Age-Related Gait Changes and Hip Flexibility

1. 100 subjects aged 65 years and older will be recruited from the Charlottesville area.

2. Participants will be asked to fill out a health questionnaire identical to that used for all preliminary studies. This questionnaire verifies that the participants meet the inclusion criteria for the proposed research project.

3. After this initial health questionnaire screening, each participant will undergo a face-to-face history and physical examination screening. Frail Elderly Subjects:

1. 100 subjects aged 65 years and older who meet the criteria of not being able to function independently, which is considered to be frail, living within the greater Charlottesville area will be recruited for participation in the study.

1. acute medical illness,

2. diagnosis or symptoms of unstable angina or congestive heart failure,

3. pulmonary diagnosis or symptoms of emphysema, chronic obstructive disease or asthma and shortness of breath as a result of pulmonary diagnosis brought about by walking on a flat surface,

4. advanced cancer,

5. neurologic diagnosis including Parkinson's Disease, stroke, brain injury, cerebellar disease, myelopathy, myopathy, peripheral neuropathy, or active radiculopathy,

6. major orthopedic diagnosis in the lower back, pelvis, or lower extremities, including hip or other fracture since the age of 50, fused joint, joint replacement, or amputation,

7. severe osteoarthritis or rheumatoid arthritis or active joint or musculoskeletal pain in the back or lower extremities occurring at rest or with walking,

8. severe osteoporosis with a history of a fragility fracture occurring in the past 12 months, and

9. regular use of an assistive device for walking. Exclusion criteria per physical examination will be:

1. physical signs of congestive heart failure,

2. muscle weakness (less than 4/5 manual muscle test strength in lower extremities or focal findings of 1/5 strength difference between sides or upper and lower extremities), absent knee extensor reflexes or positive Babinski responses,

3. corrected visual acuity worse than 20/100 or presence of a field defect,

4. poor mental state defined with a Mini-Mental Status Examination score less than or equal to 24/30,133

5. orthostatic hypotension (greater than 20mmHg decline in systolic blood pressure from supine to standing at one minute), and

6. unilateral sensory deficit in lower extremities, bilateral sensory loss in stocking distribution, proprioception less than 75% correct in identifying great toe position, or vibration (from with a 128Hz tuning fork) perceived for less than 10 seconds at either the great toe or medial malleolus in either extremity. Frail Elderly (who do not Function Independently):

1. are unable to walk independently (i.e., unable to walk without the assistance of another person), or

2. have either an acute medical condition or a chronic underlying medical condition which would make it unfeasible or unsafe to participate.

3. Regular use of an assistive device, such as a cane, for walking is not an exclusion criterion as long as:

4. Based upon the questionnaire or medical history, the following specific exclusion criteria will be used:

5. Based upon physical examination, subjects will be excluded if they have: