Bone health in the health and fitness industry is often overlooked. And as health and fitness continues to be a growing focal point for many adults and families moving forward, it’s important to educate members on this forgotten topic.
Our fitness level, ability to fight off infection from foreign pathogens with a good immune system, and our ability to prevent or manage chronic diseases will be of the utmost importance as we continue to navigate through this pandemic and look into the future. Exercise has tremendous potential to have beneficial impacts on many of the body’s systems and functions. For example, the skeletal system experiences exercise-induced adaptions that can be beneficial for long-term function, locomotion and overall wellness of individuals.
The skeletal system’s role is to provide structure, allow for skeletal muscles to facilitate movement, protect vital organs, offer nutritional and blood cell functions, and serve as a storage site for minerals. Further, as we age, bones continuously undergo bone remodeling, during which old brittle bone is removed or resorbed and replaced with new tissue. Within the bone matrix, there are specialized cells that do this. Osteoblasts, which build bone, and osteoclasts, which resorb or remove bone, are both functions necessary for bone remodeling and growth.
What is Bone Health?
Bone is a specialized type of connective tissue that is dynamic and capable of continually adapting to its changing mechanical conditions1. When bone undergoes tension, compression or torsion, the tissue of the bone becomes deformed. This deformation results in the movement of fluid within the bone that stimulates osteogenic cells (osteoblasts and osteoclasts), resulting in anatomical bone adaptations that make the bone better equipped for its new mechanical situation1,3.
In order for this deformation to occur from a movement standpoint, there needs to be a recruitment of skeletal muscle to help facilitate these osteogenic changes. The pull and torsion created by muscle contractions, coupled with other forces, such as ground reaction forces during walking or jogging, all influence the degree of deformation and subsequent remodeling.
In 2003, Frost proposed there is a “mechanostat” that attempts to keep bone tissue strain — deformation of bone — at an optimal level by continuously altering its bone architecture to maintain homeostasis2. For example, when bone undergoes heavy external loads, such as during a barbell back squat, the bone will respond by becoming stronger and increasing in mass. The exercise-induced strain can create microcracks in the bone. When these microcracks present, osteoclasts will remove damaged bone and osteoblasts will create new bone. Conversely, when bone is not put under load, or immobile for extended periods of time, the bone may adapt by shedding excess mass.
Building Stronger Bones
In order to promote the physiological building of stronger bones, an osteogenic exercise regimen should include moderate-to-high mechanical forces with rest breaks, including weight bearing activities like resistance training, stair climbing and intermittent jogging4. Since bone response to exercise in a site-specific manner, bone will be added in areas where enough strain is generated.
This is important to understand when considering an exercise program design and when working with populations dealing with bone health conditions such as osteoporosis. Further, endocrinological conditions, as well as others, may impact the bone’s response to exercise.
In general, exercise programs that include some form of resistance exercise, cardiovascular exercise and flexibility exercises will be beneficial for overall health, including bone strength. The American College of Sports Medicine recommends 30 to 60 minutes per day of a combination of moderate-to-high intensity weight bearing endurance activities three to five times per week, and resistance exercise two to three times per week1.
These exercises should target all muscle groups. Since bone is a dynamic tissue, the stimulus should be sufficient enough to create enough strain to induce these adaptations. In addition to stronger bones, exercising will also help in other areas such as cardiorespiratory health, balance, function and overall fitness.
Educating on Bone Health
Our fitness offerings should include some form of education to help participants understand the benefits from exercise. Generally, programs tend to highlight weight loss, athletic performance or muscle gain. However, there are many systems within the body that are impacted by exercise. Bone health, for example, is an adaptable system capable of remodeling itself to become stronger, depending on the stimulus or degree of strain.
This is just one of many examples where our industry plays a huge role in helping support and promote health to our members and communities. By developing and implementing inclusive fitness programming and providing education on the specific health benefits of the program, members may realize the inherent value from participating and remain with your club longer.
- ACSM’s resource manual for guidelines for exercise testing and prescription. American College of Sports Medicine. 7th ed. 2014.
- Frost HM. Bone’s mechanostat: a 2003 update. Anat Rec A Discov Mol Cell Evol Biol. 2003; 275(2): 1081-101.
- Hughes M, Petit MA. Biological underpinning of Frost’s mechanostat thresholds: the important role of osteocytes. J. Musculoskelet Neuronal Interac. 2010; 10(2):128-35
- Kohr WM, Bloomfield SA, Little KD, Nelson ME, Yingling VR. American College of sports Medicine. American College of Sports Medicine Position Stand: physical activity and bone health. Med Sci Sports Exerc. 4004;(36)11:1985-98.