exercising

To exert for the sake of training or improvement; to practice in order to develop.

“to exercise troops or horses;  to exercise one's brain with a puzzle”

To perform physical activity for health or training.

“I exercise at the gym every day.”

To use (a right, an option, etc.); to put into practice.

“She is going to exercise her right to vote.”

(now often in passive) To occupy the attention and effort of; to task; to tax, especially in a painful or vexatious manner; harass; to vex; to worry or make anxious.

“exercised with pain”

To set in action; to cause to act, move, or make exertion; to give employment to.

The act by which something is exercised.