<P> "Weak" was released as the third single from SWV's album, following the top - ten success of "I'm So Into You". It sold over one million copies domestically and was awarded a platinum certification from the Recording Industry Association of America . "Weak" hit number one on the U.S. Billboard Hot 100 in July 1993 where it stayed for two weeĸѕ . It also topped the Hot R&B Singles chart for two weeks . Outside the US, the song also reached number six on the New Zealand Singles Charts; it went on to become their signature song . </P> <P> Billboard named the song #72 on their list of 100 Greatest Girl Group Songs of All Time . </P> <Ul> <Li> Teen singer JoJo covered "Weak" in 2004 on her self - titled debut album . </Li> </Ul> <Li> Teen singer JoJo covered "Weak" in 2004 on her self - titled debut album . </Li>

Who sings the song weak in the knees