SCS Exercise Physiology & Biomechanics 3 — Questions and Answers
Question 1: Phosphocreatine (PCr) resynthesis after a maximal sprint is APPROXIMATELY how complete after 3–5 minutes of rest?
- 25–35%
- 50–65%
- 70–80%
- 95–100% (Correct answer)
Correct answer: 95–100%
PCr stores are nearly fully replenished (95–100%) within 3–5 minutes of rest, which guides sport-specific recovery intervals.
Question 2: The oxygen dissociation curve shifts to the RIGHT in response to which condition?
- Decreased temperature
- Increased pH
- Increased partial pressure of CO2 (Correct answer)
- Decreased 2,3-BPG
Correct answer: Increased partial pressure of CO2
Increased CO2 (Bohr effect), decreased pH, or elevated temperature shift the curve right, reducing hemoglobin's oxygen affinity and promoting O2 release to working muscles.
Question 3: Ground reaction force (GRF) during running is typically what multiple of body weight at foot strike?
- 0.5–1.0x
- 1.5–3.0x (Correct answer)
- 4.0–5.5x
- 6.0–8.0x
Correct answer: 1.5–3.0x
Running produces vertical GRFs of approximately 1.5–3.0 times body weight, varying with speed, footwear, and surface stiffness.
Question 4: Which hormonal response to acute intense exercise PRIMARILY drives glucose mobilization from the liver?
- Insulin
- Glucagon and catecholamines (Correct answer)
- Cortisol alone
- Aldosterone
Correct answer: Glucagon and catecholamines
Glucagon and catecholamines (epinephrine/norepinephrine) stimulate hepatic glycogenolysis and gluconeogenesis to raise blood glucose during intense exercise.
Question 5: In biomechanics, the moment of inertia of a rotating segment INCREASES when mass is:
- Moved closer to the axis of rotation
- Moved farther from the axis of rotation (Correct answer)
- Reduced uniformly
- Concentrated at the proximal end of the segment
Correct answer: Moved farther from the axis of rotation
Moment of inertia (I = mr²) increases with the square of the distance from the axis, so distributing mass farther out resists angular acceleration more.
Question 6: Which pulmonary variable is the MOST sensitive early indicator of exercise intensity approaching VO2 max?
- Tidal volume only
- Respiratory rate only
- Ventilatory threshold (VT) (Correct answer)
- Residual volume
Correct answer: Ventilatory threshold (VT)
The ventilatory threshold marks the exercise intensity at which ventilation increases disproportionately to VO2, signaling the shift to anaerobic metabolism.
Question 7: An athlete's Q-angle is defined as the angle between which two lines?
- Femoral shaft and tibial shaft
- Line of quadriceps pull and patellar tendon (Correct answer)
- Hip joint center and knee joint center
- Greater trochanter and lateral malleolus
Correct answer: Line of quadriceps pull and patellar tendon
The Q-angle is measured between the line of quadriceps pull (ASIS to patella center) and the patellar tendon line (patella center to tibial tuberosity).
SCS Exercise Physiology & Biomechanics 3
Phosphocreatine (PCr) resynthesis after a maximal sprint is APPROXIMATELY how complete after 3–5 minutes of rest?