The 30-Day Squat Challenge app for iPhone and iPad

Perform the prescribed amount of air squats each day.
Try to do them all in one set, but if you do need to take a breather, try not to pause again for at least ten more reps.
It’ll be tough, it’ll burn, but you’ll have buns of almost literal steel by the end of it.

How To Squat

1. Start by standing with your feet hip-width apart, toes pointing forward, chin up and core braced.

2. Hold your arms out in front of you or by your sides – just don’t put your hands on your legs, whatever you do.

3. Lower yourself until your thighs are parallel to the ground - the best way to describe it is like sitting down on an invisible chair. Go lower if you can – as long as it doesn’t hurt (and you can keep your balance) you’re OK. If you’re not sure if you’re going low enough, try squatting onto a box that’s slightly lower than knee height. Each time your glutes make contact with it, that’s a legitimate rep.

4. Stand back up and repeat.