These stocks face similar risks, and they're down by similar amounts over the past five years.Lululemon Athletica (LULU -0.16%) and Nike (NKE 6.17%) are two iconic, well-known apparel brands. They're popular with young consumers, and many buyers stick with the brands for years.In recent years, however, they've encountered significant challenges. Both stocks are down 44% over the past five years. Nike has been on a more steady decline, whereas Lululemon's stock has recently been in a free fall. Which of thes ...