Its been reported that active wear apparel has risen 9% this year, leaving ready to wear in it's dust (a measly 1% rise in sales).  Camilo Lyon a managing director for Canaccord Genuity (investment company) has described the four key factors for this ever rising trend.  The availability of better athletic fibers/fabrics, the better design elements or "ever-increasing fashion component" found in activewear, fantastic brand focus and that people are generally gaining more interest in activewear lifestyles.
Here's some of the higher end brands and collaborations that are getting in on the game.

Phillip Lim track pants

Stella McCartney for Addidas

Halston Heritage sweats

Moncler windbreaker 

Jen Kao quilted sweats