alking is not only a very popular activity; it also has a proven aerobic value.1 Walking has been shown to increase maximum oxygen uptake, decrease heart rates and resting blood pressure, and decrease body weight and percentage of body fat. It also strengthens hip and back support muscles, stimulates strong and dense bones, strengthens the immune system, and improves balance and coordination. Research from many fields has now documented the value of this form of exercise. Simplicity and accessibility are two other advantages to walking. Walking programs can be individualized, the equipment is relatively inexpensive, and -depending on the weather-it can be done outdoors or inside. It is also an excellent socializing activity (walking clubs are popular throughout the country). EXERCISE WALKING To improve fitness, a walking goal would be to walk for an estimated one hour, and at a rate of 3.5 mph. At a rate of more than 3.7 mph, the energy required for walking increases exponentially. Since there is an apparent tendency to break into a jog because of the biomechanics of walking at 4-4.5 mph, a walk-jog regimen may be helpful for some persons. Variations in grade, terrain, and weight carried can affect the amount of energy expended. Walking is much kinder to aging joints and is much more readily accepted by the nonathlete and by those not naturally attuned to running. The fact is that running is not easy. It is basically for a long-range program. Add to these facts our knowledge that it is not what you do but how long you do it that really counts in terms of exercise benefits and even caloric expenditure. Walking has much to recommend it. Physical fitness programs have not induced most people to be physically active. Some activities, such as jogging, are unsuitable for many people and harmful for some. Sheen-feRJ,et al., examined the efficacy of walking with a backpack load as a method for improving physical fitness. Forty-four sedentary men with a mean age of 19 years (range, 18-23 years), mean height of 178 cm, and mean weight of 76 kg walked at a speed of 5 km/hour with a 3 kg backpack load for 30 minutes a day, five days a week, for three weeks. At this time, 32 (group A) terminated the experiment and 12 continued to march for another week. Of the 12 continuing, six (group B) kept the same backpack load and six (group C) increased their load to 6 kg. By the end of the 3-to-4-week experiment, predicted aerobic work capacity had increased by 15% in the 32 men in group A, by 18% in the six men in group B, and by 32% in the six men in group C. An improvement in predicted aerobic work capacity of more than 20% occurred in 34% of the men in group A, 50% of those in group B, and 67% of those in group C. A comparison of results for seven men from group A with low initial physical fitness and for seven with high initial fitness showed an increase in predicted aerobic work capacity of 30.4% in the former group and of only 2.7% in the latter group. An increase in work capacity of more than 20% was noted in four of seven men with low initial fitness and in none of the seven with high initial fitness. It is possible to substantially improve aerobic physical fitness in just three weeks by walking daily with a light backpack load. This program is most useful for people who have low initial aerobic work capacity. Walking is relatively safe. It can easily become part of a rehabilitation program, even for elderly people. The main determinant of the rapid increase in aerobic work capacity is apparently the increase of the weight of the backpack load, rather than speed or duration of walking. This study has resulted in numerous rehab clinics incorporating backpacks as part of treadmill walking. WALKING AND SPINAL HEALTH Because it is a basic locomotor skill, walking is also a very beneficial exercise for patients with back disorders. In fact, the recently-published AHCPR Clinical Practice Guidelines for the treatment of Acute Low Back Problems in Adults lists walking as one of the rec-j ommended methods of exercising. This recommendation is consistent with what has been found empirically in many practices: with few exceptions, both acute and chronic back conditions improve much more rapidly when patients walk at least 20 minutes every day. Twenty minutes of walking at a comfortable pace is an achievable level of exercise even in very busy lives; the benefits can be felt almost immediately, and they continue as the pace is increased. When patients must be taken off work because of a back injury or condition, have them attempt to walk three times a day for at least 20 minutes each time. It seems surprising at first to the patients, who often do not think this is possible with the back hurting; but, once they start walking, they can feel how it loosens up the back muscles and decreases their pain levels. Walking on a treadmill in front of a mirror, in order to regain a smooth, naturally coordinated gait can be helpful. CONCLUSION Walking is a very useful adjunct to the treatment of most spinal conditions-and the patients gain all the benefits and advantages listed above. It is one of the very best exercises and rehabilitative activities you can recommend. Dr. Kim D. Christensen is co-director of Sports Medicine & Rehab Clinics of Washington. Dr. Christensen is a popular speaker at numerous conventions and participates as a team physician and consultant to high school and university athletic programs, as well as being a chiropractic faculty member. He is currently a postgraduate faculty member of numerous chiropractic colleges and is the current president of the ACA Rehab Council. He recently received the "Founding Father" award at the annual ACA meeting from the American Chiropractic Rehabilitation Board. He has participated in college sports, and has served as a trainer, coach and team doctor. Dr. Christensen is the author of numerous publications and texts encompassing musculoskele- tal rehabilitation and nutrition. He can be reached at Chiropractic Rehabilitation Associates, 18604 NW 64th Avenue, Ridgefield, WA 98642. REFERENCES /. Messier SP, Royer TD et al. Long-term exercise and its effects on balance in older, osteoarthritic adults: results from the Fitness, Arthritis, and Seniors Trial (FAST). J Am Geriatr Soc 2000; 48(2):131-138. Shoenfeld Y, Keren G, Shimoni T, Birnfeld C, Sohar E. Walking. A meth od for rapid improvement of physical fitness. JAMA 1980 May 23-30; 243(20).2062-2063. Bigos S, Bowyer O, Braen G et al. Acute Low Back Problems in Adults. Clinical Practice Guideline, Quick Reference Guide Number 14. Rock- ville, MD: U.S. Department of Health and Human Services, Public Health Service, Agency for Health Care Policy and Research, AHCPR Pub. No. 95- 0643. December 1994. <♦
