Gait Cycle and Lower Limb Muscles

Gait Cycle

• Normal gait is a series of rhythmical, alternating movements of the trunk and limbs that result in the forward progression of the center of gravity.
• It can be described as a series of 'controlled falls'.

Phases of Walking

• There are five stages to walking: heel-strike, support, toe-off, leg lift, and swing.
• Heel-strike: the gluteus maximus, quadriceps, and muscles in the anterior compartment of the leg work together to decelerate flexion, maintain the extended position of the knee, and keep the ankle dorsi flexed.
• Support: the quadriceps maintains the extended position of the knee, and the ankle is kept stable by the balanced contraction of the inverters and everters.
• Toe-off: the hamstring muscles flex the knee, and the ankle is plantar flexed by the muscles in the posterior compartment of the leg.
• Leg lift: the iliopsoas and rectus femoris flex the lower limb at the hip, the knee is flexed by the hamstrings, and the ankle is dorsi flexed by the muscles in the anterior compartment of the leg.
• Swing: the iliopsoas and rectus femoris keep the hip flexed, the knee is extended by the quadriceps, and the ankle is still dorsi flexed by the muscles in the anterior compartment of the leg.

Common Gait Abnormalities

• Antalgic gait: pain-relieving gait.
• Lateral trunk bending: Trendelenburg gait.
• Functional leg-length discrepancy: a difference in leg length that affects gait.
• Increased walking base: ataxia, a lack of coordination and balance.
• Inadequate dorsiflexion control: foot drop, caused by damage to the deep fibular nerve.
• Trendelenburg sign: the pelvis drops on the raised limb, indicating weakness or paralysis of the abductor muscles.
• Waddling gait: seen in patients with myopathies, such as muscular dystrophy, due to bilateral weakness of the abductor muscles.

Learn about the muscles of the lower limb and their role in the gait cycle, including the phases of walking and locomotion.