Squats.php

If you're into obstacle running, squats are your friends. Developing strong, explosive legs will help you run faster and negotiate obstacles more easily.

Squatting technique
Start in standing position, your feet shoulder width apart and your arms by your side. Now bend your knees until your upper and lower legs they make a 90° angle. It's OK if your knees and upper body move forward a little. You can even extend your arms for balance if you need to - as long as you keep your back straight and your heels stay firmly pressed into the ground.

Once you've reached the lowest point, extend your legs explosively, bringing your body to starting position. This completes a single squat. Repeat.

NOTE: Make sure not to over-extend your knees on the way up, as this may lead to knee damage.

Advanced squatting variations
If the basic squat (as explained above) isn't challenging enough for you, you can place your hands behind your head while performing your squats. This won't increase the intensity of the exercise by a large margin, but it will require a little more balance.

To actually make the squat tougher, you can grab a barbell (with or without additional weights) and rest it on your shoulders or hold it in your hands while extending your arms above your head - while performing your squats.

One legged squats
And if the aforementioned variations don't rock your boat either, you can go all in by doing one legged squats. Either hold onto a chair, table, wall or whatever or perform them without any support, the idea is this: stand on one leg, drop down into your squat (extending your non-supporting leg in front of you) and get back up. Bonus points if you go all the way down (i.e. your butt touching your heel) before getting back up.

Other leg exercises
Calf Raises
Box Jumps
Jumping Lunges
Lunges
Squat Jumps
Star Jumps
Step Ups