Maintaining strong muscles is important for the independence and quality of life in our older population. Strong muscles provide mobility and reduce the chance of falls that lead to injury. Many researchers are carrying out studies to examine different types of exercise and drug treatments to prevent loss of muscle strength in older people. Often, these research studies use x-ray computed tomography (CT) scans to measure the size and the amount of fat in different muscles. These factors are known to reflect muscle health. Large studies can involve many research subjects recruited at many different clinics with different CT scanners. To ensure that these studies provide reliable results, the investigators must have procedures to make sure that different CT scanners measure the same results for the same amount of fat or muscle. The goal of our study is to develop these procedures. In this project, the investigators will study women because they have the highest risk of bone fractures resulting from falls. Thus, the subjects are being asked to volunteer for a study where the subjects will be scanned on different scanners.

Inclusion Criteria:

• age 60-70 years old
• healthy

Exclusion Criteria:

• no history of spine surgery
• no history of hip implantation or replacement
• no scoliosis or other spine deformity
• not using walking canes or wheelchair

In this project we will study women 60-70 years old because they have the highest risk of bone fractures resulting from falls.