Maybe the more important question is:

When's the last time you even ran full throttle for any distance? In middle school I broke 3 vertebrae in a freak baseball accident. No more football after that. Just baseball, basketball, track.(and golf) High school/college ran mid 4 40s, but not low 4s.(early-mid 80s) Kept playing basketball into my early 40s till Plantar Fasciitis drove my out of court sports. Became an "endurance" athlete then doing the swim, bike, run thing. Run all distances including marathons. Now to answer your question. I think the last time I ran a timed 40 was around 2014 at the Chicago edition of the Men's Health Urban Athlon. It was one of the obstacles in the race. About the closest I come now is accelerating to cross a street during a run. No stomp on the gas explosions, though. More of a gradual push down the throttle. To much of a risk of blowing out a plantar, achilles, hamstring, etc.