Hydrolyzed Collagen Supplementation Enhances Patellar Tendon Adaptations To 12-weeks’ Resistance Training In Middle-aged Men

Middle-age marks the onset of decline in human muscle strength and power, and chronic resistance exercise (RE) with adequate protein intake can mitigate the age-related deterioration in muscle-tendon properties. Young tendon increases its size and stiffness in response to chronic RE, and these adaptations are augmented when RE is supplemented with hydrolyzed collagen (HC) intake. Although older tendon also adapts to chronic RE, it is not yet known if such adaptations would be augmented with HC supplementation in middle-age. PURPOSE: To investigate the effects of a 12-week RE program combined with HC supplementation on changes in patellar tendon (PT) properties in middle-aged men. METHODS: Twenty men (age, 47 ± 5 years) were randomly assigned into placebo (PLA, n = 11) and collagen (COL, n = 9) groups. Both groups completed progressive lower-limb RE twice weekly for 12 weeks, supplemented immediately post-RE with COL (30 g HC, 50 mg vitamin-C) or PLA (30.5 g maltodextrin, 50 mg vitamin-C). Vastus lateralis (VL) muscle thickness (using ultrasonography), barbell back squat 10-repetition maximum (10-RM), isometric knee extension maximum voluntary torque (MVT) and peak rate of torque development (pRTD) using isokinetic dynamometry were measured before and after the 12-week intervention. PT cross-sectional area (CSA) was measured at 25, 50 and 75% along its length using ultrasonography. PT stiffness (k) and Young’s Modulus (Ꜫ) were measured using ultrasonography and isokinetic dynamometry. Two-way ANOVAs examined group × time (G × T) interactions for all measures. RESULTS: MVT, pRTD, and back squat 10-RM increased by 9%, 36%, and 27% respectively (P < 0.05) with no G × T interaction for any measure (P > 0.05). VL muscle thickness remained unchanged following the intervention (P = 0.308). Mean PT CSA increased following the intervention (P < 0.001) but to a larger degree in COL (+6.8mm2) compared with PLA (+1.2mm2, G × T P = 0.027). Similarly, k and Ꜫ increased in both groups (P < 0.001,) but to greater extent in COL (k, +661 N/mm; Ꜫ, +0.24 Gpa) than PLA (k, +247 N/mm, G × T P = 0.009; Ꜫ, +0.09 Gpa, P = 0.018). CONCLUSION: Twelve weeks’ RE with 30 g HC supplementation after each RE session augments the gains in patellar tendon CSA, stiffness and Young’s modulus more than RE alone in middle-aged men.