At the catch, the rower places the blade in the water and applies pressure to the oar by pushing the seat toward the bow of the boat by extending the legs, thus pushing the boat through the water. The point of placement of the blade in the water is a relatively fixed point about which the oar serves as a lever to propel the boat. As the rower's legs approach full extension, the rower pivots the torso toward the bow of the boat and then finally pulls the arms towards his or her chest. The hands meet the chest right above the diaphragm. At the end of the stroke, with the blade still in the water, the hands drop slightly to unload the oar so that spring energy stored in the bend of the oar gets transferred to the boat which eases removing the oar from the water and minimizes energy wasted on lifting water above the surface (splashing). The recovery phase follows the drive. The recovery starts with the extraction and involves coordinating the body movements with the goal to move the oar back to the catch position. In extraction, the rower pushes down on the oar handle to quickly lift the blade from the water and rapidly rotates the oar so that the blade is parallel to the water. This process is sometimes referred to as feathering the blade. Simultaneously, the rower pushes the oar handle away from the chest. The blade emerges from the water square and feathers immediately once clear of the water. After feathering and extending the arms, the rower pivots the body forward. Once the hands are past the knees, the rower compresses the legs which moves the seat towards the stern of the boat. The leg compression occurs relatively slowly compared to the rest of the stroke, which affords the rower a moment to recover, and allows the boat to glide through the water. The gliding of the boat through the water during recovery is often called run. A controlled slide is necessary to maintain momentum and achieve optimal boat run. However, various teaching methods disagree about the optimal relation in timing between drive and recovery. Near the end of the recovery, the rower squares the blade into perpendicular orientation with respect to the water and begins another stroke. Boat classes Broadly, there are two ways to row, sometimes called disciplines: In sweep