The best workout clothes use special fabrics to keep you cool and dry -- here's what to look for when you shop.

Spandex. Spandex is one of the most common types of materials used in sportswear. This is because it has a high stretchability which makes the clothes agile and comfortable for movements. In fact, this material is known to stretch 100 times more than its original size, making it a favorite material for sportswear