Related Experiment Video
Updated: Aug 12, 2026

Simultaneous Intracellular Recording of a Lumbar Motoneuron and the Force Produced by its Motor Unit in the Adult Mouse In vivo
Published on: December 5, 2012
The muscle motor: 'simultaneous' levers or sequential impulses?
1Open University Oxford Research Unit, UK. g.f.elliott@open.ac.uk
Abstract:
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.
Related Concept Videos
Muscle Contraction
Motor Units
Muscle Contraction
Motor Units
Motor units come in different sizes, with smaller units...
Motor Unit Stimulation
The latent period of contraction marks the onset of excitation-contraction coupling, when the action potential propagates across the sarcolemma, preparing the muscle fibers for contraction. As the fibers enter the contraction phase, the...
Muscle Stimulation Frequency
Wave summation
At low firing rates, motor neurons induce individual twitch contractions in muscle fibers. These twitches...

