When you have leg cramps you can help stop the leg cramps fast by stretching the legs and massaging the legs with your hands.
Sitting too long or laying in one position too long can cause your legs to cramp up so make sure you get up and move around often as possible to avoid leg cramps.
Besides massaging and stretching the legs when they cramp up you can also use heat to stop leg cramps fast as well.
You can use a heating pad and apply the heating pad to your legs where they are cramping and then elevate your legs while applying the heating pad.
The heating pad will help relax the leg muscles and reduce and stop the leg cramps.
I always try stretching my legs and massaging them first when I have leg cramps but if that fails I then apply a heating pad which almost always works to relieve the leg cramps.