Please choose the correct ending to complete the given sentence: Sports and Fitness: [header] How to tone your abs with flutter kicks [title] Make sure you warm up first. [step] For an ab workout, incorporate dynamic stretching into your warm-up that will target your abdominal muscles and get them ready for more intense work. [substeps] Start your warm-up by walking or jogging in place for a few minutes to elevate your heart rate a little and increase your core temperature.

Ending1: Pant-pants and microfiber socks work well for maintaining dynamic stretching. You can also always warm up your legs during stretching to gauge your glucose levels before you get into the splits. Ending2: Then you might try the " good morning " stretch, which is a good way to start engaging your core. Stand with your feet about shoulder-width apart and your hands at your waist. Ending3: Run your hands over your abdomen and across your ribcage to increase blood flow to your arms and core. You can even turn onto your ab near your waist. Ending4: Your breathing needs to be slow and deep, not shallow or laboured. You don't want to burst your lungs all the way, only slow down.

Answer format: ending1/ending2/ending3/ending4