565 Biomechanics of Gait

Summary

This presentation, led by Mary Lloyd Ireland, explores the biomechanics of gait, emphasizing the importance of foot and ankle function in walking, running, and returning to sports. It highlights the roles of various phases in gait, including stance and swing phases, as well as crucial anatomical components like the ankle, sub-talar joint, and transverse tarsal articulation. The interaction between foot movement, tibial rotation, and joint stability is key to restoring normal gait, especially after injury. Practical methods, such as treadmill analysis, are recommended for assessing gait abnormalities, helping professionals optimize rehabilitation and athletic performance.

Takeaways

• 😀 Normal gait is essential for walking, running, and returning to sports, and restoring normal foot and ankle motion is crucial for people with lower extremity injuries.
• 😀 Gait is divided into two phases: stance (60%) and swing (40%). Double limb support occurs during walking (10%) but is absent in running.
• 😀 The biomechanics of the foot and ankle are vital for understanding human locomotion, including rotational relationships and movement in the ankle and sub-talar joints.
• 😀 The oblique orientation of the ankle axis causes inward deviation during plantarflexion and outward deviation during dorsiflexion, affecting tibia rotation.
• 😀 The sub-talar joint's axis of rotation is 45° from the horizontal, and internal rotation of the tibia is linked to sub-talar eversion, while external rotation corresponds to inversion.
• 😀 The transverse tarsal joint, made up of the calcaneocuboid and talonavicular joints, allows for midfoot flexibility during pronation and rigidity during supination.
• 😀 The Windlass mechanism stabilizes the longitudinal arch during toe-off by increasing tension in the plantar fascia as the great toe dorsiflexes.
• 😀 Gait has three key intervals: heel strike to foot flat (force absorption), foot flat to heel off (stabilization), and heel lift to toe-off (rigid lever for push-off).
• 😀 Coupled motions in gait involve the tibia and foot: during heel strike, the tibia internally rotates, the sub-talar joint everts, and the foot pronates, while toe-off sees opposite movements.
• 😀 Treadmills are a useful tool for evaluating gait by identifying asymmetry between sides, but gait analysis in a lab can offer more detailed insights, including upper body and hip movement.

Q & A

What is the importance of understanding gait biomechanics in the context of foot and ankle injuries?

Understanding gait biomechanics is crucial for restoring normal foot and ankle motion after injuries. It helps in diagnosing issues, planning treatments, and ensuring effective rehabilitation, enabling individuals to return to walking, running, and sports.

What are the two main phases of the gait cycle?

The gait cycle consists of two main phases: the stance phase (60%) and the swing phase (40%). The stance phase involves the foot being in contact with the ground, while the swing phase occurs when the foot is off the ground.

How does the ankle's oblique axis affect foot motion during walking?

The ankle's oblique axis allows for horizontal rotation between the foot and leg. When the foot is fixed on the ground, dorsiflexion causes internal tibial rotation, and plantarflexion results in external tibial rotation, contributing to coordinated foot movement.

What is the role of the transverse tarsal articulation in gait?

The transverse tarsal articulation, consisting of the talonavicular and calcaneocuboid joints, allows for motion at the subtalar joint while the forefoot remains fixed. This articulation becomes rigid during supination and flexible during pronation, aiding in foot stability and flexibility.

What is the Windlass mechanism and how does it relate to gait?

The Windlass mechanism refers to the increase in tension on the plantar fascia during dorsiflexion of the toes, which elevates the longitudinal arch of the foot. This mechanism plays a critical role in stabilizing the foot during the push-off phase of walking.

What are the three intervals of the walking cycle?

The three intervals of the walking cycle are: 1) Heel strike to foot flat, where the foot rapidly plantarflexes and pronates; 2) Foot flat to heel off, where the foot dorsiflexes, and the subtalar joint inverts; 3) Heel lift to toe off, where rapid plantarflexion occurs and the foot enters supination.

How do the tibia and subtalar joint interact during gait?

During gait, when the foot is fixed on the ground, internal rotation of the tibia leads to eversion of the subtalar joint, while external tibial rotation results in inversion of the subtalar joint. These interactions ensure efficient foot and leg motion during walking.

What happens to the transverse tarsal joint during the second interval of the gait cycle?

During the second interval (foot flat to heel off), the subtalar joint inverts, increasing the stability of the transverse tarsal joint. This inversion transitions the midfoot from being flexible to rigid, which is crucial for efficient push-off.

Why is treadmill analysis useful for gait evaluation?

Treadmill analysis allows for dynamic observation of a patient’s gait while walking or running. It helps identify asymmetries between the left and right sides of the body and allows for real-time feedback to patients or athletes.

How is the biomechanics of running different from walking?

In running, the stance phase is shorter and vertical forces on the body increase, sometimes reaching up to three times the body weight. The range of motion of the joints also increases by about 50%, and the muscle activity patterns are different from walking due to the higher intensity and speed.