LOADING RESPONSE (Sagittal plane)

Orientation of ground reaction force vector (GRFV) in sagittal plane

Normal GRF is located

• posterior to ankle joint
• posterior to knee joint
• anterior to hip joint

What effect will this have on joint motion and muscle activation?

During loading response, ground reaction force produces

• a plantar flexion moment at the ankle joint
• a flexion moment at the knee
• a flexion moment at the hip

The body controls these moments with

• eccentric activity in the ankle dorsiflexors
• eccentric activity in the knee extensors
• isometric activity in the hip extensors

LOADING RESPONSE (Frontal plane)

Orientation of ground reaction force vector (GRFV) in frontal plane

Normal GRF is located

• lateral to subtalar axis
• medial to knee joint
• medial to hip joint

What effect will this have on joint motion and muscle activation?

During loading response, ground reaction forces produce:

• a pronation moment at the subtalar joint
• a varus moment at the knee
• an adduction moment at the hip

The body reponds to these moments with

• eccentric activity in the intrinsic foot muscles and other supinator muscles to control subtalar pronation.
• passive tension in the lateral knee structures. Active force in the tensor fascia lata could contribute to knee stability in the frontal plane
• activity in hip abductor muscles