Biomechanics Exam 2

Front 1

kinematics

Back 1

the description of motion

Front 2

kinetics

Back 2

deals with the causes of motion i.e. force and torques (moments)

Front 3

force coupling and give example

Back 3

internal forces of muscles acting synergistically causing a rotation. they work in pairs/ coupling
it's why the scapula rotates in arm abduction

Front 4

are GRF's internal or external

Back 4

external

Front 5

what is the dip in the vertical ground reaction force during gait due to?

Back 5

as you move forward you bend down/ accelerate down briefly so like squatting on a scale you weigh less/ less force applied to force plate.

Front 6

how would you make the vertical GRF plateau instead of dipping down during walking/gait

Back 6

if kept leg streaight through stance phase you might be able to with no dipping b/c wouldn't be accelerating downwarsd

Front 7

what is impulse used for, what is it equal to, and how is it often calculated

Back 7

it's just another way to quantify the magnitude of loading.
impulse=force X time
calculated often as teh integral/ area under the force-time curve

Front 8

if somebody needed to decrease joint force, what is a simple thing to dot aht you could tell them

Back 8

slow down when you are walking b/c less joint force in loading b/c decrease in GRF. with increased speed you get more momentum and that equals increased GRF

Front 9

looking at GRF's how could you tell if somebody is runing at constant velocity or not

Back 9

by looking at anterior posterior forces (braking and propulsive impulses) . if they're equal then constant velocity. if braking phase is bigger than slowing down adn if propulsive (+) area/impulse is larger than speeding up

Front 10

is friction magnitue constant or variable, explain

Back 10

variable
until sliding occurs, friction magnitue is the motive force "limiting friction"
once sliding occurs, friction mag decreases "sliding friction"