Biomechanics Flashcards
Biomechanics
The science that examines the forces acting upon and within a biological structure and the effects produced by such forces
Quantitative Analysis
Measuring variables to optimize athletic performance
Foot forces on sprinter’s starting block (Force Platforms)
Muscle contraction sequence during running (EMG)
3-D body segment movements during a high jump (Motion capture)
Qualitative Analysis
Using sight and hearing
Usually done by coaches and teachers
Who typically do not have access to complex equipment or specialized knowledge
To identify and correct errors: “Observe, analyze and correct.”
Requires framework and a set of principles
Kinematics
Describing human motion without its forces
Focusing on motion’s spatial and timing characteristics
Measurements: Position Displacement Velocity Acceleration
Measured
with respect
to time
Kinetics
Describing forces leading to motion
Internal forces
Muscles pulling on bones
Bone-on-bone, inside joints
External forces acting on the body
Without contact (e.g., gravity)
From contact with ground, opponent or equipment
Particle Model
Dot represents centre of mass
Used when body or object is airborne and in flight
i.e., projectile motion
Stick figure model
Body segments = sticks
Used when body in contact with other objects
Describe gross motor skills in 2-D
Rigid body segment model
Body segments = irregular 3-D volume
Used for sophisticated 3-D analyses
Can include shape deformation of body segments
Linear motion
All body parts move same distance and direction, at the same time
Translation: linear motion of the whole body
E.g. Bobsled
Angular motion
Body moves on a circular path and rotates about axis of rotation
Body segments rotate about their joints
E.g., twisting somersault
General motion
Body / segments move linearly and rotate at the same time
True for most athletic and every day activities
E.g., walking
How levers work
- Rotation at the axis/fulcrum
- force and resistance arm
- Force is applied and if the turning effect of the force is greater than resistance
First Class Levers
Applied force and resistance on opposite side of axis, at un/equal distance from one another
Example: crowbar
Human body: head flexion
Either gives a mechanical or speed advantage depending on where the axis is placed
Second level Levers
Applied force and resistance on same side of axis; resistance closer to axis
Example: wheelbarrow
Human body - rare: toe raise
Always gives a mechanical advantage (FA>RA)
Third class levers
Applied force and resistance on same side of axis; force closer to the axis
Example: fishing
Human body – many: forearm flexion
Always gives a speed advantage (FA
