The first vertical GRF peak occurs during which gait phase?

The first vertical GRF peak occurs during which gait phase?

• A. Terminal swing
• B. Loading response
• C. Mid-swing
• D. Pre-swing only

Answer: (B)

The first vertical ground reaction force peak shows the moment of weight acceptance in early stance. Right after heel contact, the leg begins to bear the body's full weight, and the muscles and joints work to control that impact. The vertical force rises as the body’s weight is transferred onto the limb, reaching a maximum during this loading response phase. In contrast, during mid-swing and terminal swing there is no ground contact, so the vertical force is not elevated. The second peak in the vertical GRF occurs later in the gait cycle, during push-off (near the transition into pre-swing), not at the initial contact. So the first peak best corresponds to loading response, the weight-acceptance phase right after heel strike.

The first vertical ground reaction force peak shows the moment of weight acceptance in early stance. Right after heel contact, the leg begins to bear the body's full weight, and the muscles and joints work to control that impact. The vertical force rises as the body’s weight is transferred onto the limb, reaching a maximum during this loading response phase.

In contrast, during mid-swing and terminal swing there is no ground contact, so the vertical force is not elevated. The second peak in the vertical GRF occurs later in the gait cycle, during push-off (near the transition into pre-swing), not at the initial contact.

So the first peak best corresponds to loading response, the weight-acceptance phase right after heel strike.