Chapter 2 Flashcards
Define Biomechanics
Science of applying principles of mechanics to biological systems
Biomechanics is applied to what?
- All motor skills performed in sports
- All training modalities
Kinetics
deals with forces that cause motion
Kinematics
description of motion
What are the types of muscle actions?
- concentric
- eccentric
- isometric
- isokinetic
Concentric
muscle shortening (bicep curl up)
Eccentric
muscle lengthening (bicep curl lowering weight)
Isometric
no change in muscle length with
muscular contraction (plank)
Isokinetic
velocity-controlled CON & ECC muscle actions
Define Nonpennate
fibers parallel to muscle’s line of pull
What are the Nonpennate muscles shapes?
- Longitudinal (strap)
– Quadrate (quadrilateral)
– Fan-shaped (radiate, triangular)
– Fusiform
Longitudinal (strap) example
sartorius
Quadrate (quadrilateral) example
rhomboids
Fan-shaped (radiate, triangular) example
pectoralis major
Fusiform example
Biceps brachii
Define Pennate
fibers oblique to line of pull
What are the Pennate muscle shapes?
- Unipennate
– Bipennate
– Multipennate
Unipennate example
tibialis posterior
Bipennate example
rectus femoris
Multipennate example
deltoid
What aspects affect muscle fiber arrangement?
the Angle of pennation and Muscle fascicle length
Angle of pennation
- Angle between fibers & central tendon
- Low (≤5°)
- High (>30°)
Muscle fascicle length
the longer the fascicle, the higher the potential contraction velocity
Linear Motion
all points on object move in a
straight line
Angular Motion
all points move around an axis
(such as the elbow or knee)
Define Torque
- Rotation caused by a force about a specific axis
– Product of force & moment arm length
Define Lever
- Used to overcome large resistance & enhance speed & ROM
What are the components of Lever?
- fulcrum (pivot point)
- resistance (load)
- force
What are the types of Levers?
– There are first-, second-, & third-class levers
First Class Levers
the fulcrum placed between the effort and load
Second Class Levers
the load in-between the effort and the fulcrum
Third Class Levers
the effort between the load and the fulcrum
What assumption can be made about the human body based on the lever system?
it was designed to produce motion at higher speeds at the expense of the large force applications
Effort arm
Distance between the effort and the fulcrum
Resistance arm
Distance between the Load and the fulcrum
Area of maximal torque is equivalent to/overlaps what?
maximal actin/myosin
Action Force
Force applied to an object with the intent to accelerate,
decelerate, stop, maintain, or change direction
Reaction Force
Equal & opposite force in response to action force (Newton’s 3rd law of motion)
Friction
Force parallel to action & reaction forces that acts to oppose relative motion of these two surfaces
