- See:
Stance Phase:
- Discussion:
- single limb stance comprimises 38% of gait cycle;
- during single limb stance, the ankle begins to dorsiflex by motion of tibia over the fixed foot;
- early phase:
- subtalar joint is pronated inorder to absorbe shock;
- muscles remain quiet;
- middle phase:
- ankle continues to dorsiflex;
- stability is controlled by ligaments, aponeurosis, & extrinsic muscles primarily during the period of
single limb stance from initation to about 30% of the gait cycle;
-
muscle activity during gait:
- gastroc-soleus, posterior tibialis, peroneal, and toe flexor muscles show electrical activity;
- intrisic muscles of foot begin to contract as ankle joint reaches maximum dorsiflexion;
- gastroc-soleus activity is to control the forward progression of tibia;
- length of contracting muscle w/ forward position of tibia and body cause heel rise to occur;
- peroneal muscles become active w/ eccentric activity at midstance
- late phase:
- external rotation of the tibia accompanies this motion, which has a subsequent effect on
hindfoot and
transverse tarsal motion;
- hindfoot and mid foot invert to accommodate the external rotation transmitted from the tibia;
- sub-talar joint continues inverting from previous everted range to neutral position;
- toe dorsiflexion begins, which stabilizes arch of foot by
windlass mechanism;
- elevation of the arch occurs with dorsiflexion of the great toe;
- this maintains the foot as a somewhat rigid lever;
