Table 3.
Effects of protein supplementation on changes in bench press strength
| Groups/subgroups | SMD | 95% CI | Number of trials/intervention groups | P‐value | I 2 (%) |
|---|---|---|---|---|---|
| All RCT – bench press strength | 0.20 | 0.06:0.34 | 34/50 | <0.01 | 42.8 |
| RCT without resistance exercise | 0.89 | −0.07:1.82 | 1/1 | NA | 0 |
| RCT with resistance exercise (RE) | 0.18 | 0.04:0.32 | 33/49 | 0.01 | 39.4 |
| <65 years old | 0.18 | 0.03:0.33 | 32/48 | 0.01 | 55 |
| ≥65 years old | 0.28 | −0.51:1.07 | 1/1 | NA | 0 |
| RCT with RE testing bench press and reporting protein ingestion | 0.15 | 0.02:0.28 | 31/46 | 0.03 | 27 |
| RCT with RE ingesting <1.2 g/kg/day | −0.16 | −1.09:0.77 | 1/1 | NA | 0 |
| RCT with RE ingesting 1.2–1.59 g/kg/day | 0.17 | −0.01:0.35 | 14/21 | 0.07 | 23.3 |
| RCT with RE ingesting ≥1.6 g/kg/day | 0.13 | −0.15:0.41 | 16/24 | 0.33 | 54.7 |
| Meta regression – protein ingestion as a continuous variable (g/kg BW/day) in all RCT reporting protein ingestion | −0.00 | −0.22:0.22 | 32/48 | 0.999 | NA |
| Meta regression – protein ingestion as a continuous variable (g/kg BW/day) in studies using RE | 0.01 | −0.20:0.23 | 31/47 | 0.869 | NA |
BW, body weight; CI, confidence intervals; NA, not applicable; RCT, randomized clinical trials; RE, resistance exercise; SMD, standardized mean deviation.