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Date May 2016 Marks available 4 Reference code 16M.2.SL.tz0.5
Level Standard Level Paper Paper 2 Time zone time zone 0
Command term Describe Question number 5 Adapted from N/A

Question

Using examples of specific bones, outline the function of the axial skeleton.

[4]
a.

Describe the process of gaseous exchange at the alveoli. 

[4]
b.

Explain the phenomenon of oxygen deficit.

[5]
c.

List three tests of aerobic capacity.

[2]
d.i.

Evaluate one of these tests.

[5]
d.ii.

Markscheme

protection of vital organs eg ribs, skull✔

support and maintenance of posture / structure eg vertebral column✔

providing attachment points for the muscles / movement eg sternum✔

storage and release of minerals such as calcium and phosphorus eg ribs✔

blood cell production eg ribs, sternum✔

An example together with the bone is required for the mark to be awarded.
Award [1 max] for each function.

a.

gaseous exchange takes place through the process of diffusion✔

alveoli are one cell thick which assists in the process of gaseous exchange✔

alveoli are surrounded by a dense capillary network✔

alveoli have a large surface area✔

gas will move along a gradient of higher partial pressure to lower partial pressure✔

CO2 passes from the capillaries through the alveoli to the lungs✔

O2 passes from the lungs through the alveoli to the capillaries✔

b.

Oxygen deficit:
because oxygen needs and oxygen supply differ during the transition from rest to exercise your body incurs an oxygen deficit
OR
occurs when exercise/aerobic work is above the requirement for oxygen at rest✔

the oxygen deficit is calculated simply as the difference between the oxygen required for a given rate of work and the oxygen actually consumed✔

when exercise commences abruptly the demand for ATP is immediate✔

the initial energy is met with ATP stores✔

in spite of insufficient oxygen, your muscles still generate the ATP needed through the anaerobic pathways✔

oxygen deficit creates an oxygen debt which is paid back after exercise✔

c.

Multistage Fitness test/bleep test/beep test/leger test✔

Cooper’s 12 Minute Run✔

Harvard Step test✔

Award [2] for three correct and [1 max] for two correct.

Accept other recognised tests.

d.i.

Multistage Fitness test:

Validity:
the correlation to actual VO2 max scores is high✔

there are published VO2 max score equivalents for each level reached✔

Reliability:
the reliability of the beep test would depend on how strictly the test is run and the practice allowed for the subjects✔

reliability would be impacted by the running surface✔

Strengths:
the ability to test a large number of participants✔

no specialist equipment required✔

cost to perform the test is minimal✔

Limitations:
it is a maximal test so practice and motivation levels can impact on score✔

environmental conditions can affect results if the test is completed outside✔

may be an advantage for team sports with an agility component✔

Cooper’s 12 Minute Run:
Validity:
Cooper ‹1968› reported a correlation of 0.90 between VO2 max and the distance covered in a 12 minute walk/run✔

Reliability:
the reliability of this test would depend on practice, pacing strategies and motivation level. There should be good reliability if these issues are addressed✔

reliability would be impacted by the running surface✔

Strengths:
the ability to test a large number of participants✔

no specialist equipment required✔

cost to perform the test is minimal✔

Limitations:
practice and pacing is required, and performance on this test can be affected greatly by motivation as it is a maximal test✔

environmental conditions can affect results if the test is completed outside✔

requires someone to accurately monitor the length of time of the test✔

requires someone checking distance covered✔

Harvard Step test:
Validity:
correlation to VO2 max has been reported as between 0.6 to 0.8 in numerous studies✔

Reliability:
dependent upon the administration of the test and stepping at the correct cadence✔

Strengths:
can be used with larger groups✔

cost for equipment is limited✔

Limitations:
biomechanical characteristics vary between individuals. For example, considering that the step height is standard, taller people are at an advantage as it will take less energy to step up onto the step✔

body weight has also been shown to be a factor✔

testing large groups with this test will be time consuming✔

specific equipment is required eg metronome and bench at set height✔

Accept other recognised tests.

d.ii.

Examiners report

Often answered very poorly with most pupils only providing protection as a role of the axial skeleton. However most pupils provide suitable examples.

a.

A few pupils were able to achieve full marks. However most pupils achieved 2 marks by identifying the correct direction of oxygen and carbon dioxide.

b.

Most pupils were able to correctly identify when oxygen deficit occurs and how oxygen debt is paid back after exercise. However very few candidates were able to achieve full marks.

c.

Most pupils were able to identify Harvard step test, 12-minute cooper’s run and Multistage Fitness test. However very few pupils achieved full marks. Many pupils inaccurately referred to a VO2 max test rather than direct gas analysis with something like the Bruce Treadmill Test.

d.i.

Most pupils struggled with analysing these tests and struggled to achieve full marks. They were more intent on describing the test.

d.ii.

Syllabus sections

Topic 2: Exercise physiology » 2.1. Structure and function of the ventilatory system » 2.1.7. Explain the process of gaseous exchange at the alveoli.
Topic 2: Exercise physiology » 2.1. Structure and function of the ventilatory system
Topic 2: Exercise physiology

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