Osteoporosis is a disease that involves a loss of bone mineral density. Osteopenia is a milder form of osteoporosis. Although people with osteoporosis are more susceptible to fractures due to the thinning of their bones, they are appropriate candidates for flexibility training programs. These programs can help improve posture and maintain the alignment of the spine. However, the program should avoid repetitive exercises that involve twisting or flexing of the spine. Everyone who participates in a flexibility training program should be taught proper breathing techniques.