Exercise programs are classified as follows:
- static weight-bearing exercises e.g. single-leg standing
- high-impact weight-bearing exercises e.g. jogging, running, dancing, jumping, and vibration platform
- low-impact weight-bearing exercises e.g. walking
- high-impact non-weight-bearing exercises e.g. progressive resistance training
- low-impact non-weight-bearing exercises e.g. swimming
Prolonged aerobic training, e.g., swimming, cycling, and walking is widely beneficial to all body systems, but there are clinical evidences suggesting that none of these activities provide an adequate stimulus to bones. Since high-impact weight-bearing exercise is not always suitable for older adults due to the risk of musculoskeletal impairment in this population, low-impact non-weight-bearing exercise such as swimming has been recommended in this population. However, non-weight-bearing aerobic exercise applies no or very low impact on bones, and shows lesser osteogenic responses than weight-bearing aerobic exercise in older adults.
Regular walking, which is frequently prescribed to prevent osteoporosis, also has little or no effect on prevention of bone loss. This could be attributed that low-impact loading force applied during walking does not elicit loads of a sufficient magnitude, rate, or distribution to stimulate bone cells to lead to an adaptive skeletal response. Thus, despite the benefits of regular walking on aerobic fitness, adiposity, and other cardio metabolic factors, walking alone is insufficient to optimize the musculoskeletal health.
Other physical exercise programs including moderate- to high-impact or multi-directional weight-bearing activities have been shown to maintain or improve the hip and spine areal bone mass density.