There are three types of equilibrium: stable, unstable, and neutral. Stable equilibrium occurs when a body is displaced but forces act to restore it to its original position. Unstable equilibrium happens when initial displacement increases with applied forces, causing the body to fall. Neutral equilibrium maintains the center of gravity in relation to the base despite displacement. The human body is most stable lying down and least stable standing up as the center of gravity rises and base reduces.

1. STATES OF EQUILIBRIUM
Prof. Dr. M. Rajesh, PT, M.P.T(cardio), BCRC
TRINITY MISSION AND MEDICAL FOUNDATION
MADURAI

2. INTRODUCTION
 Equilibrium results when the forces acting upon a body are
perfectly balanced and the body remains at rest.
 It has thress types – stable , unstable and neutral equilibrium

3. STABLE EQUILIBRIUM
 If the forces acting upon a body at rest tend to restore it to its
original position after it has been displaced, the body is said to
be in stable equilibrium.
 In the condition COG is as low as possible and the LOG falls
near the centre of an extensive base.

4. UNSTABLE EQUILIBRIUM
 If a body is given an initial displacement and the forces acting
upon it increase this initial displacement, however small the
latter may be, the body is said to be in unstable equilibrium.
 The COG is as high as possible and the LOG to fall outside the
base, and the body will fall to the ground. E.g Toe standing

5. NEUTRAL EQUILIBRIUM
 If, in spite of displacement of a body, the height and position of
its COG remain the same in relation to the base, the body is
said to be in neutral equilibrium. E.g ball moves on the plane
surface.

6.  The stability of the human body is greatest in the lying position.
It becomes progressively less stable as the COG is raised and
the base is reduced, as in the sitting and standing positions.

7. THANK YOU
Prof. Dr. M. RAJESH, PT,M.P.T(cardio),B.C.R.C
TRINITY MISSIOIN AND MEDICAL FOUNDATION
MADURAI.
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