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Questions and Answers
What is the maximum extension angle of the hip joint during terminal stance?
What is the maximum extension angle of the hip joint during terminal stance?
During which phase does the pelvis tilt slightly anteriorly?
During which phase does the pelvis tilt slightly anteriorly?
How much does the pelvis tilt in the sagittal plane during the gait cycle?
How much does the pelvis tilt in the sagittal plane during the gait cycle?
What feature characterizes the two vertical oscillations of the body’s center of mass (COM) in the sagittal plane?
What feature characterizes the two vertical oscillations of the body’s center of mass (COM) in the sagittal plane?
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At what point does the hip begin its movement towards flexion after maximum extension?
At what point does the hip begin its movement towards flexion after maximum extension?
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Which motion occurs as the trunk moves forward over the foot from initial contact to midstance?
Which motion occurs as the trunk moves forward over the foot from initial contact to midstance?
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What is the angle of the hip at initial contact during a gait cycle?
What is the angle of the hip at initial contact during a gait cycle?
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What role does the pelvis serve during gait?
What role does the pelvis serve during gait?
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What is the approximate angle of knee flexion at the end of the loading response phase during the gait cycle?
What is the approximate angle of knee flexion at the end of the loading response phase during the gait cycle?
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During which phase does the hip joint achieve maximum flexion of approximately 30°?
During which phase does the hip joint achieve maximum flexion of approximately 30°?
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What occurs immediately after full extension of the knee during the gait cycle?
What occurs immediately after full extension of the knee during the gait cycle?
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What is the angle of hip hyperextension achieved at terminal stance?
What is the angle of hip hyperextension achieved at terminal stance?
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Why might exaggerated pelvic tilting during walking be problematic?
Why might exaggerated pelvic tilting during walking be problematic?
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What is the position of the knee at initial contact during the gait cycle?
What is the position of the knee at initial contact during the gait cycle?
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What degree of hip flexion is noted at the midswing phase of the gait cycle?
What degree of hip flexion is noted at the midswing phase of the gait cycle?
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At what angle does maximum knee flexion occur during the entire gait cycle?
At what angle does maximum knee flexion occur during the entire gait cycle?
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What role does the first knee flexion arc play during the gait cycle?
What role does the first knee flexion arc play during the gait cycle?
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During which point of the gait cycle is the ankle joint in a neutral position?
During which point of the gait cycle is the ankle joint in a neutral position?
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How much plantarflexion occurs at the ankle during the loading response?
How much plantarflexion occurs at the ankle during the loading response?
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What happens to the MTP joints during terminal stance?
What happens to the MTP joints during terminal stance?
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What is the angle of ankle dorsiflexion at the end of midstance?
What is the angle of ankle dorsiflexion at the end of midstance?
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What motion occurs at the ankle joint as the heel rises during terminal stance?
What motion occurs at the ankle joint as the heel rises during terminal stance?
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During what phase does the body’s center of mass move forward over the weight-bearing limb?
During what phase does the body’s center of mass move forward over the weight-bearing limb?
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What occurs to the knee during terminal swing in preparation for initial contact?
What occurs to the knee during terminal swing in preparation for initial contact?
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Study Notes
Sagittal Plane Kinematics
- The body's center of mass (COM) oscillates vertically in a sinusoidal pattern during gait.
- The highest point of the curve coincides with midstance for each foot, while the lowest point occurs during double support.
Pelvis
- The pelvis plays a crucial role in gait, providing stability and mobility for both the upper and lower extremities.
- It acts as a stable base for the lower limb and head, arms, and trunk (HAT), while accommodating the movements of the thoracic and lumbar spine.
- The pelvis must transfer weight efficiently between limbs and position the acetabulum optimally for hip motion.
- The pelvis remains relatively level in the sagittal plane, with an average anterior-posterior tilt excursion of only about 3° during the gait cycle.
- The pelvis completes two full cycles of sinusoidal motion with each step.
- It starts in a near-neutral position at initial contact and moves through midstance in a slightly posteriorly tilted position.
- By the end of midstance, as the hip begins extension, the pelvis tilts anteriorly.
- As the limb reaches preswing, the pelvis tilts posteriorly again.
- During swing, the pelvis initially completes its posterior tilt and then tilts anteriorly from initial to midswing, concluding with a posterior tilt in preparation for landing.
Hip Joint
- The hip joint undergoes 40° of sagittal motion during a single gait cycle.
- At initial contact, the hip is flexed at 25° to 30°.
- As the stance phase progresses, the hip extends, reaching maximum hyperextension at 10° by terminal stance.
