Down & Outs:
This set has two parts. The first will be a set number of 25s. This part should always be performed fast! When you reach the other side of the pool, quickly climb out of the water, wait 5 seconds, dive back in the pool and sprint to the other side. Repeat the climbing out and 5 second rest until you have completed the given number, for example: 4×25 Down & Outs.
The second part is the rest and recovery. Usually, if the number of D&Os equals 100 yards, the recovery will be 100 yards. After the recovery swim, rest an extra 30-60 seconds before repeating the set.