Swimming is a gr8 cardiovascular & aerobic exercise I know bcoz I am myself a swimmer and coach at my University...But if after watching a different events at Olympics, U r confused as to which one u shld be doing. 1) Freestyle is considered 2b d fastest swimming stroke,freestyle provides d least water resistant as U cut thro water.2)Breaststroke is d most common and 1st stroke that a coach teaches.Its easy and slowest stroke.3)Backstroke is like freestyle but on your bck 4 back problem u shld do.4)Butterfly stroke is mst demanding & difficult. Burns ur calories. Ur vws do U do swimming??