Dynamic Stretching
This form of stretching prepares the body for physical exertion and sports performance. In the past it was the practice to undertake static stretching before exercise. Dynamic stretching increases range of movement, blood and oxygen flow to soft tissues prior to exertion. Increasingly coaches and sports trainers are aware of the role in dynamic stretching in improving performance and reducing the risk of injury.
Dynamic stretching works by the practitioner gently propelling their muscles towards their maximum range of motion. It is very important to note that the practitioner should not use jerky, forced movements to increase the range of motion beyond what is comfortable as it can easily cause injury.[3] In general, the practitioner wants to move (stretch) the muscle in a similar way that they are going to move them in a workout. For example a martial arts practitioner who wants to stretch a hamstring for a kick may swing a straight leg forward to gradually increase the height they can obtain. Doing light kicks, with little explosive acceleration, while gradually increasing height, could also be considered a dynamic stretch.
Static Stretching
Static stretching is used to stretch muscles while the body is at rest. It is composed of various techniques that gradually lengthen a muscle to an elongated position (to the point of discomfort) and hold that position for 30 seconds to two minutes. 30 seconds is the minimum duration to get the benefits of stretching, whereas two minutes is the maximum (if a position can be held for more than two minutes, a farther stretch should be performed). During this holding period or directly afterwards, participants may feel a mild discomfort or warm sensation in the muscles. Static stretching exercises involve specialized tension receptors in our muscles. When done properly[citation needed], static stretching slightly lessens the sensitivity of tension receptors, which allows the muscle to relax and to be stretched to greater length.
Also a massive bodybuilder can be very flexible as Marko Savolainen.
Read more about dynamic versus static stretching:
My own stretching
I use dynamic version in my weight training warm-up after a couple of minutes elliptical trainer exercise.
My static version consists of five second stretches after my whole weight workout and over 30 second stretches about 30-60 minutes before bedtime.