Abdominal work may not be most women’s favorite activity in the gym. Still, of all the abdominal exercises that you can string together, the crunches that can be enjoyed most are on the bench. There’s just something satisfying about experiencing the short, intense contractions and then letting them develop into tingling abs while knowing that they tone toned abs better than almost anything else.
This exercise is so effective because it shortens the fibers of the abdomen and does so with constant tension throughout the exercise. Some abdominal exercises can excessively stretch and lengthen the abdominal fibers, and this can result in a protruding stomach when relaxed. The other thing I like about bench crunches is that the hips stay flexed during the contraction. This takes the psoas major, which is a powerful hip flexor, out of the equation. As a result, the front abs must bear the entire load of each rep.
The rectus abdominis muscle appears to be a long muscle, but it is actually a series of short fibers stacked vertically on top of each other. The linea alba is a thin, tendon-like line that forms a groove in the center of the abdominal wall so that the rectus abdominis has a left and a right half. Typically there are three additional rows of horizontally arranged tendons that run across the rectus abdominis. These form the abdominal “blocks” that give the abdominal wall the “six-pack” look. The fibers of the rectus abdominis run from one horizontal tendon insertion to the next.
When the rectus abdominis is tense, the short fibers between the tendon grooves arch, almost like small ropes or blocks. When both the right and left halves of this muscle contract, the trunk is simply bent forward so that the head and chest move closer to the hips and legs (assuming a firm pelvis). While there is muscle activity in all blocks during most abdominal exercises, the top two rows tend to contract and shorten most when doing sedentary abdominal crunches.
Both the external and internal oblique muscles on each side of the abdomen are strongly activated by crunching your heels on a bench. The external oblique muscle runs from the lower ribs through small bundles of muscle fibers from lateral to medial. The outer slope connects to other muscle fiber slides to anchor to the pelvic bones of the pelvis and hip structure, as well as the linea alba. When both the left and right sides of the external oblique muscles work together, they flex the trunk and move the head toward the feet.
The inner oblique muscle sits straight deep to the outer oblique muscle. Although it is not visible, its shape and function make important contributions to the overall abdominal network. It adheres to the thoracolumbar fascia, a thick sheath of connective tissue in the lower back. Its fibers run around the side of the trunk at right angles to the outer oblique muscle and attach to the lowest three or four ribs. Similar to the outer oblique muscle, the inner oblique flexes the trunk at the waist and moves the head toward the feet when both the left and right parts contract.
1. Lie on the floor with your back perpendicular to a bench. Put your feet on the bench and bend your knees 90 degrees. Loosely cross your arms in front of your chest.
2. Raise your hips just slightly off the floor to pull the lower part of your abdomen together.
3. Exhale as you lift (pucker) your torso (shoulders and center back) off the floor. Slowly and deliberately move your shoulders forward (i.e. not quickly or jerkily) and tuck your chin against your chest as you come up. This will help you practice a crunch type of crunch. You don’t want to come up like a flat board as it won’t shorten the fibers in your stomach sufficiently. Hold the top position until two.
4th Slowly return to the starting position by relaxing your shoulders and torso and inhaling as you fall. Let your hips drop to the floor. However, once you get to the starting position, don’t take a break or rest, but immediately raise your hips, arch your torso forward, and continue the crunch part by trying to get your torso off the floor to lift.
5. Repeat this slowly and deliberately for 20 reps. If you can do 20 reps without breaking a sweat, do some resistance by holding a light dumbbell over your chest.
You shouldn’t hold your breath during the crunch as this increases intra-abdominal pressure and prevents the abdominal fibers from shortening as much (although it may feel easier to sit or grind while holding your breath). If anything, it’s good to either exhale as you crunch forward, or better still, exhale before doing the contraction and then focus on getting maximum fiber shortening during exercise.
Don’t make a mistake; Toned and sexy abs require both diet and exercise. A sloppy, high fat, high calorie diet results in a belly that looks like it belonged to a sumo wrestler, but it does very little for your fitness goals. You may also need to add 20 minutes or more of cardio exercise four times a week if you want to speed up the loss of “cushion” in your midsection that may be hiding your abdominal wall. Of course, nothing valuable or permanent comes easy.
While toned abs don’t develop overnight, nothing should stop you from having tight, smoking-hot abs if you carefully set high standards and realistic goals. Even if you don’t look forward to the feel of a blowtorch in your abs during every set of bench crunches, you will definitely like the sleek and curvaceous midsection that is staring at you in the mirror after just seconds of months.
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