Here's an intense move that works one side at a time. You can also do it without a dumbbell.
- Start on all fours, with your hands directly under your shoulders and your knees directly under your hips.
- Bend your right knee at a 90-degree angle and place a dumbbell in the crook of your knee.
- Slowly pulse your flexed foot toward the ceiling by squeezing your glutes. Your back should remain perfectly still in a neutral spine. The motion should be small and controlled with the muscle doing the work and not momentum.
- Return to the starting position to complete one rep. Do three sets of 15 pulses on each side.