Clinical Biomechanics in Sports Flashcards

During a running gait cycle, which phase is associated with the greatest ground reaction force?

Answer: Initial contact (heel strike)

Initial contact produces the first peak ground reaction force, often 1.5–2× body weight during running.

The Q-angle is formed between the line of pull of the quadriceps and the patellar tendon; an elevated Q-angle in female athletes increases risk of:

Answer: ACL injury and patellofemoral pain syndrome

A wider Q-angle increases valgus stress at the knee, predisposing athletes to ACL injury and patellofemoral tracking problems.

Which term describes the tendency of a joint to return to its resting position after being displaced, related to passive soft-tissue stiffness?

Answer: Laxity

Laxity refers to the amount of passive joint displacement possible; high laxity means the joint moves far before restraint builds.

A gymnast performs a back handspring. The wrist is loaded in which primary direction during the push-off phase?

Answer: Dorsiflexion and axial compression

During push-off the wrist bears compressive load while positioned in dorsiflexion, stressing the distal radius and scaphoid.

The stretch-shortening cycle (SSC) improves power output primarily because:

Answer: Elastic energy stored in tendons is released during the concentric phase

Tendons and series elastic components store elastic potential energy during the eccentric (pre-stretch) phase and release it in the subsequent concentric contraction.

Center of mass (COM) displacement in the vertical plane is greatest during which locomotion pattern?

Answer: Walking

During walking the COM follows an inverted-pendulum arc, rising at midstance, resulting in greater vertical displacement than running.

Tibial internal rotation during knee flexion is coupled with which motion at the subtalar joint?

Answer: Pronation

Tibial internal rotation is mechanically coupled to subtalar pronation (calcaneal eversion) through the transverse tarsal joint linkage.