Worksheetsex phys lectures 5-10
Total questions: 103
Worksheet time: 54mins
1. During a steady-state endurance exercise, a measured RQ of 0.85 most likely indicates:
A) Exclusive fat metabolism
B) A 50/50 contribution of carbohydrate and fat metabolism
C) Transition to anaerobic glycolysis
D) Incomplete glucose oxidation
2. Which sarcomere band contains only actin filaments and no myosin?
A) A band
B) H zone
C) I band
D) M line
1. Under aerobic conditions, pyruvate produced from glycolysis is:
A) Converted to lactate via lactate dehydrogenase
B) Transported into the mitochondrial matrix for oxidative metabolism
C) Buffered by bicarbonate
D) Shuttled directly into the blood
2. Which physiological factor best explains why RQ approaches 1.0 during high-intensity exercise?
A) Enhanced mitochondrial biogenesis
B) Shift toward anaerobic lipolysis
C) Increased reliance on carbohydrate metabolism for faster ATP production
D) Decreased pulmonary ventilatio
3. The function of titin in the sarcomere is to:
A) Bind calcium for contraction
B) Store glycogen during rest
C) Maintain sarcomere structure and align thick filaments
D) Inhibit actin-myosin interaction
4. During muscle contraction, the sliding filament theory states that:
A) Myosin and actin filaments contract and shorten
B) Thick filaments slide over thin filaments
C) Actin and myosin filaments slide past one another without changing length
D) Tropomyosin lengthens under load
2. What best explains the accumulation of lactate during high-intensity exercise?
A) Complete mitochondrial failure
B) Insufficient NADH availability
Mismatch between glycolytic rate and mitochondrial oxidative capacity
Inhibition of lactate dehydrogenase
3. A respiratory exchange ratio (RER) of 1.15 during a graded exercise test most accurately indicates:
A) Maximal fat oxidation
B) Resting metabolism
C) Hyperventilation and bicarbonate buffering associated with near-maximal exertion
D) Protein catabolism
1. What is the minimum RERmax value expected for someone aged 20–39 during a maximal exercise test?
4. Why is RER considered less accurate than RQ for determining substrate utilization during high-intensity exercise?
A) RER accounts only for oxygen consumed in tissues
B) RER is affected by non-metabolic CO₂ production due to buffering of lactic acid
