Sprint question

Just a quick question…lets say an athlete is running some 20 yd. sprints. How much of a difference in times should the athlete see between running the sprints from a standstill compared to running them from a 5 yard jog (jogging 5 yards slowly, then exploding right as they hit the start line). What does it say about an athlete in terms of their own individual ability if their time isn’t just better from the jog but, signifcantly better from the jog? Thanks.