I had 9 of my friends, and me. So 10 of us did it. Some of us had a lot of baseball skills and sliding skills while some have never slid before and I had to teach them how to slide. Each one of us ran to first through the bag 5 times, slid into first feet first 5 times, and slid head first 5 times. Some of us did it in a different order, like some slid head first first, some ran through first, and some slid feet first first. I had them start at home plate and just sprint towards first. I timed them as soon as they started moving and stopped it as soon as they hit the bag. Almost every trial (except for maybe 2 scores) showed that sliding feet first was fastest, followed by head first, then running through. One of my friends timed me as well and I had it in that same order. I averaged all the scores and it was about .5 seconds faster to slide feet than it was to run through. And about .3 seconds faster to slide feet than slide head. I think this showed me a lot, especially since I used many different skill leveled people. I'm going to try it again this year with my HS team. While your hypothesis and experiment may be true, I think your time figures are way off. If you figure a world class sprinter covers 100m in 10 seconds, .5 seconds equates to about 4-5 meters (12.5-15.5 ft). There's no way that's possible. Now, if you were saying it was .03 and .05 seconds difference, I could buy that. That would equate out to about 1-1.5 ft, which is significant, but not completely unbelievable like the other scenario. Edit: And he realized he was wrong, rendering my post pointless. But I still find .1 and .225 seconds to be highly unlikely unless the participants are running on one leg or the timing mechanism had a huge error in it. That still gets you somewhere in the neighborhood of 3-7 feet difference in getting to the bag.