Hydrolysed Collagen Supplementation Enhances Patellar Tendon Adaptations to 12 Weeks' Resistance Training in Middle-Aged Men

Resistance exercise (RE) with hydrolysed collagen (HC) supplementation increases collagen synthesis in young and middle-aged populations, and further enhances tendon adaptations to chronic RE in young athletes. However, it is unknown if middle-aged tendon can benefit from chronic RE with HC supplementation. We investigated the effects of 12-weeks' RE, combined with HC supplementation, on changes in patellar tendon (PT) properties in middle-aged men. In a double-blind design, 20 recreationally active men (age, 47 +/- 5 years) were randomly assigned to a placebo (PLA, n = 11) or collagen (COL, n = 9) group. Both cohorts completed progressive lower-limb RE twice weekly for 12 weeks and were supplemented post-RE with COL (30 g HC and 50 mg vitamin C) or PLA (30.5 g maltodextrin and 50 mg vitamin C). The following were assessed before and after the 12-week intervention: barbell back squat 10-repetition maximum (10-RM); vastus lateralis (VL) muscle thickness and PT cross-sectional area (CSA at 25%, 50% and 75% tendon length) using ultrasonography; isometric knee extension maximum voluntary torque (MVT) and peak rate of torque development (pRTD), PT stiffness (k) and Young's modulus (E) using ultrasonography and isokinetic dynamometry. MVT, pRTD, 10-RM and VL thickness all increased post-training (p < 0.05), but there were no group x time interactions (p > 0.05). Mean PT CSA increased more in COL (+6.8 +/- 5.4 mm(2)) than PLA (+1.2 +/- 2.1 mm(2), group x time p = 0.027). Similarly, k and E increased more in COL (k, +661 +/- 331 N/mm and E, +0.21 +/- 0.13 GPa) than PLA (k, +247 +/- 305 N/mm, group x time, p = 0.009 and E, +0.09 +/- 0.13 GPa, group x time, p = 0.018). In conclusion, 12-weeks' RE with 30 g HC supplementation augmented gains in PT CSA, stiffness and Young's modulus in middle-aged men.