Osteoporosis is a chronic disease characterised by bone fragility predisposing a person to an increased risk of fracture. Two thirds of Australians over 50 years old suffer from low bone mass. Peak bone mass is achieved by the age of 30 with a natural decline in bone density thereafter, where eventually bone loss overtakes bone growth.
In order to prevent and treat this chronic condition, pharmacological intervention in conjunction with exercise has been widely recognised and implemented. However, not all exercise modalities have been found to have an osteogenic (bone building) effect. Evidence suggests exercise for osteoporosis should:
- Be cyclic not continuous – where a circuit style of training is recommended over a long bout of the same exercise
- Elicit high bone strains – this means higher intensity or higher loads for less repetitions. Also new movements that the bone is not accustomed to already
- Involve rapid loading – focusing on a faster speed of movement to develop power
Recommended exercise modalities include: progressive resistance training, high impact exercise and balance training.
Recently, an alternative intervention to increase bone density is whole-body vibration (WBV) therapy which involves performing exercises on a vibration platform. WBV was originally proposed to build bone density and muscle mass for astronauts in space, and it is now being discussed for use by people with osteoporosis due to its proposed effects. One hypothesis suggests that the vibration stimulates muscle spindles, activating motor neurons which cause muscle contraction. Another suggests that it increases muscular strength and power improving neuromuscular function.
Despite the proposed benefits of WBV, the dosage of vibration therapy (magnitude and frequency) and the frequency of treatment remains unclear and has caused confusion for the implementation in a clinical setting. It is unclear about how the dosage may vary depending on a person’s bone mineral density, body mass or even its safety for people with joint replacements. Majority of research has focused on post-menopausal women, questioning validity for other populations and has recommended further investigation. Additionally, many studies looking at the effects of WBV therapy included WBV therapy in combination with low-moderate intensity resistance training so it is difficult to identify the effects of WBV alone. However, it provides evidence that exercise is recommended to treat osteoporosis.
Exercise and Sport Science Australia along with Healthy Bones Australia still recommend methods of pharmacological and exercise-based therapies as effective treatments for people with osteoporosis. This focus is based on Wolff’s Law, where “a bone will grow and remodel in response to the forces and demands placed upon it”. Current evidence recommends impact loading and moderate-high intensity progressive resistance exercise for osteoporosis.
Individual exercise prescription must consider current bone health, comorbidities and risk factors for falls and fractures. An exercise physiologist can help ensure this!