When trying to develop the coveted v-shape body, it is important that you do not neglect your obliques – the muscles on the sides of your abdomen. You can’t make your shoulders any broader (not to any significant degree) because you are stuck with the skeleton you have; so the only way you can really get a v-shaped body is by making your core as tight as possible. If you are only doing crunches, situps, and other similar ab exercise, you are only developing your rectus abdominus and you won’t achieve the necessary tapered look your torso needs to get that v-shape. You can’t make your shoulders any broader (not to any significant degree) because you are stuck with the skeleton you have. So the only way you can really get a v-shaped body is by making your core as tight as possible.
Captain’s Chair
A study published by the American Council on Exercise (ACE) found that the Captain’s Chair (seated leg lifts) is the most effective abdominal exercise for stimulating the obliques. You’ll have to go to a well-equipped gym to find a Captain’s Chair, but if you have a pull-up, you can do hanging leg lifts to achieve the same effect.
Bicycle Maneuver (Bicycle Crunches)
In the same study published by ACE, the bicycle maneuver, or “bicycle crunches,” was rated as the second most effective in their study for activating the obliques. The exercise is called the bicycle maneuver because when you do it, you look like your pedaling an imaginary bike… on your back.
To do this exercise, get down on the floor in a normal stomach crunch position. Raise your feet off the ground so your knees are bent at a 90-degree angle to the floor. As you lift your shoulders up to do a crunch, extend one leg out and bring the other in towards you, in a pedaling fashion. Each time you do a crunch, alternate legs and touch the opposing elbow to your knee.
Dumbbell Side Bend
This is a good exercise for increasing the strength of your obliques because you can control the weight and gradually increase it as you get stronger, whereas, with the other exercises, you can only increase your number of reps. Stand feet hip-width apart with a dumbbell in one hand. I find this exercise is the most effective with a fairly heavy dumbbell. Lower the dumbbell down towards your knee then raise it back up and tilt your torso to the other side. Once you’ve completed a certain number of reps on one side, switch hands and repeat on the other side.
Sources:
http://www.acefitness.org/getfit/studies/bestworstabexercises.pdf
http://www.exrx.net/WeightExercises/Obliques/DBSideBend.html