In the years prior to WWI, knits became an important part of the sports wardrobe. But it was the Great War which brought about change for the middle class;  women needed comfortable clothing in which they could move and drive and work throughout a long day. Chanel recognized this in Paris, resulting in her jersey knit dresses.

During the 1920s leisure increased, and so did the demand for more casual clothing. Sports were no longer just for the very rich, as more people had the time and money to golf, ski and take vacations. Many department stores had opened "Sports Shops" by the mid 1920s, in which tennis and golf dresses, riding clothing and even knicker ensembles for women were offered.

1930s Linen Nautical Themed Spectator Frock

Increasingly, there was also "spectator" sportswear - casual clothing which was not for participating in a particular sport, but rather for watching.  These clothes were most appropriate for country wear, but were often dressy enough for town.  Some sportswear departments were even called "Town and Country" shops.

By the 1930s, the term "sportswear" had come to mean wear for casual occasions, not just clothing for active sports.  Fabrics were tailored and easy care - "tubable" instead of dry cleanable.  Cotton, in the form of chambray, shirting, pique, gingham, twill and increasingly as time progressed, denim, were used.  Washable linen was also popular, and for winter, tweeds, jersey, flannel, gabardine and Shetland wools were popular.

Sportswear was also catagorized by the types of clothing offered.  By the mid-1920s, daring ladies were wearing "trunks" under their sports frocks.  By the early 1930s they were called shorts and the skirt buttoned up and could be removed for play.  Slacks for women appeared in the 1920s, first in the boudoir and on the beach as pyjamas, but by the early 1930s they were worn for sailing and other leisure activities.

Dresses for golf and tennis were similar to those for picnicking and casual afternoons.  A very important development during this time was the concept of co-ordinates, or separates. These were garments made from the same or matching fabrics that were bought one piece at a time to mix and match.

Practical considerations were all important in sportswear.  For the first time, women's clothing began to have pockets.  Some designers took pockets to a whole new level, as in Vera Maxwell's travel jacket with plastic lined pockets, and Bonnie Cashin's skirts and coats that had snap-purse pockets.

By the 1940s, sportswear designers were beginning to gain recognition.  Claire McCardell was one of the first to make a name for herself, designing simple and easy to wear clothing.  Her "Pop-Over" dress, a wrap and tie kimono-style dress was made for years in dozens of different fabrics.

Many of the designers of the 1940s became known for their takes on exotic and ethnic wear.  Among there were Tina Leser, Louella Ballerino and Carolyn Schnurer. T hese designers scoured the post-WWII world for design inspiration. Bathing suits, sun dresses and other play clothes had an international appeal, but with American style comfort and ease.