How long should you stretch before working out ?!

Stretching is not warming up! It is, however, a very important part of warming up. Warming up is quite literally the process of "warming up" (i.e., raising your core body temperature). A proper warm-up should raise your body temperature by one or two degrees Celsius (1.4 to 2.8 degrees Fahrenheit) and is divided into three phases:


general warm-up
stretching
sport-specific activity
It is very important that you perform the general warm-up before you stretch. It is not a good idea to attempt to stretch before your muscles are warm (something which the general warm-up accomplishes).

Warming up can do more than just loosen stiff muscles; when done properly, it can actually improve performance. On the other hand, an improper warm-up, or no warm-up at all, can greatly increase your risk of injury from engaging in athletic activities.

It is important to note that active stretches and isometric stretches should not be part of your warm-up because they are often counterproductive. The goals of the warm-up are (according to Kurz): "an increased awareness, improved coordination, improved elasticity and contractibility of muscles, and a greater efficiency of the respiratory and cardiovascular systems." Active stretches and isometric stretches do not help achieve these goals because they are likely to cause the stretched muscles to be too tired to properly perform the athletic activity for which you are preparing your body.


General Warm-Up
Warm-Up Stretching
Sport-Specific Activity

General Warm-Up
Warm-Up Stretching: (next subsection)
Warming Up: (beginning of section)
The general warm-up is divided into two parts:

joint rotations
aerobic activity
These two activities should be performed in the order specified above.


Joint Rotations
Aerobic Activity

Joint Rotations
Aerobic Activity: (next subsubsection)
General Warm-Up: (beginning of subsection)
The general warm-up should begin with joint-rotations, starting either from your toes and working your way up, or from your fingers and working your way down. This facilitates joint motion by lubricating the entire joint with synovial fluid. Such lubrication permits your joints to function more easily when called upon to participate in your athletic activity. You should perform slow circular movements, both clockwise and counter-clockwise, until the joint seems to move smoothly. You should rotate the following (in the order given, or in the reverse order):


fingers and knuckles
wrists
elbows
shoulders
neck
trunk/waist
hips
legs
knees
ankles
toes

Aerobic Activity
Joint Rotations: (previous subsubsection)
General Warm-Up: (beginning of subsection)
After you have performed the joint rotations, you should engage in at least five minutes of aerobic activity such as jogging, jumping rope, or any other activity that will cause a similar increase in your cardiovascular output (i.e., get your blood pumping). The purpose of this is to raise your core body temperature and get your blood flowing. Increased blood flow in the muscles improves muscle performance and flexibility and reduces the likelihood of injury.


Warm-Up Stretching
Sport-Specific Activity: (next subsection)
General Warm-Up: (previous subsection)
Warming Up: (beginning of section)
The stretching phase of your warmup should consist of two parts:


static stretching
dynamic stretching
It is important that static stretches be performed before any dynamic stretches in your warm-up. Dynamic stretching can often result in overstretching, which damages the muscles (see section Overstretching). Performing static stretches first will help reduce this risk of injury.

do a warm up set before you stretch, stretching cold isn't the best for you before you lift. after you warm up then stretch your muscles for a couple minutes, after you do a lift stretch again, this will help your arms from hurting.

Generally, it is reccomended that you stretch 15-20 minutes before you begin to work out. Then, you must also stretch after. Try to stretch your arms and legs and maybe do some situps, pushups, etc.

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You should never stretch a COLD muscle. It can cause damage. You should never feel PAIN when stretching either!