If you thought you weren't going to do any core work in this workout, you were wrong. But the plank is so much more than an abs move. In fact, Kendall explained that "it's the one move everyone should do for core strength and stability and a great barometer for overall fitness."
- Start with your arms shoulder-width apart and your hands on the floor directly below your shoulders. Balance yourself on your toes with your feet almost touching.
- Lift your midsection so that your back is flat and your hips are stable. Engage your lower back muscles and brace your core. It should feel like you're pulling your navel toward your spine.
- Keep your neck and spine completely straight and do not let your hips sag or raise from this position. Hold it for as long as you can.