Not really, I'm correct. It takes about 60-70m for someone to reach their top speed. Footballers never come close to that. The closest we see is someone like Jagielka having to chase a ball for 50m which is why you often see so many defenders at the top of the "fastest players" lists. Football is all about small sprints and being fast over the first 5-10 meters matters a lot more.
You are right - it normally takes about 60 meters to reach top speed. However, judging the top speed of attackers in a game therefore says a lot about their acceleration. Time and again, Vardy shows the highest top speed clocked for Leicester, and he has the highest top speed recorded in the PL this season, alongside Martial. Martial doesn't make those long runs, so that says a lot about his acceleration. The 40 yard dash is the best way to evaluate a player's speed in a straight line, but agility is at least as important.
What is impressive about Martial more than his outright speed is his close control, even at high speed. His balance and centre of gravity are brilliant. He can work on his decision making, shooting and passing, but he has real promise.