4) Sodium ions diffuse into the muscle cell, initiating an action potential in the muscle
cell. The action potential travels along the sarcoma and T tubules to the sarcoplasmic reticulum.
- Calcium ions are released from the sarcoplasmic reticulum.
- Calcium ions bind to troponin, associated with actin myofilaments. The binding causes tropmyosin to move into the actin groove, which exposes myosin attachment sites.
- The heads of myosin myofilaments attach to the actin myofilaments, forming cross bridges.
- The heads of the myosin myofilaments attach to the actin myofilaments to slide over the surface of the myosin myofilaments.
- Muscle contraction requires energy. ATP, bound to the myosin heads, is broken down, releasing energy to myosin heads, which is used to supply the energy for movement.
- Another ATP binds to the myosin head, causing it to release the actin myofilament and the myosin bends back to it’s resting position.
- As long as calcium remains attached to the troponin, and as long as ATP remains available, the muscle continues to contract and steps 7 through 10 are repeated.
Types of muscle contractions:
Muscle contractions are classified as either isometric or isotonic. In isometric (equal distance) contractions, the amount of tension increases during the contraction process, but the length of the muscle does not change. Isometric contractions are responsible for the constant length of the postural muscles of the body, such as the muscles of the back. On the other hand, in isotonic (equal tension) contractions the amount of tension produced by the muscle is constant during contractions, but the length of the muscle decreases. In my case movements of the arms or fingers are predominall isotonic contractions. However most muscle contractions is a combination of isometric and isotonic contractions in which the muscles shorten some distance and the degree of tension increases.
Fair Test:
- The teacher will check that the Newton bathroom scale reads "0" every time before each student in the class squeezes it.
- Make sure that we separate the sex’s whilst making our tables,
- Make sure everyone has rolled their shirt up whilst getting their biceps measured. Also make sure that their biceps is totally relaxed and not tensed when measuring the fat.
- Make sure you ask the person if he trains a lot, i.e. exercise.
- Nobody will be allowed to have a practise turn.
- Each person will have to hold the Newton bathroom scales in the same manner.
- Once each person reaches their highest strength on the Newton bathroom scales, they will have to hold it there for at least 2 seconds before they release it, to ensure that the readings are accurate and not unfair.
Secondary Data: I have obtained my secondary data from the book called Sport Science.From the results in Sport Science they also say that “the bigger the bicep muscle the bigger and stronger grip.” Also for extra secondary data I could obtain results from another class or another age group, such as teenagers or adults.
Key Features:
- To see how much training that student does.
- To see how much of his/her bicep muscle is fat.
- To see how big the students hand is.
Safety:
- Do not mess about with the equipment.
- Do not play with the callipers or swing the measuring tape about.
- Make sure your hands aren't wet before you squeeze the Newton bathroom scales.
- Be careful with the scale and do not drop it onto the floor or your feet.
Method:
- First of all the teacher gets the entire apparatus ready and set up.
- Then each person in the class takes it in turn to go to the front of the class and have their biceps, handspan and fat measured with a tape measure by the teacher. Making sure that no muscles are tensed and can be fully seen.
- Each person then takes it in turn to attempt to squeeze the Newton bathroom scales as hard as they can.
- Everyone has a total of three attempts and the best result of the three gets recorded on to the graph.
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Repeat the experiment again and a good average of results.
Apparatus:
- Newton bathroom scales - (to measure finger strength 1000N –10N )
- Tape measure - (to measure the biceps)
- Callipers - (for fat layer measurement)
- Pen and paper - (to record the results)
Analysis for Males
Comments: From my table one can see that John has the highest grip of 560 N and Fahim has the biggest biceps of 35 cm.
The Mean grip force for the males calculates to be:
The mean bicep size, in cm for the males calculates to be:
Gradient from Graph :
This tells me that a force of 26 N can be applied toeach CM in the biceps of the boys.
Comments: From My table you can see that Recina had the biggest biceps and Amy has the biggest grip.
The Mean grip force for the females calculates to be:
The mean bicep size, in cm for the males calculates to be:
Gradient from Graph :
This tells me that a force of 20.7 N can be applied to each CM in the biceps of the females. This is approxametly 6 N less than the males.
