The crossover turn is the fastest back-to-breast transition, used by mostly all U.S. Olympians, such as 200 IM World Record Holder Ariana Kukors seen in this video.

At minimum, it is 0.3 seconds faster than a traditional open turn. On the middle turn of a 200 free race, would you do an open turn when everyone else does a flip turn? For the same reason, you should strongly consider incorporating a crossover turn into your arsenal of skills. 

The most common reasons why people don't do the crossover turn are because of the greater level of difficulty and inability to get a breath on the wall. 

Interestingly, those same facts apply to freestyle flip turns too, yet everyone does those. 

Simply put, the crossover turn is a sideways flip turn:

1. With your last backstroke arm stroke, extend toward the wall and roll onto your side. The extended arm is closest to the surface. The other arm remains at your side. 
2. Be sure not to roll past vertical onto your stomach before touching the wall. It helps to keep your shoulder behind your ear. 
3. Touch the wall and throw your head toward your knees to do a forward somersault. 

Dolphin kick backstroke is one of the best ways to learn how to develop a fast stroke rate. Many swimmers struggle in getting their arms through the stroke cycle fast enough in backstroke. It is difficult to know how to maintain that high stroke rate throughout a race if it is not practiced so we like to use the dolphin kick backstroke drill to learn how to maintain a high stroke rate. Synchronizing each kick with a single arm pull, Junya shows us how this technique enables a swimmer to pull faster and increase the overall speed of the backstroke. In this Race Club #swimisodes, you will see how Junya still manages to rotate his body quickly from side to side while pulling at this higher stroke rate, gaining power and speed.
There are only two stroke rates for backstroke, fast and faster. Dolphin kick backstroke drill is a wonderful technique to develop a faster stroke rate. Swimmers who cannot find a way to turn their arms over quickly might discover a faster way to swim with dolphin kick backstroke. Introduce fins using this technique while synchronizing the arms and suddenly the swimmer is backstroking on the freeway, motoring down the pool. At the Race Club, we have found this technique to be very effective in improving backstroke among swimmers who come to us of all ages and abilities.