some of the 10%

Power is force times velocity.

A man Hill, in 1938, developed an equation which illustrates how humans exert maximal amounts of power during concentric contraction of muscles ( i.e. when they get shorter ).

Without going into much detail, maximum power is generated at about 1/3 of maximum velocity and 1/2 of maximum force. It might help to think of it as an impulse, in terms of generating power. For reference, maximum velocity is achieved with no load, and maximum force is exerted when one can't resist a weight ( hold it up ).

Maximum strength is exerted at an angle of about 130 degrees in the leg, modelled quite well here by Sisyphus. The rock is for illustration purposes only.

The good news is we can exert up to twice that force when we land ( eccentric muscle action ). As one might intuitively expect, it's easy to take off, but it's not so when we land...