Health Related Physical Fitness

Written and reviewed by Rohit Singh, Computer Science & Commerce faculty at UniDrill (MCA, Osmania University · 6 years teaching). Based on NCERT Health and Physical Education Class XI, Chapter 8.

Who is fitter: a weightlifter or a marathon runner?

Put a weightlifter and a marathon runner in the same room and ask who is "fitter". Both are at the top of their game, yet one cannot run 42 km and the other cannot lift 200 kg. The answer is that fitness is not one thing. It is a set of abilities, and this chapter names the five that matter for health: how well your body copes with daily life, protects itself from disease and keeps you well.

Physical fitness is a state of health and well-being. It develops your capacity to perform better in sports, in your job and in day to day work, and it is achieved through moderate or vigorous physical activity, a balanced diet and proper recovery. Regular planned activities such as walking, jogging, cycling, swimming and yoga lower the risk of heart disease, diabetes, hypertension and depression.

The five components in one line: Muscular strength → Endurance → Flexibility → Body composition → Cardiovascular endurance

Muscular strength: the force behind every movement

Strength is the muscle's ability to produce force. Even flexing a finger needs it. A newborn cannot stand because its strength is low, and a paralysed person cannot move a body part because the capacity to produce force is lost. Muscular strength is the ability of a muscle or muscle group to exert force on a resistance, either to overcome it or to act against it, according to the demand of the sport.

The resistance can be internal (your own body weight, as when running up a hill) or external (an opponent's weight, or a barbell).

Three types of strength. Sports demand force in different ways: all at once, fast, or for a long time. The three types differ in how much effort they take and for how long.

Pause and predict: a shot putter and a 400 m swimmer both train in the gym. Which one needs mostly maximum strength, and which one needs strength endurance?

Check your answer: the shot putter needs maximum strength (one huge effort), and the swimmer needs strength endurance (steady force for a long time). Sorting a sport by how long and how hard the effort is will solve most such questions.

What decides how much force a muscle makes. Five factors.

Beyond the textbook. For the exam: fast twitch means white, anaerobic and more force; slow twitch means red and aerobic. In reality: every person carries a mix of both fibre types, and the mix is partly inherited, which is one reason some people are natural sprinters and others natural distance runners. Training improves each type but does not make a distance runner into a sprinter. The proportion of fibres decides what you are naturally good at.

How to build strength. Strength is a conditional ability, so training improves it. Use the kind of resistance your sport uses.

Endurance: working for a long time

Endurance is the ability to keep doing a particular type of work for a long time with the desired quality, even under fatigue. It is both physiological and psychological, and it is task specific. A teacher can stand and teach for hours but cannot run for an hour. A long distance runner can run for an hour but may not manage long hours of office work. Mental toughness, interest in the task and physical qualities all play a part.

Three types of endurance.

What decides endurance. Five factors: muscle fibre type, aerobic capacity, anaerobic capacity, movement pattern and psychological factors.

Why anaerobic work is short. The phosphogens ATP and CP last only 8 to 10 seconds, and training can raise their amount. During anaerobic work lactic acid builds up and lowers the muscle's capacity. It is pushed into the blood, which makes the blood acidic, and alkali reserves in the blood neutralise the acid. This is the buffer system, and it helps endurance performance. A person's tolerance to lactic acid also matters.

The difference between the two capacities is simple: aerobic capacity is the capacity to work with plenty of oxygen for a long time, and anaerobic capacity is the capacity to work with less oxygen for a short time.

Pause and predict: why can you sprint flat out for only a few seconds but jog for an hour?

Check your answer: sprinting runs on the phosphogen system (ATP and CP), which lasts only 8 to 10 seconds, and then lactic acid builds up. Jogging is slow enough for oxygen to supply the muscles, so it can go on for a long time.

Methods to improve endurance. Endurance is highly trainable. The methods differ most in how they treat rest.

Beyond the textbook. For the exam: Fartlek is the continuous method with unplanned changes of pace, and interval training has incomplete recovery. In reality: the word Fartlek comes from Swedish and means "speed play". A footballer's match is itself like a Fartlek session, with jogging, sprints and walking mixed in with no fixed plan. This is why many team sports use Fartlek style running for fitness.

What endurance training does to the body. NTA likes this table because each row is a short fact.

Why it matters. A trained runner's heart pumps more blood per beat (higher stroke volume), so it can beat slower at rest. That is why athletes often have a lower resting heart rate, and why a drop in resting heart rate is a sign your endurance is improving.

Flexibility: how far your joints can move

Flexibility is the ability to move body parts through the maximum range around a joint. It is measured in degrees, radians or centimetres, and it matters for sports and for a normal healthy life.

What decides flexibility. Four factors: the structure of the joint (a ball and socket joint has the greatest range of motion), the stretchability of ligaments and muscles, coordination between agonist and antagonist muscles, and the strength of the muscle (a weak muscle cannot move the bone to its full range).

How to improve it.

Beyond the textbook. For the exam: ballistic stretching is the rhythmic swing method used in gymnastics, and it is effective. In reality: ballistic stretching is effective but uses momentum, so coaches advise it only after a proper warm up and for trained athletes. The PNF technique works because an isometric contraction followed by stretching helps the muscle relax and lengthen further.

Body composition: what your weight is made of

Body composition classifies the body into fat weight and lean body weight.

$$\text{Body weight} = \text{Fat weight} + \text{Lean body weight}$$

Two people with the same body weight can have very different compositions, which is why a weighing scale alone cannot tell you how fit someone is. A sprinter and a long distance runner of the same weight may carry different amounts of muscle and fat.

Cardiovascular endurance: the delivery system

Cardiovascular endurance is the ability of the heart, lungs and blood vessels to supply enough oxygen and nutrients to the cells to meet the demands of an activity with moderate contractions of large muscle groups over a long time. It can be evaluated by the twelve minute run or walk test.

Why it matters. This component is the one most linked to heart disease, diabetes and hypertension, the very conditions the chapter says regular activity reduces. A body with a strong delivery system copes better with everyday activity as well as with sport.

Exam traps

60-second revision

Where this chapter connects

• Previous: Safety and Security shows how fitness reduces injury risk.
• Next: Measurement and Evaluation gives the tests used to measure these fitness components.
• Related: Physical and Physiological Aspects of Physical Education and Sports builds on the muscle, heart and energy system ideas used here.