Most people want to be fit but that raises a question. What does it mean to be fit? The answer is fairly simple. To be fit, one must have physical capability in four areas: aerobic capacity, muscular strength and endurance, flexibility and body composition.
1. Aerobic Capacity . Aerobic capacity, which is also known as cardiorespiratory fitness, refers to the health and function of the heart, lungs and circulatory system. Simply stated, aerobic fitness is the ability of the cardiorespiratory system to deliver an adequate supply of oxygen to exercising muscles. As your aerobic capacity increases, your ability to participate in more intense and longer lasting exercise also increases (eg, walking, running, swimming and bicycling). It can be argued that aerobic capacity is the most important of the four elements of fitness because of the health benefits it bestows. According to the American College of Sports Medicine, increased aerobic capacity leads to reduced blood pressure, decreased total cholesterol, increased HDL (good) cholesterol, decreased body fat, increased heart function and increased risk of Type 2 diabetes.
2. Muscular Strength and Endurance . Muscular strength is the maximum amount of force a muscle or muscle group can generate during a single contraction. Muscular endurance is the number of repeated contractions a muscle or muscle group can perform without tiring. Both are important components of overall fitness because increasing your strength through various types of resistance training (eg, weightlifting) leads to increased bone strength, increased bone loss, decreased muscle loss, increased tendon and ligament strength, increased physical capacity, improved metabolic function ( eg, burn more calories at rest), and decreased risk of injury.
3. Flexibility . Flexibility is the range of motion within a joint. Increased flexibility provides a variety of benefits such as increased risk of injury, increased flow of blood and nutrients to joint structures, increased neuromuscular coordination, decreased risk of low back pain, improved posture and reduced muscular tension.
4. Body Composition . Body composition refers to the relative percentage of body weight that consists of body fat and fat-free mass (everything other than fat such as muscles, organs, blood, bones and water). Generally speaking, the lower your body fat percentage the better because of the diseases linked to excess body fat such as heart disease, diabetes, hypertension, arthritis and sleep disorders. I am often asked, "Can you be fat and fit?" The answer is an overwhelming NO. A significant element of fitness is the possession of a healthy body fat percentage because increased fat leads to increased athletic performance and increased risk of disease (although it is possible to be overweight and healthy since health is merely the absence of disease or illness). According to the American Council on Exercise, the average body-fat percentage for men is 18-24%. For fit men the percentage is 14-17%. The average percentage for women is 25-31%; however fit women will be in the range of 21-24%. Body-fat percentages above 25% for men and 32% for women are considered obese.