Rule #1

The targeted muscle should be completely relaxed and then firmly and slowly stretched to a point of moderate pain, (moderate not agonizing). You want to gradually restore its full normal length.

Rule #2

Maintain the stretch for a minimum of 30 seconds and repeat 3 to 4 times with a moderate rest period between stretches. However don't hold the stretch so long that it becomes painful.

Rule #3

Painful muscles cannot be stretched if they are not relaxed, full relaxation requires a comfortable, warm and relaxing environment. This improves the quality of your stretching routine and has a de-stressing affect.

Rule #4

Don't forget to breathe; you want your breathing to be slow and regulated. You need to concentrate on your breathing while stretching, a lot of runners unconsciously hold their breath while stretching.

Rule #5

Stabilize you position before you stretch. Ensure that whatever you are using, (bed, chair ect.) provides adequate support for the opposite side of your body.

Rule #6

Constantly compare paired muscle tone on opposite sides of the body. Target the muscle that is more stiff or provides greater resistance. For example your left and right calf muscle. Your aim is to equalize muscle tone on both sides.

Rule #7

After you are fully and completely stretched, then return to neutral must be smooth and gradual. Take your time, be patient- relax.

Rule #8

General soreness after stretching can be reduced by applying moist heat to the targeted muscle for a few minutes. Try relaxing in a hot bath or shower with the water pressure directed onto the sore muscle.

Reference