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KIN122- Chapter 5

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Four Factors Contribute <br />to Muscle Strength and Size

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Lecture Notes

On this slide we'll talk about four factors that contribute to both muscle strength and muscle size. The first two, exercise and diet, are under our control, but the second two, genetics and hormones, are not something that we can control. Exercise, if you remember the principle of overload, if you participate in resistance training activities, or muscular strengthening activities that make the muscles do more work than they're accustomed to, that develops muscle strength and muscle size. And again, that really goes back to the principle of overload from week 1. Diet is another factor that can contribute to muscle strength and muscle size. Just like we need energy to participate in cardiovascular or aerobic activities, we also need energy to build up our muscles, and a common myth is that you need to increase your protein intake above the recommended daily levels in order to build more muscle, and that simply isn't true. It's not necessary to increase your protein levels above the recommended daily levels to build muscle, but you do need to make sure that you have a balanced diet of carbohydrates, proteins and fats, because that all allows the muscles energy to build and work efficiently. And so the last two are genetics and hormones. Our genetics determine our somatotype, or the shape of our body, and you should be familiar with the three different types of shapes, body shapes that are identified in your textbook: mesomorphs, ectomorphs and endomorphs. The mesomorphs are the body types that find it the easiest, or relatively easy, to build muscle. And finally, the levels of testosterone and androgens in your body determine how easy it will be for you to put on muscle, and so that's why some people seem to go to the gym and lift a couple weeks and they start to show signs of improvement, whereas others may lift for months and months and not be able to build the same amount of muscle. So certainly there are multiple different factors included, partially determined by things we can control such as exercise and diet, but partially controlled by things like genetics and hormones that are out of our hands.