C) RER requires invasive blood testing
D) RER underestimates carbohydrate usage
5. A rising RER during progressive exercise testing typically indicates:
A) Greater mitochondrial efficiency
B) Increased lactate clearance
C) Greater reliance on carbohydrate fuels and anaerobic buffering
D) A transition from aerobic to fat-based metabolism
6. Which scenario best describes the concept of oxygen deficit?
A) Reduced oxygen availability at high altitude
B) The lag between exercise onset and full activation of aerobic ATP production
C) Oxygen uptake exceeding oxygen supply
D) Steady-state O₂ consumption reached immediately
7. Which energy systems are primarily active during the oxygen deficit phase of exercise onset?
A) Beta-oxidation and ETC
B) Anaerobic glycolysis and ATP-PCr
C) Gluconeogenesis and lipolysis
D) Krebs cycle and glycolysis
8. Steady-state exercise is defined by:
A) Lactate accumulation exceeding clearance
B) Rapid increase in respiratory rate
C) Balance between oxygen delivery and ATP demand
D) Use of anaerobic metabolism exclusively
9. Which of the following would NOT be observed during steady-state submaximal exercise?
A) Stable VO₂
B) Gradual rise in blood lactate
C) Steady heart rate
D) Plateaued CO₂ production
10. Which condition would most likely delay the onset of steady-state VO₂?
A) Trained endurance status
B) Low exercise intensity
C) High-intensity interval bout with short rest
D) Proper warm-up
10. Which condition would most likely delay the onset of steady-state VO₂?
A) Trained endurance status
B) Low exercise intensity
C) High-intensity interval bout with short rest
D) Proper warm-up
11. Which statement best defines VO₂max?
A) The maximum amount of carbon dioxide exhaled per minute
B) The highest oxygen uptake value recorded regardless of plateau
maximum rate of oxygen consumption under maximal effort where a plateau in VO₂ is observed
D) The total oxygen used at rest
12. In a graded exercise test, a true VO₂max is confirmed when:
A) The subject reports feeling exhausted
B) Blood lactate exceeds 4 mmol/L
C) A plateau in VO₂ occurs despite increasing workload
D) The test reaches 15 minutes
13. VO₂peak is best defined as:
A) The average VO₂ across all stages of a test
B) The highest VO₂ value recorded regardless of plateau
C) The estimated VO₂ using heart rate
D) Oxygen consumption only during recovery
5. Which region of the sarcomere shortens during concentric contraction?
A) A band
B) M line
C) I band
D) Z disc
14. Which physiological adaptations most directly improve VO₂max?
A) Increased skin perfusion
B) Enhanced bicarbonate buffering
C) Increased mitochondrial density and cardiac output
D) Elevated blood glucose concentration
15. A participant fails to reach a VO₂ plateau during a maximal test but shows an RER of 1.18 and 98% of age-predicted max heart rate. This is considered:
A) An invalid test
B) An indication of submaximal effort
C) A valid demonstration of VO₂peak using secondary criteria
D) An anaerobic threshold test
16. Which of the following variables is NOT a determinant of VO₂max?
A) Haemoglobin concentration
B) Muscle capillarization
C) Muscle fiber type
D) Plasma sodium concentration
17. Increased substrate availability (e.g., glycogen stores) enhances VO₂max primarily by:
A) Decreasing resting heart rate
B) Prolonging aerobic ATP production capacity
C) Reducing pulmonary ventilation
C) Reducing pulmonary ventilation
18. Which best describes the fast component of EPOC?
A) Restoration of muscle glycogen
B) Resynthesis of ATP and PCr, and replenishment of oxygen stores
C) Conversion of lactate to glucose
D) Cellular repair and protein synthesis
19. The slow component of EPOC is largely attributed to:
A) Carbon dioxide exhalation
B) Passive rest
Immediate ATP-PCr resynthesis
Lactate clearance, glycogen restoration, and muscle repair
20. Which of the following conditions would result in a larger EPOC following exercise?
A) 10-minute low-intensity cycling
B) Short rest periods between intervals
C) High-intensity, prolonged resistance training
D) Steady-state walking below lactate threshold
3. The enzyme responsible for converting pyruvate to lactate is:
A) Pyruvate kinase
B) Lactate oxidase
C) Lactate dehydrogenase
D) Isocitrate dehydrogenase
During the first 3 minutes of moderate-intensity exercise, a subject’s measured total oxygen uptake is 3.9 L. Had steady-state oxygen uptake (at 1.5 L/min) been achieved immediately at exercise onset, what would the oxygen deficit be?
17. Which factor influences oxygen utilisation during exercise?
Lung capacity
Mitochondrial density
Haemoglobin content
Stroke volume
6. Which of the following best describes the concept of the lactate shuttle?
A) The passive diffusion of lactate through the sarcolemma
B) Lactate as a waste product cleared solely by the liver
C) The transport of lactate between cells and within muscle fibers for oxidation or gluconeogenesis
D) Lactate being converted directly into ATP in the mitochondria
4. Which transport proteins are responsible for lactate shuttling across cellular membranes?
A) Na+/K+ pumps
B) Aquaporins
C) Monocarboxylate transporters (MCTs)
D) Glucose transporters (GLUTs)
5. What determines the direction and rate of lactate movement through MCTs?
C) Lactate concentration gradients
A) VO₂max
B) Local capillary density
D) Blood pressure
4. Muscle biopsy analysis shows a high percentage of Type I fibres in the soleus muscle. This indicates that the soleus is best suited for:
A) Sprinting and jumping
B) Fine motor control
C) Postural support and endurance
D) Explosive lifting tasks
1. Which factor primarily determines the tension produced by a sarcomere?
5. Why does muscle force production decline at high contraction velocities?
1. Which of the following most accurately describes the structural organization of skeletal muscle from largest to smallest unit?
