Lecture 1: Biomechanics

Question 1

Why is a pushing force actually a pulling force?

Answer 1

Muscles only pull on tendons and tendons only pull on muscles. Tendon pulls the the ligament even though it may seem like a push. Triceps active Biceps: inactive

Question 2

Muscle as a pulling force

Answer 2

Triceps inactive

Biceps: active

Question 3

Anatomical Plane

Answer 3

sagittal
transverse
coronal/frontal

Question 4

Anatomical Axis

Answer 4

frontal
sagittal
vertical
(be able to draw)

Question 5

Cartwheel through…

Answer 5

• frontal plane

- sagittal axis

Question 6

360 through

Answer 6

• transverse plane

- vertical axis

Question 7

origin

Answer 7

• attachment of a muscle tendon to the stationary bone

- usually proximal

Question 8

insertion

Answer 8

• attachment of a muscle tendon to teh movable bone

- usually distal

Question 9

agonists

Answer 9

contraction is primarily responsible for a particular movement
-prime movers

Question 10

synergists

Answer 10

helper to the agonist

• usually at the start
• also help stabilize origin of agonist

Question 11

antagonist

Answer 11

actions oppose the agonist

-stabilizes agonist action

Question 12

pitching

Answer 12

• agonist=triceps

- antagonist= biceps (slows and controls the movement)

Question 13

lever

Answer 13

a rigid or semi-rigid body that when subjected to a force whose line of action does not pass through its pivot pointe exerts force on any object impeding its tendency to rotate

Question 14

Torque

Answer 14

magnitude of force times the length of its moment arm

Question 15

Mechanical Advantage

Answer 15

-ratio of Maf to Mrf

Question 16

MA greater than 1

Answer 16

allows the Fa to be less than the Fr to produce an equal amount of torque

Question 17

MA less than 1

Answer 17

is a disadvantage in the common sense of the term (at which most levers of the body act)
-sacrifice power but increase ROM

Question 18

First Class Lever

Answer 18

The forearm
Fm Fulcrum Fr
-typically produces disadvantage

Question 19

Second Class Lever

Answer 19

body acts as a 2nd class lever 
Fm    Fr    Fulcrum 
ex) calf raise- fulcrum=ankle applied force=calf

Question 20

Third Class Lever

Answer 20

*most common lever in the body
Fulcrum Fm Fr
mechanical disadvantage

Question 21

Changes in Mechanical advantage

Answer 21

• most of the skeletal muscles operate at a considerable mechanical disadvantage
• during sporst and other physical activities, forces in teh muscles and tendons are much higher than those exerted by the hands or feet on external objects or the ground

Question 22

Bicep Curl

Answer 22

• not consistent all the way through
• increase length of moment arm with tendon insertion a bit further away
• change in the moment arm which is then going to affect muscle torque
• larger moment arm when muscle is attached further away from the joint

Question 23

Patella

Answer 23

structure in place to help decrease the disadvantage throughout the ROM

• keeps the moment arm the same
• increase force of quad

Question 24

In a bicep curl where is the resistive force the greatest?

Answer 24

middle because the moment arm is the longest

Question 25

Moment of failure

Answer 25

• usually just before 90 degrees or at the bottom (aka sticking point) where you must overcome inertia
• usually more of a free weight thing

Question 26

Supporting the vertebral column during lifting

Answer 26

-ned to keep the spine in line to prevent compression on either side.

Question 27

Fluid ball

Answer 27

process of keeping the abdominal area tight to aid in supporting the vertebral column during resistance training
-engaging the core section

Question 28

valsalva manoeuvre

Answer 28

holding everything tight and not being able to move

why use it? should be able to lift more weight