lecture 4: biomechaics

Question 1

what are the passive strtuctures of th musculoskeltal system

Answer 1

bones
carinlage
joiints
ligaments

Question 2

what are the active elements of the musuloskeltal sysmte

Answer 2

muscles/tendons

Question 3

what is the MSK system

Answer 3

systems capable of resisiting or generation motion at joints

Question 4

what is biomechanism

Answer 4

the strudy of the structure and functon of living systems through principles of mechanics

Question 5

what is biomechannics in terms of the MSk

Answer 5

largerely the study of movement (locomotion)
=forces (kinetics)
movement (kinematics

Question 6

whats the name for forces

Answer 6

kiinetics

Question 7

whats the name for movment

Answer 7

kinematics

Question 8

what is tthe function of knowing biomechanism

Answer 8

treating muscles bones, joints as lever systems helps to understand their function, if if you cant remember it

Question 9

why use biomechanisms for dysfunction

Answer 9

many patietnes will have symptoms that reflect inablity and/or weakness in performing certain movements

Question 10

what is the definition of a lever

Answer 10

a simple machine consisting of a rigid body that can rotate at a fixed point (fulcrum) in response to forces applied somewhere along its length

Question 11

what is torque

Answer 11

the tendency of a force to cause an object to rotate around a certain points

Question 12

what is the formula for torque

Answer 12

torque= force x perpendicualr distance to the fulcrum (lever)

Question 13

Ffor the same force, would a half lever length or full lever length generate most torque

Answer 13

full levre length

Question 14

what happens is the force and lever are parralel

Answer 14

no torqur created

Question 15

in the MSK, what is considered the lever

Answer 15

the bones

Question 16

in the MSK, what is considered the fulcrums

Answer 16

joints

Question 17

in the MSK, what is considered the forces applied

Answer 17

external (gravity) or muscular
=creates torques at the joints

Question 18

true or false: muscles can produce force by pushing

Answer 18

false, muscles can only pull (ie: muscles work thru tension)

Question 19

true or false and why: MSK lever systems are composite

Answer 19

true because there are greater than 2 muscles that generate torques on opposite sides of the joint (ie: triceps vs biceps brachii)

Question 20

whta is the agonist and give ane xample

Answer 20

perform the action (ex: bicep flexion of elbow)

Question 21

what is an antagonist and give example

Answer 21

performs opposite action of agonist
(ex: tricps extends the elbow)

Question 22

what is the synergiest and give example

Answer 22

assists the agonists (brachialiss assists in. biceps in elbow. flexion)

Question 23

what are. stabilizers and give. examples

Answer 23

stabilize the joints, fine tunes the movements
(ex: anconeus stabilizes elbow jointns in extension)

Question 24

what are the muscle common external forces

Answer 24

gravoty
ground raection forces

friction

Question 25

what are ground reactiton fcores

Answer 25

for every force there is an equal and opposite force (ex: gravity vs the ground pushing back p)

Question 26

what is the difference between load arm and lever arm

Answer 26

load arm is the distance between the joints to the load and the lever arm is the distance btween the joints (fulcrum) to the muscles line of action

Question 27

external force is AKA

Answer 27

load

Question 28

distance to. load is AKA

Answer 28

load arm

Question 29

internal muscle force is AKA

Answer 29

effort

Question 30

distance to effort is AKA

Answer 30

lever arm

Question 31

when is equilibrium reached

Answer 31

torques are equal and cancel out (effort=load)

Question 32

how do we get from torque to actual angular motion

Answer 32

torques are not equal angular motion (rotation) direciton and speed depends on which torque is greatest

Question 33

what is angular motion

Answer 33

force that generations rotational force

Question 34

what does angular motion's speed and direction depend on

Answer 34

which troque is greatest

Question 35

Picture a man holding the points stead (equilibirum), explain the muscle involvement and the torques

Answer 35

isometric contraction of the biceps (effort) that generates equal and opposite torque to resist the torquecreated by weight of the pint

Question 36

picture a man taking a sip of his beer and explain the muscles and torqur involved

Answer 36

biceps torque is greater tthan the pint torque =causes elbow flexion through concentric cocntraction of the biceps (fibers shortneing)

Question 37

picture a man putting his beer down after drinking and explain the muscles and torqur involved

Answer 37

pint torque is greather than biceps torque which causes elbow extension but controlled through the eccentric conraction of the biceps

Question 38

how can you get more torque

Answer 38

increase the force (ie: larger muscle) longer lever arm increase D (upside down T)

Question 39

how can some mnuscle lever systems be boostted

Answer 39

by bony protructions that length the lever arm (exL processes, tubercles =improves muscle ability to generate torque)

Question 40

when you squat, what external force is applied to the femur and what torque is produced at the knee

Answer 40

trunk weight

Question 41

what kind of angular motion would squatting created

Answer 41

flexion of the knee

Question 42

what would resistt the trunk weight

Answer 42

extensors of the knee (quads)

Question 43

how does quadricep effort chagne with increases knee flexion

Answer 43

incrase flexion=increase effort (more gravity load arm increases)

Question 44

how does muscle contrtaction change with increasing/decreasing flexion

Answer 44

static=iso down squation-eccenttric up squat= concentric

Question 45

angular motion AKA

Answer 45

rotation

Question 46

fulcrum defintion

Answer 46

center of rotation= axis

Question 47

external force aka

Answer 47

load out-force resistnace

Question 48

internal force AKA

Answer 48

muscle force effort

Question 49

load arm is condiered what lever

Answer 49

out lever

Question 50

lever arm is consideered what lever

Answer 50

in. lever

Question 51

what is the def of torque

Answer 51

moment of force