TERMINAL STANCE (Sagittal plane)

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

Normal GRF is located

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

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

During terminal stance, ground reaction force produces

• a dorsiflexor moment at the ankle joint
• an extensor moment at the knee
• an extensor moment at the hip

The body controls these moments with

• activity in the ankle plantarflexors. The plantar flexors, which have acted eccentrically through midstance, now act isometrically. The continued advancement of the pelvis and lower extremity now move the tibia anteriorly, which causes the heel to rise at around 35 to 40 percent of the gait cycle.
• passive force which develops in the posterior knee structures as they elongate during knee extension; knee muscle activity is unnecessary.
• eccentric activity in the hip flexors

TERMINAL STANCE (Frontal plane)

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

Normal GRF is located

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

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

During terminal stance, ground reaction forces produce:

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

The body reponds to these moments with

• activity in the intrinsic foot muscles, soleus, and other supinator muscles. These muscles do not oppose the GRFV's supination moment, but augment it in order to supinate the subtalar joint and produce an increasingly rigid foot.
• 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