It has been emphasized that having too long rests between the individual series and workouts we decrease the intensity of training. However we should not underestimate the risks of too great shortening of rests done to increase the intensity. It is advisable to make up a training schedule with a gradual lengthening of rests – not keeping equal lengths during the whole training cycle, especially if it takes years. In preparing to shorten the rests between the series the athlete should work from operative point of view. Thus we need to think over out initial approach to rest length.

Swimming differs from the other cardiovascular activities in the following:
- one has to keep the body weight on the surface of the water while at the same time moving in the horizontal plane with the help of the arms and legs;
- it is the best way to develop coordination skills;
- it is done into the water environment which increases the energy drain due to increased temperature exchange;