Abstract:

Acco rding to swinging cross-bridge model,muscle contraction is produced by cyclical attachment and detachment of cross-bridges towards thin filament.The cooperat ive behaviors of cross-bridges in muscle isotonic contraction in one dimensional condition is investigated.Firstly, we suppose a relationship betw een energy and time for a single cross-bridge during the working cycle. Then we invest ig ate two particular cooperative behaviors of cross-bridges in muscle isotonic contractio n(in which the ex tern load F is constant):(1)n0 attached cross-bridges work at the same tempo, the working process is not af fected by the environment ;(2)n0 at tached cross-bridges work at the same tempo, and the working rate is propo rtional to the very velocity of thin filament in the cont raction.We have calculated the relationship between the extern load to muscle and the velocity of muscle cont raction in the two condit ions.We find that in the first case it is similar to the Hill curve in shape, and in the second case the velocity is inversely proportional to the force.

Key words: muscle contraction, molecular mo tors, cooperative behaviors