Where does movement begin?
Moving through scales: from muscle to molecule
5–11 nmWorking stroke · one myosin head · where movement begins
A myosin head binds actin, swings its lever arm, lets go and resets, sliding the rope a few millionths of a millimetre towards the centre; the exact step varies with the myosin and conditions. With many heads, each cycles on its own timing, so some always hold on and the force is sustained. A real stroke is over in under a thousandth of a second; here it plays about 5,000 times slower.
force1–5 pN per head
1 / 9 ·
Illustrations are schematic and not to scale. Forces are illustrative estimates; real values depend on biomechanics and loading.
Infographic by Sri Sri Institute for Advanced Research