Under Armour sued over claims about Rush workout fabric

Christian Berthelsen

Under Armour Inc.’s claims about performance-enhancing technology in its UA Rush line of workout wear are allegedly fraudulent, according to a would-be class-action lawsuit filed Monday in New York against the sports-apparel manufacturer.

Under Armour claims "the mineral-infused fabric takes the energy you give off when you workout in the ColdGear® long sleeve mock and reflects it back into your muscles, increasing blood flow and helping them work harder."

Under Armour says materials in the Rush fabric absorb energy emitted by the body and reflect it back into tissues and muscles, improving endurance and strength. The lawsuit, filed in Brooklyn federal court, says claims that the Rush fabric works like “the fabric version of an infrared sauna” are not scientifically possible. Infrared would be unable to penetrate the skin and achieve the promised effects such as increased circulation, the lawsuit alleges.

A spokesperson for the Baltimore, Maryland-based company declined to comment.