The sliding filament hypothesis

The sliding filament hypothesis

The research also showed that individual protein filaments do not themselves undergo contraction but remain a constant length. Instead, the filaments slide between one another and so collectively shorten or lengthen the whole muscle.

During muscle contraction, thin actin proteins interpolate between thicker myosin elements thus contracting the entire fibre and the muscle structure as a whole - the 'sliding filament mechanism'. Furthermore, the simple elegance of the model was borne out by the visual evidence that A-bands always remained the same length apart, as would be expected if the model were correct.