David "Dave" Charles Berkoff (born November 30, 1966) is an American former competition Hall of Fame swimmer, Olympic champion, and former world record-holder in two events.

He is also remembered for his powerful underwater backstroke start, the eponymous "Berkoff Blastoff" which after a strong push-off from the side of the pool used a horizontal body position with locked arms outstretched overhead and an undulating or wavelike aerodynamic dolphin kick to provide thrust and build speed.

He began swimming with Dick Shoulberg's Germantown Academy Aquatics Club in Fort Washington, Pennsylvania outside Philadelphia when he was only eight years old around 1974.

[5] Berkoff attended and swam for the William Penn Charter School and around the age of 15 broke the swimming team's pool record for the 100-yard backstroke in a 1982 meet against St. Joseph's Prep with a time of 1:02.10.

Stroke technique, strength training, and arduous workouts were all part of Berkoff's club Coach Dick Shoulberg's focuses.

[11] Known later as the "Berkoff Blastoff", early in his Harvard career, Berkoff began swimming his backstroke start and turns underwater for a distance as long as 35 meters using a powerful push-off from the side of the pool remaining horizontal and as aerodynamic as possible, with a powerful wavelike dolphin kick and outstretched locked arms for the starts and turns.

[12][13] After the 1988 Olympics, a limit of 10 meters was initially set for a few years by FINA officials for the distance a backstroker could swim underwater at their starts and turns, but the use of the underwater dolphin kick at starts and turns with outstretched locked arms would be adopted by a great number of competitive backstroke swimmers as well as butterfly and freestyle swimmers.

[16][17] At the 1992 Summer Olympics in Barcelona, Spain, where Shoulberg was an Assistant Coach, Berkoff earned another gold medal by swimming for the winning U.S. team in the preliminary heats of the men's 4×100-meter medley relay.

[19][4] Beginning his studies in the fall of 1992, after his competitive swimming career, he eventually received a Masters in Environmental Science and a Juris Doctor degree from the University of Montana.

[20] He has coached the Missoula Aquatic Club for many years, and in 2016, two of his swimmers, his 15-year-old daughter Katharine and 19-year-old Hannah Leach, were both scheduled to attend the June 2016 Olympic trials in Omaha Nebraska, competing in the 100 and 200 backstroke events.