SRI LANKA GOVERNMENT JOB EASTERN UNIVERSITY - SRI LANKA

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.....Activity

The Elderly Population Is Growing Very Fast But Care Of The Elderly

Is Deteriorating Gradually. Write An Essay On “It Is Our Duty To Look

After The Elderly” Stating How This Situation Can Be Prevented From

Getting Worse.

It Is Important As An Adolescent That You Try To Help The Elderly As Much As Possible.

Let Us Identify Principles

Of Biomechanics To Maintain

Correct Postures

Maintaining A Correct Posture Means Keeping The Body Parts In Proper Positions So

That Minimum Amount Of Energy Is Spent And No Strain Is Caused To Any Part Of The

Body During Movement Or Remaining Still. Maintaining Correct Postures Pave The

Way For The Development Of A Fine Personality. It Is Difficult For Every Individual To

Maintain Postures In The Same Way As Others. The Way That Postures Are Maintained

May Differ From Person To Person Depending On Factors Like Body Weight, Body Size

And Age. To Maintain Correct Postures, It Is Important That You Learn The

Principles Of Biomechanics.

Out Of The Principles Of Biomechanics That Influence Postures, You Learned The Two

Principles ‘Center Of Gravity’ And ‘Balance’ When You Were In Grade 10.

In This Lesson, You Will Learn Some More Principles Of Biomechanics That Influence

Postures And Physical Activities, And How The Body And Equipment Are Manipulated

Using Those Principles.

Principles Of Biomechanics That Influence Postures

Postures Are Mainly Of Two Types:

1. Static Postures

Egg: Sitting, Standing, Lying

2. Dynamic Postures

Egg: Running, Jumping, Walking

The Following Principles Of Biomechanics Influence These Postures.

1. Centre Of Gravity

2. Balance

3. Inertia

4. Force

5. Direction Of Force

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6. Momentum

As We Have Already Learnt About ‘Center Of Gravity’ And ‘Balance’, Let Us Now Study

The Other Principles Of Biomechanics.

Inertia

Inertia Is The Property Of Resistance Of A Body That Remains At Rest To Move Or The

Resistance Of A Body That Is In Motion To Stop.

Let Us Consider Two Objects (A And B) That Have Been Kept On The Ground For Lifting.

If It Is More Difficult To Lift Object B Than A, Inertia Of The Object B, Or The Resistance

Of Object B To Move, Is Higher. (Figure 3.1)

A B

Figure 3.1

Think Of A Leather Ball And A Tennis Ball That Are Rolling Over. You Will Understand

That It Is Easier To Stop The Tennis Ball Than Stopping The Leather Ball. This Means That

Inertia Of The Leather Ball Is Higher.

Force

An Effect That Causes An Object Which Remains At Rest To Move Or Which Changes The

Nature Of Motion Of An Object In Motion Is Called A ‘Force’.

When A Weightlifter Is Lifting A Barbell That Is On His Shoulders, He Pushes It Upwards.

When The Barbell That Is On The Ground Is Lifted, The Weightlifter Must Pull

It Upwards. We See Such Acts Of Pushing And Pulling In Different Forms In Sports.

(Figure 3.2)

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Actions Like Pulling, Pushing And Lifting Are Results Of Exerting Force.

Figure 3.2