Major Terms Related to Movement in Physical Education

Every living thing on Earth moves, but each one moves in the way its body is built and in the way its life needs. A fish swims by beating its fins, a bird flies by spreading its wings, and a snake slides forward along the ground. Human movement is very different from all of these. We walk, run, jump, turn suddenly, lift heavy loads and can even thread a needle with our fingers. There is a large difference between the movements people make and the movements other animals make.

For movement to be good, the different parts of physical fitness have to be properly developed. Being strong is not enough for a player. The same player also needs to keep going for a long time, to turn quickly, to stay upright without falling and to make the parts of the body work together. So, to develop a player's performance and to make sport and physical activity better, it is necessary to understand the seven terms below, which all describe movement.

• Flexibility
• Strength
• Power
• Endurance
• Balance
• Agility
• Co-ordination

Because our joints can bend and stretch, we can do many everyday tasks easily. Bending down to tie a shoelace, reaching up to take a book from a high shelf and twisting round to look at a friend behind you all use flexibility. Without flexibility, a person cannot fully use the speed, strength and endurance they already have. For example, a runner with strong legs but stiff hip joints cannot take long strides, so they take short steps and end up slower.

Flexibility plays an important part in completing the body's activities and movements. Gymnastics, athletics, basketball, volleyball, cricket, swimming, dance and physical exercise are all impossible without it. The table below shows the main joints that give the body its flexibility and the movement each one makes.

Strength is the amount of force a muscle produces when it contracts once. No task at all is possible without strength. Lifting a bucket of water, pushing open a door and climbing a slope all need it. But strength is not only the result of a muscle contracting. The nerves tell a muscle when to tighten and how hard, so strength is the product of nerves and muscles acting together and of the contraction itself.

A person is said to have good strength when they can resist a pressure pushing against them and drive their movement in the opposite direction. A swimmer is constantly pushed back by the water and pressed by the air. When the swimmer drives the body forward in the chosen direction against the resistance of the water and the pressure of the air, that is strength being put to proper use. In a tug of war, pulling your team backwards while the other team pulls the opposite way is strength too.

Strength is used most in games such as weightlifting, wrestling and kabaddi. A weightlifter raises a heavy load, a wrestler pushes against an opponent, and in kabaddi a raider breaks free from the grip of the defenders.

Power is strength and speed joined together. A person with strength can lift a heavy sack, but a person with power lifts that same sack quickly. So power looks at two things at once: how much work was done, and how long it took. The player who does the most work at the highest speed in the least time is the most powerful. The take off in a long jump, a smash in volleyball and fast bowling in cricket are good examples of power.

To know how much work was done within a fixed time, or to find the rate of work, the total work done is divided by the time taken. This gives the rate of work or play, and that rate is taken as the person's power. For example, if a boxer throws 96 punches in 2 minutes, the total number of punches is divided by 2 minutes. That gives a rate of 48 punches per minute. If another boxer throws only 70 punches in the same 2 minutes, the rate is 35 punches per minute, so the first boxer has more power. This rate of work is, in other words, power. The formula below is used to find it.

\[ \text{Power} = \frac{\text{Work}}{\text{Time}} \]

The work in this formula is itself found from another formula:

\[ w = f \times d \]

Here \( w \) stands for work, \( f \) for the force used to push or pull, and \( d \) for the distance the object moves. The bigger the force and the longer the distance, the more work is done.

Sita pushes a heavy box of sports equipment across the school hall. She pushes with a force of 150 newtons (N) and moves the box 8 metres (m) in 4 seconds (s). What is her power?

Step 1: Putting the values into work = force × distance:

\[ w = 150 \text{ N} \times 8 \text{ m} \]

Step 2: Multiplying force by distance gives the work in joules (J):

\[ w = 1200 \text{ J} \]

Step 3: Dividing the work by the time taken:

\[ \text{Power} = \frac{1200 \text{ J}}{4 \text{ s}} \]

Step 4: Working out the division gives the power in watts (W):

\[ \text{Power} = 300 \text{ W} \]

Now Ram pushes the same box the same 8 m, but he takes 6 s. His work is still 1200 J, but his power is only \( 1200 \div 6 = 200 \) W. Both did the same amount of work, but Sita did it in less time, so her power is greater. This is how much time matters in power.

Developing endurance is considered the most important part of a person's fitness. The respiratory system takes oxygen in, the circulatory system carries that oxygen to the muscles, and the muscular system uses it to do work. Endurance develops properly in a player only when these three systems work together. This is why endurance depends on the work of the muscles and of the heart and lungs.

If a person or player does not have good endurance, they cannot keep doing a set task at the same speed for a long time. You can see this in a student who runs the first lap of a school race very fast and then starts walking in the second lap. When a player cannot keep up a physical activity for a long time without tiring, the real standard of the game drops, it becomes less effective and the competitive spirit fades. The spectators who love the game also lose their interest and their good feeling towards it.

If a long distance runner can finish a marathon in about two hours, running at the same pace from the start to the finish, that runner's endurance is well developed. In the same way, football and basketball players who keep playing at the same pace for the whole match show that their endurance is well developed.

In everyday language, balance means that something is under control. A balanced object does not wobble or tip up and down. A glass standing firmly on a table without falling over is an example.

Without balance, the human body cannot even stand. To take part in any physical activity or sport, a person has to be in a balanced state. Balance is the ability to keep the body steady and in the right position even against an outside force. Not falling when someone bumps into you in a crowd, walking along the narrow raised edge of a rice field and climbing a slope with a loaded basket on your back all need balance.

An object in a balanced state is hard to move or shake, but with a simple machine it can be set moving using only a little force. For physical activity, keeping the body in balance is essential, and several principles and rules have to be followed for it. The skeleton does the main job of carrying the whole weight of the body. But the main role of balancing that weight and producing movement is played by all the joints, muscles and the nervous system adjusting to each other. Without balance we could not keep the body upright, and even while simply walking about we could not stop ourselves from losing balance and falling.

Only when agility is well developed can a person turn quickly to the right, to the left, this way and that, forwards and backwards, and still work, play and run. In kho kho, the chaser runs after a runner and then suddenly turns the other way. The chaser neither falls nor loses speed while turning. That is agility.

Producing agility needs the skeleton, the muscles moving in response to one another, and the brain linking and co-ordinating them. The brain decides in an instant to change direction, the muscles carry out that order and the skeleton supports the body. To become skilled at basketball, handball, football, kho kho, kabaddi, rugby, dance and tennis, a player must have well developed agility.

Think of a cricket fielder catching a high ball. The eyes follow the ball, the brain judges where it will land, the legs carry the body there and the fingers close at exactly the right moment. If any one of these parts is late, the ball hits the ground. Sport needs practical skill as well as physical growth, development and maturity. For co-ordination, the eyes, hands, legs, joints, muscles and nervous system must all be properly developed and linked to one another. Along with these, speed, agility and balance also need to be developed.

The table below puts the short meaning of each quality beside the sports or activities where it shows most. It is a quick way to revise all seven before a test.