quarta-feira, 28 de outubro de 2009
How should this website be read?
To make your reading easier, below is the order in which the posts must be read.
1)How should this website be read? (Yes, this post being read now)
2)Muscular Contraction
3)What limits and enhances muscular contraction?
4)How will the measurements be made?
5)So where's the Chemistry in all this?
All information in the website was extracted from:
Biology for the IB Diploma Study Guide
Physics for the IB Diploma Study Guide
Chemistry for the IB Diploma Study Guide
The Encyclopedia of Bodybuilding by Arnold Schwarzenegger
click4biology.info
bodybuilding.com
wikipedia.org
All content was written by Charles Echols Spragins III, Julian Pascal Saadi, Henrique Luz, Stephanie Whyte, Ana Clara Biolchini and Ana Beatriz Valladares.
Edited by Charles E. Spragins III
So where’s the chemistry in all this?
We used our collective knowledge in chemistry to effectively choose the correct springs. Springs are usually made of a metal as they are the strongest and can be used for a variety of things; such as trampolines, slinkies and vehicle suspensions. But in our project, we decided to use them to measure in newtons, the force (and hence an approximate of the strength) that a certain muscle could produce (e.g. Biceps). The springs we have are both made of hardened steel. This form of steel is made by rapidly cooling the high carbon steel (quenching) and then by heating it (tempering) to produce Martensite (final form of the steel – hardened steel). Although hardened steel seems like it would be too “strong” to stretch, during the fabrication, the steel is only tempered and quenched for a certain amount of time to obtain the exact atomic constitution of the metal.
If you were wondering why we didn’t choose a different material for our spring, the answer isn’t complicated. In our situation, this one was the best choice; it’s strong, was cheap and looks good. We needed to make sure it wouldn’t either become permanently damaged when unbearable force is applied or lose its elasticity (Hooke’s Law). And so, depending on the person, we chose to use two springs, both of the same chemical material, but of different lengths and appearance. Our first spring is designed for the stronger experimenters (this spring has a shorter length, a larger diameter and a larger circumference). The second spring is destined to the less physically apt student (with a longer length, smaller circumference and a smaller diameter). Although the chemical properties are the same in both cases, the physical properties differ, and that’s what makes a difference. The fact that one of them is longer and has a smaller diameter will make it easier to pull it. The same explanation goes for the other spring.
How will the measurements be made?
This law states that if there are two bodies (body A and body B), and body A exerts a force on body B, then body B exerts an equal and opposite force on body A. This can also be called the law of reciprocal action. So, if you pull the spring, the force you pull with will be equal to the force of the spring pulling you.
Hooke’s Law:
Hooke's law is the basic theory used in our project. It is an approximation that states that the extension of a spring is in direct proportion to the load added to it as long as this load does not exceed the elastic limit. The elastic limit is the maximum amount of force you can exert on the object before it is permanently physically deformed.
The formula for Hooke’s law is F=kx, where F is the restoring force exerted by the material, x is the displacement of the end of the spring from its equilibrium (starting) position and k is the spring constant.
Both these laws apply to our project. Hookes law helps explain that depending on how hard/how much force you use to pull the spring, will influence the extension of the spring. In simpler terms, the harder you pull on the spring, the more the spring will extend. Newtons third law applies, because the amount of force you apply on the spring, will then be pulled on you by the spring itself.
Two springs will be used in the experiment. The first graph accounts for the thinner spring and the second accounts for the thicker one. From these graphs, we will be able to calculate the force exerted by the person by just reading it from the graphs. If a person can easily exert 60N on the thinner spring, they will attempt to extend more on the thicker one.
terça-feira, 13 de outubro de 2009
What Limits and Enhances Muscular Contraction?
1.The process of contracting a muscle involves the process of oxidation-in effect, a form of burning, which is why we say you "burn calories" (create heat by the release of energy usually stored as fat) when you exercise. Oxidation requires both a source of fuel, which in the muscles is ATP, and oxygen. Whenever ATP or oxygen is in too short supply, the muscle fibers can't contract until they are replenished as you rest and recover.
2.Another limiting factor is the buildup of waste products that result from the burning of calories due to the muscular contraction. The burning sensation felt in a muscle as you continue to carry out repetitions of an exercise is due to the accumulation of lactic acid in the muscles used. When you stop to rest, the body removes the lactic acid from the area and you are able to do more repetitions.
Enhancing Factors:
1. Increase in amount of ATP available for muscles. This can be achieved by using a nutritional supplement called creatine phosphate. The way creatine works is: it transports the phosphate required in the conversion of ADP (Adenosine Diphosphate) to ATP (Adenosine Triphosphate). ATP provides the muscle with the energy needed for it to contract. Muscles have only a limited supply of ATP and once it is used up, the body has to find ways to convert the useless ADP back to ATP. The fastest way this reaction happens in the body is using the phosphate from creatine phosphate.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjORiqmNMTV2fc6P0paz5eYjbo2eMqKxug5jzuTIaTsSPtGgJ0pvvEA8mpQWs5v_PRYp1exyLbtQSQsdaIb1U6ByUtP9V0uBmpai1M__ztE892qRmmZ5YpzNeiUK6lo4UCL0uUIQSRhQGY/s320/Creatine+Molecule.png)
2.Continuously training your muscles by lifting weights will gradually lead to muscle growth, thus enhancing muscular contraction . When muscles contract continuousl times to move a heavy load, the muscle fibers will tear. If a sufficient amount of protein is available, your body will naturally overcompensate for the muscle fibers which were broken down during the workout. Overcompensating means regenerating the already existent fibers and creating new ones.This overcompensation is what causes muscles to become bigger, consequently making them stronger
Muscular Contraction
When a spring is extended by a person, the muscles in the body used to extend it contract. The muscles being used will depend on how the body is positioned in relation to the spring. The muscles used to lift weights, exerting forces and create movement in our body are called skeletal muscle tissues. This is because they are attached by tendons to the bones of the skeleton and allow the skeleton to move. Skeletal muscle is also known as voluntary muscle, as its contraction is controlled, as opposed to cardiac muscle, a muscular tissue which its contraction is involuntary.
