CCSP Clinical Biomechanics in Sports 5 — Questions and Answers
Question 1: The valgus extension overload syndrome in baseball pitchers involves impingement of which structures at the posteromedial elbow?
- Radial head and lateral epicondyle
- Posteromedial olecranon tip and olecranon fossa (Correct answer)
- Medial epicondyle apophysis and UCL
- Annular ligament and capitellum
Correct answer: Posteromedial olecranon tip and olecranon fossa
Valgus stress during throwing drives the posteromedial olecranon tip into the olecranon fossa, causing impingement, osteophyte formation, and loose bodies.
Question 2: Muscle pennation angle affects force production such that a greater pennation angle:
- Maximizes fiber shortening velocity at the expense of force
- Allows more fibers to pack into a given cross-section, increasing force capacity (Correct answer)
- Reduces physiological cross-sectional area
- Decreases the elastic energy storage of the muscle
Correct answer: Allows more fibers to pack into a given cross-section, increasing force capacity
Higher pennation angles allow more fibers per unit volume (greater PCSA), increasing maximal force output despite reducing the component of force transmitted along the tendon.
Question 3: During sidestep cutting maneuvers, female athletes demonstrate greater knee abduction moments than males, which is partly attributed to:
- Greater quadriceps activation amplitude
- Narrower pelvis and smaller Q-angle
- Reduced hip and trunk neuromuscular control and wider pelvis (Correct answer)
- Higher hamstring-to-quadriceps strength ratio
Correct answer: Reduced hip and trunk neuromuscular control and wider pelvis
Females tend to have wider pelves (larger Q-angle) and exhibit reduced hip abductor and trunk activation during cutting, increasing dynamic knee valgus and ACL stress.
Question 4: In cervical spine biomechanics, the C1-C2 (atlantoaxial) segment is responsible for approximately what percentage of total cervical rotation?
- 10–15%
- 25–30%
- 50% (Correct answer)
- 70–80%
Correct answer: 50%
The atlantoaxial joint contributes approximately 50% of total cervical axial rotation due to the dens-pivot articulation.
Question 5: The 'degrees of freedom' of a joint refers to:
- The number of muscles crossing the joint
- The number of independent directions in which a segment can move (Correct answer)
- The ligamentous restraint capacity under load
- The number of nerve roots innervating the joint
Correct answer: The number of independent directions in which a segment can move
Degrees of freedom describe the independent axes of motion available to a joint; the shoulder has 3 rotational DOF, making it the most mobile joint in the body.
Question 6: A sprinter with excessive anterior pelvic tilt is MOST likely to develop which overuse injury pattern?
- Posterior tibial tendinopathy
- Proximal hamstring tendinopathy and hip flexor shortening (Correct answer)
- Lateral ankle instability
- Plantar fasciitis
Correct answer: Proximal hamstring tendinopathy and hip flexor shortening
Anterior pelvic tilt places the hamstrings in a lengthened, high-strain position at the ischial tuberosity while keeping the hip flexors adaptively shortened.
Question 7: When assessing shoulder scapulohumeral rhythm, the normal ratio of glenohumeral to scapulothoracic motion during arm elevation is approximately:
- 1:1
- 2:1 (Correct answer)
- 3:1
- 4:1
Correct answer: 2:1
The classic scapulohumeral rhythm is 2:1, meaning for every 3° of shoulder elevation, 2° occur at the glenohumeral joint and 1° at the scapulothoracic articulation.
CCSP Clinical Biomechanics in Sports 5
The valgus extension overload syndrome in baseball pitchers involves impingement of which structures at the posteromedial elbow?