I think you go down so your chest is roughly a fist away from the ground. How I have always done it.
I play rugby 2-3 times a week and when injured (quite often
) hit the gym before work.
Including an hour walk to college and back everyday
Also with the stretches Dynamic stretches are the best kind for any games player or athlete as said before it does not reduce your mucsle power before an event. However do not bounce into the stretches cos then you will die with pain when your hamstring tears
Static stretches are geared towards gymnasts and the like to improve flexibility. Also good for rehab.
I study this ****