Changes to the sport

Swimming times have dropped over the years due to better training techniques and to new developments. The first four Olympics competitions were not held in pools, but in open water (1896 Ц The Mediterranean, 1900 Ц The Seine River, 1904 Ц an artificial lake, 1906 Ц The Mediterranean). The 1904 Olympics' freestyle race was the only one ever measured at 100 yards, instead of the usual 100 meters. A 100-meter pool was built for the 1908 Olympics and sat in the center of the main stadium's track and field oval. The 1912 Olympics, held in the Stockholm harbor, marked the beginning of electronic timing.[clarification needed] Male swimmers wore full-body suits until the 1940s, which caused more drag in the water than their modern swimwear counterparts did. Competition suits now include engineered fabric and designs to reduce swimmers' drag in the water and prevent athlete fatigue. In addition, over the years, pool designs have lessened the drag. Some design considerations allow for the reduction of swimming resistance, making the pool faster. Namely, proper pool depth, elimination of currents, increased lane width, energy absorbing racing lane lines and gutters, and the use of other innovative hydraulic, acoustic, and illumination designs. The 1924 Summer Olympics were the first to use the standard 50-meter pool with marked lanes. In the freestyle, swimmers originally dove from the pool walls, but diving blocks were incorporated at the 1936 Summer Olympics. The tumble tur was developed by the 1950s and goggles were first used in the 1976 Olympics. There were also changes in the late 20th century in terms of technique. Breaststrokers are now allowed to dip their heads completely under water, which allows for a longer stroke and faster time. However, the breaststrokers must bring their heads up at the completion of each cycle. In addition, a key hole pull in the breaststroke start and turns has been added to help speed up the stroke. There have been some other changes added recently[when?] as well. Now off the start and turns, breaststrokers are allowed one butterfly kick to help increase their speed. Backstrokers are now allowed to turn on their stomachs before the wall in order to perform a "flip-turn". Previously, they had to reach and flip backwards and a variation of it, known as a "bucket turn" or a "suicide turn", is sometimes used in individual medley events to transition from backstroke to breaststroke.Goggles or safety glasses are forms of protective eyewear that usually enclose or protect the area surrounding the eye in order to prevent particulates, water or chemicals from striking the eyes. They are used in chemistry laboratories and in woodworking. They are often used in snow sports as well, and in swimming. Goggles are often worn when using power tools such as drills or chainsaws to prevent flying particles from damaging the eyes. Many types of goggles are available as prescription goggles for those with vision problems.