Pace plans for 200m events

The pacing plans seem to be similar for all 200 m events. Ideally, swimmers should start out at the fastest pace they can maintain throughout the race without losing speed at the end. They should swim the first 50 m of these races 2 to 3 sec slower than their fastest time for 50 m. The first 100 m should also be 2 to 3 sec slower than their best time for that distance. Their drop off times from the first to the second half of freestyle and backstroke events should be between 1 and 2 sec. In butterfly and breakstroke events their drop off times should be 3 to 4.5 sec. There are two main reasons for the larger drop off in those events. First, velocity flunctuations are greater in butterfly and breaststroke than in the other two competitives styles. Thus, more effort is required of breaststroke and butterfly swimmers to accelerate their bodies during every stroke cycle. Second, the split for the first 100 m does not include a turn in these races, whereas the split for the second 100 m includes a turn. 

Pace plans for 100m events

A properly paced race will be faster than a poorly paced one. Pacing involves swimming the first half to three quarters of races slower so that the remainder can be swum faster. Swimmers find that the total time for races is faster when they do this.

Athletes can race at maximum effort for only 40 to 45 sec before severe acidosis sets in. This does not mean that athletes can maintain maximum speed for 40 sec. The effects of progressive acidosis actually begin reducing the rate of anaerobic glycolysis after approximately 15 sec of all out effort. In races of 100m or longer, swimmers delay acidosis by swimming slower in the early stages.