During which phase of gait is heel off observed in the new terminology?

Heel off is observed during the terminal stance phase of gait. In this phase, the body shifts its weight onto the forward limb, and the heel of the stance leg lifts off the ground, marking the transition from being in contact with the ground to preparing for the next phase of gait. During terminal stance, the individual is maximizing forward propulsion by allowing the body weight to move past the stance foot, thus enabling the heel to lift at the end of this stance.

In contrast, the initial contact phase is the moment the foot first strikes the ground, characterized by heel contact. The pre-swing phase occurs immediately after the terminal stance when the weight shifts to the opposite limb, and the toes of the stance leg are still in contact with the ground, meaning heel off has already occurred. Mid-swing is when the stance leg is off the ground entirely, and the leg is moving forward, but this does not involve heel off from the support phase. Therefore, the best categorization of heel off clearly aligns with terminal stance.