what is biomechanics?

it is the application of mechanical laws to living structures, specifically to the locomotor system of the human body.

what are the uses of biomechanical analyses?

• improvement of sports skill techniques
• design of sport equipment
• prevention of injuries
• clinical analysis of movement pathologies
• design of prosthese
• design of rehabilitation devices
• video game movement

how many types of analysis are there?

what are they?

there are 2

qualitative analysis and quantitative analysis

what is the difference between QUALITATIVE and QUANTITATIVE analysis?

qualitative: non numerical description of a movement based on direct observation; -- by coachs and teachers

quantitative analysis: movement is analyzed numerically based on measurements from data colect during the performance of the movement. --- researchers

which analysis is conducted by researchers or by teachers and coaches?

quantitative and qualitative analysis. respectively

what are the three parts to a lever?

force point: exact point where the effort is applied.

resistance point: exact point on which the resistance acts

fulcrum : axis of motion

what is a lever?

which one do we mostly use?

a lever is as a rigid bar that turns about an axis, contractions of the muscles provide the force to move the levers.

we mostly use speed levers

what is the force point in a human body?

resistance point in a human body?

force arm? FA

resistance arm? RA

force point: the insertion point of the muscles of interest on a bone.

resistance point: center of graviy of the moving body segment

FA: perpendicular distance from the fulcrum

RA: perpendicular distance from the fultrom to the line of action

what are first class levers?

the fulcrum is between the force point and the resistance point.

ex: teeter-totter--- tricep muscles

R___________A_________F

what are second class levers?

resistance point is between force and fulcrum

a___R___F

ex: wheelbarrow, nutcracker, bottle opener

third class levers?

force is between the fulcrum and resistance

bicep muscle

what is mass?

the quantity of matter contaied in an object (kg)

what is force?

weight?

force:mass x acceleration (N)

weight: amount of gravitational force exerted on the body

mass X acceleration of gravity.

what is the principle of levers?

levers of any class will balance when the product of the force times the distance from the point of applicaion of the force to the fulcrum is equal to the resistance X distance from the point of the reistance to the fulcrum or axis.

F x FA = R x RA

what is torque?

what is moment arm?

what is the mechanical advantage of levers?

T: rotarty force:

MA: perpendicular distance b/w the forces line of action and the axix of rotation

MA = FA/RA

what is volume and pressure?

v: amount of space that a body occupies

p: force distributed over a given area

P = F/A

N/cm²

compression

tension

shear

mechanical stress

c: pressing/ squeezing force directly axial through a body

t: pulling/stretching force directly axially through a body

s: force directed parallel to a surface

ms: F/A similar to pressure

what do you do when you're lifting a heavy ass object from the ground?

1. get someone to help you

2. stand facing the object with flat feet @shoulders width

3. face the object in the direction you intend to move it

4. keep the object close to the body

5. get a good grip

6. bend at the knees and hip; back straight

7. lift with the knees and hip

8. carry object close to COG

define COG; 3 definitions.

1. point of intersection of the 3 cardianal planes - F, S, T

2. point of exact center; where we rotate

3. point where the weight is equal on all opposite slides

where is COG in the human body?

5cm anterior to the sacral vertebra;

6 cm below the belly button

males have higher belly buttons than females
57 vs 55

what contributes to the change in COG?

• location varies depending on body proportions

• body position or limb position

• additional of external weight -- backpack

• each body area has their own COG

what are the three reasons to determine COG?

1. important for stability

2. describe the movement of the body through space

2. imortant factor in calculation of amount of work done

how can you locate COG?

1. reaction board method -- static position of the human body

2. segmental method -- locating CG of a body in motion

explain these two methods.

1. lay on the board and dont move

2.

what is balance ?

balance: maintaining a stationary position

CG must be over the base of support

CG must be outside of the Base of support

what is stability?

how can you increase it?

firmness of balance

1. increase body mass

2. increase the size of base of support

3. vertical position the CG as low as possible

4. increases friction b/w the body and surface contact

5. place CG near the edge of the Base of support

explain all the newtons law of motion

1st law: law of inertia -- body will maintain at rest unless acted upon

2nd law: law of accelration: F=MA

3rd law: law of reaction: for every action there is a reaction

what is momentum?

mechanical quantity that is important in situations involving collision

M x V

what is work and power?

w: F x D

p: F x V

what are the differences btween walking and running?

1. running has a period where both feet are off the ground. -- series of jumps

2. no period where both feet are on the ground

3. stance phase is much smaller portion in the gait cycle

what is running speed?

stride length x stride rate

what is the length of stride dependent on ?

leg length and power of the stride.

muscle contraction

neuromuscular cooridnation