chapter 8-biomechanics Flashcards
(26 cards)
biomechanics
mechanical principals related to the human body
statics
force of object at rest
dynamics
moving systems
2 types
kinetics
study of forces causing movement in a system
kinematics
time, space, and mass aspects of a moving system
force
measurable influences acting on body, push or pull action, instigator of movement
linear force
2 of more forces act along the same line, can be in same direction or opposite direction
parallel force
same plane and in same or opposite direction, 3 force must be present in between 2 forces to provide counterforce
concurrent force
2 or more forces act on a common point but pull in different directions
-example is deltoid
force couple
2 forces act together, but in opposite but equal directions resulting in turning
-example is scapula
torque
force with a twist, rotate
equilibrium
all forces are equal
center of gravity
balance point of an object, where planes intersect
base of support
where the body is in contact with the supporting force
- the wider the BOS the more stable the object is
- when COG is not over the BOS, less stable the object is
lever
rigid bar that can rotate around a point when force is applied
axis or fulcrum
fixed point, in the human body it is the JOINT
force in body
muscle that is moving
resistance
the load the force must overcome in order to move, the parts of the body that is moving + gravity + anything being lifted
force arm
perpendicular distance or length between line of force and axis, distance between the joint and the muscle attachment
resistance arm
perpendicular distance between line or resistance and axis, determines type of lever
first class lever
axis is located between force and resistance (seesaw)
F A R
second class lever
axis at 1 end, resistance in middle, force at other end (wheelbarrow)
A R F
third class lever
axis at one end, force in the middle, resistance at the other end
A F R
force arm rule of thumb
the longer the force arm (lever arm) the less resistance you will need to apply
