well since opensim turns out to be some mocap cheat than real dynamic walking,

whats the CloSEST thing in (basic) mathemathics/physics that can help me predict the proper cycle to walking dynamics, including the fullbody orientations towards the dominant gait at the current timeframe?
i suppose t = time and F= ma is considered, and 3d cartesian for directional control.

It doesnt have to be exact and precise, just have to be natural: countermotion in turns, body orientations and maybe some non uniform timing between front and hind leg?

no need to be super impossible either just basic intro equation model to the subject maybe

or maybe whatever basic expression to describe/ understand about how the cycle happens and the symmetrical pattern