Back pain affects 60-80% of American adults at some time during their lives, and it is estimated that up to 50% have back pain within any given year. Back pain symptoms are among the 10 leading reasons for visits to emergency rooms and physicians' offices. Back pain is the most common disability for persons under age 45. Costs for low back pain and disability exceed an estimated $55 billion annually.

Although symptoms are usually acute and self-limited, low back pain often recurs, and in 5-10% of patients, low back pain becomes chronic. The condition is diagnosed as acute if lasting less than a month and not caused by serious medical conditions. Most cases clear up in a few days, although recurrence after a first attack is common. Low back pain is considered chronic when it persists beyond 3 months (Mannion AF, et al. 2001). This constitutes less than 5% of all low back pain cases.

Adolescents can experience back pain, too, but usually for different reasons than adults (see below).

ANATOMY OF THE SPINE

The spine is a column of small bones called vertebrae that support the entire upper body. The column is grouped into sections, listed here from top to bottom:

• 7 cervical vertebrae that support the neck
• 12 thoracic vertebrae that connect to the rib cage
• 5 lumbar vertebrae that make up the lower back
• the sacrum, a shield-shaped bony structure that connects with the pelvis
• the coccyx, or "tail bone", consisting of four, tiny partially-fused vertebrae

These vertebrae are each separated by small cartilaginous cushions known as intervertebral discs. Each vertebra surround and protect an arch-shaped central opening, which encloses the spinal cord. Nerves pass from the spinal column to other parts of the body through small openings between each vertebra. Because the lumbar area of the spine supports most of the body's weight and stress, it is a common location for back pain.

CAUSES OF BACK PAIN

Many back injuries are related to lifting and various repetitive motion activities, however, in more than 80% of back pain cases, the cause is often unknown.

Some of the known causes of back pain include:

• Posture-related causes (poor posture while sitting or standing, discrepancies in leg length leading to an uneven pelvis, etc.)
• Disorders of the spine itself (herniated disc, spinal stenosis, bone spurs on the vertebrae)
• Obesity (a large stomach, combined with weak abdominal muscles, pulls the spinal column forward and out of alignment)
• Systemic diseases (osteoarthritis, osteoporosis, cancer, infection)

LACK OF EXERCISE AS A CAUSE OF BACK PAIN

It turns out that lack of regular exercise is one of the most common causes of back pain. Lower back pain is very common in western, industrialized countries (Volinn E. 1997). And, rates of exercise are also very low in these countries. Is this purely coincidence? Unlikely. In one study, only 47% of persons suffering from low-back pain exercised regularly, whereas 86% of people without back pain exercised regularly (Cox JM, et al. 1987). A study from Denmark revealed that middle-age people who exercise for at least 3 hrs per week have a reduced risk of low-back pain (Harreby M, et al. 1997).

TOO MUCH EXERCISE CAN CAUSE BACK PAIN, TOO

Unfortunately, some activities, or, too much exercise can lead to back pain. Athletes can develop back pain, too. As sporting events become more aggressive and the activities become more specialized, particular types of back pain tend to increase. At the 2000 Olympics in Sydney, athletes with back pain were found to have a higher prevalence and a greater degree of lumbar disc degeneration than the normal population (Ong A, et al. 2003). In adolescents, the number one cause of back pain is a condition called spondylolysis. It can occur in young athletes, between the ages of 10 and 15 years old, who are involved in sports that require continuous hyperextension of the lower back.  Even low-impact sports such as swimming can be the cause (Nyska M, et al. 2000).

Conversely, most sports do not appear to increase the risk of herniated discs (Mundt DJ, et al. 1993), something that is fairly common in sedentary people.

EXERCISE AS THERAPY FOR BACK PAIN

As mentioned above, people who exercise regularly have lower rates of back pain (Cox JM, et al. 1987). The American Academy of Family Physicians recommends "back-conditioning exercises" for persons aged 19-64 years who are at increased risk for low back injury because of past history, obesity, or inactivity.

But, is there any proof that exercise helps people who already suffer from back pain?

In a small Swedish study, patients who had had low back pain for 6 weeks or longer were treated with strength-training of the abdominal and lumbar areas, or with manual therapy (stretching, traction). Assessments at 3 months and 12 months showed that the patients who participated in strength-training improved more than the manual therapy group. In addition, the strength-training group required less treatment for recurrent back pain than the manual therapy group (Rassmussen-Barr E, et al. 2003).

EXERCISE PRINCIPLES

So, the key to relieving back pain is to do back-strengthening exercises, right? Yes, but it is not as simple as lifting more and more weight to increase the strength of your back muscles.

