WRONG! and you are backpeddling now LOL
You are a moron as tendons do not creat energy or force, what a shmuck!
Balancing on the toes is what a ballerina does when dancing, I guess you went to the wrong classes ahahahhahahha
Do you even know what reactive strength and the stretch shortening cycle has to do with the serve?
You don't even know what you are saying, you are making this up as you go along.
No the soleus in this situation is nothing more than as stabilizer as with most movements. You do not even understand what the solues role is in planter flexion do you even know what that is? You know nothing of biomechanics
The feet in no shape or form assist elevation off the ground other than as a medium to transfer energy from the kinetic chain, none of which came from the toes