Reebok Rbx 550 English Manual - Page 31

Several studies have reported that regular walking at moderate to brisk speeds appears to increase bone density. Specifically, Fradin and his colleagues6 found that 70-year-old subjects who walked at least 30 minutes per day had higher bone mineral content than subjects who walked less than 30 minutes per day. Jones and his colleagues7 reported that sedentary women (aged 30 to 61 years old) who began a regular walking program and continued for one year increased their bone density. Since walking can be comfortably performed by people of any age, walking appears to be practical and effective in reducing a person's risk for developing osteoporosis. WALKING AND STRESS REDUCTION During a 24-week study, not one of 59 participants who walked five days a week at speeds between 3 and 5 miles per hour sustained a walking-related injury that necessitated consulting with a physician. Carroll and his colleagues10 reported that 14% of the elderly subjects participating in a walking study suffered trainingrelated orthopedic injuries, mostly to the lower leg and foot. The majority of injuries occurred in the group assigned to "fast walking." It is important to note that all forms of exercise have some degree of risk associated with the activity. Generally, the less mechanical stress on the musculoskeletal system, the less risk of becoming injured. Because of the low-impact nature of walking, the incidence of injury appears to be low when compared to other high-impact activities. There are many stressors in today's society, including economic concerns, work-related pressures and the need to balance career goals with home responsibilities. People who are unable to cope with these types of stressors are often tense and anxious, and may even become physically or psychologically ill. Researchers have found that exercise is one way to help people reduce stress. For example, subjects who engaged in a regular aerobic conditioning program and who altered their diets experienced significant gains in self-concept, feelings of well-being and reduced depression.8 Cramer and his colleagues9 specifically examined the effect of brisk walking on mildly obese sedentary women and found that walking improved general psychological well-being. Walking therefore appears to be an effective tool for improving psychological well-being. WALKING AND INJURIES Walking is often associated with a low injury rate. Walking is considered to be a "low impact" activity because one foot remains in contact with the ground at all times. Walking at speeds of 3 miles per hour produces vertical impact forces that are around 1.25 times body weight, whereas running at 7 miles per hour increases vertical impact forces to more than 2.5 times body weight. REFERENCES 1. Rippe, J., Ross, J., et. al. ÒCardiovascular effects of walking.Ó (Abstract), Proceedings of the Second International Conference on Physical Activity, Aging and Sports, July, 1985, p. 47. 2. Pollock, M., Miller, H. Jr., et. al. ÒEffects of walking on body composition and cardiovascular function of middle-aged men.Ó Journal of Applied Physiology, 1971, 30:126Ð130. 3. Duncan, J., Gordon, N., et. al. ÒWomen walking for health and fitness. How much is enough?Ó Journal of the American Medical Association, 1991, 266(23):3295Ð9. 4. Paffenbarger, R., Hyde, R., et.al. ÒPhysical activity, all-cause mortality and longevity of college alumni.Ó New England Journal of Medicine, 1986, 314:605Ð613. 5. ÒBetter walking workouts.Ó University of California at Berkeley Wellness Letter, 1992, 8(12):4Ð5. 6. Fradin, K. Grimby, G., et. al. ÒWalking habits and health-related factors in a 70-year-old population,Ó Gerontology, 1991, 37(5):281Ð8. 7. Jones, P., Hardman, A., et. al. ÒInfluence of brisk walking on the broadband ultrasonic attenuation of the calcaneus in previously sedentary women aged 30Ð61 years.Ó Calcified Tissue International, 1991, 49(2):112Ð5. 8. Blair, S., Collingwood, T., et. al. ÒHealth Promotion for Educators: Impact on Health Behaviors, Satisfaction, and General WellBeing,Ó American Journal of Public Health, 1984, 74:147Ð49. 9. Cramer, S., Nieman D., et. al. ÒThe effects of moderate exercise training on psychological well-being and mood state in women.Ó Journal of Psychosomatic Research, 1991, 35(4Ð5):437Ð49. 10. Carroll, J., Pollack, M., et. al. ÒIncidence of injury during moderate and high intensity walking in the elderly.Ó Journal of Gerontology, 1992, 47(3):M61Ð6. 31