1.)There is no difference between stronger, larger, and firmer muscles. Those three go hand in hand. It is simply untrue that one kind of exercise will build a different kind of muscle than another. The only three variables you can influence with any type of exercise are: muscle mass, muscle shape, and the amount of body fat.
2.)Each pound of muscle (1 pound = 0.45 kilograms) burns 75-100 calories every day simply by being.
3.)A pound of body fat stores 3500 calories.
4.)Your muscles do not grow during exercise. Exercise is only the stimulus. The body strengthens the muscles while you are resting
5.)The amount of rest needed in order for muscles to grow depends on their current size. The larger it is, the more it needs to rest. Gym beginners should rest at least two days between exercise. After a year in the gym you should probably rest three days. And so on. By exercising every day you are hurting your body and retarding muscle growth!
6.)The only way that you can know that you have stimulated the muscles enough is to train to failure. If, after some number of repetitions, the muscle is unable to move for 15 seconds even though you are willing it to, then you know that you have provided maximum stimuli.
7.)Your body doesn't care if you muscle failed after five repetitions of an exercise or after 50. Use the weight that allows you to do 4-8 repetitions for maximum safety and time efficiency. And there is no reason to do more than one set.
8.)You can hurt yourself during exercise if you apply excessive force to your muscles. The force when lifting a weight is F = m*(a + g), where m is the mass of the weight, a is the acceleration, and g is the force of gravity. Mass usually doesn't vary greatly. If you can lift 100 pounds 10 times, the max you can lift once is 133 pounds. A 33 percent increase. However, people who use quick, jerky movements experience the acceleration differences of over 400 percent. So work very slowly. Raise the weight for ten seconds and lower it for ten seconds.
9.)There is a myth that says that "aerobic" exercise is good for you heart. But if you keep breaks during exercise very short (~ 1 minute), your pulse should be at 120-180, exactly what people try to achieve with "aerobic" exercise.
10.) Nerver skip meals because after a wile your body eats it self.