Exercise Physiology Questions and Answers

Answer: B

The correct combination is (1), (4) and (5).

Anabolic steroids are synthetic derivatives of testosterone. In women their known hazards include liver dysfunction (including liver tumours and cysts with oral steroids), menstrual disturbance and infertility, and virilisation: growth of male secondary sexual characteristics such as facial and body hair, a deepened voice and male-pattern baldness.

Muscle atrophy is wrong because steroids increase muscle mass; that is why athletes misuse them. Breast cancer is not the recognised hazard; steroids tend instead to shrink breast tissue. So every option containing (2) or (3) is wrong.

Answer: A

The key's answer is Carbonic acid.

Carbon dioxide from the tissues diffuses into the blood. Most of it enters the red blood cells, where the enzyme carbonic anhydrase combines it with water to form carbonic acid, which dissociates into hydrogen ions and bicarbonate. About 70% of carbon dioxide is carried this way; the rest travels dissolved in plasma or bound to haemoglobin as carbaminohaemoglobin.

Lactic acid is a product of anaerobic glycolysis, not a carrier of CO₂. Oxyhaemoglobin carries oxygen, and carboxyhaemoglobin is haemoglobin bound to carbon monoxide, not carbon dioxide.

Answer: B

Both men and women experience a gain in FFM (fat-free mass).

Cardiorespiratory endurance training such as running, cycling or swimming reduces body fat, because it burns large amounts of energy, while fat-free mass is maintained or increases slightly. Exercise physiology texts report this pattern for both sexes: a small fall in total body mass, a fall in fat mass and a small rise in lean mass.

A gain in body mass and a gain in body fat are the opposite of what endurance training produces, so options A and C are wrong, and 'None of the above' is wrong because the FFM change does occur.

Answer: A

The gland is the adrenal gland.

In emotional arousal, the 'fight or flight' response, the adrenal medulla releases adrenaline and noradrenaline. These hormones raise the heart rate, blood pressure, breathing rate and blood sugar, producing the bodily state of arousal that accompanies fear, anger and excitement before competition.

The thyroid controls the basal metabolic rate and the pancreas blood sugar through insulin and glucagon; neither produces the emergency response. The hypothalamus in the brain sets the response going through the sympathetic nerves, but the hormones that produce the aroused state come from the adrenal glands.

Answer: C

The usual formula is 220 - Age.

Maximum heart rate falls by roughly one beat per minute for each year of age, and the common estimate subtracts the age in years from 220. A 30-year-old, for example, has an estimated maximum of 190 beats per minute. This figure is the basis of training-zone calculations such as the Karvonen method.

RHR + MHR adds the resting heart rate to the very quantity being calculated, and the other two expressions bring in height and weight, which do not determine maximum heart rate.

Answer: C

Slow twitch fibres have (II) and (III): greater Krebs cycle enzyme capacity and lower nerve conduction velocity.

Slow twitch (type I) fibres are built for endurance. They have many mitochondria, much myoglobin and a high activity of the oxidative enzymes of the Krebs cycle (II). They are supplied by small motor neurons whose axons conduct impulses more slowly (III).

A greater cross-sectional area (I) and a greater glycolytic capacity (IV) are features of fast twitch (type II) fibres, which are designed for fast, powerful, anaerobic work. Every code that includes (I) or (IV) is therefore wrong.

Answer: A

The code is a-2, b-1, c-4, d-5.

• Amphetamines are stimulants that raise alertness and mask fatigue.
• Beta-blockers lower the heart rate and steady tremor, which is why they are banned in shooting and archery.
• Erythropoietin stimulates red cell production and raises haemoglobin, increasing oxygen-carrying capacity.
• Alkaline salts such as sodium bicarbonate raise blood pH and buffer acid during intense exercise.

Options B, C and D each pair a substance with urine formation or swap haemoglobin and pH, so only A matches every pair.

Answer: C

That volume is the vital capacity.

Vital capacity is the greatest volume of air that can be breathed out forcefully after the deepest possible breath in. It is the sum of the inspiratory reserve volume, the tidal volume and the expiratory reserve volume, typically 4 to 5 litres in a young adult man, and it is measured with a spirometer.

Tidal volume is the air moved in a normal quiet breath, about 500 ml. VO₂ max is the maximal rate of oxygen uptake, not a lung volume. Second wind is the sudden feeling of relief during prolonged exercise, not a measurement.

Answer: D

The key's answer is that (A) is true but (R) is not the correct explanation of (A).

(A) is true: at rest the heart spends longer filling, in diastole, than contracting, in systole. The figures in (R) are consistent with this and with each other, since at 74 beats per minute one cycle lasts 60/74, about 0.81 s, and 0.44 + 0.37 = 0.81 s.

(R) is a numerical example for one heart rate. It shows the diastolic phase being longer, but it does not say why. The textbook split at 75 beats per minute is about 0.3 s of systole and 0.5 s of diastole, so the paper's figures differ a little from it, and I could not confirm them against a published source. The key reads (R) as a true example that does not explain (A), so options A and C do not fit it.

Answer: C

The action potential releases Ca⁺⁺ from the sarcoplasmic reticulum.

In excitation-contraction coupling the action potential travels along the sarcolemma and down the transverse (T) tubules into the fibre. This triggers the release of calcium ions from the sarcoplasmic reticulum. Calcium binds to troponin, which moves tropomyosin away from the binding sites on actin, so the myosin heads can form cross-bridges and the muscle contracts.

ATP powers the cross-bridge cycle and ADP is its product, but neither is released from the reticulum. Chloride ions play no part in triggering contraction.