Final answer:
Knee valgus during an overhead squat suggests that the gluteus Medius and other hip abductors are underactive, leading to instability and the inward movement of the knees.
Step-by-step explanation:
If the knees cave in, which is also referred to as knee valgus during an overhead squat assessment, this is usually an indication that certain muscles might be underactive. In particular, the gluteus Medius and other hip abductors are typically responsible for stabilizing the knee outwards during squatting movements.
When these muscles are underactive, they do not perform their job effectively, leading to the inward movement of the knees. This may also be combined with overactivity of the adductor muscles, which pull the knees inward. The condition of knee valgus can contribute to issues like Runner's Knee or patellofemoral syndrome, where there is a dull, aching pain around the front of the knee and deep to the patella.
Corrective exercises aimed at strengthening the gluteus Medius and hip abductors, and stretching the adductors may help in addressing muscle imbalances and preventing the knees from caving in during squats.