Exercise Physiology Questions and Answers

Answer: D

The compound is PCr (phosphocreatine).

Muscle contains only a small store of ATP. As ATP is split to ADP to power contraction, phosphocreatine is broken down by creatine kinase, and its phosphate and energy are used to rebuild ATP from ADP:

\[ \text{PCr} + \text{ADP} \to \text{Cr} + \text{ATP} \]

This ATP-PCr system supplies energy for the first few seconds of maximal effort, such as a sprint or a jump.

ADP is the product of ATP breakdown, not the store that rebuilds it, and free phosphate alone carries no energy. 'Cohline' (choline) has no role in this reaction.

Answer: A

The keyed role is the breakdown of glycogen to glucose in liver and muscle.

The catecholamines of the adrenal medulla, adrenaline and noradrenaline, are released in stress and exercise. One of their main metabolic actions is to stimulate glycogenolysis: they activate glycogen phosphorylase, breaking glycogen down to glucose in the liver (to supply the blood) and in muscle (for the muscle's own use).

Protein synthesis is promoted by hormones such as insulin, growth hormone and testosterone, not by catecholamines. Glucose utilisation is promoted by insulin. Maintaining blood glucose is a result of this breakdown and of other hormones such as glucagon and cortisol, while glycogenolysis is the specific action the question names.

Answer: D

The keyed reason is a decline in protein synthesis.

With ageing, the rate at which muscle cells build new protein falls, and muscles respond less to the anabolic effect of exercise and food. This contributes to the loss of muscle fibres, the shrinking of fast-twitch fibres and the decline of neuromuscular function in the elderly, and it is why resistance training and adequate protein intake are advised for older people.

Oxygen consumption, ATP synthesis and fat synthesis describe energy metabolism, which does decline with age but is not the cellular impairment the question links to the loss of neuromuscular function.

Answer: A

The term is sarcopenia.

Sarcopenia (from the Greek sarx, flesh, and penia, poverty) is the age-related loss of skeletal muscle mass, strength and function. It typically begins in the fourth decade and accelerates after about 65, raising the risk of falls and disability. Resistance training is the main way to slow it.

Osteopenia (printed 'Ostiopenia') is a reduction in bone mineral density, not muscle. 'Musclepenia' and 'Mayopenia' are not medical terms.

Answer: C

The keyed answer is hydroxy methyl butyrate (HMB).

HMB (beta-hydroxy-beta-methylbutyrate) is a metabolite of the amino acid leucine. Taken as a supplement it is promoted for reducing the breakdown of muscle protein during and after hard exercise and for supporting gains in muscle mass and strength, particularly in untrained people beginning resistance training.

Conjugated linoleic acid (printed 'linoleum') is a fatty acid promoted for fat loss, carnitine is a compound involved in transporting fatty acids into mitochondria, and chromium is a mineral promoted for insulin action. None is associated with slowing muscle breakdown in the way HMB is.

Answer: B

The purpose of carbohydrate loading is to enhance endurance performance.

Muscle glycogen is the main fuel in prolonged exercise, and fatigue in events lasting more than about 90 minutes coincides with glycogen depletion. By eating a high-carbohydrate diet for several days before the event while tapering training, the athlete can raise muscle glycogen well above normal, delaying fatigue.

The extra stored glycogen binds water and adds some weight, but that is a side effect, not the purpose. The practice does not aim to lower blood sugar or reduce hydration.

Answer: C

Athletes should consume sports drinks.

In prolonged exercise, athletes lose water and electrolytes, especially sodium, in sweat, and they use up carbohydrate. A sports drink containing about 6-8 percent carbohydrate and electrolytes replaces fluid, sodium and energy together, and the sodium helps the body retain the fluid.

Plain water replaces fluid but not electrolytes, and drinking large amounts in very long events can dilute blood sodium. Carbonated drinks cause bloating and are often too concentrated, and alcohol increases fluid loss.

Answer: B

The primary role of protein is building and repairing tissues.

Proteins supply the amino acids from which the body builds and repairs muscle and other tissues, and makes enzymes, hormones and antibodies. Athletes need adequate protein to recover from training and to build muscle.

Energy production is mainly the role of carbohydrates and fats; protein contributes only a small share. Temperature regulation depends mainly on water and sweating, and flexibility is not a function of dietary protein.

Answer: C

Bones in the human body are classified on the basis of size and shape: long bones (femur), short bones (carpals), flat bones (skull, scapula), irregular bones (vertebrae) and sesamoid bones. This is option C.

Structure and function can describe the kinds of bone tissue and what bones do (support, protection, movement), location and attachment describe the skeleton as axial or appendicular, and joint and movement relate to the articulations; none of them is the basis of the standard classification of bones.

Answer: B

Absorption of digested food in the small intestine takes place in the villi, the finger-like projections of its lining, so items II (vilus) and IV (villi) are the same structure, option B.

The duodenum (I) and ileum (III) are regions of the small intestine, not the structure through which the absorption takes place, although absorption does occur along their length. Options A, C and D combine these regions with the villi and so are not the intended pair.