Figure 1  .

(A), (B): Collagen content and amount of hydroxylysine (Hyl) residues per collagen molecule in normal supraspinatus tendon (ST-N, filled circles) and degenerate supraspinatus tendon (ST-D, open circles) as a function of age. (C), (D): Collagen content and amount of Hyl residues per collagen molecule in normal biceps brachii tendon (BT-N, closed circles). Linear regression was performed on normal tendons from mature subjects, > 20 years only; no significant correlations with age were found.