Week 2- Biomechanics and Levers

In a first class lever, what is in the middle

Axis

In a second class lever, what is in the middle

Resistance

In a third class lever, what is in the middle

Force

For resistance, what are three external forces

gravity, inertial, contact

For anatomical levers, what is the bar

bones

for anatomical levers, what is the axis

joints

for anatomical levers, what is the force

muscles

where is force applied in the body

where the muscle meets the bone (the insertion)

what point moves the least

the axis

where is the most weight

at the point of resistance

any lever where FA is longer than RA

power

which lever is true for all 2nd class levers and some 1st class levrs

power

any lever where FA is shorter than RA

speed/ROM lever

which is true for all 3rd class levers and some 1st class levers

Speed/ROM lever

where FA=RA, force=resistance

balance lever

what equation is used for levers

F*FA=R*RA

what does an increase in lever arm length do

decreases force required

what do longer levers have

faster moving end point

the shorter the lever…

the more quick a movement is