Stuart M. McGill, PhD, a professor at the University of Waterloo in Ontario, Canada, is a recognized expert in spine injuries and rehabilitation. He has published extensively on spine management. Surprisingly, McGill claims that stretching and muscular strength are not as critical to low back health as you might expect:

•Flexibility: It is commonly thought that stretching the back and increasing the range of motion is beneficial and reduces back problems. However, according to Dr. McGill, people with a greater range of motion (in their back) have a greater risk of future trouble. Thus, this casts doubt on the benefits of excessive stretching to relieve back problems.

•Muscular Strength: Here again, according to McGill, misconceptions arise. While it seems logical to conclude that back pain is a result of weak back muscles, in fact, improving the strength of the back muscles has little association with low-back health. Further, some people injure their back in the process of trying to increase the strength of their back muscles.

•Muscular Endurance: McGill recommends that resistance-training programs for the back be designed to increase muscular endurance, as opposed to muscular strength. When using weights to achieve this, the weight should be kept low and the number of repetitions should be relatively high. For example, in a Norwegian study, subjects with chronic low back pain performed 7-9 different exercises, either with free weights or weight-machines. For each exercise, 2-3 sets of 20-30 repetitions were performed (Tortenson TA, et al. 1998). This works out to 40-90 reps per exercise, or, nearly 800 reps per exercise session!

RECOMMENDED EXERCISES FOR THE BACK

So, the key principle for back exercise is to increase muscular endurance, not necessarily muscular strength.

But, weights and weight-machines are not the only way to strengthen the back. The following exercises can be done by anyone in their home:

•Cat-Camel: This is an excellent exercise for the back. Start by getting on the floor on your hands and knees. Make sure your knees are at a 90-degree angle and your hips are directly above your knees. Tip your head down while raising your back upwards (keep your hands on the floor). At this point, the line from your head to your hips should resemble a continuous curve. Next, raise your head up so that you are looking forward while letting your belly hang down. At this point, your lower back and your thighs should be forming a 90-degree angle (your hips should still be directly above your knees). Keep in mind that this is a "motion" exercise; ie., it is not a stretch. So, alternate back and forth between these 2 positions in a fluid movement. Do 5-8 cycles of this exercise.

AVOID THIS: Do not hold your body motionless in either position.

•Curl-Ups (or, modified crunches): Lie on your back, with your hands, a pillow, or a rolled-up towel under your lower back. One leg should be straight, flat against the floor. The other leg should be bent with your foot flat on the floor. (Your legs should be together, one straight, one bent.) Now, contract your abdominal muscles to lift your head and shoulders off the ground, but do not do a complete sit-up. Do 10, then reverse the positioning of your legs and do another 10.

AVOID THIS: Do not flatten your back against the floor when doing this exercise. The spine is not perfectly straight. So, flattening the back violates the "spine neutral" position that is best when doing crunches.

•Birddog: This exercise is a yoga-like isometric. Start with your hands and knees on the floor. Extend 1 leg straight out behind you, keeping it level with the ground. Extend your arm on the opposite side straight out in front of you, also keeping it level with the ground. Your head should be positioned so that you are looking down at the floor.

AVOID THIS: Do not hold these positions for longer than 5-6 seconds. Research shows that sustained contraction of the torso muscles causes them to lose oxygen rapidly. Instead, build up your endurance by doing more reps, NOT by holding each position as long as you can.

•Side Bridge: This is an isometric exercise for the lateral muscles of the torso (abdominal obliques, quadratus lumborum). Start by lying on your side. Raise your body off the floor by resting on the elbow of your lower arm. (Keep your hand and forearm also on the floor for added stability.) Keep your body (and spine) straight, so that your hips are also off of the floor. At this point, only your forearm and the sides of your feet should be touching the floor. If this is too difficult, then bend your knees and support your body with your knees instead of your feet.

AVOID THIS: As with the bird-dog, do not hold these positions for longer than 5-6 seconds.

These exercises should be done 5-7 days per week.

•Aerobics: Researchers from Switzerland demonstrated that a combination of aerobics classes with stretching was just as effective as strengthening exercises using weight machines for adults with chronic low back pain. In this study, aerobics sessions were held twice per week for 3 months (total = 24 sessions). Each session lasted 1 hour and consisted of stretching, aerobic exercises, and muscle-toning exercises. The first 15 minutes involved whole-body static stretching and low-impact aerobic exercise, followed by 30 minutes of exercises targeting the trunk and leg muscles. The final 15 minutes of each session consisted of cool-down and relaxation exercises (Mannion AF, et al. 1999) (Mannion AF, et al. 2001).

•Pilates: Pilates is an excellent method to develop "core" strength (eg., the muscles of the torso).

