Biomechaincs lecture 6 linear forces
resistive force examples
- eccentric tension - Resistance of connective tissue to being stretched -contact forces = bone to bone or other - Viscosity of muscle tissues and joint capsules.
Compression
A force that pushes on or squeezes a material.
muscular redundancy
Different muscles perform the same action
motive force
Force that causes a change in motion of a system (e.g., body, body segment, object).
angle of attachment
angle between a muscle and the bone to which the muscle inserts
right horizontal or orientation of angle
angle indicating the direction of force
joint angle
angle indicating the position of two jointed body segments relative to each other
stabilizing
component is parallel to the bone lever and pointing towards the joint axis of rotation
Motive (rotary)
component that is always perpendicular to the bone lever
foot pressure
compression equals the measure of
10,000 N
failure point at a human vertebra is at about what compressive force
resistive force
force that opposes or resists movement of a system within a frame of reference
spondylolisthesis
forward slipping of one vertebra over another involves bilateral fracture of the pars interarticularis. The defect causes instability and allows the superior vertebra to slip anteriorly
Spondylolysis
fracture of pars interarticularis involves a fracture of the pars interarticularis
Destabilizing (dislocating) component
is parallel to the bone and pointing away from the joint axis of rotation
Motive component
perpendicular to the bone where the muscle inserts
destabilizing component
pointing away from the joint axis
stabilizing component
pointing towards the joint axis
motive force examples
•Concentric tension of muscles attached to the segment. •Recoil of elastic connective tissue to being stretched (tendons, ligaments).
relative joint angle
(intersegmental angle) expresses the angle between two body segments
degrees
(pi/180) = Radians
absolute joint angle
(segmental angle) expresses the segmental position relative to the right horizontal
Magnitude of force
The length of a force vector represents the
