It should give you an idea how they are done... here's what Kelly B wrote about stretching in his article Football Speed
To be able to perform you'll need to have an optimum range of motion which is determined in large part by your level of flexibility.
Dynamic flexibility is the ability to move a joint through a full range of motion using muscular assistance or with movement. Throwing a kick above your head is an example of this. You can also call this type of flexibility "active flexibility."
Static flexibility is the ability to stretch without any momentum or muscular assistance. Sitting in place and doing the splits is an example of this.
It turns out there isn't always a good correlation between static flexibility and dynamic flexibility. That is, you might not be very flexible when doing the splits (static flexibility), yet still might be able to kick well above your head (dynamic flexibility). The reverse can also be true. You might see someone with very good static flexibility, yet not very good dynamic flexibility.
What's more, performing static flexibility prior to a workout has been shown to lead to a decrease in strength in that workout. Too much static flexibility work can also have a negative influence on reactive strength. An overly flexible muscle-tendon complex can dampen the reactive reflex, or spring-like effect. The muscle-tendon complex needs an optimal stiffness in order to function optimally. Since the type of flexibility you need in football is dynamic anyway, I recommend you focus the majority of your time in achieving optimal dynamic flexibility. Some static flexibility work can be beneficial, but it should only be done after your workout and never before. The following dynamic flexibility workout will greatly assist you in achieving and increasing the range of motion necessary to have awesome football speed. Perform it at least 3 times per week along with a good general warm-up.
Overspeed quick toe touches x 20 reps
Dynamic bodyweight lunges forward x 10 reps per leg
Dynamic bodyweight lunges side to side x 10 reps per leg
Wide stance bodyweight speed squat x 20 reps
Walking forward heel to toe bend over and touch the ground with each step x 20 reps
Crescent kicks outside to inside x 10 reps per leg
Crescent kicks inside to outside x 10 reps per leg (with your leg straight and knee completely locked kick and make a big circle with your leg - you should feel a stretch in your hamstrings)
Back leg roundhouse kicks- x 10 per leg
Duck under hurdles (real or imaginary hurdles)- x 10 each direction (imagine a row of 10 hurdles. Moving horizontally duck low under each hurdle and rise up between them)
Duck under hurdles with twist- same as above but twist 180 degrees in between each hurdle
5-10-5 drill forward/back- run forward 5 yards/backward 5 yards/forward 10 yards/backward 10 yards/forward 5 yards/backward 5 yards
Pro agility- stand in the middle of 2 cones or marks set 10 yards apart - Run in one direction 5 yards to one cone and then reverse direction and run 10 yards back to the opposite cone and then reverse direction and run back to the middle where you started..."