Biomechanics & Gait Analysis Flashcards

What is the difference between step length and stride length in gait analysis?

Answer: Step length is heel to heel of opposite feet; stride length is heel to heel of the same foot

Step length is the distance from heel strike of one foot to heel strike of the opposite foot, while stride length is the full gait cycle distance from heel strike of one foot to the next heel strike of the same foot.

Which of the following best describes the concept of the center of mass (COM) during normal gait?

Answer: It moves in a sinusoidal vertical and lateral pattern

The center of mass follows a sinusoidal path, moving up and down vertically as well as side to side laterally throughout the gait cycle, with each oscillation approximately 5 cm.

A patient with tibialis anterior weakness requires which AFO design to address the gait deficit?

Answer: Posterior leaf spring AFO

A posterior leaf spring (PLS) AFO provides dynamic dorsiflexion assistance during swing phase to correct foot drop caused by tibialis anterior weakness while allowing some ankle motion.

What is cadence in gait analysis?

Answer: The number of steps taken per unit time, typically steps per minute

Cadence is defined as the number of steps taken per unit time, most commonly expressed as steps per minute, with a normal adult value of approximately 110–120 steps per minute.

Excessive subtalar pronation during gait most commonly leads to which secondary biomechanical consequence at the knee?

Answer: Internal tibial rotation and increased medial compartment stress

Excessive subtalar pronation causes obligatory internal tibial rotation through the subtalar/tibial coupling mechanism, increasing medial knee compartment loading and medial patellar stress.

Which gait parameter is most directly reduced in a patient with bilateral hip flexion contractures?

Answer: Stride length

Bilateral hip flexion contractures prevent full hip extension during terminal stance, directly limiting stride length because the trailing limb cannot extend behind the body to complete the normal gait cycle.

During the push-off phase of gait, which joint motion sequence is most important for efficient propulsion?

Answer: Knee extension, ankle plantarflexion, MTP dorsiflexion

Efficient push-off requires knee extension to stabilize the limb, followed by powerful ankle plantarflexion to propel the body forward, with MTP dorsiflexion activating the windlass mechanism to create a rigid lever.