This document discusses different types of muscle contractions that can occur during physical therapy. It describes isometric contractions where the operator and patient forces match so no movement occurs. It also describes isotonic eccentric contractions where the operator force overcomes the patient's effort, moving the joint in the opposite direction. The effort of the patient should be 20% of their strength and held for 7-10 seconds.

5. (1) The operator’s force may exactly match the effort of the patient
allowing no movement to occur ( isometric contraction). This
isometric contraction in combination of:
a. RI of antagonist of the muscle being contracted.
b. PIR of agonist of the muscle being contracted.
(2) The operator force may overcome the effort of the patient, thus
moving the area or joint in the direction opposite to that in which
the patient is attempting to move it (isotonic eccentric
contraction, also known as an isolytic contraction).
(3) The effort of the patient is 20% of strength.
(4) The length of time the effort is held 7-10 seconds.