Video: UNC's T.J. Logan runs fastest RB 40 time at NFL Combine Posted Mar 4, 2017 Former North Carolina running back T.J. Logan put on quite the performance at the NFL Combine on Friday. His 4.37 second 40 yard dash was the fastest time for a running back on the day. He followed it up with a 4.40. That number will certainly turn the heads of some NFL scouts and executives. Here are some reactions to Logan's performance at the combine: (247 Sports)