We investigated the effects of two types of nonweight-bearing exercise on changes in bone-specific alkaline phosphatase (BAP) and pro-collagen type 1 C-peptide (P1P). BAP is a specific marker of bone synthesis, whereas P1P reflects synthesis of type 1 collagen in other organs as well as bone. Eight participants performed static and dynamic unilateral knee extensions. BAP and P1P were measured before, and at 1, 2, 24, 48, and 72 hr after exercise. P1P increased at 24 hr after a static knee extension exercise, whereas BAP did not change during the experimental period. We found no changes in these markers after dynamic exercise. These results imply that type 1 collagen synthesis in tendons increases after static exercise. (Contains 3 tables and 2 figures.)