8/30a Biomechanics Part 1

Question 1

Define biomechanics

Answer 1

the study of structure and function of bio systems by the means of the methods of mechanics

Question 2

What aspects of the movement system pertain to biomechanics

Answer 2

Motor control and elaboration of motion, force, and energy

Question 3

Description of movement without respect to forces hat caused the motion of the body

Answer 3

kinematics

Question 4

3 components of kinematics

Answer 4

velocity, displacement, height

Question 5

Movement in 1 constant direction

Answer 5

linear/translational motion

Question 6

Moving the body’s center of mass to project forward is an example of:

Answer 6

linear/translational motion

Question 7

each part of the body has its own center of mass, how do you get the whole body’s center of mass?

Answer 7

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

Question 8

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

Answer 8

slope tells you the velocity of the body at that given position

Question 9

Rotation and axis of rotation

Answer 9

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

Question 10

Active motion vs passive motion

Answer 10

active - muscles actively lengthen, not necessarily conscious
passive - no activation needed, someone else moves your body through space

Question 11

osteokinematics

Answer 11

describes motion of a bone relative to cardinal plane of motion

• sagittal: medial/lateral axis
• frontal: anterior/posterior axis
• transverse: proximal/distal (longitudinal) axis

Question 12

What is harder distal on proximal or proximal on distal motion? Give an example

Answer 12

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

Question 13

Hip AB vs AD proximal on distal vs distal on proximal

Answer 13

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.

Question 14

Number of permitted planes of angular motion at a joint

Answer 14

Degrees of freedom
Hip - 3 DOF
-Flexion/extension
-abduction/adduction
-External/internal rotation of the foot

Question 15

DOF of the elbow

Answer 15

2 DOF

• flexion/extension about med/lat
• AB/ADD about ant/post (minimal)

Question 16

what determines the joint’s DOFs

Answer 16

the shape

• hinge, 1
• pivot, 1
• ball and socket, 3

Question 17

differentiate osteokinematics vs arthrokinematics

Answer 17

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)

Question 18

Movement that occurs between joint surfaces

Answer 18

Joint play

natural looseness of the joint at rest, translation motion arises from active muscle natural laxity or looseness

Question 19

Concave surface on convex surface at a joint (knee)

Answer 19

motion between surfaces, roll, slide, and spin (arhthrokinematics) occur in the same direction as the osteokinematic motion (knee flexion)

Question 20

Convex surface on concave surface at a joint (knee)

Answer 20

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)

Question 21

***Functional examples of arthrokinematics

Answer 21

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

Question 22

Joint is most stable in this motion and has the least amount of motion

Answer 22

closed pack position

knee is closed when sitting with your leg extended out

Question 23

Resting position of the joint that has a lot of joint play because ligaments are loose. Can undergo inflammation

Answer 23

open packed position

Question 24

Tactics to analyze kinematics during a task

Answer 24

ensure you describe the plane, the motion and the type of joint
CASSS (control, amount of motion, speed, symmetry, symptom)