A sports physiologist investigates the physical response of three endurance runners to a standardized high-intensity step-test.
First, each runner's heart rate is measured while resting. The runners then perform a 3-minute step-test on a 30 cm platform. Immediately upon completion, their heart rates are measured again.
The recorded pulse rate measurements (in beats per minute, bpm) are as follows:
Display these results in a suitable table.
Explain why the runners' heart rate is higher after completing the step-test.
Suggest two ways the physiologist could improve the validity or reliability of this investigation.
