CSC Biomechanics and Movement Analysis 2 — Questions and Answers
Question 1: What is the 'stretch-shortening cycle' (SSC) and how does it apply to explosive athletic movements?
- A static stretching protocol for recovery
- A pre-activation eccentric phase followed immediately by a concentric contraction, storing and releasing elastic energy (Correct answer)
- A cool-down sequence post-training
- A breathing technique during heavy lifts
Correct answer: A pre-activation eccentric phase followed immediately by a concentric contraction, storing and releasing elastic energy
The SSC involves a rapid eccentric (pre-stretch) phase that stores elastic energy in tendons and activates the stretch reflex, augmenting the subsequent concentric force output.
Question 2: What is 'rate of force development' (RFD) and why is it critical for sport performance?
- The maximum force an athlete can produce given unlimited time
- The speed at which force is generated — critical because sport actions occur in very short time windows (Correct answer)
- The endurance capacity of a muscle
- The recovery rate after maximal effort
Correct answer: The speed at which force is generated — critical because sport actions occur in very short time windows
RFD describes how rapidly force can be developed; since most sport actions (ground contacts, collisions) last <200ms, the ability to generate force quickly is often more critical than absolute maximum strength.
Question 3: Which movement screening finding most directly indicates a hip mobility deficit during a bodyweight squat assessment?
- Arms drifting forward
- Excessive anterior pelvic tilt and early lumbar flexion ('butt wink')
- Bilateral heel rise (Correct answer)
- Knees tracking over toes
Correct answer: Bilateral heel rise
Bilateral heel rise during a squat indicates limited ankle dorsiflexion, a common restrictor of squat depth and quality, often confused with hip mobility issues.
Question 4: What is the primary biomechanical advantage of a hip-width stance (versus narrow stance) in the squat for most athletes?
- Increases quadriceps activation exclusively
- Allows greater hip external rotation, facilitating deeper squat depth with reduced lumbar stress (Correct answer)
- Reduces glute activation
- Decreases total force output
Correct answer: Allows greater hip external rotation, facilitating deeper squat depth with reduced lumbar stress
A hip-width stance allows the femurs to externally rotate and abduct around the hip socket, reducing impingement and enabling deeper squat depth while maintaining a more neutral spine.
Question 5: What does 'ground reaction force' (GRF) represent in sport biomechanics?
- The force the athlete exerts directly on the ground
- The equal and opposite force the ground exerts back on the athlete (Newton's Third Law) (Correct answer)
- The frictional force only
- The gravitational force only
Correct answer: The equal and opposite force the ground exerts back on the athlete (Newton's Third Law)
By Newton's Third Law, when an athlete applies force to the ground, the ground returns an equal and opposite GRF — this is the force that propels the athlete into motion.
Question 6: In Olympic lifting, what is the primary biomechanical purpose of the 'third pull' (catching phase) in the snatch?
- Generating vertical bar velocity
- Actively pulling the body under the bar while turning the elbows over to receive the barbell in a stable overhead position (Correct answer)
- Slowing the bar down
- Extending the hips maximally
Correct answer: Actively pulling the body under the bar while turning the elbows over to receive the barbell in a stable overhead position
The third pull involves pulling under the bar by actively driving elbows around and up while simultaneously pushing the floor away to receive the bar overhead in a locked-out position.
CSC Biomechanics and Movement Analysis 2
What is the 'stretch-shortening cycle' (SSC) and how does it apply to explosive athletic movements?