The event that starts pre-swing is toe-off. This moment marks the transition from stance to the forward swing of the leg: as the toes push off the ground, the foot leaves contact and the limb begins to move into swing. During this brief interval, weight shifts to the opposite limb, the knee and ankle work to position the leg for swing, and propulsion from the plantarflexors helps propel the leg forward for the upcoming phase.

Rocker mechanisms during stance are about making forward progression over the foot energy-efficient. By allowing the body to roll over the foot instead of forcing large, continuous ankle movements, the system reduces the muscular work needed to advance the tibia and propel the body. The heel rocker starts the rollover at contact, easing initial tibial forward motion with less ankle torque. The ankle rocker continues that smooth progression through midstance, and the forefoot rocker at the end of stance provides a favorable lever for push-off. This coordinated rolling action minimizes active muscle demand, lowering the energy cost of walking. So, the main goal is to conserve energy during stance. The ideas of limiting ankle motion, preventing heel rise, or increasing energy expenditure don’t reflect the primary function of rockers in normal gait.

The swing periods are the consecutive stages of leg movement from toe-off to the next heel strike, and this set lays out that sequence as preswing, initial swing, mid swing, and terminal swing. Preswing marks the transition into forward leg movement, initial swing is the early part of swinging the foot through the air, mid swing covers the mid-portion of the forward arc, and terminal swing finishes the swing as the leg decelerates and prepares for contact. This ordering and these four subphases together define the entire swing phase, which is why this grouping is the best match. The other sets mix in terms that belong to other parts of the gait cycle or disrupt the known progression, so they don’t fit as the swing periods.

Loading response is the initial weight-acceptance portion of the stance phase right after the foot makes contact. It occupies about 0–10% of the gait cycle, the first slice of stance in which the body begins to transfer weight onto the limb and absorb shock. Functionally, the knee flexes slightly and the ankle lowers the heel into plantarflexion, with the foot pronating to adapt to the ground while the muscles control the rate of loading. This brief window sets up stability for the subsequent phases of stance (midstance and terminal stance) and is shorter than those later portions. That’s why 0–10% is the correct range for loading response.