The motion of a horse in trot can throw about a rider who has locked his hip and back muscles, causing uncomfortable bumping against the saddle.

• 马匹在小跑步时，会让骑士上/下跳动，并将骑士的臀部和背部肌肉拉紧，造成骑士在马鞍上现不舒服的跳动情况。