lunging
n.— «Later, Ferris and a second trainer, Laura Conroy, each led a horse out on a long rope lead and did something even non-horse folks could relate to. They let the horses run in circles, to discharge pent-up energy, a practice called lunging.» —“Searching for signs of spring” by Mariella Savidge The Morning Call (Allentown, Pennsylvania) Mar. 21, 2008. (source: Double-Tongued Dictionary)