Lie on your back with your arms out by your sides and extend both legs up over your hips as straight as you can.
Drop your left leg straight down towards the ground as far as you can control without touching the ground.
Quickly raise your left leg back up while simultaneously lowering your right leg towards the ground. Alternate back and forth, continuing the motion for a set number of repetitions or a set time period. Up and down on each leg is one repetition.
This is a core exercise that engages the lower abdominals and obliques but primarily focuses on your hip flexor strength. It’s a good move for strengthening your hip flexors and toning and defining your thighs, abs and obliques. These use muscles throughout the entire body for stabilization; coupled with a quick leg motion, it makes a great training option for a boot camp style workout routine. It is also a good tool to use for sports conditioning, especially for soccer, track and field, and cycling.