As a swimmer you must be proficient at several key pieces, at least two strokes, diving and flip turns being the most notable to the time one receives in a race. Equal and opposite reactions are major points of a stroke, a swimmer kicks in the water the swimmer is pushing against the water which in turn propels him forward and the stroke (arms) are use to push against the water which further propels said swimmer. When the swimmer starts the race is also key as a good dive can give you important milliseconds that can give you the race. during the dive you push off of the starting block, this pushes the swimmer off of the block and into the water. the final but by no means least important part to the race is flips turns. A flip turn is when a swimmer reaches one end of the pool then do something of a summersault onto the wall and use their feet to push against it which depending on how hard the swimmer pushes against it leads to various speeds off the wall.