THE BOOK--Playing The Percentages In Baseball

Are you aware of someone researching the stress on the arm in windup vs. stretch?  Maybe pitching from the stretch just doesn’t do much in terms of leverage...after all, when a pitcher throws from the windup, the throw comes from essentially the same position as the stretch.  If they’re using so much more arm power from the stretch, then why not also use it in the windup in addition to the assumed increased leg power?

Millsy/1, the guys from ASMI researched this and found no additional stress on the arm from pitching from the stretch.  The paper was published in the American Journal of Sports Medicine in 2008.  Abstract here:
http://ajs.sagepub.com/content/36/1/137.abstract

But Smoltz is talking about game conditions.

This reminds me of when researchers are showing there are less injuries on artificial turf than grass, presumably because one surface is even, while the natural can have all kinds of small indentations, sprinklers, puddles, or whatnot.

But if Andre Dawson is saying that the Big O’s turf is killing his knees, while Wrigley’s grass is heaven to him, well, that’s the reality.  If the experiment doesn’t reflect this, then the experiment was not modeled well enough.

I’m not saying anectodal evidence should be considered as the representative evidence, but it can’t be ignored.

Tango/3, I don’t think there is any evidence that I have seen so far that says that it’s more stressful for a pitcher to pitch from the stretch than from the wind-up.  Or that it affects velocity in a meaningfully noticeable way.  My MLB data showed a difference of 0.1 mph.  The ASMI study showed a difference of 0.2 mph in the lab, although the abstract didn’t say in which direction (presumably the stretch was slower in the lab).

That is not the same thing as saying that it’s not harder or requiring more effort for a pitcher to pitch with runners on base.  But that would be true even if he pitched from the windup with runners on (ignoring the baserunning element for the moment).

Those are two separate, although closely related, things.

There may be other reasons that a pitcher would want to pitch out of the windup with the bases empty other than the 0.2-mph bump in velocity (if ASMI is correct and applicable), even if there is no leg leverage advantage.  He may find his delivery more repeatable, for instance, improving his command.

But you have no idea how much effort he is putting into the throw.

Imagine you are in a pool, doing laps casually.  Then someone turns on the whirlpool, and you are doing laps really hard.  In either case, you did a lap in 60 seconds.

The evidence that the pitcher is exerting more energy is that the pitcher is telling you he is exerting more energy.  That you are not testing for that exertion (in game situations) doesn’t mean it’s not there, nor does it even require us to be able to infer it from other data.  Smoltz is exerting the extra energy to balance out against whatever change in motion he has to apply.

This is what he is saying.

Are we saying he is not doing that?

Tango/5, no I’m not saying anything either way in regard to what Smoltz said.  I’m allowing that it’s possible, but I’m not offering any evidence pro or con.

I’m saying that extra exertion stretch-v-windup is a different question than extra exertion runners-v-no_runners.  Their data sets happen to have a significant overlap such that it is difficult to separate the two when measuring the effect, but they are not the same question.

Conceivably, a pitcher could pitch from the stretch with no runners on base (and many relievers do) and face no additional exertion by this choice.  The extra exertion comes from pitching under pressure when runners get on base, irrespective of what delivery you may choose to use at that moment.