The ability of the body to perform prolonged, large-muscle, dynamic exercise at moderate to high levels of intensity. This is dependent on the ability of the heart and lungs to deliver oxygen to the working muscles. As fitness levels improve, the body functions more efficiently and the heart can better withstand the strains of everyday stress.
The maximal amount of force a muscle can exert with a single maximal effort. Strong muscles are important for carrying out everyday tasks, such as carrying groceries, doing yard work, and climbing stairs. Muscular strength can help to keep the body in proper alignment, prevent back and leg pain, and provide support for good posture.
The ability of a muscle or group of muscles to perform repetitive contractions over a period of time. Endurance is a key for everyday life activities and operates with muscular endurance to help maintain good posture and prevent back and leg pain. In addition, endurance can enhance performance during sporting events, as well as help an individual cope with everyday stress.
This refers to the range of motion in a joint or group of joints, correlated with muscle length. This component becomes more important as people age and their joints stiffen up, preventing them from doing everyday tasks. Additionally, good range of motion will allow the body to assume more neutral positions to help maintain good posture. Stretching is therefore an important habit to start, as well as continue, as one ages.
The relative proportion of fat-free mass to fat mass in the body. Fat-free mass is composed of muscle, bone, organs, and water, whereas fat is the underlying adipose tissue. Excessive fat is a good predictor of health problems because it is associated with cardiovascular disease, high cholesterol, and high blood pressure. Higher proportions of fat-free mass indicate an increase in muscle, and thus an increased ability to adapt to everyday stress.