Benefits: Deadbug exercises teach your core to work as it was designed to do — keeping your spine stable while your arms and legs do their own thing. This variation cranks it up a notch by requiring an extra ab squeeze to keep the stability ball in place, while also targeting your obliques.

• Lie with your back flat on the floor with your arms extended straight up, your legs bent at 90 degrees, and holding a stability ball between your knees and your hands. This is the starting position.
• Keeping the ball in place with your right hand and left knee, brace your core and slowly lower your right leg and left arm to within six inches of the floor (both should remain in line with your body). Only go as low as you can with your low back pressing in to the floor.
• Reverse the move to return to the starting position, and repeat on your other side.
• Continue alternating sides, performing equal reps on each side.