Lifting a weight 10 times is a kind of ISOTONIC contraction. Holding a heavy machine part steady while securing it in place may be categorized as ISOMETRIC contraction. Lifting heavy cans and putting them on a shelf may be called an ISOTONIC contraction. Flexing your leg muscles and holding the flex is an ISOMETRIC contraction. Lifting your heavy book bag several times is good ISOTONIC contraction.
I believe it is either one or five, i am not sure though.
I believe the answer to your question will be atrioventricular but don't cross out pulmonary it could possibly be the answer.