Muscle performance, size, and safety responses after eight weeks of resistance training and protein supplementation: a randomized, double-blinded, placebo-controlled clinical trial.
Study Goal
The researchers aimed to compare the effects of bioenhanced whey protein (with additional PEG leucine) versus standard whey protein or placebo on muscle performance, size, and blood markers during resistance training.
Results Summary
The study found no significant differences in muscle strength, endurance, body composition, or muscle cross-sectional area between groups, regardless of supplementation. However, the bioenhanced whey protein groups showed a higher Albumin:Globulin ratio compared to the standard whey protein group.
Population
Healthy, recreationally trained, college-aged men (n = 106).
Effective Dosage
5 g of additional polyethylene glycosylated (PEG) leucine per shake, consumed twice on training days and once on non-training days.
Duration
8 weeks.
Interactions
None mentioned.
| Intervention | Direction | Endpoint | Population | Dosage | Impact | Claim # |
|---|---|---|---|---|---|---|
bioenhanced whey protein with low-volume resistance training | no change | muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers | healthy, recreationally trained, college-aged men | p > 0.05 | no interactions | #1 |
bioenhanced whey protein with moderate-volume resistance training | no change | muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers | healthy, recreationally trained, college-aged men | p > 0.05 | no interactions | #2 |
standard whey protein with moderate-volume resistance training | no change | muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers | healthy, recreationally trained, college-aged men | p > 0.05 | no interactions | #3 |
placebo with moderate-volume resistance training | no change | muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers | healthy, recreationally trained, college-aged men | p > 0.05 | no interactions | #4 |
no supplementation with moderate-volume resistance training | no change | muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers | healthy, recreationally trained, college-aged men | p > 0.05 | no interactions | #5 |
resistance training | increase | muscle strength and endurance variables, body composition, muscle cross-sectional area, and safety blood markers | healthy, recreationally trained, college-aged men | p ≤ 0.05 | main effects for training were observed | #6 |
standard whey protein with moderate-volume resistance training | decrease | Albumin:Globulin ratio | healthy, recreationally trained, college-aged men | p = 0.037 | Albumin:Globulin ratio was lower | #7 |
bioenhanced whey protein with low-volume resistance training | increase | Albumin:Globulin ratio | healthy, recreationally trained, college-aged men | - | Albumin:Globulin ratio was higher | #8 |
bioenhanced whey protein with moderate-volume resistance training | increase | Albumin:Globulin ratio | healthy, recreationally trained, college-aged men | - | Albumin:Globulin ratio was higher | #9 |
bioenhanced whey protein with low-volume resistance training | increase | relative protein intake | healthy, recreationally trained, college-aged men | p < 0.001 | had a greater intake | #10 |
bioenhanced whey protein with moderate-volume resistance training | increase | relative protein intake | healthy, recreationally trained, college-aged men | p < 0.001 | had a greater intake | #11 |
standard whey protein with moderate-volume resistance training | increase | relative protein intake | healthy, recreationally trained, college-aged men | p < 0.001 | had a greater intake | #12 |
placebo with moderate-volume resistance training | decrease | relative protein intake | healthy, recreationally trained, college-aged men | p < 0.001 | had a lower intake | #13 |
no supplementation with moderate-volume resistance training | decrease | relative protein intake | healthy, recreationally trained, college-aged men | p < 0.001 | had a lower intake | #14 |
8 weeks of resistance training | increase | muscle performance and size | healthy, recreationally trained, college-aged men | - | improved muscle performance and size similarly among groups regardless of supplementation | #15 |
The purpose of this study was to examine the effects of 2 different types of protein supplementation on thigh muscle cross-sectional area (CSA), blood markers, muscular strength, endurance, and body composition after 8 weeks of low- or moderate-volume resistance training in healthy, recreationally trained, college-aged men. One hundred and six men were randomized into 5 groups: low-volume resistance training with bioenhanced whey protein (BWPLV; n = 22), moderate-volume resistance training with BWP (BWPMV; n = 20), moderate-volume resistance training with standard whey protein (SWPMV; n = 22), moderate-volume resistance training with a placebo (PLA; n = 21), or moderate-volume resistance training with no supplementation (CON; n = 21). Except for CON, all groups consumed 1 shake before and after each exercise session and one each on the nontraining day. The BWPLV, BWPMV, and SWPMV groups received approximately 20 g of whey protein per shake, whereas the BWP groups received 5 g of additional polyethylene glycosylated (PEG) leucine. Resistance training sessions were performed 3 times per week for 8 weeks. There were no interactions (p > 0.05) for muscle strength and endurance variables, body composition, muscle CSA, and safety blood markers, but the main effects for training were observed (p ≤ 0.05). However, the Albumin:Globulin ratio for SWPMV was lower (p = 0.037) than BWPLV and BWPMV. Relative protein intake (PROREL) indicated a significant interaction (p < 0.001) with no differences across groups at pre; however, BWPLV, BWPMV, and SWPMV had a greater intake than did PLA or CON at post (p < 0.001). This study indicated that 8 weeks of resistance training improved muscle performance and size similarly among groups regardless of supplementation.