Collagen Peptide Supplementation Enhances Muscle-Tendon Stiffness and Explosive Strength: A 16-wk Randomized Controlled Trial

Miyamoto N, Ishihara K, Oshima T, Kawai M, Oritani Y, Iemoto N · Medicine and Science in Sports and Exercise

The rare collagen tendon trial without a training co-intervention, and it reports the outcome the training trials keep missing: Achilles tendon stiffness rose in the collagen group (d=0.38) and medial gastrocnemius stiffness rose more (d=0.59), with a matching gain in rate of torque development, while the placebo group changed on none of them. Cross-sectional area of muscle and tendon did not change in either group — the mirror image of the Freiburg trials, which found size without stiffness.

Population

Healthy young sedentary men, not undertaking a training programme

Intervention

10 g collagen peptides daily in a beverage for 16 weeks

Comparator

Placebo beverage

Limitations

The reported statistics are within-group changes rather than a between-group comparison, which overstates how cleanly the arms separated. Sedentary healthy young men. Author affiliations point to a Japanese collagen manufacturer's research group and the intervention is a proprietary beverage. Tendon and muscle, not cartilage.