If you're trying to lose weight, walk more steps each day, or push yourself through a brutal morning workout, this app can help. it's ideal assistants for health, fitness, and weight-loss because they is always with you, and it's quite personal. Maintaining fitness requires daily habits and lifestyle changes, and a few little nudges in the right direction from your mobile phone might make all the difference. We all want a toned, flat stomach. No surprise there. But since many women are still relying on crunches to get it, we want to make one thing clear: Crunching is not the most effective abs workout. "Crunches work only the muscles on the front and sides of your abdomen, but it's important to target all the muscles of the core to get more defined absincluding lower back, hips, and upper thighs, " says Lou Schuler, co-author of The New Rules of Lifting for Abs. To lose belly fat and uncover amazing abs, Schuler recommends a series of core stabilization exercises based on a training program devised by co-author and personal trainer Alwyn Cosgrove. "Core exercises like the plank help train muscles to stabilize the spine and pelvis so you can avoid back pain and improve posture, Schuler says. "They also burn more calories than crunches because they work more muscles. "Trade crunches for these three super-effective abs exercises from The New Rules of Lifting for Abs and youll be on your way to a perfectly toned, flatter tummy. The Best Abs Exercises: Side PlankWhy it works: This abs exercise is more challenging than a traditional plank because you're supporting your entire body weight on two points of contact instead of four. As a result, you must work your core harder to stay stabilized.