All about base excess â to BE or not to BE. In 1948, Singer and Hastings introduced the concept of buffer base (BB). The change in BB from normal was called deltaBB (Î´BB). This change in BB was an expression of the non-respiratory (metabolic) component of an acid-base disturbance.
Empirically from http://www.usaswimming.org/_Rain..., free style is the fastest stroke. This is also called the front crawl (see Front crawl). However as Swimming stroke notes, there are at least 6 variations of that technique.
For most swimmers, the front crawl is the fastest and most efficient stroke. With proper training, a swimmer in good condition can exceed 4 miles per hour using the front crawl. As of September 2014, the record for the 50-meter crawl was 20.91 seconds, which is the equivalent of swimming 5.39 miles per hour.