Effects of specific collagen peptide supplementation combined with resistance training on Achilles tendon properties

Jerger S, Centner C, Lauber B, Seynnes O, Sohnius T, Jendricke P, Oesser S, Gollhofer A, König D · Scandinavian Journal of Medicine & Science in Sports

A positive tendon result on the trial's stated primary endpoint: Achilles tendon cross-sectional area rose 11.0% on collagen against 4.7% on placebo (p=0.002), with greater medial gastrocnemius thickness too (7.3% against 2.7%, p=0.014). Two things sit beside it. The collagen group started with the smaller tendon — 67.8 mm² against 75.4 mm² — and finished at 75.2 mm², about where the placebo group began. And on the mechanical measures the direction runs the other way: tendon stiffness rose 16% on collagen and 35% on placebo, and maximal voluntary torque rose in both, neither difference significant. The tissue got bigger without measurably performing better.

Population

Healthy male volunteers, mean age 26, completing a 14-week high-load resistance training programme

Intervention

5 g specific collagen peptides daily

Comparator

5 g placebo, same training

Limitations

Healthy young men, so it tests augmentation of normal training adaptation rather than repair. 40 were randomised and 27 completed, a 32.5% dropout, with post-hoc power above 0.9 for the tendon measures. Part of the costs were paid by GELITA AG, and co-author Oesser is at the GELITA-linked Collagen Research Institute and a co-inventor of collagen-peptide patents. Tendon and muscle were measured by ultrasound at one site each, so adaptation elsewhere in the tendon or the triceps surae would not be seen. The independent 15-week MRI trial (pmid-37436929), in the patellar tendon, found no between-group difference in size, which is where this trial's positive result sits; on stiffness the two agree.