LOADING RESPONSE

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?

LOADING RESPONSE

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 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

compare to frontal plane

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