Bobbed

Moved up and down in a quick, bouncy manner; or cut hair short in a bob style (especially popular in the 1920s).

From bob, a verb with multiple related meanings. The primary sense comes from Middle English bobben, likely imitative of bouncing motion. The hair-cutting sense developed in the 20th century when the 'bob' hairstyle became fashionable. Both senses share the idea of quick, rhythmic movement.