Complex sentence: In 2011, the line announced an ongoing partnership with all 32 NFL teams and began selling apparel containing NFL team logos and names, part of a marketing strategy for the NFL to market to teenage girls and college-aged women.
Split into simpler sentences: In 2011, the line announced a partnership with all 32 NFL teams and began selling apparel containing NFL team logos and names. The partnership is part of a marketing strategy for the NFL to market to teenage girls and college-aged women.