Health, Fitness and Components of Fitness

Health and Fitness: Not the Same Thing

Most people use the words “healthy” and “fit” interchangeably, but in sports science they have precise, separate definitions. Health is defined as a state of complete physical, mental and social well-being — not simply the absence of illness. A person can feel stressed, anxious or socially isolated and still have no diagnosable disease, meaning their health is compromised even if a doctor finds nothing wrong.

Fitness, in contrast, is defined as the ability to meet the demands of the environment. This makes fitness specific to purpose: a sprinter needs explosive power and speed; a marathon runner needs cardiovascular endurance; a goalkeeper needs agility and reaction time. A person who is highly fit for one sport may be relatively unfit for another.

Two further definitions complete the picture. Exercise is any form of physical activity that maintains or improves health and fitness — it is a subset of physical activity that has a deliberate fitness aim. Performance refers to how effectively a person executes a skill or task during physical activity or competition. All four concepts — health, fitness, exercise and performance — are distinct but closely related: regular exercise improves fitness, which supports both health and performance.

Health-Related Components of Fitness

The eleven components of fitness are divided into two groups. The health-related components are those most directly linked to a person’s physical health and ability to resist lifestyle diseases. There are five:

Cardiovascular endurance (also called aerobic endurance) is the ability of the heart, lungs and circulatory system to supply oxygen to working muscles over a sustained period. Distance runners, rowers and cyclists have very high cardiovascular endurance. Strength is the maximum force a muscle or group of muscles can exert in a single effort against a resistance. A rugby prop in a scrum relies heavily on strength. Muscular endurance is the ability of a muscle or group of muscles to sustain repeated contractions against a resistance for an extended period — a rower completing a 2,000-metre race or a cyclist climbing a hill over many minutes both need muscular endurance. Flexibility is the range of movement possible at a joint. Gymnasts require extreme flexibility across multiple joints. Body composition is the ratio of fat mass to lean mass (muscle, bone and organs) in the body. A healthy body composition supports both performance and long-term health.

Skill-Related Components of Fitness

The skill-related components are those that primarily affect the quality of sporting performance rather than general health. There are six:

Agility is the ability to change direction quickly and accurately while maintaining control. A rugby winger sidestepping a defender or a tennis player changing court position both rely on agility. Balance is the ability to maintain the body’s centre of mass over its base of support, either statically (standing still) or dynamically (moving). A gymnast performing a handstand uses static balance; a surfer uses dynamic balance.

Coordination is the ability to use different body parts together in a smooth, accurate and controlled way. A cricket batsman hitting a ball requires the coordination of eyes, hands and body rotation. Power is the ability to exert maximum muscular force in the shortest possible time — it combines strength and speed. A sprinter leaving the starting blocks and a discus thrower generating release velocity both rely on power. Reaction time is the time taken to detect a stimulus and initiate a response. A swimmer diving off the blocks in response to the starting signal, or a goalkeeper reacting to a penalty kick, both rely on short reaction times.

Finally, speed is the ability to move the body or a limb quickly from one point to another. A 100 m sprinter requires maximum running speed; a fast bowler in cricket needs arm speed to generate ball velocity.