A) Fascicle → Fiber → Myofibril → Sarcomere
B) Fiber → Fascicle → Sarcomere → Myofibril
C) Sarcomere → Myofibril → Fiber → Fascicle
D) Myofilament → Myofibril → Fascicle → Fiber
2. According to the 210 - age formula, what is the minimum % of APMHR a person aged 40–59 must reach during testing?
7. What physiological adaptation would enhance intracellular lactate clearance in trained athletes?
A) Increased LDL cholesterol
B) Upregulation of MCT1 transporters in oxidative fibers
C) Inhibition of lactate dehydrogenase
D) Increased resting heart rate
1. What initiates the opening of voltage-gated sodium channels during an action potential?
2. What is the primary result of sodium (Na⁺) influx during depolarisation?
8. Which statement best describes Lactate Threshold 2 (LT2)?
A) The first rise in blood lactate above baseline
B) The intensity at which lactate production is minimal
C) The highest intensity where lactate appearance equals disappearance
D) The point of exhaustion
9. Why is LT2/MLSS a better performance predictor than VO₂max in endurance events?
A) It reflects anaerobic power
B) It is less affected by pacing strategies
C) It identifies the highest sustainable intensity over time
D) It does not require blood sampling
10. How does endurance training typically affect the blood lactate curve?
A) Shifts the curve upward
B) Shifts the curve to the left
C) Shifts the curve downward and to the right
D) Eliminates the LT1 threshold
3. What role do voltage-gated potassium (K⁺) channels play during an action potential?
2. Why does an overly shortened sarcomere lead to reduced force production?
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11. What is a primary limitation of using the 4 mmol/L method for determining LT2?
A) It requires VO₂ measurement
B) It assumes a fixed lactate threshold across individuals
C) It is not reproducible
D) It underestimates anaerobic capacity
4. At approximately what sarcomere length does maximal force production occur?
12. Compared to the 4 mmol/L method, the D-Max method:
A) Assumes a universal blood lactate concentration at threshold
B) Identifies threshold as the point farthest from a line between baseline and peak lactate
C) Uses only heart rate data
D) Cannot detect lactate threshold below 3 mmol/L
13. A key critique of many lactate threshold measurement methods is that:
A) They rely too heavily on VO₂max testing
B) Their reliability is high but their validity varies widely
C) They don’t require blood sampling
D) They are only useful for sprint athletes
14. Establishing lactate thresholds is useful for:
A) Determining sweat rate
B) Predicting maximal strength
C) Identifying training zones and endurance potential
D) Measuring lung capacity
15. A runner with a LT2 at 17 km/h is predicted to complete a 10 km race in approximately:
B) 35:20
C) 40:00
C) 40:00
6. The primary role of calcium ions (Ca²⁺) in muscle contraction is to:
A) Break down ATP
B) Bind to tropomyosin
C) Bind to troponin, triggering tropomyosin movement and actin binding site exposure
D) Propagate the action potential across the sarcolemma
7. What initiates cross-bridge formation between actin and myosin?
A) Acetylcholine binding to myosin heads
B) ATP hydrolysis in the sarcoplasmic reticulum
C) Exposure of actin binding sites following Ca²⁺ binding to troponin
D) Tropomyosin disintegration
8. The resting membrane potential of a neuron is primarily maintained by:
A) Passive potassium diffusion
B) The sodium-potassium pump actively maintaining a charge differential across the membrane
