determinants of gait

What defines a gait cycle?

The interval from heel strike of one foot to the next heel strike of the same foot

What are the two main phases of the gait cycle?

Stance Phase (Closed Kinetic Chain) and Swing Phase (Open Kinetic Chain).

What percentage of the gait cycle is the stance phase?

Approximately 62%.

What occurs during the stance phase?

Weight-bearing activities from heel strike to toe off of the same foot

What occurs during the swing phase?

Non-weight-bearing period from toe off to heel strike of the same foot.

What motions does the foot go through during the swing phase?

Pronation followed by supination.

What is the function of pronation during swing phase?

Shortens the limb for ground clearance and conserves energy.

What is the function of supination at the end of swing phase?

Prepares the foot for stable heel strike.

What are the three periods of stance phase?

Contact period, midstance period, propulsive period.

What percentage of stance phase does the contact period take?

27%.

What happens during the contact period?

Between heel strike of observed foot and toe off of opposite foot.

When does the midstance period begin and end?

Begins after toe off of opposite foot; ends with heel lift of observed foot.

What marks the start and end of the propulsive period?

Starts with heel lift and ends with toe off of the same (weight-bearing) foot.

What motion occurs at the subtalar joint during early stance phase?

Pronation for shock absorption and terrain adaptation.

What joint motion converts the foot from mobile adapter to rigid lever?

Supination of the subtalar joint.

What occurs if the foot is pronated during propulsion?

Muscle fatigue, hypermobility, and risk of callus formation due to increased shearing forces.

What foot structures are heavily loaded just before toe off?

Metatarsal heads 2, 3, and the hallux.

What is a key event that occurs simultaneously with forefoot loading during the contact period?

Toe off of the opposite foot.

Why is it important that the foot supinates before heel strike?

To stabilize the osseous structure and prepare for weight acceptance.

What is the significance of the hallux during propulsion?

It plays a critical role in weight transfer and efficient push-off.

How does external rotation of the leg contribute during the propulsive period?

It assists in supination and enhances foot rigidity for propulsion.

What happens to the body's weight distribution just before toe off?

It shifts medially across the foot, concentrating on the medial metatarsals and hallux.

What biomechanical consequence arises from prolonged pronation during propulsion?

Inefficient propulsion, increased muscle workload, and potential foot pathology.

What transformation does the subtalar joint enable during midstance to propulsion?

It converts the foot from a shock absorber (mobile adapter) to a rigid lever.

What kinetic chain is associated with the stance phase?

Closed kinetic chain.

What kinetic chain is associated with the swing phase?

Open kinetic chain.

Why does the foot slightly pronate before toe off?

To assist in smooth transition and load transfer to the opposite limb.