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

PURPOSE: This study investigated whether 16 wk of daily collagen peptide (CP) supplementation affect muscle and tendon stiffness and explosive muscle strength.

METHODS

Fifty healthy young sedentary males were randomly assigned to either the CP ( n = 25) or the placebo (PLA) ( n = 25) group in a double-blind, randomized, placebo-controlled trial. Participants consumed a beverage containing 10 g of CP or PLA daily for 16 wk. Before and after the intervention, the cross-sectional area of the medial gastrocnemius (MG) and Achilles tendon was measured using magnetic resonance imaging, and their stiffness was assessed using ultrasound shear wave elastography. Maximal voluntary isometric contraction torque and rate of torque development (RTD) of ankle plantar flexion were also measured.

RESULTS

The CP group exhibited significant increases in MG stiffness ( P < 0.001, Cohen's d = 0.594) and Achilles tendon stiffness ( P < 0.001, Cohen's d = 0.378), whereas no significant changes occurred in the PLA group. Similarly, the normalized RTD increased significantly in the CP group ( P < 0.001, Cohen's d = 0.525) but not in the PLA group. No significant changes were observed in MG or Achilles tendon cross-sectional area or maximal voluntary isometric contraction torque in either group. Positive correlations were found between MG stiffness and normalized RTD in both groups before and after the intervention ( P ≤ 0.033, r ≥ 0.427).

CONCLUSIONS

Daily CP supplementation increases both muscle and tendon stiffness in healthy young males. The enhancement of muscle stiffness appears to contribute to improved explosive muscle strength. These findings suggest that CP supplementation may serve as an effective nutritional intervention for modifying muscle mechanical properties and potentially enhancing athletic performance, particularly in activities requiring rapid force production.