The phrase "bringing knees" can be described with a variety of synonyms. Some alternatives include flexing, bending, lifting, hoisting, raising, hauling, heaving, and jerking up. Each of these synonyms adds a slightly different nuance to the action of bringing one's knees up. For example, flexing might connote a slower, deliberate movement, while jerking up suggests a sudden or forceful action. Using different synonyms can also add variation and interest to your writing or speaking. So instead of always using the same phrase, experiment with incorporating different synonyms for "bringing knees" into your vocabulary.