Choose a detergent that is designed for the gentle cycle of the washing machine for your sports apparel. Quality fitness clothes are an investment, and they will last for years if you take care of them. Use gentle detergents such as Woolite or Downy that are designed for the gentle cycle of the washing machine. When washing black or colorful clothes, try Woolite Dark, which is a gentle detergent formulated for black clothes and colors to help keep them from fading. If you just need to wash out that favorite bra for tomorrow's yoga class, fill the sink with cold water and no more than ¼ cup of detergent. Wash the garment in soapy water, then empty the sink, refill with cold water, rinse, and hang to dry.