The traditional plank exercise is great for strengthening the core and you can add intensity and variety by inserting a knee bend into the exercise. You'll challenge the core even more in this 3-point stance (just two hands and one foot) and engage the lower body muscles of the working leg as well.
- Begin in a plank position, on the hands and toes.
- Make sure the body is in a straight line from the head to the heels, core braced.
- Lift the left foot off the floor and bend the knee, pulling it in towards the chest. Your torso might bend a little as you bring the knee in.
- Cross the left foot over the right leg, hold briefly, then take left knee back to the chest.
- Bring the left foot back into your full plank and repeat on the other side.
- Repeat, alternating sides, for 1-3 sets of 8 reps (1 rep includes a knee bend with both the right and left legs).