Final answer:
The gluteus medius and minimus are active during the mid-stance phase of gait, helping to stabilize the pelvis and maintain balance when walking, or during actions like foot-tapping or jumping.
Step-by-step explanation:
The muscles of the gluteus medius and minimus are primarily active during the mid-stance phase of gait. This stage is crucial for stabilizing the pelvis and maintaining posture while walking. These muscles work to prevent the dropping of the contralateral pelvis and control the movement of the thigh, which is essential for a smooth, balanced gait.
Specifically, when the foot of one side is in the mid-stance, these muscles prevent the pelvis from tilting downwards on the opposite side, which would otherwise occur due to the weight of the body being supported largely on one leg. Additionally, during activities such as foot-tapping or jumping, as well as while walking, the gluteus medius and minimus play an important role in controlling the level of the pelvis, lowering the sole of the foot to the ground, and contributing to overall postural stability.