C) Continuous action potentials
D) High intracellular calcium
9. An action potential is triggered when the membrane potential reaches approximately:
A) -70 mV
B) -55 mV
C) 0 mV
D) +30 mV
15. A failure in the function of the sarcoplasmic reticulum would most directly impair which process?
A) Glucose uptake
C) Calcium release and reuptake during contraction and relaxation
D) Sodium-potassium balance in the neuron
B) ATP synthesis
10. Which ion is primarily responsible for repolarization during the action potential?
A) Na⁺ influx
B) Cl⁻ influx
C) K⁺ efflux
D) Ca²⁺ release
11. What prevents the backward propagation of an action potential along a neuron?
A) Synaptic fatigue
B) Closed sodium channels
C) The absolute refractory period during potassium efflux
D) Acetylcholine reuptake
13. Which of the following is true during the cross-bridge cycle?
A) ATP binding causes the power stroke
B) ADP release causes detachment of the myosin head
C) ATP binding causes detachment of myosin from actin
D) Calcium binds directly to myosin heads
12. Which process links the neural action potential to muscle contraction?
A) The all-or-none law
B) Cross-bridge cycling
C) Excitation-contraction coupling
D) The size principle
14. Which structure stores and releases calcium in the muscle fiber?
A) T-tubule
B) Mitochondrion
C) Sarcoplasmic reticulum
D) Actin filament
2. Compared to Type I fibres, Type IIx fibres demonstrate:
A) Slower shortening velocity
B) Greater fatigue resistance
C) Greater glycolytic capacity
D) More mitochondria per fibre
3. What is the primary physiological reason Type II fibres produce more power than Type I fibres?
A) Greater capillary density
B) Higher glycogen content
C) Faster cross-bridge cycling rate
D) Greater actin-myosin overlap
1. Which of the following characteristics is most typical of Type I (slow-twitch) muscle fibres?
A) High myosin ATPase activity
B) Low mitochondrial density
C) High fatigue resistance
D) Rapid calcium handling
3. For participants aged 60–69, what is the required RERmax to confirm a valid maximal test?
5. Which training stimulus is most likely to induce a shift toward a more oxidative (Type I) fibre profile?
A) High intensity, low volume, explosive movements
B) Low intensity, high volume endurance training
) Maximal resistance training
D) Short-interval sprint training
5. Boyle’s Law explains the mechanism of ventilation by stating that:
A) Pressure increases with lung volume
B) Volume is directly proportional to surface tension
C) Pressure and volume are inversely related at constant temperature
D) Volume is directly related to alveolar resistance
6. During inspiration, which of the following occurs first?
A) Intrapulmonic pressure rises
B) Diaphragm relaxes
C) Air is forced out of the lungs
D) Diaphragm and external intercostals contract
6. Which of the following statements best reflects the concept of fibre type continuum?
A) Each fibre is exclusively Type I or Type II
B) Fibre types can adapt along a spectrum depending on training
C) Hybrid fibres do not exist in trained humans
D) Fibre type is entirely fixed after early childhood
7. Approximately what percentage of muscle fibre type is determined by genetic factors?
A) 25%
B) 45%
C) 65%
D) 90%
1. What structural feature allows myocardial cells to function as a single coordinated unit?
A) Desmosomes
B) Sarcomeres
C) Intercalated discs
) Pacemaker fibres
8. In elite power athletes, such as Olympic lifters, which muscle would you expect to contain the highest proportion of Type II fibres?
A) Soleus
B) Gastrocnemius
C) Triceps brachii
D) Vastus medialis
4. Using the 208 - 0.7 × age formula, what is the minimum % APMHR required for someone aged 20–39 to meet maximal criteria?
