Warm Ups & Stretching...
Some years back, I was sitting with a friend at his gym (he owns it) when a Jat entered. His warmup routines were really amusing. He first tried to touch his toes 2-3 times in very jerky movements. Then he did something weird resembling jogging for 4-5 seconds. And finally, he did 6-7 squats. Great!! I've seen too many people with routines of this sort. Actually people realize that doing warmup is important but not many people know exactly why are they required and consequently ignore them or at most do something like the example above.
Now these exercies may be divided into warmup and stretching exercies. Warmup basically refers to some aerobic sort of workout which that work as a signal for your body that something big is coming. Stretching means....well ofcourse you know what stretching is.
If you start lifting heavy weights directly with cold muscles, you risk tearing them up. So before doing anything serious you need to "warm" them up. Once you aerobics for 15-25 minnutes, your heart starts pumping more blood into the body, your lungs start inhaling more oxygen and the overall temperature of the body rises. This helps reduce risks of injuries considerably as your muscles become ready and "expectant" for it. Also you achieve fuller benefits from your workout.
To do warmups, you can do anything that "warms" you up. You can do jogging, jumping, some quick sets or anything else that is easy on your muscles (I mean doesn't start breaking them before you actually start lifting weights) and good enough to increase your breathing rate. Just don't skip them.
Now lets take stretching. When you workout hard, you actually break and tear (injure)your muscles a bit. When your muscles repair themselves they endup a little smaller. So, instead of huge/heavy and bulging muscles, you end up with tighter and smaller muscles (relatively). Here stretching comes into the picture. Stretching lengthens and loosens the muscles, fills them with blood and allows for greater girth. So, when your muscles heal, they are heavier and look better. Also, it makes your tendons more pliable, and as a result there are less chances of torn muscles when you go for reasonably heavy weights (especially in failure sets).
Stretching is a little clumsy. Most people just do those 5-6 jerky movements and go for the weights. But this is wrong. First of all you need to stretch the very part that you are going to work. Secondly you must "stretch" the muscle. To do this, whatever you are stretching, go to your most stretched position and remain there for about 10 seconds. After 10 seconds, try to stretch a little more and be still untill your muscles give up. The funda is to make the muscles realize that they must loosen up there rigidity. When you do it in jerks or for smaller amount of time, they try to maintain their rigid state by pulling back. You must get them to undestand that there is no point in pulling back now and they must become loose.
Another very important thing I want to point out here is that when you need to stretch or do warmups. Most of the people tend to think that like warm ups and stretching are needed to be done only before the actual workouts. Although its ok but think of this this way : Suppose you stretch each every part of your body form head to toe (if you somehow plan to do a full body workout->hypothetical example). Now if you manage to work your upper body in one hour, are your legs still warm and stretched? Obviously no. So, you better stretch each body part thouroughly before and in-between working that part. So, you need to stretch once after doing one or two sets. Stretch as much as you can. You are not wasting your time on that. Try to do some stretching daily. There is no harm in that and ofcourse you are not supposed to overdo it (like those chinese acrobats who touch their heads and ankles byleaning back, still standing).
