Audience: Anyone who goes to the gym - PowerPoint Presentation

Slide1

Audience: Anyone who goes to the gymBy Jose M Batista

Lever Systems Slide2

Levers consist of

Fulcrum (Axis, joints)

Force (muscle pulling from tendon

Lever ( Long bone)Resistance

What is it?Slide3

Less force is needed

Disadvantage in speed

and ROM

Not as FarAdvantage in Force ProductionSlide4

Further and faster

Disadvantage in force

Harder to lift

Human movement

A

dvantage

in

motion

and speedSlide5

Torque (moment)=force x moment arm

With this equation we can calculate how much force do we need to move objects around.

C

alculationsSlide6

There are three types of levers

First Class Levers

Second Class Levers

Third Class Levers Breaking it DownSlide7

Axis is in the middle

Examples are see-saw and cutters

Advantage in force production

In the body (cervical extension)First Class LeversSlide8

Example First Class LeversSlide9

Force arm is longer than the resistance arm

Examples are wheelbarrow and nut cracker

In the body (plantar flexion)

Second Class LeversSlide10

Example Second Class LeversSlide11

Resistance arm is always longer than force arm

These are most

used

in the bodyThird Class LeverSlide12

Example Third Class LeversSlide13

Body must create torque while objects create an opposite torque

Weight

of ball creates torque

Resistance*moment or resistance armWeight of ball*distance ball is from axisLength of Lever and Effect Slide14

When lifting weights is it more advantages to have longer arms and legs or would it be a disadvantage and why?

Longer

arms means the resistance arm is going to create more force/torque

.Would you expect 100 meter sprinters to be taller or shorter and why? Its advantageous for a longer stride but it’s a disadvantage as well because you need more force to move that leg.Why do you think kids going through puberty seem to run awkwardly

? Their resistance arms are growing and its difficult for them to move each

limb.

Practical QuestionsSlide15

Objects held in longer limbs travel a greater distance in a given time period and so can move with higher velocities and speeds.Tennis players can hit a tennis ball with more speed with a straight-arm drive than with a bent elbow because the lever is longer.

Examples

Baseball pitchers, golf, football punter, etc.

Kids leg lengths in running.Running speed (cycling rate)While they will need more force to move limb, they have a “mechanical advantage in speed and ROM”.Objects

of Different LengthsSlide16

What affect does choking up on the bat do and how does it affect hitting the ball? Talk about mechanics and why?

Moving

the axis will either make the lever longer or shorter letting you hit the ball further.

Can a skilled lacrosse player shoot a ball faster with a defensive pole(72in.) or an attackers pole(42in.)? An attackers pole is easier to hit the ball because its moment arm is shorter. What affect does hitting a tennis serve have when you hit the ball at its highest point vs. at a lower point? When you hit the ball at its highest point it would be easier to cover more ground.

Practical QuestionsSlide17

We use levers for everything

Our muscles and bones act together to form a lever

We use levers to move things more efficiently

Levers can be used to increase movement How is it used in general?Slide18

Strength advantage

M

ovement advantage

But not bothAble to pick up thingsMove efficiently Obtain better ROM

Why is it important?Slide19

Recap Slide20

Clinicians

Physical Education Teachers

Curriculum Developers

Athletic Trainers Exercise Physiologists Sport Psychologists Careers

Careers

using Lever Systems