I'm sorry for any confusion, but "physical phenomena" is not a term typically used in medical definitions. It is a broader term that refers to observable events or processes in the natural world that can be explained by physical laws and principles. This might include things like gravity, electromagnetism, or motion.

If you're looking for medical definitions related to physical phenomena, you might consider terms like "physical examination," which refers to the process of evaluating a patient's health status using observation, palpation, percussion, and auscultation to assess various body systems. Or, you might consider "physiological response," which refers to the body's natural reaction to a stimulus or change in environment.

If you meant something different by "physical phenomena" in a medical context, could you please provide more context or clarify your question? I'm here to help!

Physical fitness is a state of being able to perform various physical activities that require endurance, strength, flexibility, balance, and coordination. According to the American Heart Association (AHA), physical fitness is defined as "a set of attributes that people have or achieve that relates to the ability to perform physical activity."

The AHA identifies five components of physical fitness:

1. Cardiorespiratory endurance: The ability of the heart, lungs, and blood vessels to supply oxygen to muscles during sustained physical activity.
2. Muscular strength: The amount of force a muscle can exert in a single effort.
3. Muscular endurance: The ability of a muscle or group of muscles to sustain repeated contractions or to continue to apply force against an external resistance over time.
4. Flexibility: The range of motion possible at a joint.
5. Body composition: The proportion of fat-free mass (muscle, bone, and organs) to fat mass in the body.

Being physically fit can help reduce the risk of chronic diseases such as heart disease, diabetes, and some types of cancer. It can also improve mental health, increase energy levels, and enhance overall quality of life.