Concepts of Biomechanics PT2 Flashcards
Joint Mobility
The degree of movement around a joint before movement is restricted by surrounding tissue
What joints typically need more mobility?
Foot/ankle, hip, thoracic spine, shoulder, and wrist
Joint Stability
The ability of muscles around a joint to control movement or hold the joint in a fixed position
What joints typically need more stability?
Knee, Lumbar spine, cervical spine, and elbow
What are Sir Isaac Newtons 3 Laws of Mobility?
Intertia: Motion tends to stay in motion while body at rest tends to stay at rest
Acceleration: Change in acceleration of mass occurs in the same direction of the force causing it
Action and Reaction: For every action, there is an opposite and equal reaction
What are the types of force?
Compression force
Tensile force
Shear force
Compression force
When two surfaces press toward one another, causing them to be compacted
Tensile force
Pulling two contact surfaces apart
Shear force
is created when two surfaces move or glide across one another
What are the two types of motion for human movement?
Linear and angular motion
Displacement
The distance an object moved from it’s starting point
Linear displacement
the distance an object moves in a straight line
Angular displacement
change in location measured in degrees of rotation of an object that’s rotating around an axis
Friction
A physical force affecting the body’s ability to create force, accelerate and decelerate
Static Friction
The friction of an object that doesn’t move
Sliding Friction
Friction between two surfaces where one or both are moving against one another
Rolling Friction
Force that resists a surface rolling across another such as a ball bearing or wheel on a road surface
What are the 7 principles of biomechanics?
- Stability
- Production of maximum force
- Production of maximum velocity
- Force-velocity relationship
- Direction of movement
- Ground reaction forces
- Angular motion
Work
Energy transferred when force is applied to an object
W = F x D
Power
The amount of work done in a unit of time
Levers
A rigid or semirigid bar rotating around a fixed point when force is applied to one end
Fulcrum
The point at which the lever rests or is supported and on which it pivots
First Class lever
Fulcrum located between the effort and the load; creates the balanced movements when the fulcrum is centrally located between the effort and the load
Second Class Lever
The load (resistance) is located between the fulcrum and the effort; Force movements are easily created by these levers because the load can be moved with relatively small effort.
