Gait cycle

Question 1

Initial Contact (stance phase, double support)

Answer 1

Critical event: heel contact with neutral dorsiflexion

Ankle
* ROM at 0 degrees. (correct position for loading). Heel rocker initiated.
* Anterior tibialis eccentric control along with the pretibial musculature.

Knee
* Knee to 0-5. (contact creates a moment/torque)
* Quadriceps extend knee.
* Hamstrings contract to counteract contact torque.

Hip
* Hip flexion 20. (high intensity torque)
* Gluteus maximus and adductor magnus are active in preparation for loading response

Question 2

Loading Response (stance phases, single support)

Answer 2

Critical event: hip stability, controlled knee stability: shock absorption, ankle is in plantarflexion

Ankle
* ROM at 5 degrees of plantarflexion (rapid change) Heel rocker initiated.
* Eccentric contraction of pretibial muscles (EHL, EDL, AT), peak anterior tibialis activity (eccentric)
* Tibialis posterior stabilizes throughout stance phase. Gastroc soleus activated in LATE LOADING RESPONSE

Knee
* ROM knee to 15 degrees (shock absorption)
* Eccentric quadriceps activity: shock absorber (knee flex), diminished HS activity

Hip
* ROM flexion 20 (high torque: 2nd highest torque demand for stability)
* Lower fibers of gluteus maximus, adductor magnus and HS are activated to counteract flexor torque. Peaking are TFL, gluteus medius and minimus, and upper fibers of gluteus maximus to stabilize the frontal plane.

Question 3

Midstance (stance phase, single support)

Answer 3

Critical event: controlled tibial advancement

Ankle
* ankle moves to 5 degrees of dorsiflexion. Foot is in a closed chain position. Ankle (talocrural joint) moves over fixed foot. Ankle 2nd rocker is obtained).
* Gastroc-soleus restrains the tibia, which allows forward progression of tibia
* Soleus and gastroc control the forward progression of the tibia (eccentric control)

Knee
* knee moves into extension (still maintains 5 degrees of flexion)
* Tibial advancement begins after midstance.
* Quadriceps provide dynamic knee stability up until midstance eccentric

Hip
* Hip extends to neutral (0), pelvis and hip is stabilized.
* No sagittal plane muscle activity with exception of gluteus maximus upper fibers
* gluteus medius provides frontal plane stability
* TFL provides stability (co-activation for stability)

Question 4

Terminal Stance (Stance phase, single support)

Answer 4

*loaded limb is in Single limb stance
Critical event: controlled dorsiflexion with heel rise. Force generation for propulsion forward.

Ankle
* Ankle moves to 10 dorsiflexion. 1st metatarsal moves moves to 30 degrees of extension. 3rd ankle rocker or forefoot rocker emerges.
* Gastroc-soleus muscle peaks in activity to prevent tibial collapse (providing propulsion)
* Tibialis Posterior stability
* Peroneal longus and brevis provide stability

Knee
* Calf muscle increases motor function to prevent collapse of loaded limb. Variable knee 0-5 degrees.
* No knee quadriceps muscle activation with biceps femoris activation preventing knee extension

Hip
* Hip ROM extends to hip ext 20 degrees.
* TFL anterior fibers activate posterior ceases this is highly variable.

“Trailing Limb” allows for greater step length. KEY importance for clinical interventions.

Question 5

Pre-Swing (stance phase, double support)

Answer 5

*preparing for limb advancement
Critical Event: passive knee flexion to 40 degrees, ankle plantarflex

Ankle
* moves to 15 degrees of plantarflexion. Metatarsals move to 60 degrees of flexion. Forefoot contact to 1st metatarsal contact (toerocker)
* Gastroc soleus ceases activity early in pre swing

Knee
* Knee moves to 40 degrees of knee flexion. Critical for knee to flex to clear foot in preparate.
* Gracilis for prep for knee flexion

Hip
* Hip moves to 10 extension, limb advancement is beginning.
* Adductor longus contributes to flex femur with rectus femoris

Question 6

Initial Swing (swing phase, single support)

Answer 6

Critical Event: Thigh begins to advance. Hip flex 15 degrees, knee flex to 60 degrees

Ankle
* moves to 5 degrees of plantarflexion (moving toward neutral).
* Pretibial muscles are active to initiate dorsiflexion: EDL AND EHL shows peak activity. AT continues to mid swing.

Knee
* moves to 60 degrees.
* Biceps femoris short head, sartorius & gracilis peaks to flex knee

Hip
* hip flexion to 15.
* Iliacus initial phase & stops, sartoris & gracilis peak in activity.
* HS come in late mid-swing (co-activation @hip: decelerate

Question 7

Mid Swing (swing phase, single support)

Answer 7

Critical event: hip flex to 25, ankle to 0, foot clears the ground

Ankle
* moves to neutral, 0 (clears the ground by one cm).
* Pretibial are active and carries momentum

Knee
* moves rapidly to extension, moves to 25 degrees.
* Carries knee extension through momentum. HS begin to decelerate the momentum.

Hip
* hip flexion moves to 25.
* Carries on motor activity from initial swing with the gracilis carrying momentum

Question 8

Terminal Swing (swing phase, single support)

Answer 8

*limb reaches out to achieve step length
Critical event: knee extension to neutral (or 5 degrees to flex)

Ankle
* Dorsiflexion to neutral
* Pretibial muscles are concentrically active

Knee
* knee extends to neutral (or 5 degrees). Active quads to achieve step length.
* Quadriceps are concentrically activating
* In late terminal swing, the HS will activate to reduce the acceleration of the quads.

Hip
* hip flex to 20 degrees.
* HS peak at their activity
* Hip stabilizers: lower fibers of gluteus maximus, adductor magnus stabilize hip

Limb is positioned for heel contact.