The long-term objective of this research is a prophylactic approach that can reduce the incidence of falls and the resulting injuries among older adults at risk and thus reduce its escalating medical cost. This project explores perturbation training through the use of treadmill device and a motor learning approach, in which experience with slip-like perturbation generated by that treadmill is used to prepare the motor system to develop and then put to use fall-resisting skills outside of training environment (cross-environment transfer). The computer-controlled treadmill is portable, safe and easy to operate, thus conducive for use in clinics or community centers. The study logically builds on and complements the team's previous and current research programs, and will further test that after such a single session, older adults at risk can retain such cross-environment transfer and reduce their likelihood of falls in everyday living for the next 6 to 12 months. Finally, the study will explore that such reduction of falls does not come merely from these persons' familiarity with the training or testing setup, protocol and environments.

Inclusion Criteria:

• Subjects with no known history of musculoskeletal, neurological, cardiovascular, or pulmonary impairment that may affect their ability to perform the testing procedures will be included.

Exclusion Criteria:

• Ultrasound calcaneus bone mineral density T score < -2.5 (osteoporotic)
• Mini-Mental State exam score < 25 (cognitive impairment)