Physics to Mark Teixeira: Don’t Dive by Jeff Zimmerman September 10, 2012 Most people will remember the bad out call of Mark Teixeira by Jerry Meals from Saturday’s game against the Orioles. While Teixeira was obviously safe on replay, but perhaps the entire thing could have been avoided if Teixeira had simply run through the bag instead. There have been a multitude of scientific studies on the merits of running through the bag or diving, including this recent one from ESPN’s Sports Science. The video is worth watching, but the conclusion is definite – running through the bag was 10 milliseconds faster on average than diving, and the difference can be significantly larger if the dive results in too much kinetic friction due to landing in the dirt too early. How good was Teixeira’s dive? Let’s take a look. As you can see in the GIF, Teixeira doesn’t come anywhere close to landing on the base with his hand, and has to slide through the dirt for several feet before he reaches first base. This is exactly the kind of dive that was evaluated to add even further deceleration, and so the gap between running through the bag and diving was likely much more than 10 milliseconds. To test this further, I decided to break out the old stop watch and compare this double play to another one that he hit into from the left side and ran through the base from earlier in the season (May 22 vs. Royals). I timed each run to first, and as expected, the time he ran through the bag was a fraction of a second faster. Here are the two double plays from the point of contact to touching 1B. When creating the two GIFs, the one from earlier in the season ended up being one frame shorter (each frame is 0.1 sec). Diving didn’t seem to help him get to the base any faster, and this lines up with all the other research on the subject previously. If Teixeira was not going to gain any time by diving into first base, he should have run through the bag. The umpire is positioned and ready to get a good view of the runner’s foot when it reaches the bag and the ball getting to the 1B. When a player dives, they throw off the umpire’s line of sight and make the call more of a toss-up, as the umpire then has to measure both ball and hand with his eye, a significantly more difficult distinction than listening for the sound of the foot hitting the bag while concentrating on the ball. However, there is an extenuating circumstance here. This was Teixeira’s first game back since missing 10 days with a calf injury, and he admitted after the game that he aggravated the injury on the play. Teixeira didn’t give himself much of a push with his legs on the dive, as this was more of a fall forward type of dive, and it is possible that his calf injury prevented him from continuing to run through the bag at full strength. Whether or not that grimace on his face right before he leaves the ground is simply effort from trying to beat out the throw or pain from an injured leg muscle is obviously impossible to determine, but we have to acknowledge that Teixeira’s full sprint speed might also have been reduced in this instance. Diving into first base is almost always a bad idea, with only tag or collision avoidance as a reasonable defense for leaving your feet on a close play at first base. Had Teixeira continued to run through the bag as fast he could, there’s a stronger chance he would have been called safe, and the game would have continued with a tie score. If Teixeira didn’t have the calf injury, we could safely call this a blunder on his part. Given that injury, however, it’s possible that he felt diving gave him a better chance to beat the throw, especially if he knew he wasn’t going to be able to push off that leg one more time. So, Teixeira’s calf gives him a little bit of a pass, but also illustrates that diving into first base remains a poor idea in almost every circumstance.