| Date | May 2011 | Marks available | 3 | Reference code | 11M.3.SL.TZ2.4 |
| Level | Standard level | Paper | Paper 3 | Time zone | Time zone 2 |
| Command term | Discuss | Question number | 4 | Adapted from | N/A |
Question
Backflow is the return of blood to the heart. In legs, backflow is enhanced by the pumping action of leg muscles during movement. When this does not occur efficiently, serious health problems can arise. The backflow speed of 40 patients was measured during the application of different therapy methods. The lying position is the control.
State which activity reduces backflow speed in relation to the control.
Suggest a reason why backflow speed is reduced by the activity stated in (a)(i).
Determine the difference in backflow speed between the lying position and pedal exercise.
Discuss the benefits of exercising to promote high backflow speed.
Markscheme
standing position
leg muscles are not pumping/contracting to help return of blood to the heart;
gravity pulls the blood back towards feet / circulation must overcome gravity to return blood to heart;
340 (arbitrary units)
better oxygenation enhances muscle metabolism;
better blood flow/cardiovascular fitness prevents pooling/swelling of ankles and feet/varicose veins;
prevention of thrombosis;
maintenance of muscle strength from better circulation;
maintenance of muscle strength from use of muscles;
Examiners report
A relatively small number of candidates answered this option, but those who did generally achieved well.
A relatively small number of candidates answered this option, but those who did generally achieved well.
A relatively small number of candidates answered this option, but those who did generally achieved well.
In B1 (c) there were some problems with candidate understanding of the term ‘backflow” though it was defined at the beginning of the Option to aid student responses. This perhaps highlights the importance of noting/highlighting/underlining key terms in the stem of questions to aid in responses.
