We will determine when to transition from the common vertical jump to chair stand depending on age and physical activity levels.

Assessing individuals' power, while it is useful in measuring fitness and performance levels, often requires expensive materials. Vertical jump height has been used to assess peak power output using specific regression equations. The issue with this test, although it is often used with older persons, is that it is not practical or useful in assessing the power output in elderly adults due to possible injury risk and lack of familiarity with providing a maximal jump performance. Power is important for elderly adults; because, higher power output in elderly adults has been shown to highly correlate with overall functionality, the ability to do activities of daily living (ADL), and a reduction in fall probability. A recent study examined the capacity of a regression equation to quantify power in elderly adults using a sit-to-stand test and determined; however, the sit-to-stand lacks the difficulty and exhibits a ceiling effect in younger individuals. Therefore, this study will attempt to determine when to transition from the vertical jump to the sit-to-stand, so that the differences in chronological versus physiological age may be determined during aging, and conversely, during improvements through physical or other interventions.

Inclusion Criteria:

• between 18 and 89 years old willing to commit to two days of testing

Exclusion Criteria:

• severe musculoskeletal impairment,
• neurological impairment that would affect balance,
• severe cognitive impairment (Mini-mental 19 or below),
• unstable chronic disease state,
• severe vestibular problems
• severe orthostatic hypotension,
• Simultaneous use of cardiovascular, psychotropic and antidepressant drugs.
• Adults unable to consent
• Prisoners
• Pregnant females

Men and women 18-100