Describe the regulation of heart rate.

Analyse oxygen deficit.

Explain the differences in dietary recommendations for a runner during marathon training and a sedentary individual both with healthy body mass index (BMI).

The diagram shows a person performing a somersault dive from a 10 m platform.

Outline how they use the law of conservation of angular momentum to perform a somersault dive.

heart has its own pacemaker / SA node/ is intrinsically regulated;

heart rate is regulated by brain/ medulla oblongata/pons/ is influenced by extrinsic factors/ autonomic nervous system;

actions of the parasympathetic system slow down the heart rate;

actions of the sympathetic system increase the heart rate;

heart rate is regulated by adrenaline/noradrenaline/epinephrine;

deficit is calculated as the difference between the oxygen required for a given rate of work and the oxygen actually consumed
OR
deficit takes place during the initial stages of exercise;

muscles generate ATP through anaerobic pathways;

oxygen transport system is not immediately able to supply the needed quantity of oxygen to the active muscles
OR
oxygen consumption requires several minutes before a homeostatic level is reached;

homeostatic level is reached when the aerobic system meets the demands;

the greater the intensity of exercise, the greater the oxygen deficit;

deficit is repaid during rest period/after exercise;

oxygen deficit can be minimised by the athlete doing a <suitable> warm-up;

if the exercise intensity is too high the athlete will have to stop exercising or reduce their intensity;

<aerobically> trained individuals may have a smaller deficit/smaller EPOC compared to an untrained individual at the same intensity;

Accept appropriate labelled diagram 1st and 6th mp.

Marathon runner:
use more calories <than sedentary individuals> and therefore are recommended to have a higher calorie intake/ energy intake;

has a high training volume and therefore have a much higher recommendation for carbohydrate intake;

need some fat stores and are recommended a <slight> increase in fat consumption;

need to recover after activity and are recommended a <slightly> higher protein intake;

thermoregulate more and are recommended to have a higher water/ electrolyte intake;

greater mineral and vitamin intake for bone strength/blood cell production/growth;

Accept in the converse.

angular momentum is defined as angular velocity × moment of inertia;

Newton’s first law / a rotating body will continue to rotate with constant momentum unless an external force / torque is applied
OR
angular momentum of the diver is constant during the dive
OR
there is an inverse relationship between moment of inertia and angular velocity;

first point of the dive:
the diver starts off with a high moment of inertia before jumping;

during somersault:
in order to complete sufficient rotations in the dive, diver tucks body in towards centre of mass/ reduces the moment of inertia;

therefore causing an increase in angular velocity;

preparation for entry:
in order to safely enter the water <in streamlined position> diver straightens out body / increases moment of inertia;

therefore slows them down and reduces their angular velocity;

Award [1 max] for aspects of definition of angular momentum.

A good number of candidates managed these questions well. They were able to describe the intrinsic control mechanism and then the impact of adrenaline was also a common effector. The other extrinsic control mechanisms were less likely to come up in their responses.

Candidates generally knew key features of oxygen deficit, especially that it occurred at the start of exercise and that the anaerobic energy systems were what was used to get through the initial phase. They knew that oxygen deficit was paid back at the end of exercise. The other responses on the mark scheme were less common.

Candidates generally did well with this question and knew that the marathon runner needed more carbohydrates, protein and even fat. The last marks about water or micronutrient intake were less likely to be mentioned.

For a fairly complex biomechanical concept, this question was usually done very well. Those candidates that wrote down the equation and then applied it to the diagram tended to achieve top marks.