4. Butt: Butt raise with leg extension
2 x 10 reps on each side, 15 to 30 seconds rest between sets

Lie on your back with your hands by your sides. Bend knees to a 45-degree angle, with feet hip-width apart. Tuck bottom under into a C shape, and press into your heels to lift your bottom off the ground to make a straight line from shoulders to knees. Be careful not to arch back.

Hold for one second, and while keeping hips still, stretch one leg out straight with your knees together. Place your foot back down and slowly curl the back down to the ground, with the top of the back touching first, easing down to the bottom last. Ensure the knees stay hip-width apart throughout.

Repeat on the other leg and continue.

Why it works: This exercise is great for working the butt as well as developing core stability. If you're feeling unstable, build up to adding in the leg extensions.