To fully comprehend the remainder of this study, a thorough knowledge of the anatomical chart of muscles must be developed. The diagram below shows a well developed muscular physique in which all muscles are clearly visible.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgv8jw_KNtQugbNumM9YpyXuDWODxK4ZLIgAF81N91rj-Dide3rU3qhDAHd9IUrAffGr98KibDLBOt8amJcaTTBEAMTLk46xU3oBe5thWamEwbebCuAnEu3VEcKurmHXz5dfWIQEQi_ovg/s320/Anatomy+Front+View.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjbCPxyYBa4oe-yQz4GFeJhrpzG8ph_FDYWCejAh1E9LD7wczBAp5p6CBr91FPnDhatQ-T-ckUmFOsgVusB9khz_xzfBG8-UAQxWLcNa8A604sG5hIRUZTunuhAkOPURfpXIo6XwKE239w/s320/Anatomy+Back+View.jpg)
The simplest way to lift a weight from the ground at a standing position is by contracting the bicep with the aid of the forearm flexors carrying out a movement commonly known as the bicep curl.. This is a common weightlifting exercise. Every exercise has a correct form in which it should be carried out. This form should be followed for two main reasons:
- Prevent injuries.
- Work out target area which the exercise is designed to.
deltoid and point of insertion below the elbow.
Its basic function is to lift and curl the arm and to pronate (twist downward)
the wrist.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgauua25SXbCY0jC9CqQto4xJNUskM0rY4B3pfDJFC0CGT1mvlBA5UgTje65U_zySt7Qf4PbIkXM9M3DgfIZtYAxdHkTGyA-vL9lDUo3C1KG_WriIgJoO-NczgYawf5ky69SO3hDTIPV5Y/s320/Bicep+Anatomy.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhTYNTLa4dzBykNi1oz5B5wUowuDYIRUfZdGh7mmpA7uaxtJm2SvuzWIPcQuiEqShkB6yk-38lY69ZOk5m6k8tMt11w7v1P6nZ2_WonFJYQCoeqz9SkXzo3mPWCkTNxad1Zkg05YTv5kLA/s320/Bicep+Heads.jpg)
The correct form to isolate the biceps performing a bicep curl is shown in the diagrams below:
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh14Wv-FzGDFqJp7yiJu9hIcH-ErS9xJSaWumN4xZ8fVJoaEWMYDwnFMUdYMOp7T7dRM8aOqVY2IhjzJ_-Hy8CPam3fqfttndEkHqYg8LaD8_Lbhf5MCuVrDoPafxdW4PM-mAeKf2LPxrg/s320/Bicep+Curl+Front.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgioXjGLuF9erHHtKP6WugTOkes2xHLK1iMn73obO4U7a0L7OogStRBeO2AEHE8jyiNkhf2UI9hzKa9QOGGyhmMSt3hcLz5I4YegZiIFEn3pTD9aEdPsuBSFWI6rP7b7xLAh46p5NBefx8/s320/Bicep+Curl+Side.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg2ZS5L7gIFAALY9D0lXhy8nKjDGLJczoS8K9sVQkCgOs4j2VMm2i2KE6LHFIn64ujd8rzUHk4YMgzLDKnM7uoI_38oDXV8KBieVZk1y_MbVt7Py2sicZ3hkW1XPaZ5HcfK67GFOuRYntI/s320/Bicep+Curl+Side+Cheat.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiI9yyf_W8slrRMkaRuPrlpwSazm6WDw0Q_ysLQQ4kaPP9Hsmk4qWp_Cwiq27BUfqnq8Blp4_fPPTMTt6MGF3_GWvFvKgdV9EZeb0IFjait_81YsEgzbVnGee1JcZlrMzOB-BKLn4PBMWQ/s320/Bicep+Curl.jpg)
Its basic function is to straighten the arm and supinate (twist upward) the wrist.
As said previously, the tricep is made up of three heads. This mean the muscle is divided into three segments. The image below shows this clearly.
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiRm_DKDlzjnLZfXiJ9r_39mZrFgWmka91fGW8f8bCiEe73dYSHRQeIHjio8FoMoeovkNmbFPEi31hcOZFLDfEzwnyLF_3YE0vcA3Cg_Zyr5fusH3_GyJcARcqZccSHQ_NXUd4MzD6EWVU/s320/Tricep+Anatomy.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhUgfyS9t3528WmHgbKRTFvZdFm5YCnGjo7ut_g7qX3TDwyL84Ag1XREqcarktJfMK-b9nBVCtph231lLYrnZ9NYHyi8fD47C1TLLPCNTsQw5NVjc-rROKjiaMUuAI7VOeWM7jN9U_LPN0/s320/Tricep+Heads.jpg)
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgLBp8EmwAclhLm1lkm017bSE1Gr8ms6lSoJD_T1J-KNRzLujei10P8B7A4TjyUL_K9b_leyEBL39W0ZpKrJzTcjWf783nQSQ93XCb85bt4cvrc6MAZsp5YaFcppLSRM1UQpGp2eYqzoCc/s320/Tricep+Extension.jpg)
The reason why this specific exercise was chosen is because it is very hard to cheat at. But yet again, we will make sure that when this exercise is done for our measurements, we will make sure that the form is followed correctly.