Resistance Training Biomechanics Flashcards

A muscle with a high physiological cross-sectional area (PCSA) is best suited for:

Answer: Generating high force output

PCSA is directly proportional to maximal force-producing capacity; muscles with greater PCSA can generate more force regardless of fiber length or pennation.

Which of the following best describes 'valgus collapse' at the knee during a squat and its biomechanical implication?

Answer: The knee caves medially, increasing valgus torque and stress on the medial knee structures and ACL

Knee valgus collapse (medial knee displacement) increases frontal-plane valgus torque, placing harmful stress on the ACL, MCL, and medial compartment of the knee.

Which variable most directly determines the mechanical work performed during a resistance exercise set?

Answer: Force applied multiplied by the displacement of the load

Mechanical work equals force multiplied by displacement (W = F × d); in lifting, this reflects the load moved and the distance it travels.

In a Romanian deadlift (RDL), compared to a conventional deadlift, the hamstrings experience greater mechanical stimulus primarily because:

Answer: The hip hinge in the RDL creates a larger moment arm for the hamstrings and allows greater hip flexion under load

The RDL maintains minimal knee bend and emphasizes hip hinging, placing the hamstrings under a large moment arm and stretching them under significant load.

Which principle explains why an athlete can generate more force at the beginning of a concentric contraction after a brief pause (vs. from a static start with no stretch)?

Answer: Stretch reflex and elastic energy utilization from the SSC

A controlled eccentric pre-stretch activates the stretch-shortening cycle, utilizing stored elastic energy in tendons and the myotatic reflex to boost subsequent concentric force.

When performing a lat pulldown with a wide overhand grip, the primary axis of motion is at the:

Answer: Shoulder joint

The primary pulling motion in a lat pulldown is shoulder adduction (and extension), with the shoulder joint as the main axis of rotation.

The concept of 'joint reaction force' in biomechanics refers to:

Answer: The compressive and shear forces acting on joint surfaces as a result of muscle forces and external loads

Joint reaction forces are the net compressive and shear forces at articular surfaces resulting from the combined effects of muscle contractions, body weight, and external loads.