention period | 
| maximal isotonic strength | lower-limb maximal isotonic strength will be assessed in the leg-press exercise by means of the one-repetition-maximum test (1-RM test) | 1-RM tests will be taken both at baseline (before the comencement of the study) and immediately after the 12-week intervention period |