Firstly lets start with how do muscle grow anyways? Muscle growth occurs in two stages, The first part is happens when the muscle is under stress and the second part is when the muscle starts to repair itself.
When you exercise, you're stressing the muscle, you're putting added weight and tension there and as that happens the cells in your muscle break down and causes Micro-tears. Micro tears are very small ( hint: microscopic) cuts in your muscle, these cuts are almost like a small cut on the skin, however you'll have a lot of them and while they may be small they are what give you that very sore feeling after you workout.
That's the first part of muscle growth, which is cell break down, The second part needed for a muscle to grow is after you have Micro-tears, your body will work hard to repair that damage, however the human body is an intelligent thing, when it repairs those tiny Micro-tears, it will replace them with stronger, bigger cells, Because the body figures out It needs to be stronger so it wont have to repair itself anytime soon.
Now all this is nice to know, but what you should know basically is that the more Micro-tears you make, the better, and to make as many cuts as you can, you should stress out the body as hard as possible, and to do that you should exercise with intensity and not with high reps.
This is why intensity > reps, bench pressing 100 pounds for 10 times will stress your muscles much much more then say bench pressing 20 pounds 50 times. The more the muscle contracts, the more cuts you will have, the more pain you will feel the next day, but also the bigger your muscles will get.
Some of the new machines and exercises seem to promote almost no intensity or effort from your part, those will never work, you cannot "shake" off fat and build muscle, it doesn't work like that.
Oh right, I'll say it again, train with intensity, not with high reps.
But be smart about it, if you're sore all over, you should just rest and let muscle repair do its work.
For muscle repair to happen you need a lot of rest, which is why almost everyone will tell you that you should only exercise 3-4 times a week.
Muscle growth requires a massive amount of protein, if you want to help grow your body, you need about 0.7-1 gram of protein for each pound you weight, this amount varies and can go up to 2 grams of protein for each pound for very high level athletes.
That's just to sustain your body, but do you know that each pound of muscle in your body has 100 grams of protein in it? so you should get excess amount of protein, its better to have more then you need then less then you need, still try not to overshoot too much, experiment and see what works for you.
By the way, each pound = 450 grams, the 350 grams left on each muscle are made up of fat, blood and carbohydrates.
Here's a list of some popular foods and how much protein they contain.
|250mill of milk has about 8 grams of protein|
|A boiled egg has around 6 grams of protein|
|100 grams of sausages has around 17 grams of protein|
|A roasted chicken leg has around 26 grams of protein.|
And that's pretty much it for natural muscle growth, I'll add more information later about the effects of steroids on athletes.
Love your body.