Under Armour has just filed suit against Nike for using the phrase “I Will,” which Under Armour unveiled in a recent ad campaign. While Under Armour has long been the successful underdog in a market dominated by Nike, it has never before sued Nike. Under Armour alleges that Nike has used their tag line in social media and other online advertisements, such as in the twitter post found here. Trademark lawsuits often sound peculiar to those outside of the legal field, but this case may just have legs.

While Nike has so far refused to comment, it is probable they will argue that the phrase “I will” is one of the most common in the English language. However, given the prominence of the “I will” slogan in UA’s new ads (they have a whole website dedicated to it) and the close competition between the two companies, UA’s lawyers may have a strong case to make. Apple successfully argued in its lawsuit with Samsung that its trademark for rounded corners, a certain shade of green, and an icon based on the decades-old “Ma Bell” were all legitimate. It remains to be seen if Under Armour will be able to replicate Apple’s success in upholding copyrights on intellectual property that many in the public would see as commonplace.