Ratings of perceived exertion can be used as a practical method for measuring and prescribing training intensities. The 1962 Borg Perceived Exertion Rating Scale can beused for this purpose. Once the descriptors and numbers of the different categories are learned, they can be used reliably and repeatedly. A value of these descriptors is that they are independent of swimming speed. They can be used universally with a group comprising varied performance and fitness levels.