COF Biomechanics & Gait Analysis 2 — Questions and Answers
Question 1: During normal gait, which muscle group is primarily responsible for controlling the rate of foot lowering (foot slap prevention) immediately after heel strike?
- Gastrocnemius
- Tibialis anterior (Correct answer)
- Peroneus longus
- Extensor digitorum longus
Correct answer: Tibialis anterior
The tibialis anterior eccentrically contracts after heel strike to lower the foot to the ground in a controlled manner, preventing foot slap.
Question 2: What is the term for the excessive outward rotation of the foot during ambulation, often compensating for limited hip internal rotation?
- Supination
- Pronation
- Out-toeing (Correct answer)
- Equinus
Correct answer: Out-toeing
Out-toeing refers to external rotation of the foot during gait, commonly seen as a compensatory mechanism for reduced hip internal rotation range of motion.
Question 3: The 'double support phase' of normal gait refers to the period when:
- Both feet are in the swing phase simultaneously
- Both feet are in contact with the ground simultaneously (Correct answer)
- One foot is fully loaded and the other is at mid-swing
- The center of mass reaches its highest point
Correct answer: Both feet are in contact with the ground simultaneously
Double support occurs twice per gait cycle when both feet are simultaneously in contact with the ground, comprising approximately 20% of the gait cycle at normal walking speeds.
Question 4: A patient with a spastic equinovarus foot in cerebral palsy would most likely exhibit which gait deviation during swing phase?
- Steppage gait
- Vaulting on the contralateral limb
- Circumduction of the affected limb
- All of the above are common compensations (Correct answer)
Correct answer: All of the above are common compensations
Spastic equinovarus causes foot clearance problems during swing, leading patients to compensate with steppage gait, vaulting on the stance limb, or circumduction of the affected limb.
Question 5: Which parameter of gait is most directly measured by counting the number of steps taken per unit of time?
- Stride length
- Cadence (Correct answer)
- Velocity
- Step width
Correct answer: Cadence
Cadence is defined as the number of steps taken per minute and is directly measured by counting steps over a given time interval.
Question 6: In the biomechanical model of the foot, the 'subtalar joint neutral position' is clinically important because it represents:
- Maximum pronation of the foot
- The position where the foot is neither pronated nor supinated (Correct answer)
- The position of maximum weight-bearing efficiency
- The point of greatest ankle dorsiflexion
Correct answer: The position where the foot is neither pronated nor supinated
Subtalar neutral is defined as the position where the subtalar joint is neither pronated nor supinated, serving as a reference point for orthotic casting and assessment.
Question 7: Which component of the ground reaction force vector is responsible for the 'anterior shear' force experienced at the knee during the loading response?
- Vertical component
- Anterior-posterior (horizontal) component (Correct answer)
- Mediolateral component
- Torsional component
Correct answer: Anterior-posterior (horizontal) component
The anterior-posterior horizontal component of the GRF creates an anterior shear at the knee during loading response, contributing to knee joint stress and ACL loading.
COF Biomechanics & Gait Analysis 2
During normal gait, which muscle group is primarily responsible for controlling the rate of foot lowering (foot slap prevention) immediately after heel strike?