If You Want to Slim Your Waist And Sculpt A Strong Defined Core These Are the 6 Best Side Plank Variations -... 
he plank is one of the best exercises for a flat, toned stomach because it works all the muscles in your core, including the rectus abdominus (the "six-pack muscles" you can see), transverse abdominus, internal and external obliques, hips, and back.Why not just focus on the six-pack muscles? Strengthening your entire core is not only crucial for sculpting a flat stomach, but these muscles also provide support for the entire body in everyday movements, reduce back pain, and improve posture.