- The trunk moves forward over the foot and continues its forward movement to advance in front of the foot immediately after midstance.
- Hip hyperextension at terminal stance is accompanied by lumbar spine extension and an anterior pelvic tilt.
- Once the hip reaches maximum extension, it starts flexing during preswing to prepare for limb lift-off.
- By the end of stance, the hip is near neutral and continues flexing during swing until reaching slightly more than 30° of flexion at midswing.
- After midswing, the hip flexion decreases slightly and remains until terminal swing, when it starts extending in preparation for initial contact.
- These typical sagittal plane arcs, 10° of hyperextension (terminal stance) and 30° of flexion (midswing), occur during normal walking speed.
- The arcs are slightly higher in fast walking.
Clinical Note
- Exaggerated pelvic tilting during walking can increase stress on the lumbar spine due to the mechanical link between the pelvis and lumbar spine at the sacroiliac joint.
- These stresses can irritate structures in the region, potentially leading to low back pain.
Summary of Hip Joint Motion
-
Stance phase:
- Initial contact (IC): 30° flexion
- Loading response (LR): 25° flexion
- Midstance (MSt): 0°
- Terminal stance (TSt): 10° hyperextension
- Preswing (PSw): 0°
-
Swing phase:
- Initial swing (Isw): 20° flexion
- Midswing (MSw): 30° flexion
- Terminal swing (TSw): 30° flexion
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Key note: the hip extension arc facilitates weight transfer to the contralateral limb, while the hip flexion arc elevates the foot off the ground.
Knee Joint
- The knee joint undergoes two cycles of flexion and extension during the gait cycle.
- At initial contact, the knee is near full extension (about 3° to 5° of flexion).
- The knee flexes during loading response to absorb compression forces from ground contact and assist in weight transfer as the body moves towards single limb support.
- By the end of loading response, the knee is flexed 15° to 20°.
- The knee extends during midstance, minimizing muscular effort required during single limb weight-bearing.
- Maximum knee extension occurs during terminal stance.
- The knee starts flexing immediately after reaching full extension and achieves maximal stance-phase flexion of 35° to 40° by preswing.
- The knee flexes during initial and midswing to shorten the limb and clear the foot from the ground.
- The knee reaches maximum flexion of the entire gait cycle at 60° to 65° during midswing.
- The knee extends to near full extension during terminal swing to assist other limb joints in achieving adequate step length, advancing the limb, and preparing for initial contact.
Summary of Knee Joint Motion
-
Stance phase:
- IC: 5° flexion
- LR: 15-20° flexion
- MSt: 5° flexion
- TSt: 0°
- PSw: 35-40° flexion
-
Swing phase:
- Isw: 40-60° flexion
- MSw: 60-65° flexion
- TSw: 0°
-
Key notes: The first knee flexion arc acts as a shock absorber, while the second knee flexion arc lifts the foot off the ground.
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The first knee extension arc transfers weight to the contralateral limb, while the second knee extension arc prepares for the next step.
Ankle Joint and Foot
- The ankle plantarflexes and dorsiflexes twice during the gait cycle.
- At initial contact, the ankle is in sagittal plane neutral.
- The ankle rapidly plantarflexes (15° plantarflexion) during loading response to ensure the entire plantar foot surface contacts the floor.
- The tibia advances forward over the fixed foot during midstance, leading to 5-10° of dorsiflexion by the end of midstance.
- 10° of ankle dorsiflexion represents the close-packed position of the ankle, providing maximal talocrural joint congruency.
- As the heel lifts off the floor during terminal stance, a second wave of plantarflexion occurs, peaking at around 20°-30° by preswing.
- This plantarflexion propels the limb into swing phase, followed by a gradual decrease in plantar flexion to 10° at initial swing.
- The foot dorsiflexes to neutral or slight dorsiflexion to clear the toes from the floor and maintains this position throughout midswing and terminal swing.
Metatarsophalangeal Joints (MTP)
- A significant sagittal plane motion occurs in the MTP joints during the stance phase after midstance to preswing, often overlooked.
- During loading response, the MTP joints are neutral.
- The MTP joints hyperextend as the body's COM moves forward of the weight-bearing limb and the ankle starts to plantarflex.
- This extension becomes more pronounced during terminal stance until the MTPs reach their maximum motion, 55° to 60°, by the end of preswing.
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Description
Explore the complex role of the pelvis in gait dynamics and its influence on the body's center of mass during walking. This quiz covers the oscillatory nature of the center of mass and the crucial stabilization functions of the pelvis throughout different phases of the gait cycle.
