Andika mwendelezo wa aya hii - Katika FIL Luge Ulaya Michuano, Gruber alishinda medali tisa na dhahabu mbili (Wanaume doubles: 2008, 2014), fedha nne (Wanaume doubles: 2004
; Timu mchanganyiko: 2004, 2006, 2013), na shaba tatu (waume doubles: 2006; Timu mchanganyiko: 2012, 2014).