•Swimming: Because it combines low resistance with high repetitions, swimming would seem to be an ideal activity for people with back pain. We are not aware of any research studies evaluating the benefit of swimming on back pain, however, one study showed that "aquatic exercise", which included walking in water and swimming, was beneficial for back pain if performed at least twice per week (Ariyoshi M, et al. 1999).

•Walking: By itself, walking has been shown to be less effective than physiotherapy and weight-training therapies for back pain. In this study, subjects were asked to walk 1 hour per day, 3 times per week, for 12 weeks. Patients were allowed to walk on their own, so how far or how fast they walked was not determined (Tortenson TA, et al. 1998).

•Yoga: In people who do not currently have back pain, yoga can be beneficial. Like Pilates, it is a good way to develop core strength. However, because some of the positions hyperextend, and/or put strain on the lower back, avoid yoga until after you have been pain-free for 6 months.

Whatever you choose, select low-impact activities, and avoid those that demand high-risk moves. Sports that involve a lot of twisting (golf, tennis), quick stops and starts (basketball, racquetball) and contact sports (football, rugby) pose the greatest risks to your back. Also be cautious of activities that force you to hold your posture in an uncomfortable position, for example, riding a racing bike and in-line skating where you are bent over, or water-skiing and wind-surfing which require you to contract your back muscles for sustained periods of time.

EXERCISES TO AVOID

•Leg-Lifts: Leg-lifts put a tremendous amount of strain on your lower back. To lift your legs off the ground while lying on your back, the hip flexors pull against the pelvis, causing the lower back to tilt forward, causing strain. Avoid straight-leg leg-lifts. Instead, while lying on your back, bring your heels up towards your buttocks, and point your knees out (away from each other). You should now be in a "frog-leg" position. Placing your legs in this position removes the hip flexors from the motion and emphasizes the lower abdominal muscles. Put your hands, a pillow, or a towel under your lower back. Now, you can do a modified leg-lift.

•Bent-over Rows without support: NEVER do bent-over rows with a barbell. Instead, use a single dumbbell and exercise each side separately. For example, if you are going to exercise your left side, first place your right hand and right knee on a bench (your left foot is on the ground). Now, your spine is supported like a table with 3 legs.

•Dead Lifts: If you are looking for 1 exercise with the highest likelihood of producing a back injury, then this is it. For example, people with osteoporosis can injure their back by simply bending over to pick up a pencil. Imagine what kind of pressures are being exerted within your lower spine when you bend over at the waist and try to lift a barbell.

SUMMARY

The best treatment of back pain is prevention through regular exercise. But, if you already have back problems, consult your doctor before you begin any routine.

Before beginning back-strengthening exercises, keep the following in mind:

•Begin slowly. Your back muscles may be weak and susceptible to injury if you're out of shape. Pace yourself. As you get stronger, work up to 15 minutes of exercise a day.

•Weight-machines: Use a light weight and do a high number of repetitions. Pick a weight where you can do at least 20 reps. Your goal is to develop your core muscles by increasing muscular endurance.

•Yoga/isometric exercises: Remember not to hold these positions for longer than 5-6 seconds.

•Consider hiring a personal trainer. Research shows that a custom-designed back-strengthening program achieves better results than when a standardized (ie., "one-size-fits-all") approach is used (Descarreaux M, et al. 2002).

When to see a doctor about your back pain:

If you experience any of the following signs, immediately consult with your physician.

•Pain that does not go away after two days of rest

•Numbness, weakness or tingling down the leg to the feet and toes or the inability to move your toes

•Loss of bladder or bowel control

•You feel ill as a result of this episode of back pain

FOR MORE INFORMATION

Texas Back Institute (TBI) (www.TexasBack.com) is the largest freestanding spine specialty clinic in the US. The Institute, based in Plano, TX, was established in 1977 and provides comprehensive medical care for individuals with back and neck pain. TBI specializes in spinal arthroplasty and minimally invasive spine surgery. TBI's professional staff includes board-certified spine surgeons, internists, chiropractors, physiatrists, pain specialists, exercise physiologists and a team of physical and occupational therapists. As an academic health care organization, TBI has trained hundreds of physicians, scientists and allied health professionals. Its research institution employs state-of-the art technology to treat patients and is actively involved in clinical trials of artificial discs.

A highly-regarded book is Dr. McGill's Low Back Disorders: Evidence-Based Prevention and Rehabilitation.

Readers may be interested in these related stories:

• Core Training (coming soon)
• How To Choose A Personal Trainer
• Stretching
• Yoga

MEDICAL TERMINOLOGY

Herniated Disc: "Hernia" is a general medical term to describe an organ, or part of an organ, that has pushed through the wall of the cavity where it normally resides. With regards to the spine, a herniated disc describes a disc that has squeezed out of its normal alignment with the vertebrae. This term should not be confused with "subluxation".

