People's calf muscles don't all work the same way when you push off your toes. Because everyone's muscles behave differently, one-size-fits-all computer models might not accurately predict how each person's leg will move.

To properly understand how the calf muscle's force and length change in the body, researchers need to study a large number of people. Using too few people might miss important natural differences, which could lead to inaccurate models and medical applications.

When you move your ankle or push off your toes, your calf muscle doesn't work across its full strength range. Instead, it only uses a specific part of its strength curve, and this part is different for most people, with most using the rising part of the curve and only a few using the falling or flat part.

When you move your ankle from pointing your toes down to pulling them up, the main calf muscle gets longer and generates more force in a straight-line pattern. This shows that how your calf muscle is built and how much power it produces directly changes as your ankle joint bends.

When you move your ankle normally, your calf muscle gets stronger the more it stretches, instead of reaching a maximum strength and then getting weaker. This means your calf muscle is designed to keep producing more force the more it's pulled during everyday movements.