Conclusion:
From our results one can see that Recina and Fahim had the biggest biceps both being 35cm. However both of their grips differed and were not the highest in the class proving part of my prediction wrong. Recina was the highest female and got a grip of 350 N and Fahim the highest male, got a grip of 460 N. The difference between the two grips is quite substantial (110). I believe the main reason for this was because Fahim being the male was more physically stronger. Also Fahim also had less fat than Recina and therefore had more muscle in his biceps then fat. Another factor which gave Fahim stronger grip was because Fahim had a much bigger hand span than recina and therefore was able to use the size of the fingers, palm and basically the whole hand, as an advantage. As with bigger hands you can have a better grip and apply your full strength. The person who did have the largest grip however was John. His grip was measured as 560 N. John did not have the biggest biceps in class but was quite close with 32 cm. I believe john got a higher grip than people with bigger biceps than him like Recina and Fahim because John had less fat than both of them which means that he had more actual muscle than fat. Another factor why I believe john got a bigger grip even though he didn’t have the biggest biceps was because john did more training then Recina and Fahim and therefore his muscles were more used and built. John also had quite a large handspan and was therefore apply his full strength through his finger and hand muscles. The weakest in the class was Rakhi a female proving part of my prediction corrects. She had a bicep size of 21 cm and a grip of 200 N. Salah a male in the class had the weakest grip of 200N but surprisingly had quite big biceps of 30. On the other hand I, Zahid had biceps of 27 cm and yet still got a much higher reading in grip of 390 N. The size of the hand span did not really effect us two, as we both had similar size hand, Salah being bigger by 1 cm. I believe I got a stronger grip because I do a lot more training compared to Salah and had less fat than he did. So one of the reasons why I believe I performed better than Salah in grip even though he had bigger biceps than me had to be my training.
Training can increase the amount of muscle in the body, and can help to make muscles work more effectively. Training usually improves the heart and lungs as well as individual muscles. This will insure a good supply of blood reaches the muscles during exercise. However, training does strain the body and an inappropriate exercise programme can do damage to the muscles and joints.
A muscle is made up of many elongated cells, each of which contains many muscle fibres. These fibres contain chemicals that produce the force that shortens the muscle. So strength of a muscle depends on the number of contractile fibres it has. The easiest way to estimate the number of fibres in a muscle is to measure its width. Thicker muscles contain more fibres and so are stronger like in our case john had quite thick biceps and therefore giving him more contractile fibres making him stronger and in turn giving him the largest grip.
From my graph and results above I observed that the male gender of the class was mostly stronger than the female gender of the class, with a few exceptions. The gradient in my graphs also supports this as the males in the class overall give a larger force per cm in the bicep muscle than the girls. Also from both my graphs all the points for both females and males are all concentrated in one section. This proves that the larger the bicep is the higher the grip force is because no one really was marked on my graph with big biceps but week grip or viceverser. I believe if we repeated this experiment my points will begin to get closer and closer to my line of best fit as we would have much better and more accurate results. These results and my graphs supported and backed up my prediction quite well except for a few exceptions.
Evaluation:
The instruments I used were quite accurate. To measure the biceps we used tape measure, which was measured in cm. To record down the grip results we used callipers. The accuracy was 10 N- 100N, which is quite accurate. I could further more improve the accuracy’s of these measurements by telling people to roll their sleeves up to the top of the arm or tell them to put a T-shirt on before hand.
To see whether my results were accurate enough I am going to use the % error equation.
So to see whether my Biceps results are quite accurate I will use Recina’s and John’s results.
Biceps accuracy = 1 cm
% error = 1 35 x 100 = 3 % : This proves Recina’s result of biceps is quite accurate but still need improvement.
% error = 1 32 x 100 = 3.1 % : This also proves John’s biceps results are quite accurate but also still need improving..
From my two equations one can see that the results for biceps were quite accurate, making them reliable enough for this investigation but could still further more be improved
I am going to use Fahim’s and John’s grip results to see whether they are accurate enough.
Grip accuracy = 10N
% error = 10 460 x 100 = 2 % : This proves that Fahim’s grip reults are more accurate than his biceps results.
% error = 10 560 x 100 = 2 % : This shows me that the grip results are quite accurate but still can be improved.
From these two equations one can observe that the grip results were more accurate than my biceps results. The percentage error for both grip and bicep results was quite low making them good results. These results were good enough at proving my prediction correct as these results did prove that the larger the bicep muscle the bigger the grip force.
If I was to do further work in this field I would try different age groups, compare sexes and look at their family history and see their variation and genetics. I would also look in to training more and maybe compare people who do a lot of training and people who don’t but are quite health and have lots of fat on their skeletal muscles. If I were going to do the experiment again I would firstly improve my method by making everyone come in wit a T-shirt before hand and would get more better and accurate equipment so I can get more accurate results. I would also use my callipers and measure round my forearm as those muscles effect the grip the most.
Overall I have enjoyed this experiment thoroughly and have learnt quite a lot about the relationship between biceps and grip with factors like muscles and training coming in to it.
Zahid Siddique.
