I know you asked about free patterns, but you may want to check out
http://kwiksew.mccall.com/swimwear--...pages-3350.php Kwiksew patterns. They are multi sized and have really good instructions.
Jalie
http://www.jalie.com/sports-apparel/...vbo310cjat5a24 also has great active wear patterns. They are almost all in sizes 2 to very large adult.
I used Kwiksew patterns to make my daughter gymnastic and figure skating outfits. I have not used the Jalie ones, but have read great reviews (although they can run small in the sleeve) on them at Pattern review
http://sewing.patternreview.com/cgi-...&search=Search