Sciatica: Sciatic pain is caused by compression of the sciatic nerve, which branches out from the spinal cord at the lumbar and sacral areas. Each of the two branches of this nerve is as wide as a thumb and threads through the pelvis and deep into the buttocks, then down the hip and along the back of the thigh to the foot. Sciatica usually occurs on one side when a sciatic nerve has been stretched or pinched, although spinal stenosis or other vertebral abnormalities can also cause this pain.

The sensation of sciatica can vary widely from a mild tingling to severe immobilizing pain. Pain may be experienced in one part of the leg or hip, with numbness in other parts. It typically increases after prolonged standing or sitting and can be aggravated by sudden movements.

Spondylolisthesis: Occurs when the lower lumbar vertebra slips forward on the sacrum.

Spondylolysis: Literally, the breaking-down of a vertebral structure.

Subluxation: A partial, or incomplete, dislocation of a vertebra.

PERSONALIZED FITNESS COUNSELING

If you'd like some help designing your personal fitness program, or have questions regarding exercise, or simply want some regular motivation, sign-up for our Fitness Counseling Service. It may be the best investment in your health that you'll ever make.

REFERENCES

Ariyoshi M, Sonoda K, Nagata K, et al. Efficacy of aquatic exercises for patients with low-back pain. Kurume Med J 1999;46:91-96. Abstract

Axler C, McGill SM. Low back loads over a variety of abdominal exercises: searching for the safest abdominal challenge. Med Sci Sports Exerc 1997;29:804-811. Abstract

Baras T, Baras M, Zeev A, et al. Physical activities and low back pain: a community-based study. Med Sci Sports Exerc 2004;36:9-15. Abstract

Brumitt J. Advanced lumbar stabilization exercises. NSCA's Perf Train J 2005;4:11-12. (no abstract)

Cox JM, Trier KK. Exercise and smoking habits in patients with and without low back and leg pain. J Manipulative Physiol Ther 1987;10:239-245. Abstract

Danneels LA, Vanderstraeten GG, Cambier DC, et al. Effects of three different training modalities on the cross sectional area of the lumbar multifidus muscle in patients with chronic low back pain. Br J Sports Med 2001;35:186-191. Abstract

Descarreaux M, Normand MC, Laurencelle L, et al. Evaluation of a specific home exercise program for low back pain. J Manipulative Physiol Ther 2002;25:497-503. Abstract

Harreby M, Hesselsoe G, Kjer J, et al. Low back pain and physical exercise in leisure time in 38-year-old men and women: a 25-year prospective cohort study of 640 school children. Eur Spine J 1997;6:181-186. Abstract

Hodges PW, Richardson CA. Inefficient muscular stabilization of the lumbar spine associated with low back pain. Spine 1996;21:2640-2650. Abstract

Mannion AF, Muntener M, Taimela S, et al. A randomized clinical trial of three active therapies for chronic low back pain. Spine 1999;24:2435-2448. Abstract

Mannion AF, Muntener M, Taimela S, et al. Comparison of three active therapies for chronic low back pain: results of a randomized clinical trial with one-year follow-up. Rheumatology 2001;40:772-778. Abstract

Mundt DJ, Kelsey JL, Golden AL, et al. An epidemiologic study of sports and weight lifting as possible risk factors for herniated lumbar and cervical discs. Am J Sports Med 1993;21:854-860. Abstract

Nyska M, Constantini N, Cale-Benzoor M, et al. Spondylolysis as a cause of low back pain in swimmers. Int J Sports Med 2000;21:375-379. Abstract

Ong A, Anderson J, Roche J. A pilot study of the prevalence of lumbar disc degeneration in elite athletes with lower back pain at the Sydney 2000 Olympic Games. Br J Sports Med 2003;37:263-266. Abstract

Rasmussen-Barr E, Nilsson-Wikmar L, Arvidsson I. Stabilizing training compared with manual treatment in sub-acute and chronic low-back pain. Manual Therapy 2003;8:233-241. Abstract

Torstensen TA, Ljunggren AE, Meen HD, et al. Efficiency and costs of medical exercise therapy, conventional physiotherapy, and self-exercise in patients with chronic low back pain: a pragmatic, randomized, single-blinded, controlled trial with 1-year follow-up. Spine 1998;23:2616-2624. Abstract

Volinn E. The epidemiology of low-back pain in the rest of the world. Spine 1997;22:1747-1754. Abstract

ABOUT THE AUTHOR

Stan Reents, PharmD, is a former healthcare professional. He holds Personal Trainer and Lifestyle Counselor certifications from the American Council on Exercise and has been certified as a tennis coach by USTA. He is the author of Sport and Exercise Pharmacology (published by Human Kinetics).  He can be reached at: Editor@athleteinme.com.