Rapid movement of limbs stimulates receptors in the skeletal muscles and tendons. These transmit impulses to the heart, leading to a further increase in the heart rate.
Diagram.
Method.
Note: You can either use a staircase or a block step to do the step-ups depending on which you can get hold of.
- Find your pulse (wrist or neck most common places) and measure it for 1 minute. Record this on some paper.
- Get your stopwatch and time yourself doing the step-ups for 1 minute with no weight.
- Record the result and keep it in a safe place.
- Have a minute rest to get your pulse rate roughly back to its resting rate.
- Then carry on doing the same by adding 2kg packs of paper to your bag for the following weights shown in the table below:
- Once you have done the test for those weights repeat it again so that you can compare your results to check they are accurate.
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Once you have done the experiment the 2nd time record your results in a table that looks like the one I did above.
Fair Testing And Safety.
- Wear trainers so that you don’t hurt your ankles, do not wear shoes.
- Do not run up and down the steps just take it at a nice steady pace.
- Each time you do the experiment make sure that you stick to using the same 2kg packs of paper and the same bag to store it in.
- Make sure all the equipment you use is the same when repeating the experiment again.
- Make sure you or your helper stops the stopwatch as soon as it reaches 1 minute and make sure you count your pulse rate for 1 minute accurately.
- Try and do the experiment in the same room and roughly the same temperature because your results will be affected if there is a drastic change in temperature.
I will now put the results from both times I did the experiment into a table.
As you can see I would say I have got quite accurate results because the results are roughly the same.
I will now put both these sets of results into a graph to try and spot any patterns.
As you can see from the graph I have produced it is now quite obvious that the more weight you carry the higher your pulse rate will be when you exercise.
Conclusion.
As you can see from the graph my prediction was correct in that the higher the mass carried the higher the pulse rate was when exercising, so I have now been able to come to the conclusion that the more mass you carry the higher your pulse rate will be when exercising, so in turn I have investigated what I needed to and I have come to a firm conclusion. There are several reasons why when you carry more mass your pulse rate goes up. Before and during the early stages of exercise the sympathetic nervous system is alerted and adrenaline is secreted in to the bloodstream. Triggered by impulses from the brain before exercise, the heart beats faster and general constriction of the arterioles except for those serving vital organs so that the blood under high pressure is diverted to the active muscles.
The metabolic rate increases. This is caused by the shortage of ATP. The increased metabolic rate results in carbon dioxide building up in muscle tissue. If the level of carbon dioxide builds up then this is monitored by chemoreceptors. This makes adjustments in the ventilation rate because you need more oxygen to replace the carbon dioxide. The heart rate increases to carry the waste away and replace it with oxygen quicker.
Rapid movement of limbs stimulates receptors in the skeletal muscles and tendons. These transmit impulses to the heart, leading to a further increase in the heart rate.
Evaluation.
If I was to do the experiment again I think I would use a step-up block rather than a flight of stairs because not only is it safer but it can be moved so that you can keep a constant temperature while doing the experiment so that my results would be more accurate. In general I am very pleased with the results that I achieved and I believe that my results were very accurate for the equipment I had available to me. I was also very pleased with the fact that there were no anomalous results and my experiment went together as I had planned it. As you can see if you look at my conclusion and results my prediction was correct in that I did state that the more mass someone carried while exercising the higher their pulse rate would be and I also went on to state reasons to why I believed this. If I was to carry out the experiment again at a later stage I think I would stick to the plan I used this time because although it wasn’t brilliant it achieved me the results and in turn the conclusion that I predicted.
