Aug. 30, 2004

Sara L. Neal, M.D., M.S.
Department of Family & Community Medicine
Wake Forest University Health Sciences

The first time I saw a field hockey game I was impressed with the players' speed and agility. Even more amazing, they performed all their activities while hunched over in that position unique to field hockey. They are bent in forward at the hips much of the time while they are dribbling the ball or tackling an opponent.

One Parents' Day I overheard an older woman ask, "Doesn't that make her back hurt? Will that affect her posture?" I had to laugh even though I had wondered some of the same things -- at least about the back pain.

In the general population back pain is common. It is second only to the cold in reasons people visit their doctor. In the athletic population however, back pain is low on the list of complaints and injuries, despite the fact that many sports place great demands on the back.

What do athletes do to keep their backs healthy? Much of it has to do with their conditioning programs, almost all of which have some component of "core strengthening". Core strengthening prepares the muscles of the back, abdomen and pelvis to do their job stabilizing the spine and protecting the spinal cord.

For many years it was assumed that flexibility was the main element in preventing athletic injury. Recently we have begun to realize that while flexibility is important, an equal or greater component is the underlying muscle strength combined with sport specific proprioception, (knowing where the body is in space). This is especially important in back health as the spine is central to all athletic endeavors. The back provides support to the limbs so they can run, leap over a hurdle, swing a bat or throw a pass.

The back is uniquely designed for these activities, made up of bony elements and soft tissue. The bony elements are the vertebral bodies which form a column around the spinal cord. These vertebrae are held together by ligaments and further supported by muscles that wrap around the column of bone. The muscles attach to the bone with tendons. The muscle-tendon unit must be strong, yet flexible, as it has multiple functions.

The muscles allow for movement, protect the abdominal organs and support the spine. The "core muscles" are largely involved in support of the spine and stability of the trunk. The abdominal muscles are part of this supporting group, providing up to 30% of the strength and flexibility of the trunk. Sometimes overlooked, these muscles have recently become famous as the "six pack" that defines a trim abdomen. Realize though, these muscles do not need to look like a body builders' abdomen to do their job. Also, they are only a portion of the "core".

Other core muscles include the adductors and abductors of the hip, the erector spinae and multifidus groups associated with the vertebra and the quadratus lumborum of the back. Unfortunately not many people get excited about how big their multifidus group is or how strong their erector spinae are. Yet these muscles are the key to back health, often preventing or limiting injury. Even when the core is well conditioned though, back pain and injury can occur.

There are several problems that can plague the athletic back. These also occur in the general population. To understand these, and to determine who plays and who stays, it is first necessary to understand a little about the anatomy of the back. As mentioned before, the spine is made of a stack of vertebral bodies held together by ligaments.

In between each vertebral body is a vertebral disc which acts as a shock absorber. In some athletic activities, the disc is put under tremendous stress. Weight lifting can put over 400 pounds of stress on the disc. Blocking done by football lineman has been shown to generate 200 pounds. Even a golf swing can generate 40 pounds of rotational force. So the disc must be very rugged. It is partly protected by the mechanics of the spine, meaning the other elements of the back are in proper position, alignment and functioning appropriately.

Disc problems are more common in some sports than others. Weight lifters, those participating in collision sports, gymnastics and figure skating are at higher risk. This is because of their sport specific activities place large axial loads on the spine or push the muscles to perform at their limits of range of motion (hyperextension).

In the adolescent population, approximately 10 percent of back injuries will involve discogenic pain but acute rupture (herniation) of the disk is uncommon. Symptoms can include local back pain with radiation to the buttock, thigh or leg. Certain activities such as coughing, sneezing or prolonged sitting may make symptoms worse. Ultimate evaluation for a disc problem may involve a MRI scan.

A back sprain occurs when the ligaments holding the vertebra together are stretched or torn. A back strain involves a disruption of the muscles or muscle -tendon units in the soft tissue supporting the vertebra. Either of these injuries can present as an acute onset of localized back pain, sometimes associated with muscle spasm. Imaging studies such as a MRI are rarely needed in the initial work-up or management of these injuries. They usually respond to ice and a brief period of rest followed by stretching and strengthening exercise with a gradual return to activities.

The bony portion of the back can have problems as well. Fracture of the vertebral body is rare, but other problems can arise. A stress fracture means that the bone is still grossly intact but has undergone some damage that can be seen microscopically.

A stress fracture of part of the vertebra (the arch or isthmus) is called spondololysis. It causes acute low back pain with intermittent episodes of increased severity of pain. There is usually no radiation of pain down the leg or into the buttock. Spondololysis occurs in the athlete usually during the teenage years. Certain activities such as the walk over in gymnastics or blocking in football can exacerbate symptoms.

Spondololysis may not be seen on x-rays. Special tests such as a MRI, CT/SPECT or bone scan may need to be used to identify this type of fracture. A bone scan can detect increased bone activity in an area where there is a small fracture as it begins to repair.

Treatment for this type of problem is somewhat controversial. All treatment plans involve an initial period of rest followed by a rehabilitation program that centers on strengthening abdominal and trunk muscles. These are some of the same exercises that are integrated into the preseason core strengthening program.

Some physicians recommend placing the athlete in a back brace 23 hours a day during this treatment period. Since these fractures take several weeks to heal, this can be a major commitment. Scientific evidence that bracing is necessary is lacking but many physicians have the clinical experience of success using bracing to consider it.

A well designed core strengthening program can help prevent many of these injuries or limit their severity. The program should train the abdomen, back and pelvic muscles for endurance strength rather than strength alone. Many athletic injuries occur during the latter part of the contest, when muscles begin to fatigue.

Enduring strength means that the muscles have been challenged often enough and in the appropriate fashion so they can maintain their function throughout a long practice or game situation without becoming too fatigued to do their job. They need to be able to last well in to overtime situations, providing support and trunk stabilization. An athlete who has insufficient core strengthening may show loss of "form" as he or she fatigues. This is when the athlete is at higher risk for injury.