repeated action

• Collection is improved and achieved by engaging the hind legs , with the joints bent and supple , forward under the horse ' s body by a temporary but often repeated action of the seat and legs of the rider , driving the horse forward towards a more or less stationary or containing hand , allowing just enough impulsion to pass through
  要达到或加强收缩，是靠骑手用骑坐和脚短促而反复的动作，驱使马迎向稳定而又包容的手，允许有足够的前进气势，使马匹后肢各关节柔韧弯曲，前伸到马体下面。