The How's and Why's of Sit-ups
By Terry Robinson, PT, ATC


There is an awful lot of hype about strengthening the abdominal muscles. Infomercials and fitness stores are stocked full of oddly shaped gadgets that tout the fact that they can give you, in three minutes, that six pack of muscles in the midsection that are sought after by many. However, the sit-up is probably one of the least understood exercises that doesn't really take much time or equipment to do effectively.

So why do you do sit-ups? Is it because your coach tells you to or because other teammates do them? Hopefully, by learning a little more about the abdominal muscles, their purpose and why they can help you perform better, your sit up routine will be less painful.

The Rectus Abdominus, as the "Abs" are termed medically, is a vitally important muscle group located at the front of the torso area. These muscles are important in stabilizing the front of the body, but more importantly, in giving support to the back and spine during any upright activity, especially in the athlete.

Diving is no exception. The abdominal muscles are important in diving during the twisting, piking and arching of the spine. If insufficient strength or control exists in the muscles, then excessive strain is put on the spine during the dive, primarily during entry. Lack of strength also slows the execution of the dive, throwing off balance and timing.

The abdominal muscles attach to the rib cage and lower breast bone area and extend down to the pubic bone area well below the belly button. They are composed of several thick broad layers that extend vertically and diagonally on the side of the torso. Its main function is to flex the spine as in laying down and raising the head and chest off the floor or in bringing the knees or legs up toward the chest as in the pike or tuck positions. They also assist in the rotation of the spine in twisting motions. Another lessor known function is the stabilization of the pelvis during walking, running and jumping activities.

The abdominal muscles are very powerful. Weakness or early fatigue in these muscles results in excessive overload of the lower back muscles and instability of the pelvis and hips. Weakness here can result in low back pain and an increased occurrence of knee, hip and even shoulder instability.

The abdominal muscles can be classified into upper abs and lower abs. The separation point can be thought of as the belly button area.

The lower abdominal area plays a more important role in the spine and hip area. Strengthening both areas will help, but emphasis on the lower abdominal area will pay off with greater strength and control. How you strengthen these muscles determines how they will perform during athletic competition.

Almost everyone knows how to do the regular sit up. While lying down on the floor, knees are bent and arms are either behind the neck or across the chest. Tighten up the stomach muscles and raise the head, shoulders and shoulder blades off the ground. This particular exercise works primarily the upper ab area. Doing sit-ups this way, though, puts a lot of stress on the neck and upper spine area. Also, if you have weakness in the abs, there is a lot of stress put on the lower spine area as well.

Another common way of doing sit-ups is lying down on your back, legs straight and feet together. Raise your legs straight up off the floor and over your waist area. You can also do this exercise while raising the chest up also. "V" ups or pike ups are a common variation of this type. Lying down, come up in the pike position, bringing your legs up towards your chest and arms. This exercise works both the upper and lower abdominal areas.

To isolate the lower abdominal area lay down on your back, bend your knees and put a small ball, rolled up towel or folded pillow between your knees. Squeeze you knees together tight and raise your knees and the ball up toward your chest. Squeezing something between your knees or feet kicks in the inside thigh muscles, the groin and the muscles that make up the pelvic floor. Doing it this way works several muscle groups and isolates the lower abdominal area, and as stated before, this area gives the greatest stability during activity.

Another good way to get an abdominal workout is to lay down on your back. Have a partner stand over your head area. Bring your legs up straight toward your partner and as he quickly throws your legs down. You have to try to stop your legs from hitting the ground by using your abs. You can grab onto your partner's ankles for support.
With any sit-up routine, do as many repetitions as you can do while maintaining good form. Sloppy, fast sit-ups are ineffective. Good, slow and quality one's are more beneficial, although harder, and give quicker desired results. Usually three to five sets of 20 repetitions are enough.

With any type of sit-up, it is very important to keep your lower back flat against the surface or mat. If your back arches up, the abdominal muscles shut off, putting the strain on your hip flexors and lower back area. Most importantly, if you experience back, neck or excessive abdominal pain while doing sit-ups, consult your physician, a physical therapist or athletic trainer knowledgeable in the sport of diving or back care.

Even if you already have a nice "six pack", as well-toned abdominal muscles are called, you should incorporate sit-ups into several parts of your routine. They are a great warm up exercise early in the morning, just as running around the pool, doing jumping jacks or jumping on a trampoline can get you loosened up. You can also do some light sit-ups as your cool-down routine after you get out of the pool. You shouldn't over fatigue your abs right before a major workout or competition. Save a hard and long AB workout program when you are not going to dive for several hours.

So next time you are out at the pool and coach yells for everyone to get down and do their sit-ups, you will understand why this is such an important exercise, and not just look forward to getting through with them.

Terry Robinson, PT, ATC has been a physical therapist/athletic trainer with US Diving since 1990. He was on staff at the 1996 Olympic Games in Atlanta and has provided medical coverage at numerous National and International diving events. He is the owner of Grapevine Physical Therapy in Grapevine, TX. Comments or questions can be directed to GPTSM@aol.com.