This action builds up torque, and stretches the muscles, creating an involuntary elasticity in the muscles, providing extra power and momentum. When the athlete prepares to release, the left foot is firmly planted, causing the momentum and energy generated to be conserved, pushing the shot in an upward and outward direction. Another purpose of the spin is to build up a high rotational speed, by swinging the right leg initially, then to bring all the limbs in tightly, similar to a figure skater bringing in their arms while spinning to increase their speed. Once this fast speed is achieved the shot is released, transferring the energy into the shot put. Until 2016, a woman has never made an Olympic final (top 8) using the spin technique. The first woman to enter a final and win a medal at the Olympics was Anita Márton. Currently, most top male shot putters use the spin. However the glide remains popular since the technique leads to greater consistency compared to the rotational technique. Almost all throwers start by using the glide. Tomasz Majewski notes that although most athletes use the spin, he and some other top shot putters achieved success using this classic method (for example he became first to defend the Olympic title in 56 years). The world record by a male putter of by Randy Barnes was completed with the spin technique, while the second-best all-time put of by Ulf Timmermann was completed with the glide technique. The decision to glide or spin may need to be decided on an individual basis, determined by the thrower's size and power. Short throwers may benefit from the spin and taller throwers may benefit from the glide, but many throwers do not follow this guideline. The shot is made of different kinds of materials depending on its intended use. Materials used include sand, iron, cast iron, solid steel, stainless steel, brass, and synthetic materials like polyvinyl. Some metals are more dense than others making the size of the shot vary. For example, different materials are used to make indoor and outdoor shot - because damage to surroundings must be taken into account - so the latter are smaller. There are various size and weight standards for the implement that depend on the age and gender of the competitors as well as the national customs of the governing body. The current world record holders are: The current records held on each continent are: Below is a list of all other throws equal or superior to 22.43 m:   Best women's throw using a spin technique is 19.87 by Anita Márton and Jillian Camarena-Williams.