The muscle motor: 'simultaneous' levers or sequential impulses?

We use the step-size distance equation z = u/n developed in our two previous papers (z is the step-size distance, u is the actin filament relative velocity and n is the rate of ATP splitting on a given actin filament), and introduce one additional concept: that the impulsive contractile forces developed on an actin filament should proceed sequentially along a given actin-myosin train. This enables us to elucidate some unexplained and puzzling data in the literature, and to predict the surprisingly high values of ATPase in intact muscle that have recently been found experimentally. It seems that a sequential impulsive model of the actin-myosin interaction may give a better explanation of many phenomena in muscle physiology than does the current model of the action of simultaneous levers. (C) 1997 Elsevier Science B.V.