The important components to evaluating physical fitness are cardiovascular capability, muscle strength and endurance, joint flexibility, and body composition, according to Functional Fitness Facts. A physically fit individual, regardless of weight, has a strong heart, vascular system and lungs.
A healthy heart, lungs and vascular system work together to send oxygen-rich blood to muscles during physical activity. The ability of muscle groups to push back against heavy resistance and to repeat movement or sustain position over a period of time constitutes muscle strength and endurance. Joints are healthy when they can fully flex and extend, plus demonstrate a full range of motion. Functional Fitness Facts explains that measurable fat is compared to the amount of lean mass in the body, such as muscle and bone, to determine body composition.
Time magazine states that physically fit individuals do not suffer from high blood pressure, low levels of good cholesterol, diabetes, high triglycerides or insulin resistance. Contrary to popular thought, weight alone is not a valid marker for determining whether an individual is physically fit. Dr. Timothy Church, director of the Laboratory of Preventive Medicine at Pennington Biomedical Research Center in Louisiana, maintains that weight only becomes an issue when it's combined with an abnormality like hypertension or abnormal cholesterol.