Activity Analysis of the Upper
Extremity and Trunk
Today’s Activities
1. Presentation of Lower Extremity Exercises
2. Vectors
3. Activity Analysis
a. Baseball Swing [Leading Arm]
Presentations
Remember to pay attention and TAKE NOTES
These exercises will be on the FINAL PRACTICAL
Vector Analysis
Force vectors give the magnitude and direction of muscle
and joint force needed to move a load. They also have
two key components, a point of application and line of
action.
• Magnitude (how much force) is designated by the length
of the vector
• Direction (of force) is designated by the direction of the
arrow
• Point of application is where the force is applied (typically
the center of the muscle’s attachment)
• Line of action is the infinite line at which the force is
acting.
Vector Components
Hamill & Knutzen, 2009
2-Dimensional Vectors
When looking at muscle vectors in two dimensions
(i.e. on one plane) it is the result of two components
• Horizontal Component:
• Stabilizing component: degree of parallel forces
generated on the lever (bone and joint) when the muscles
angle of pull is less than 90 degrees.
• Dislocating component: degree of parallel forces
generated on the lever (bone and joint) when the muscle's
angle of pull is greater than 90 degrees.
• Vertical Component/ Rotary Component:
• Force of a muscle contributing to bone's movement
around a joint axis; greatest when muscles angle of pull is
perpendicular to bone (i.e. 90 degrees).
Drawing Muscle Vector Components
1. Begin at the axis
2. Draw the Horizontal component
- Parallel to Lever
- Start at muscle insertion
90˚ all rotary (movement force)
> 90˚ Dislocating (force generated away form joint)
< 90˚ Stabilizing (force generated towards joint)
3. Draw Vertical Component
- Perpendicular to Horizontal Component
- Start at muscle insertion
4. Draw vectors ONLY long enough to make a perpendicular angle to the
resultant vector.
Start With Resultant Vector
Mark the length of Horizontal Component
Draw Horizontal Component
Draw Vertical Component
Example of Vectors at Different Points
of a Bicep Curl
Example of Vectors at Different Points
of a Bicep Curl
Lever Review
Lever Review
Lever Review
Lever Review
Lever Review
Lever Review
Activity Analysis
Break the Baseball Bat Swing into 3
Phases:
1.
Wind Up
2.
Swing
3.
Deceleration
http://www.youtube.com/watch?v=7JS
MEOv4dXQ&feature=fvwrel
Baseball Swing
For Next Week
Lab Report 6
Readings: TG: pp 311-321, 326-329, 332 (not palpation)