Skills in the study of sports, exercise and health science practice questions.

A track sprinter completes a 30 s all-out effort on a cycle ergometer against a fixed braking force. Which quality is this test designed to measure?

• Maximal oxygen uptake of the working legs
• Anaerobic power output and its decline
• Flexibility of the hip joint
• Efficiency of the aerobic system at steady state

Answer: Anaerobic power output and its decline

The 30 s maximal effort is predominantly anaerobic, drawing on the phosphagen system and anaerobic glycolysis, with the aerobic system already contributing a measurable share. Peak power and the fall in power across the effort are therefore its outcome measures, whereas maximal oxygen uptake requires expired air to be analysed during an incremental protocol.

A cyclist works at a steady submaximal intensity and her respiratory exchange ratio settles at 0.85. What does this value indicate about the fuels being oxidised?

• Only fat is being oxidised
• Only carbohydrate is being oxidised
• Carbohydrate and fat are both contributing
• Protein has become the main energy source

Answer: Carbohydrate and fat are both contributing

A ratio of about 1.00 indicates carbohydrate alone and about 0.70 indicates fat alone, so an intermediate value shows both fuels contributing. The ratio drifts towards 1.00 as intensity rises and carbohydrate use increases.

Two swimmers have the same hamstring and lower-back extensibility, yet the one with longer arms relative to her legs records the higher sit-and-reach score. Which limitation of the test does this illustrate?

• It measures flexibility at every joint of the body
• It requires a maximal effort against a braking force
• It cannot be repeated reliably
• Limb proportions influence the score achieved

Answer: Limb proportions influence the score achieved

The score is the distance the fingertips travel past the toes, so favourable limb proportions produce a good score without greater hamstring or lower-back extensibility. The test therefore compares athletes only in relative terms.

A team physiologist records the sum of skinfolds at seven marked sites in a group of rowers. What does this sum provide?

• A direct measurement of total body fat mass
• An estimate of subcutaneous fat only
• Limb muscle mass
• A measurement of whole-body bone density

Answer: An estimate of subcutaneous fat only

Calipers compress a double fold of skin and the fat directly beneath it, so the sum tracks subcutaneous fat only and says nothing about visceral fat or muscle mass. Converting the sum into a percentage adds the error of the prediction equation, which is why many laboratories report the raw sum.

A coach palpates the radial pulse for 15 s immediately after a shuttle-run test and multiplies the count by four. Which limitation does this method introduce?

• Recovery has already begun, so the value is too low
• Palpation records stroke volume rather than heart rate
• Multiplying by four converts beats into litres
• The count includes only the atrial contractions

Answer: Recovery has already begun, so the value is too low

Heart rate falls steeply in the first seconds of recovery, so a count that begins after the effort underestimates the true exercise heart rate, and the error grows with every second of delay. A chest strap logging every beat during the run removes this problem.

In an incremental cycle test used to track blood lactate, each stage lasts at least three minutes before a sample is taken. What is the reason for this stage length?

• Heart rate must return to its resting value before each sample
• Muscle glycogen must be depleted at each stage
• Blood lactate needs time to reach a steady value at the new work rate
• The ergometer flywheel takes three minutes to stabilise

Answer: Blood lactate needs time to reach a steady value at the new work rate

Lactate has to diffuse from the muscle into the blood, and the blood value settles only once production and clearance are in balance at the new work rate, so a short stage samples a value that is still rising. Stages that are too brief displace the whole curve and move the apparent inflection point.