Benefits to health of being active practice questions.

After a 16-week endurance programme a recreational runner's resting heart rate has fallen from 70 bpm to 56 bpm. Which adaptation best explains this fall?

• Resting cardiac output has decreased
• Maximal heart rate has increased
• The arteriovenous oxygen difference at rest has decreased
• Resting stroke volume has increased

Answer: Resting stroke volume has increased

Training enlarges the left ventricular cavity and improves filling, so more blood is ejected per beat and the same resting cardiac output is reached at a lower heart rate. Maximal heart rate is set largely by age and is unchanged or slightly lower after training, and resting cardiac output itself is essentially unchanged because resting oxygen demand has not changed.

An adolescent gymnast trains with regular landings and weight-bearing work. Which skeletal adaptation is expected?

• A reduction in the mineral content of bone at the loaded sites
• An increase in bone mineral density at the loaded sites
• An increase in the length of the long bones
• A conversion of compact bone into cartilage

Answer: An increase in bone mineral density at the loaded sites

Mechanical loading stimulates osteoblast activity so mineral is laid down where the strain is greatest, which is why the adaptation is site-specific rather than whole-body. Bone length is determined by growth at the epiphyseal plates and is not increased by loading.

A previously inactive adult has played recreational football twice a week for three months and now handles a glucose load better than before. Which muscular adaptation contributes most directly to this?

• A rise in the resting concentration of blood glucose
• A fall in the number of mitochondria in the muscle fibres
• An increase in GLUT4 transporter density in the muscle fibres
• A reduction in the glycogen storage capacity of the muscle

Answer: An increase in GLUT4 transporter density in the muscle fibres

More GLUT4 transporters at the muscle membrane increase insulin-stimulated glucose uptake, so less insulin is needed to clear the same load. Trained muscle also stores more glycogen, which provides a larger sink for that glucose rather than a smaller one.

A community coach designs the first eight weeks of activity for a group of previously inactive adults over 65. Which feature of that plan follows the principles of exercise prescription for this group?

• The starting intensity is taken from the group's competition history
• Load is raised by a large step each week to shorten the adaptation phase
• Frequency and duration are built up before intensity is raised
• Resistance and balance work is left out so that only aerobic work is trained

Answer: Frequency and duration are built up before intensity is raised

Prescription for a previously inactive group starts from a low baseline and increases the volume variables first, because raising intensity early carries the greater risk of injury and of drop-out. Resistance and balance work belongs in the prescription for older adults rather than being an optional extra, since those qualities decline earliest with age.

A coach writes the first four weeks of an aerobic programme for an adult with type 2 diabetes who has not trained for years. Which feature of the prescription matters most for this client?

• Sessions are set at a fixed absolute workload, so that every client covers the same distance
• Sessions are placed after meals and the client is taught to recognise hypoglycaemia
• Sessions begin at maximal intensity, so that glucose tolerance improves as fast as possible
• Sessions avoid all resistance work, because muscle contraction raises blood glucose sharply

Answer: Sessions are placed after meals and the client is taught to recognise hypoglycaemia

Exercise drives glucose into muscle by a route that does not depend on insulin, so the timing of sessions against meals and medication is the practical safety issue for this group. Resistance work is recommended rather than avoided, and intensity is built gradually from a low starting point.

The WHO physical activity guidelines for adults set a weekly target for moderate aerobic activity. Which further component do the same guidelines include?

• Muscle-strengthening activity on at least two days a week
• A minimum of one maximal effort session every week
• A daily period of complete rest from all movement
• A fixed daily step count that is identical for every adult

Answer: Muscle-strengthening activity on at least two days a week

The aerobic target is only half of the guidance: strength, and in older adults balance, are named separately because they protect bone, muscle mass and independence in ways that aerobic work does not. A single step count for everyone is a popular target but not part of the guidance.