Single Leg Over
Lie down on the ground on your back. Place your arms out like a T, then take your left leg and put it on the right side of your body, making a 90 degree angle with it. Keeping your left hand on the ground (to help keep your back on the ground), take your right hand and grab your left leg, pulling it to the side. Hold it for 20-30 seconds. Once complete, switch legs.
Sit down on the ground, and put your feet together. Grab your ankles and pull towards you. Hold for 20-30 seconds. A lot of people grab their toes when doing this exercise, but that just raises their toes up, if you grab your ankles instead, you'll be sure you're getting the proper stretch because you're bringing your legs in and not just your toes raised.
Stand with your hands on your hips and take a big step forward. Stand as far forward as you can while keeping your back heel on the ground, and your front leg straight up and down. If you don't feel a stretch in your calf, take a bigger step forward until you do. Hold for about 20-30 seconds, and then switch legs.
Extend and Flex
Front leaning rest position...move! I heard a lot of this during my time at Basic. Front leaning rest position means get into the position of a push up. Once you're in the position, place your knees and hips on the ground while keeping your elbows locked. Look up to the sky and arch your back. Hold this for about 20-30 seconds. Then get back to the push up position, and stick your butt in the air. You should walk your hands back a little bit, keeping your legs and elbows locked. You should be making an upside down V right now. Hold this for 20-30 seconds.
Hamstring Stretch Standing
This will be the final exercise I mention. Stand with your feet together and then bend down to touch your toes. Just go as far as you can to where you feel the stretch. Hold for about 20-30 seconds. Once completed, do NOT just stand up. While still bending down, bend your knees and then slowly come up. This prevents damage to your hamstring.
Well there you have it, 10 simple and easy things to do to cool down and help your body recover. I covered sprinting, calves, arms, chest, abs, and even back. So just make sure your cool down consists of stretching all of your muscles and joints, and has a safe workout!