In this activity, your students are participating as subjects to provide data for analysis. This raises ethical issues, some of which could be addressed by using the briefing sheet and consent form attached. The activity involves students exerting themselves in light exercise and monitoring their heart rate for a period afterwards. Collating class data allows you to develop ideas about averages and variation within a
population. Adapt and use the attached briefing and consent form before the lesson to prepare your students for the activity. Develop a text-based alternative, or devise a non-exercising role for students who cannot or do not want to take part in the exercise activity. Set out a personal results table for individual students. Set up a class results table (on whiteboard or computer) to collect the data from the activity. If you can use a spreadsheet it will be easier to
analyse the input data later. Make sure the students know how to take their pulse to measure their own heart rate. Give students an appropriate exercise to do for an appropriate time and collect the data for analysis. Identify and remove anomalous results before calculating mean averages. Stopwatch or stopclock Access to a pulse oximeter (optional) Bench or step to exercise
on Chocolate (optional) (Note 1) Health & Safety and Technical notesDoing low impact exercise as described in this procedure should be safe for most students. Ensuring that any individuals with identified health issues do not take part, and ensuring that the activity does not become competitive (and hence boisterous) should reduce the risk of the activity causing damage. Ensure that any equipment used on which students exercise is well-constructed and stable. If you choose a staircase as the site for exercise, instruct them to use the handrail and ensure by supervision that this is obeyed. 1 If you choose to observe the effects on heart rate of sucking a small piece of chocolate, you will need to think how to give students chocolate without the risk of contamination from the laboratory. This will be easier if you are working in a regular classroom, not a laboratory space. Ethical issuesIn effect, this practical uses students as participants in a piece of research. Ethical procedures associated with using students in this way should be followed. This should include:
Student briefing and consent form. ProcedureSAFETY: Supervision of activity by teachers will ensure that the activity does not become competitive or too boisterous. The activity should be appropriate to footwear and clothing worn by students, for example, walking briskly up/ down stairs or steps up onto a low bench in the lab. Students with identified physical/ health conditions should not be involved. Asthmatics may be able to take part if they use their inhalers before starting the exercise. Preparation a Check student health status, and discuss any issues with colleagues in PE. Investigation b Take resting heart rate and O2 saturation (if a pulse oximeter is available). c Show the range of resting heart rate. Plot on a frequency histogram with bands of heart rate 51-55, 56-60, 61-65 etc. d Show the range of resting O2 saturation. There will be less variation in O2 saturation than in resting heart rate. e Discuss variation across a population. Establish that variation of some sort is what we expect to see in any measured feature of the population, but that the amount of variation may be different for different factors. f Tell the students that they are going to do some exercise. Take heart rate again. g Note that the warning about exercise increases the heart rate a little, and explain that some of the systems in our body can be consciously or deliberately controlled. h Give each group of students an exercise to do – some vigorous, some less vigorous. Take heart rate again during exercise if possible. Calculate percentage increase in heart rate and plot average percentage increase in heart rate for each exercise. i Get some student volunteers (perhaps you could select members of school sports teams as those likely to be the fittest) to do more exercise – the same exercise, but for different times. j For each student, note how long they exercise. Take heart rate at the end of the exercise, and then every minute until the heart rate returns to near their normal level. for few minutes. Plot heart rate against time after exercise. Plot recovery time against duration of exercise. Teaching notesA common weakness in examination answers on this topic are that candidates do not correctly identify the beginning of the exercise. Take care that students’ personal responses are anonymised to the rest of the group – so although each individual may see their own position in the range, the group will not identify individuals at the extremes. Factors affecting resting heart rate:
Control of heart rate from brain via autonomic nervous system Adrenaline, intensity of exercise and recovery Oxygen debt and recovery DownloadsInclude a Student briefing and consent form and set some answers and questions in a student sheet.Health & Safety checked, December 2008 Web links
http://news.bbc.co.uk/1/hi/magazine/7581120.stm (Website accessed October 2011) |