1. Which of the following best describes pulmonary ventilation?
A) The cellular consumption of oxygen
B) The diffusion of oxygen into mitochondria
C) The movement of air in and out of the lungs
D) The exchange of gases in capillary beds
2. Which stage of respiration occurs at the cellular level to produce ATP using oxygen?
A) Pulmonary ventilation
B) Pulmonary respiration
C) Cellular respiration
D) External respiration
13. What function is unique to the respiratory zone of the lungs, not shared with the conducting zone?
A) Immunoglobulin secretion
B) Vocalisation
C) Gas exchange via alveolar-capillary diffusion
D) Humidification of inspired air
14. In the respiratory control centre, a drop in arterial oxygen (PaO₂) would likely:
A) Reduce tidal volume
B) Suppress ventilation
C) Stimulate an increase in ventilation rate
D) Decrease carbon dioxide production
3. According to Fick’s Law, the rate of gas diffusion is directly proportional to:
A) Tissue thickness
B) Mitochondrial surface area
C) The pressure gradient across a membrane
D) Lung volume
4. Fick’s Law also states that gas diffusion is inversely proportional to:
A) Surface area
B) Tidal volume
C) Membrane thickness
D) Partial pressure of oxygen
7. What causes air to move into the lungs during inhalation?
A) Pulmonary pressure becoming greater than atmospheric pressure
B) Atmospheric pressure falling below intrapulmonic pressure
C) Intrapulmonic pressure falling below atmospheric pressure
D) Active contraction of internal intercostals
9. The respiratory zone is distinguished from the conducting zone because it:
A) Begins at the mouth
B) Primarily controls airway resistance
C) Contains alveoli where gas exchange occurs
D) Involves tracheal expansion
8. Which of the following is not a function of the conducting zone of the ventilatory system?
A) Humidification of inspired air
B) Surfactant secretion
C) Particle filtration
D) Vocalisation
10. Pulmonary ventilation is regulated by the respiratory centres in the:
A) Hippocampus and frontal cortex
B) Medulla oblongata and pons
C) Thalamus and hypothalamus
D) Cerebellum and basal ganglia
12. During forced expiration, which muscle group is actively recruited to assist exhalation?
A) Diaphragm
B) Internal intercostals and abdominal muscles
C) External intercostals
15. Which condition would most reduce the rate of gas diffusion across the alveolar membrane, assuming constant pressure gradient and surface area?
A) Increased number of mitochondria
B) Increased tissue thickness
C) Reduced tidal volume
D) Increased inspiratory reserve volume
2. The high mitochondrial density in the myocardium reflects its:
A) Ability to contract anaerobically
B) Need for rapid glycolysis
C) Dependence on aerobic metabolism
D) Role in regulating heart rhythm
11. Which of the following would most likely increase pulmonary ventilation during intense exercise?
A) Increase in blood pH
B) Elevated arterial oxygen levels
) Elevated blood CO₂ concentration
D) Decreased body temperature
3. Which phase of the cardiac cycle corresponds to ventricular contraction?
A) Diastole
B) Systole
C) Atrial filling
D) Isovolumetric relaxation
4. What is the formula to calculate Mean Arterial Pressure (MAP)?
A) MAP = SBP - DBP
B) MAP = DBP + [0.333 × (SBP – DBP)]
C) MAP = SBP + DBP / 2
D) MAP = CO × HR
5. Why does diastolic blood pressure have a greater influence on MAP than systolic pressure?
A) Diastole occurs for a shorter period
B) Systolic pressure varies with breathing
C) The heart spends more time in diastole
D) Diastolic pressure has lower variability
6. Cardiac output (Q) is calculated by multiplying:
A) Stroke volume × respiratory rate
B) Heart rate × blood pressure
C) Stroke volume × heart rate
D) Systolic × diastolic pressure
7. Stroke volume is defined as:
7. Stroke volume is defined as:
A) Volume of blood pumped in 1 minute
B) Volume of blood ejected per heartbeat
C) Total blood volume in the ventricles
D) Peak systolic output
8. An increase in stroke volume while heart rate remains constant will cause:
A) No change in cardiac output
B) A decrease in cardiac output
C) An increase in cardiac output
D) A decrease in blood viscosity
9. Total Peripheral Resistance (TPR) can be calculated as:
A) MAP × HR
B) MAP / cardiac output
C) SV / MAP
D) MAP × stroke volume
12. A decrease in blood vessel radius by 50% would cause:
A) A 2-fold increase in resistance
B) No significant change in resistance
C) A 4-fold increase in resistance
D) A 16-fold increase in resistance
10. Which of the following would increase TPR?
A) Increased cardiac output
B) Vasodilation
C) Increased blood vessel length
D) Increased heart rate
11. How does blood viscosity influence resistance in the vascular system?
A) Higher viscosity reduces resistance
B) Lower viscosity increases resistance
C) Higher viscosity increases resistance
D) Viscosity only affects pulmonary circulation
14. Which of the following statements best describes systolic blood pressure (SBP)?
A) Pressure during ventricular filling
B) Average pressure during a cardiac cycle
C) Pressure during ventricular contraction
D) Pressure during atrial diastole
13. Which of the following variables has the greatest effect on vascular resistance?
A) Vessel length
B) Blood pressure
C) Blood viscosity
D) Vessel radius
15. In a healthy adult, which change is most likely to increase stroke volume during exercise?
A) Decreased venous return
B) Increased end-diastolic volume
C) Shortened ventricular filling time
D) Decreased preload
