The Presentation consists of Reaction Board Method Practical that is a part of Sports Biomechanics Syllabus at Graduation and Post-graduation level at University of Delhi.
3. PREREQUISITE KNOWLEDGE
Force
“It is the push or pull
exerted by a body/system
on other body/system”
S.I Unit- Newton (N).
Law of Action and Reaction
“Action force=Reaction
force”
5. PREREQUISITE KNOWLEDGE
Center of Gravity (C.O.G.)
“Point at which all parts of body exactly balance
each other and where entire weight of body is
concentrated.”
Equilibrium
The state where net forces= 0.
7. AIM & REQUIREMENTS
To determine the height of center of gravity
using reaction board method.
Requirements
A board of length 1.83 m.
One subject.
Weighing machine.
8. PROCEDURE
Board will be placed horizontally on the knife
edges : one on block of wood & another on
platform of weighing machine.
Initial reading will be recorded(R1).
9. PROCEDURE
Then subject lies in supine position on board.
New reading(R2) will be recorded.
As, board was in equilibrium before subject laid
on it , and it is again in equilibrium thus, forces &
moment introduced are in equilibrium.
10. PROCEDURE
Introduced forces are: 1.Weight of subject
2. Reaction to weight
force.
Consider moments rotate about
Moment of Reaction weight force= (R2-
R1).L
11. PROCEDURE
Moment of weight force= W.x
As they are equilibrium = W.x = (R2-R1).L
x = (R2-R1).L
W
12. CALCULATE
If W= 52
R2=31.2, R1= 10.7
what is the location of C.O.G
using Reaction board method
(board length=1.8 meters).
13. CALCULATION
x = (R2-R1).L
W
Where, R2 = 31.2
R1 = 10.7
W = 52
x = (31.2 – 10.7) x 1.8
52
= 0.39 x 1.8 = 0.70 m
The height of the centre of gravity of the subject by reaction
board method is determined as x = 0.7m.
14. FULL PRACTICAL
For full practical consult:
Shaw, D. (2007).
Mechanical Basis of
Biomechanics. New
Delhi: Khel Sahitya
Kendra.
