An analysis of sarcomere dynamics using a viscoelastic approximation to the sliding filament model

Abstract

One of the conceptual difficulties inherent in the widely-accepted sliding filament model for striated muscle contraction (Huxley, A. F. and Niedergerke, 1954; Huxley, H. E. and Hanson, 1954) is the problem of sarcomere length instability. As pointed out by A. V. Hill (1953a), a length-tension relation where tension decreases with increasing length, such as the one obtained by Gordon et alia (1966b), predicts instability of sarcomere lengths in that region, called the descending limb. Associated with sarcomere length instability is the phenomenon of tension creep (Huxley and Peachey, 1961; Gordon et alia, 1966a; Julian and Morgan 1979a.b, Julian and Moss, 1980; Saldaña and Smith, 1991).
The present work investigates sarcomere length instability and tension creep by analyzing the dynamics of a series of half-sarcomeres using a viscoelastic approximation to the sliding filament model of muscle contraction.