Biomechanics basics

1. Dr
Jitendra
Sharma
Active and Passive
Insufficiency
Dr Jitendra Sharma

2. Dr
Jitendra
Sharma
• Insufficiency is the term used for describing the inability of a muscle
to generate adequate force bring out a desired action / movement.
• In absence of disease process, muscle insufficiency is seen when the
length tension relation is altered.
• Muscle lengthened = Passive insufficiency
• Muscle shortened = Active insufficiency
• Active and Passive insufficiency is seen only in two joint or multi-joint
muscles.

3. Dr
Jitendra
Sharma • Active insufficiency occurs when a
multi-joint muscle shortens over
BOTH joints simultaneously, and
hence, creates so much slack, that
muscle tension is almost
completely lost. It cannot
maintain or generate active
tension.
• Passive insufficiency occurs when
the multi-joint muscle
is lengthened to its fullest extent
at both joints, but also preventing
the full ROM of each joint it
crosses. The muscle cannot
elongate further.

4. Dr
Jitendra
Sharma
• Rectus femoris causes Hip flexion and Knee extension. It cannot cause
full ROM together of hip flexion and knee extension….this is active
insufficiency.
• Similarly, Flexor Digitorum Profundus loses capability to make a tight
fist when the wrist is flexed…….active insufficiency.
• When the hip is fully flexed, the knee cannot be extended to fullest
without pain or damage…………..passive insufficiency.

5. Dr
Jitendra
Sharma
PASSIVE INSUFFICIENCY
NORMAL
ACTIVE INSUFFICIENCY

6. Dr
Jitendra
Sharma
Length Tension Relationship

7. Dr
Jitendra
Sharma
Relationship between Active and Passive
Insufficiency?
• When the agonist is trying to contract, the antagonist is relaxing/
lengthening.
• The extensibility of the antagonist therefore is a factor in limiting
capability of the agonist……passive insufficiency.
• Therefore, the agonist becomes:
• Actively insufficient when it is placed in shortened position.
• Passively insufficient if the antagonist is tight.

8. Dr
Jitendra
Sharma
QUESTIONS??