Answer: flexing

AnswerCrossword Clue
FLEXINGWarming up for gymnastics
FLEXINGShowing off one's muscles
flexing(of a material) Be capable of warping or bending and then reverting to shape
flexing(of a muscle) Contract or be tensed
flexingCause (a muscle) to stand out by contracting or tensing it
flexingBend (a limb or joint)
flexingPlace (a corpse) with the legs drawn up under the chin
flexing(of a limb or joint) Become bent
flexingFLEX, to bend (to curve (to bend))