8/30a Biomechanics Part 1 Flashcards
Define biomechanics
the study of structure and function of bio systems by the means of the methods of mechanics
What aspects of the movement system pertain to biomechanics
Motor control and elaboration of motion, force, and energy
Description of movement without respect to forces hat caused the motion of the body
kinematics
3 components of kinematics
velocity, displacement, height
Movement in 1 constant direction
linear/translational motion
Moving the body’s center of mass to project forward is an example of:
linear/translational motion
each part of the body has its own center of mass, how do you get the whole body’s center of mass?
average all of them
each body has a variable center of mass, but for the most part it is anterior to the sacrum in the pelvis
If you have a graph that shows displacement in the x and y axis for say a parabola of motion (squat requires x and y), what does the slope tell you
slope tells you the velocity of the body at that given position
Rotation and axis of rotation
all points on a rigid body move in a circular path around a pivot joint
Axis of rotation - point that remains constant/stationary about which the motion occurs
Active motion vs passive motion
active - muscles actively lengthen, not necessarily conscious
passive - no activation needed, someone else moves your body through space
osteokinematics
describes motion of a bone relative to cardinal plane of motion
- sagittal: medial/lateral axis
- frontal: anterior/posterior axis
- transverse: proximal/distal (longitudinal) axis
What is harder distal on proximal or proximal on distal motion? Give an example
Elbow flexion:
Distal on proximal is just lifting arm up and bending elbow
WHILE, proximal on distal could be a push up.
Proximal on distal is definitely more difficult
Hip AB vs AD proximal on distal vs distal on proximal
Hip AB leg raise is distal on prox (right leg raised, standing leg is left)
Hip dip yields hip ABduction (standing leg is right and the AB is on the right leg as well) proximal on distal.
Number of permitted planes of angular motion at a joint
Degrees of freedom Hip - 3 DOF -Flexion/extension -abduction/adduction -External/internal rotation of the foot
DOF of the elbow
2 DOF
- flexion/extension about med/lat
- AB/ADD about ant/post (minimal)
what determines the joint’s DOFs
the shape
- hinge, 1
- pivot, 1
- ball and socket, 3
differentiate osteokinematics vs arthrokinematics
osteo-motion of a bone relative to cardinal plane of motion (flex/ext - sagittal, AB/AD - frontal, INT Rot/EXT Rot - transverse)
arthro-motion between joint surfaces (roll, slide, spin)
Movement that occurs between joint surfaces
Joint play
natural looseness of the joint at rest, translation motion arises from active muscle natural laxity or looseness
Concave surface on convex surface at a joint (knee)
motion between surfaces, roll, slide, and spin (arhthrokinematics) occur in the same direction as the osteokinematic motion (knee flexion)
Convex surface on concave surface at a joint (knee)
motion of the roll is in the opposite direction as the slide and the spin. Arthrokinematics move opposite to osteokinematics (sit to stand closed chain)
***Functional examples of arthrokinematics
head of humerus ROLLS up the slightly convex glenoid fossa, then the head of the humerus concurrently slides downward.
If the head of the humerus does NOT slide concurrently, the impairment will be a pinching of the shoulder and the subacromial bursae yielding supraspinatus pull
Joint is most stable in this motion and has the least amount of motion
closed pack position
knee is closed when sitting with your leg extended out
Resting position of the joint that has a lot of joint play because ligaments are loose. Can undergo inflammation
open packed position
Tactics to analyze kinematics during a task
ensure you describe the plane, the motion and the type of joint
CASSS (control, amount of motion, speed, symmetry, symptom)
