Question

Lifting a heavy weight is a demonstration of which measure of fitness? absolute strength muscular endurance muscular relaxation flexibility

Answer 1

absolute strength I would say. It is 100% not muscular relaxation or flexibility, I would say your best bet is absolute strength.

Answer 2

Lifting a heavy weight is a demonstration of  ABSOLUTE STRENGTH.
Absolute strength refers to the amount of force one can exerted regardless of body size or muscles capacity. Absolute strength is measured by the amount of weight one can lift regardless of body size.