A strong lower body is essential for things like that final explosive burst in your 2.4km run during IPPT, or even something as simple as climbing the stairs when the elevator is out of order. Also, if you want to avoid ugly chicken legs (which is usually caused by an over emphasis on the upper body), it is important to ensure that you take an all-rounded approach when it comes to strength training.

Here are some lower body exercises that will keep you strong (and proportionate):

Towel Squat

Start: Stand leaning against a wall with your feet slightly wider than shoulder-width apart and about 2 feet in front of you. Put an unfolded towel behind you so that your back presses against it rather than directly on the wall.

Finish: Bend your knees and let your back slide down the wall along with the towel until your upper thighs are parallel to the floor. Pause, then push yourself back up.
 

Swiss-Ball Wall Squat

Get into position as for the towel squat, but put a Swiss ball, not a towel, between you and the wall. The ball will press against your middle or lower back in the up position, and against your upper back in the down position.
 

Split Squat

Start: Stand with one leg 3 to 4 feet in front of the other, with your toes pointed forward. Your front foot should be flat on the floor, but only the ball of your back foot should be planted. To help yourself balance, line up each foot with its corresponding buttock, not with the other foot. Keep your torso erect. Rest your hands behind your head.

Finish: Bend both knees to lower your body straight down until your back knee is a few inches off the floor and your front leg is bent at a 90-degree angle – that is, with the thigh parallel to the floor and the lower leg perpendicular to the floor. Your torso and rear thigh should form a straight line. Return to the starting position. Finish the set, then switch your front and back legs and repeat.
 

Bulgarian Split Squat

Start: Place one foot on the floor 2 to 3 feet in front of you and rest the instep of the other on the surface of a chair, bench, or bed 2 feet behind you. Hold your hands behind your ears.

Finish: Balancing on your front foot, execute a split squat. Finish the set, then switch your leg positions and repeat.