After the age of 50, one in three women and one in eight men will experience at least one fragility fracture during the rest of their lives. It is currently recognized that physical activity has an osteogenic actions, especially when it includes the impact transmitted to the skeleton. In this context, the investigators propose a study to determine whether the regular practice of golf could be particularly beneficial for the skeleton, not only in the lower limbs, due to repeated impacts to the ground when it requires sustained walking, but also the upper limbs due to the impacts transmitted by the club at the time of striking the ball, as has been amply demonstrated with racquet sports.

Each patient will have 1 blood samples and 1 measure of bone by 3D micro-tomography (3D CT Scan).These examinations and sampling will take place on 1 day.

Inclusion Criteria:

• Golfers: Regular playing golf for over 2 years at 8 to 12 hours per week recruited into golf clubs.
• Walkers: regular practice of walking for over 2 years at 8 to 12 hours per week recruited into the walking clubs.
• Sedentary: no intensive physical activity (<2 hours / week), recruited in clubs seniors.

Exclusion Criteria:

• concomitant bone disease ,
• Hip prosthesis the dominant side
• Endocrinopathy
• hypercalcemia, vitamin D deficiency, hypo- or hyper calciuria
• Active smoking (more than 5 cigarettes / day), chronic alcoholism,
• Treatments received in the previous six months and resounding on bone metabolism such growth promoters, all osteoporosis, corticosteroids.

Subject practicing foot walk or golf or sedentary