Biomechanics

Front 1

RA

Back 1

Resistance Arm

Front 2

resistance arm

Back 2

the perpendicular distance from the fulcrum to the line of action of the resistance acting on the resistance point.

Front 3

force lever

Back 3

When the force arm of a lever is longer than its resistance arm, the mechanical advantage favors application of force, at the sacrifice of speed.

Front 4

speed lever

Back 4

When the resistance arm of a lever is longer than its force arm, the mechanical advantage favors application of speed, at the sacrifice of force.

Front 5

first class lever speed or force type?

Back 5

can be either – either, depending on relative position of FA, RA, and A.

Front 6

first class lever

Back 6

fulcrum at some location between the force point and the resistance point. eg: triceps on elbow joint. elbow=fulcrum, triceps insertion is forcepoint on olecranon, gravity = resistance point.

Front 7

second class lever

Back 7

resistance point at some location between force point and the fulcrum.

Front 8

third class lever

Back 8

force point at some location between the resistance point and the fulcrum – most common in body. muscle can be inserted near joint to produce distance and speed of movement.

Front 9

Describe the force-velocity curve. How does fibre type distribution effect this curve?

Back 9

Force velocity curve assesses influence of speed of shortening or movement of muscle on strength of contraction. more type II = more force. more speed = less force.

Front 10

Identify the factors that can affect the strength of a muscle.

Back 10

1. speed of shortening of fibres

Front 11

Torque:

Back 11

muscular force over a range of motion (force times distance.) distance = moment arm.

Front 12

isotonic muscle contraction definition and example

Back 12

muscle shortening while lifting a constant load

Front 13

isometric muscle contraction definition and example

Back 13

no visible muscle shortening or change in angle of bones

Front 14

isokinetic muscle contraction definition and example

Back 14

constant speed of contraction: tension maximal over full range of motion

Front 15

eccentric muscle contraction definition and example

Back 15

lengthening of muscle during contraction. controlled elongation of muscles toward original resting length.

Front 16

Identify the factors that affect the tension of a muscle undergoing an isotonic contraction in the body and explain how they affect tension.

Back 16

tension of muscle and force it can produce effected by: initial length of fibres (able to exert most force from relaxed position – as it shortens, less tension can be exerted.), angle of pull of muscle on skeleton (there is an optimal range of angles at which muscles can apply the most force.), speed of shortening (affected by distribution of fibres also. type I or type II fibre availability can effect tension availability) + speed at which muscle can contract.

Front 17

Describe muscle force-velocity relationships and muscle power-velocity relationships. How does fibre type distribution affect the shape of force-velocity curves and power velocity curves?

Back 17

peak torque decreases with increased velocity.
torque is greatest at lowest speeds.
At any velocity, higher % torque is produced with higher % type two fibres.
Higher % type one = less torque.

Front 18

Distinguish between muscular strength and muscular endurance.

Back 18

strength = greatest amount of force that a muscle or muscle group can
produce in a single, maximal contraction.
endurance=capacity of a muscle group to
perform repeated contractions against a load for an extended time period.

Front 19

third class levels force levers or speed levers?

Back 19

Always speed levers - FA always less than RA.

Front 20

FA

Back 20

force arm

Front 21

mechanical advantage

Back 21

force arm divided by resistance arm: efficiency with which a lever is able to magnify forces.

Front 22

centre of gravity

Back 22

point at which body may rotate freely in all directions

Front 23

balance

Back 23

ability to control equilibrium

Front 24

stability

Back 24

when a body is able to resist disruption of equilibrium

Front 25

kinetics

Back 25

study of forces associated with motion

Front 26

kinematics

Back 26

appearance of motion, movement of bodies with respect to time or precise speed and movement of body parts.

Front 27

weight

Back 27

mass corrected for gravity=
kg x 9.81 m/s2

Front 28

work

Back 28

force times distance

Front 29

PE

Back 29

Potential energy. Weight times height.

Front 30

Kinetic energy unit

Back 30

joules

Front 31

Momentum

Back 31

mass times velocity

Front 32

Mechanical advantage

Back 32

force arm divided by resistance arm

Front 33

biomechanics

Back 33

quantifies direction and forces of human movement

Front 34

inertia

Back 34

tendency of a body to maintain a motionless state or a state of constant velocity.

Front 35

acceleration formula

Back 35

force equals mass times acceleration f=ma

Front 36

weight formula

Back 36

mass in kg x 9.81 (acceleration caused by gravity.)

Front 37

force

Back 37

a push or a pull acting on an object.

Front 38

work

Back 38

force against a resistance, and the distance the resistance is moved.

Front 39

joule

Back 39

unit of work. J= units of force multiplied by units of distance.

Front 40

energy

Back 40

capacity to do work.

Front 41

potential energy

Back 41

energy of position, which provides the potential to do work.

Front 42

potential energy formula

Back 42

Potential energy is a body’s Weight (Wt) times its height above a surface. PE=(Wt)(h)

Front 43

kinetic energy

Back 43

energy possessed by a body as a result of linear motion

Front 44

kinetic energy formula

Back 44

KE= ½ mv2

Front 45

momentum

Back 45

the quantity of motion that an object posesses.

Front 46

momentum formula

Back 46

M=mv (Momentum equals mass times velocity)

Front 47

lever

Back 47

a rigid bar that turns about an axis

Front 48

force point

Back 48

point where force is applied. In humans, this is the muscle insertion.

Front 49

resistance point

Back 49

the exact point on which the resistance acts

Front 50

fulcrum

Back 50

the axis of motion

Front 51

force arm (FA)

Back 51

perpendicular distance from the fulcrum to the line of action of the force acting on the force point.

Front 52

distinguish between force and speed levers

Back 52

force levers are longer levers that are better at imparting force due to their longer length. Speed levers are usually shorter, and can move faster through the same number of degrees because of their shorter length.

Front 53

what is the law of conservation of mechanical energy?

Back 53

(PE+KE)=C
the sum of potential energy plus kinetic energy is constant.