TABLE 3.
Quadriceps, hamstrings, gluteus maximus, and total, muscle volume pre‐ and post‐15 weeks of lower‐body resistance training, with collagen peptide (CP, n = 19) or placebo (PLA, n = 20) supplementation
| CP | PLA | ANOVA interaction | Change (%) | Unpaired t‐test | Between‐group effect size | ||||
|---|---|---|---|---|---|---|---|---|---|
| Pre | Post | Pre | Post | (g × t) | CP | PLA | |||
| Quadriceps (cm3) | |||||||||
| RF | 258 ± 70 | 292 ± 76*** | 275 ± 54 | 303 ± 69*** | p = 0.446 | 14.1 ± 11.0 | 9.9 ± 8.0 | p = 0.183 | 0.43 “Small” |
| VM | 473 ± 124 | 539 ± 113*** | 491 ± 77 | 538 ± 81*** | p = 0.031 | 15.6 ± 8.9 | 9.7 ± 5.4 | p = 0.017 | 0.80 “Large” |
| VI | 576 ± 126 | 645 ± 117*** | 619 ± 123 | 669 ± 119*** | p = 0.102 | 13.0 ± 8.5 | 8.5 ± 5.5 | p = 0.055 | 0.63 “Moderate” |
| VL | 617 ± 144 | 720 ± 155*** | 648 ± 114 | 729 ± 130*** | p = 0.154 | 17.6 ± 9.0 | 12.8 ± 7.0 | p = 0.069 | 0.60 “Moderate” |
| Q | 1924 ± 440 | 2196 ± 434*** | 2033 ± 318 | 2238 ± 339*** | p = 0.071 | 15.2 ± 8.2 | 10.3 ± 5.2 | p = 0.032 | 0.71 “Moderate” |
| Hamstrings (cm3) | |||||||||
| BFsh | 103 ± 32 | 121 ± 33*** | 108 ± 34 | 123 ± 33*** | p = 0.180 | 19.0 ± 11.2 | 15.4 ± 11.2 | p = 0.323 | 0.32 “Small” |
| BFlh | 187 ± 53 | 212 ± 57*** | 190 ± 41 | 210 ± 43*** | p = 0.220 | 14.4 ± 7.3 | 11.1 ± 8.0 | p = 0.186 | 0.43 “Small” |
| SM | 229 ± 51 | 249 ± 49*** | 228 ± 48 | 243 ± 48*** | p = 0.216 | 9.3 ± 6.0 | 6.8 ± 6.0 | p = 0.199 | 0.42 “Small” |
| ST | 187 ± 50 | 235 ± 60*** | 204 ± 48 | 245 ± 51*** | p = 0.190 | 26.7 ± 9.6 | 21.7 ± 9.5 | p = 0.111 | 0.52 “Moderate” |
| H | 706 ± 161 | 817 ± 174*** | 730 ± 137 | 821 ± 144*** | p = 0.122 | 16.5 ± 6.8 | 12.8 ± 6.1 | p = 0.089 | 0.56 “Moderate” |
| Gluteus maximus (cm3) | 894 ± 213 | 1035 ± 227*** | 973 ± 164 | 1097 ± 181*** | p = 0.346 | 16.6 ± 7.7 | 12.9 ± 5.4 | p = 0.091 | 0.55 “Moderate” |
| Total of the trained muscles (cm3) | 3523 ± 785 | 4048 ± 804*** | 3737 ± 582 | 4156 ± 618*** | p = 0.078 | 15.7 ± 7.2 | 11.4 ± 3.9 | p = 0.026 | 0.74 “Moderate” |
Note: Data are mean ± SD, Within‐group pre to post effects were determined from paired t‐tests and are denoted by: ***p < 0.001. p values are shown for ANOVA group × time (g × t) interactions and unpaired t‐tests on percentage change data. Effect size is calculated between‐groups using percentage change data. Total lower body muscle volume is the sum of quadriceps, hamstrings, and gluteus maximus muscle volumes.
Abbreviations: BFlh, biceps femoris long head; BFsh, biceps femoris short head; H, overall hamstrings; Q, overall quadriceps; RF, rectus femoris; SM, semimembranosus; ST, semitendinosus; VI, vastus intermedius; VL, vastus lateralis; VM, vastus medialis.