SPEAKER_01 24:55–26:23
So again, there's a tremendous amount of gray area in this discussion. If you were just taking a step forward, and your foot lands on the ground out in front of you, you're in an early propulsive representation. The foot is on the ground and applying force to the ground, but the greatest force is the one that placed the foot there. As soon as the foot makes contact with the ground, the force is still directed away from you towards the ground, then you start pushing against the ground, and the force comes towards you. As you apply more force into the ground and push harder, it becomes a proximal to distal force that is primary. Even though the foot is on the ground the whole time, the degree of energy moving towards you versus away from you differs. Both are present, just like ERs and IRs are always there, inhales and exhales are always there, and proximal and distal forces are always there. The key is the degree to which each is represented, which allows us to classify an early, middle, or late representation. Since both are always present, every exercise has an element of both open and closed chain.
kinetic chainbiomechanicsgait analysisforce applicationexercise classification