Lesson 1 Flashcards
Introduction to Biomechanics
Force
Push or pull that produces displacement
External agent enabling body to change direction and be at a state of motion from rest
Contains magnitude (strength of force) and direction (w/c direction the object goes based on the force exerted on it)
Gravity
most prevalent force
Usually the weight of an object, in physics: g=9.8 m/s2
Muscle Force
force generated by either passive or
active contraction to produce motion
Muscle contractions allow the body to
produce actions or movements
Externally applied resistances
tools/equipment that the muscles have to work against to produce motion
E.g. Manual resistance (during palpation), Pulley, Door (like in Mcdo), Windows
Friction
resistance to movement between 2 objects when in contact with each other
Kinesiology
Study of motion and the internal and external
forces involved in movement
In occupations, OPTIMAL movements should be used to perform occupations
Anatomy
study of structures of human body
Biomechanics
human body mechanics (study of forces and motion applied to a certain thing)
- study of forces and motion applied to human body
- Application of kinematics and kinetics to the mechanics of human movement
Statics
Study of objects that are either at rest or
in constant motion
Dynamics
Study of objects that involve acceleration
Kinetics
Study of motion that involves forces
Type of Kinetics
Linear (one direction)
Angular (angles on motion)
Kinematics
Study of motion WITHOUT regard to
forces that produce
motion
Types of Kinematics
Arthrokinematics
- concerned with the
movement of 2
articulating joint
surfaces
- Automatic,
non-voluntary
2.2.2.2. Osteokinematics
- movements of bony
levers through their
ranges of motion
Frontal / Coronal / XY Plane
Z-axis
● Divides the body into front and back
● Example Motions:
○ Shoulder/Hip abduction and adduction
○ Wrist ulnar and radial deviation
○ Trunk lateral flexion
Sagittal / Vertical / YZ Plane
X-axis
● Divides the body into right and left
● Example Motions:
○ Elbow/Knee flexion and extension
○ Ankle dorsiflexion and plantarflexion
○ Hip flexion and extension
○ Trunk flexion and extension
○ Wrist flexion and extension
Horizontal / Transverse / XZ Plane
● Y-axis
● Divides the body into upper and lower
parts
● Example Motions:
○ Shoulder Internal and External Rotation
○ Elbow pronation and supination
○ Horizontal abduction and adduction
○ Ankle adduction and abduction
○ Trunk rotation
Center of Gravity
The intersection of the center of all three of
these planes
Theoretical point around which the mass of
the object is balanced. It is around this center
that gravity acts.
COG of Adults
S2 Level
Stable
line of gravity is within the base of
support
Unstable
line of gravity outside the base
of support
Hinge
Uniaxial
Sagittal plane
Flexion and Extension
Elbow
Pivot
Uniaxial
Transverse plane
Supination, Pronation, Inversion, and Eversion
Forearm
Condyloid
Sagittal and Frontal planes
Flexion, Extension, Abduction, and Adduction
Metacarpo phalangeal
joints, Metatarsophalyngeal joints
Ellipsoidal
Sagittal and Frontal planes
Flexion, Extension, Radial and Ulnar
Deviation
Radiocarpal joint
Saddle
Sagittal, Frontal, and
some in Transverse planes
Flexion, Extension, Abduction, and Adduction
Carpometacarpal joint of the thumb
Ball and Socket
Sagittal, Frontal, Transverse Flexion,
Extension, Abduction,
Adduction, and
Rotation
Shoulder, Hip
Open Kinematic Chain
the DISTAL
segment of the chain moves in space
while the PROXIMAL is planted or
stationary
Closed Kinematic Chain
the
PROXIMAL segment of the chain moves in
space while the DISTAL is planted or
stationary
Closed Pack Position
Joint is compressed & difficult to distract
Joint surfaces are mostly in contact.
● Ligaments and capsular structures are slack
Open Pack Position
● Ligaments are farthest apart and under tension
● Capsular ligaments are taut
● Joint surfaces may be distracted
● Allow motions such as spinning, rolling, & sliding
● Injuries are more common in this position
Sliding
1 joint surface is
parallel to the plane
of the adjoining joint
surface
Spinning
1 point of contact
on each surface
remains in contact
with fixed location
on another
surface
Rolling
Each point on 1
surface contacts a
new point on the
other surface
Last 20° of extension of the knee
knee
joint demonstrates a combination of rolling, sliding,
and spinning
Principle 1 of Concave-Convex Principle
If the bone with the convex joint surface
moves on the bone with the concavity, the
convex joint surfaces move in the OPPOSITE
direction to the bone segment
Ex. When the humerus (bone segment) moves
upward, the CONVEX head (joint surface)
moves downward
Principle 2 of Concave-Convex Principle
If the bone with theconcavity moves on the convex surface, the concave articular surface moves in the SAME direction as the bone segment.
Ex. When the elbow flexes, the CONCAVE
trochlear notch (joint surface) moves upward, in
the same direction of the ulna (bone segment).
Isokinetic
● Occurs when rate of movement is constant
● Only happens when we use machines
● Ex. pedaling a stationary bike at the same speed
Isometric
● Static/Holding Contraction
● No change in the joint angle = muscle length
stays the same while producing force
● Ex. Plank exercise
Isotonic
● Constant tension as muscle changes length
● Muscles change length while producing force
Eccentric
muscle lengthening
Concentric
muscle shortening
Mechanical Advantage (MA)
Ratio between the length of the force arm and
the length of the resistance arm
● Greater mechanical advantage = task is easier
to accomplish
1st Class Lever
Exerted force on opposite sides of the axis or fulcrum
2nd Class Lever
Weight/resistance is situated in between
effort force and axis
easiest to carry
effort arm>resistance arm
3rd Class Lever
Effort force is between axis and resistance force
most difficult to carry
