i don't think so... You are describing balance rather than equilibrium. I do not want to be in equilibrium while skiing, In contrary, I welcome forces to throw me out of equilibrium and shoot my skis across my body and vice versa... Equilibrium would suck... how do you change turn shape or control speed with equilibrium? Staying in balance? Sure, you didn't fall.. Yet... . So you were balanced. The old "stability with mobility" mantra. But equilibrium?
I can see no correlation of any meaning for "equilibrium" and a dynamic sport. So dancers are in equilibrium?
Turning and controlling speed imply forces and acceleration, no uniform motion, no equilibrium. I guess skidding at constant speed strait down the hill would be uniform motion...?
P.S but I have this new thing I would like to sell you, it is the same old thing but in this new package is much more better, you see... and more effective for sure... sometimes.
the dancers and skiers we want to emulate are are the closest to "equilibrium", its why we know it when we see it. It depends on how one would define it though.
Equilibrium point hypothesis and threshold control
In the Equilibrium Point hypothesis, all movements are generated by the nervous system through a gradual transition of equilibrium points along a desired trajectory. "Equilibrium point" in this sense is taken to mean a state where a field has zero force, meaning opposing muscles are in a state of balance with each other, like two rubber bands pulling the joint to a stable position. Equilibrium point control is also called "threshold control" because signals sent from the CNS to the periphery are thought to modulate the threshold length of each muscle. In this theory, motor neurons send commands to muscles, which changes the force–length relation within a muscle, resulting in a shift of the system's equilibrium point. The nervous system would not need to directly estimate limb dynamics, but rather muscles and spinal reflexes would provide all the necessary information about the system's state.