homework and exercises - What is physics of a normal jump?

What is the physics behind a normal human jump ?

when a normal human wants to jump.

1. First, some energy is stored in their thighs and The elastic tendons Just like a spring. In mechanics and physics, Hooke's law of elasticity is an approximation that states that the extension of a spring is in direct proportion with the load applied to it. Many materials obey this law as long as the load does not exceed the material's elastic limit

$$F=-k.x$$ where x is the displacement of the spring's end from its equilibrium position (a distance, in SI units: metres); F is the restoring force exerted by the spring on that end (in SI units: N or kg·m/s^2); and k is a constant called the rate or spring constant (in SI units: N/ m

what is human rate constant k?