ANN ARBOR, Mich., JUNE 10, 2009 — Physical activity, exercise, and sport all provide a variety of benefits to our heart, lungs, and other vital organs. Researchers at the University of Michigan have confirmed that exercise is just as important for a healthy skeletal system.
Ronald Zernicke, director of the University of Michigan Bone & Joint Injury Prevention & Rehabilitation Center, concluded that exercise, specifically weight-bearing activities such as running, gymnastics, basketball, and dancing, are effective in building and enhancing overall bone health. Zernicke’s scholarly review, to be published in the July/August issue of Sports Health: A Multidisciplinary Approach, synthesized information over the last 50 years on the role of exercise on skeletal tissue and overall bone health.
A combination of collagen (protein) and calcium phosphate (mineral) make bone strong and flexible and provides the framework to withstand the stresses of physical activity. During an individual’s childhood and teenage years, new bone is added to the skeleton faster than old bone is removed. Bone formation and bone mass density (BMD) also continues at a faster pace than it is removed until we are about 30 years of age. Bone mass density increases are possible across all age groups; however, the most beneficial time to improve BMD with exercise is before and during puberty.
Bone deformation rates and magnitudes, the amount of pressure put on bones, bone mass composition (BMC), and BMD in physically active populations were all important components of the review. Past research has shown, for example, female gymnasts will have greater total BMC and higher bone strain rates while in training and during pre-pubertal to post-pubertal stages of life. Other activities, such as ballet and competitive jump rope, will also produce higher total BMC and increase bone strength in this population. Non-weight bearing sports and activities like cycling and swimming are healthy activities and have excellent cardiovascular benefits, but are not as effective as weight bearing activities in adding bone.
“Our skeletons respond to a combination of weight-bearing activities and muscular movements. The review found the most bone friendly exercises are those that have high deformation rates, such as jumping for the lower body, and racquet sports, like tennis, for the upper body,“ Zernicke said. He went on to say, “This evidence makes a strong case for physical activity being one of the best, non-pharmacological ways to develop and maintain healthy bones.”
Bone is dynamic tissue. Physically demanding, continuous exercise regimes are not necessarily the best activities to build and enhance bone health. Zernicke says “rest” periods within exercise plans can help stimulate bone growth as much, if not more than activities executed without rest. For example, bones can respond to strength building from jumping sessions three shorter times a day better than a longer continuous jumping session — think jumping rope three minutes per day three times a day versus jumping rope for 10 solid minutes. The bottom line: Exercise may help increase bone density and protect against bone mass decline when performed properly.
Zernicke concluded, “Physical activity is absolutely beneficial for overall bone health. It is a modifiable factor that we can have control of for the development and maintenance of healthy bone mass. Our skeletons are responsive to exercise at different times across our lives. While research stresses adolescence as a critical time for bone development with exercise, physical activity for older men and women equally can improve BMD while at the same time strengthen muscles and improve their balance and coordination — a win-win for the body as a whole.”
As important as exercise is for everyone, Zernicke recommends the following actions to build and maintain healthy bone with physical activity:
Participate in weight-bearing activities such as dancing, jumping, and running – these activities will be more effective for bone health than non-weight bearing activities like swimming and cycling.
Encourage adolescents to exercise because they have “a window of opportunity” to enhance bone mass and strength that will carry on for rest of their lives. Activities that can influence good bone health for adolescents include aerobics, football, and jumping activities.
Incorporate “rest” periods into an exercise plan – instead of continuous physical activity, break up exercises into multiple sessions so your body can rest. Periods of rest will help your bones program themselves for strength building and improvement.
Exercise no matter what your age – activities for older populations, such as walking, can be effective in enhancing bone health, especially in older men and post-menopausal women.
Don’t think that inactivity is protecting your bones (the fear of exercising and falling). Not providing the body with exercise or physical activity can actually cause bones to become weak and brittle. For older populations, a brisk walk can strengthen bones and benefit the body beyond simply bone building.
Always consultant with a physician before starting any exercise program.
Ronald Zernicke is the director of the University of Michigan Bone & Joint Injury Prevention & Rehabilitation Center, professor in the Departments of Orthopaedic Surgery and Biomedical Engineering and the School of Kinesiology at U-M.
About the Center
The University of Michigan Bone & Joint Injury Prevention & Rehabilitation Center is a collaborative effort between the Medical School, the College of Engineering, the Division of Kinesiology and the School of Public Health. The Center’s mission is to excel in the creation of new knowledge in all areas relevant to the prevention, treatment, and rehabilitation of musculoskeletal injury and arthritis. The Center is dedicated to conduct mission-driven research, train the next generation of multi-disciplinary researchers, provide leadership for local, national, and international collaborations and partnerships, promote the effective translation, use, and exchange of knowledge and develop organizational excellence. For more information about the Center, visit http://bjiprc.umich.edu.