In your quest for a rock solid core, the exercises you choose to do are important to consider. Crunches alone will not get you very far in your quest. A variety of exercises are necessary to hit all the major core musculature.
How you accomplish these exercises is important as well. A specific intensity must be met to stimulate the muscles in such a way that they will grow, especially if visible stomach muscles are one of your goals. Notice how distance runners do not have large leg muscles, despite working out their legs for hours each week. For the same reason, doing hundreds of crunches will not cause significant muscle growth. Exercises must be of a certain intensity that fatigue is reached in about 8-15 repetitions, or 20-45 seconds of work for maximal muscle growth to occur.
AND BY FAR, the most important factor to consider if “Six-pack abs” are a goal of yours is body fat percentage. If you’re not down to at least 13% body fat for men and 20% body fat for women, all the crunches in the world won’t be enough.
You should begin a core program with about 5 minutes of exercise activity. As you progress, you can increase the number of exercises and time spent exercising the core area for additional gains. The first time you complete each exercise below, try to do 1 set of 8-15 repetitions. As you progress, increase the number of sets and progress to more difficult exercises. If you are easily able to do more than 15 repetitions in any one set, the exercise is no longer challenging enough and must be modified. Now for the exercises:
Lay on your back with knees bent and hands at the sides of your head. While keeping your lower back pressed into the floor, lift bent legs and begin a slow and controlled pedaling motion (as if you were pedaling a bicycle). As your right knee comes toward your head, perform a crunch motion, bringing your left elbow to right knee (see picture). Repeat this with the right elbow and left knee. Making a larger pedaling motion or adding ankle weights are two ways to increase the intensity of this exercise
Hanging Knee Raises
Hanging from a pull-up bar, lift your knees to your chest in a controlled motion. This exercise can target the obliques (side muscles) by rotating your lower body to that side during the motion. Adding ankle weights or raising your legs without bending at the knees are two ways to increase the intensity of this exercise
Crunch on Exercise Ball
Begin by sitting on an exercise ball with your feet shoulder width apart and flat on the floor. Now lay back on the ball until your thighs and trunk are parallel to the floor. With your hands across your chest, perform a crunch motion, keeping tension in your stomach muscles throughout the whole range of the exercise. To challenge your obliques, bring your feet together or crunch to the right and left. To increase the intensity of this exercise, put your feet together or hold weight across your chest.
Begin by lying on your stomach with forearms and toes on the ground. Tighten your stomach and raise your whole body while keeping it straight (don’t let your back arch!). Keep elbows directly under your shoulders and spread your weight through your forearms and toes evenly. Hold this exercise for 6 seconds per repetition. Weights on your back will increase the difficulty of this exercise but proceed with caution – if your form is suspect, additional weight is not suggested for safety reasons. To further stimulate the obliques, lie on one side and raise your body while keeping only one forearm on the ground. It’s tougher than you think!
Don’t forget the low back muscles! Lying on your stomach with arms and legs spread, lift all 4 limbs together in a controlled manner. Ankle weights around legs and small dumbbells in hands will significantly increase the intensity of this exercise.
While the possibilities for core exercises are nearly endless, the above exercises are the ones that consistently rate the highest in studies that utilize EMG testing (testing for electrical activity in core muscles). Because of this, these exercises are thought to give you the “best bang for the buck”. And as we know, for the time-crunched student, nothing is more important than that! Good luck.