OT: Why do we limit Major league pitchers innings and pitches?

Maybe because what they do with their arms and shoulders approaches and sometimes exceeds the physical limits of what the connective tissues can sustain? See also "Why we don't all have Formula 1 engines in our street cars."

I haven't read all of the data or anything, but you don't need to have an MD to know that limiting your use of something typically lowers the chance that you injure it or wear it out.  Pitchers are throwing harder than they were 50 years ago as well, and I'm sure that contributes to the increase.  

I also think a part of the pitch count monitoring isn't just about long-term issues, but to determine when a pitcher becomes fatigued within a game.  This varies from pitcher to pitcher and we see that.  It's not incommon for a pitcher to start missing pitches once he's thrown between 90 and 110 pitches in a game.  

-s-

The pitching coach for the Atlanta Braves when Maddux and Glavine were around has been interviewed by Sirius XM Radio a few times on this subject.

He never put a limit on the pitchers and encouraged frequent (daily if I recall) workouts in the bullpen. However, he taught his guys to throw at 85-90% "cruising" speed.

Nowadays, he says everyone is taught to throw at 100% all the time and the practice is shredding arms.

Pitchers have always been injury prone.  The game was approached differently back in the day and if you don't think folks like Bob Feller or Walter Johnson or Bob Gibson felt the consequence of pitching that much you're crazy.  There is also data that correlates stressful pitches to injury when a pitcher has a long inning with men on base and lots of pitches.

is that more than half of Tommy John surgeries are now on teenagers.

Great interview with Jeff Passan on NPR recently, talking about his new book The Arm. it comes down mostly on the side that it's not so much the use at the MLB level that's the problem, but that kids are throwing earlier and harder than ever before, and that actualy does have statistical correlation with surgery later on. 

Worth a listen or a read of the transcript:

http://www.npr.org/2016/03/31/472541597/injuries-increase-as-pitchers-t…

Adding a blurb on the mechanics and physiology for those interested (clipped from interview linked above)

 

PASSAN: The way that throwing anything not just the ball but any overhand throwing works is through something called the kinetic chain. And the kinetic chain is essentially the building up of energy because every part of your body is intertwined and all of that energy loading into a particular place. And when you're throwing something overhand, it starts down at your feet, your ankles up through your backside, all the way up your back, and the energy goes into the shoulder. And when the energy is in the shoulder, imagine a rubber band being pulled back as far as it possibly can and as tight as it actually can. That's what happens when your foot lands and when your hips start to turn. Your arm almost lays back flat and parallel to the ground. And at that point, once it reaches as far as it can go, the motion going forward is the fastest movement the human body can make. It is 8,000 degrees per second. It's faster than an eye blink, and that's called the internal rotation of the shoulder. When the shoulder is internally rotating, all of that energy goes down the arm and into the elbow and onto this ulnar collateral ligament which is just a 2-inch triangular band of flesh. And unlike shoulder muscles which can be strengthened, ligaments cannot be. And so all of this pressure going onto the ligament time after time after time will wear you down. The harder you throw, the more force is going down there.

I dunno what baseball was like in the 70s and 80s, but I think it's less the number of pitches and more the kind of pitches.  Triple digit fastballs, sliders, slurves, etc. are all murder on a pitcher's arm.  I dunno how prevalent those kind of pitches were back then.

As an ex minor leaguer I'll tell you the major difference between than and now is the bullpen sessions for starting pitchers, you throw around 90 pitches in a session on the 3rd day after a start, back in the day they would pitch that day. The announcers always talk about oh he's pitching on 3 days rest but he would have been anyways just not in a game

Pitch counts and innings pitched are just statistics.

/Devin Funchess says hi!

"There are MORE Tommy John surgeries now than there were 20 years ago before we started taking better care of pitchers arms" You realized this is an extremely oversimplified comparison. There can be a lot of reasons for this besides "babying" pitchers.

Isn't it super weird that Tommy John needed Tommy John Surgery, and Lou Gehrig had Lou Gehrig's Disease? Also, Achilles was killed by getting shot in the Achilles Heel with an arrow. I just blew my own mind...

Knowing nothing about pitching, I always thought that the injury issues stemmed from throwing curveballs too young.

You see this argument pop up at least once a year. Basically, it's saying that pitchers in a prior generation didn't have pitch counts, and had fewer instances of TJ surgery...so why have pitch counts? The issue is that you're dealing with multiple variables here. Pitchers today throw, on average, harder/faster than in previous years. The science of hitting has evolved, and the only way that pitching has been able to keep up is with faster fastballs and more and curvier curveballs. It's not a valid comparison to A/B players from two different eras. Today there's also a lot more financial incentive for teams and players to be worried about player health. That's another part of it. Also, players who would have previously quit baseball can get the TJ surgery and come back. That's another variable. Sure, there will always be Justin Verlander types who need no pitch limit. But they're rare. It was undoubtedly easier to get by on a tired arm 25+ years ago. Try that today, and any hitter on a major league roster is going to eat you alive. TL/dr - pitch counts are one way that baseball is dealing with a changing physiological landscape and a changing pitching philosophy. On an individual level, there is definitely evidence that pitch limits help pitchers stay effective.

The framing of this issue highlights an important pitfall with respect to obsessions over "data-driven" decisions. Obviously, it's better to know more about the world than less, and we should use real knowledge to do smarter things. But good (less charitably: non-useless) empirical work can be *really* hard. As highlighted in this thread: there are a million things -- changing body types, different training methods, different approaches to pitching intensity -- that confound and are likely endogenous to pitch counts. Teasing out all the different causal pathways to pitcher injury rates would be an enormously difficult thing to do well. Which is not to say that we shouldn't try to do it, or that it wouldn't be useful if we did. But the absence of solid empirical evidence in favor of pitch counts doesn't count as evidence against them. More generally: there are other good reasons to do things besides overwhelming empirical evidence.

The same reason NBA players take nights off to "rest."

We've become soft and coddle our stars.

Now get off my lawn.

and cell phones.

Part is the mound is lower. When they were throwing with more down angle, it was harder to square up a ball. Lower mound means the level change has to come from spin and movement. That's harder on the elbows. Taller guys have less of an issue with this. Add to that the extra bullpen sessions and warmup pitches and there's a lot of extra work on the pitchers. Adam wainwright a few years back decided to limit warmup pitches and pregame to allow a higher pitch count in game. Not sure if he or anyone still does this.

More and more injuries occur like Tommy John because more and more kids are stronger like a lot of kids mention. But the bigger issue is kids are stronger and more talented at a young age so more pitchers need to develop breaking balls earlier in life which puts a massive strain on their arms. I use to pitch and trained with Tom house, who was a pitching coach for Greg maddux, Randy Johnson etc.. Also does a lot with kinetics etc.. He talked a lot about this, but a lot of guys also just throw hard and do not have great form. He use to preach how Greg maddux had the best form he has ever seen, and he hardly put any effort into his pitching. He only topped out at about 85, but he made it so effortless. A old teammate if mine got a scholly to mich, he threw 90-92, but never pitched an inning because of Tommy John. He threw a really stressful curve, which was effective but damaged his arm drastically and he was throwing it since he could pitch. I truly believe more of the damage is done from so many young kids needing to throw breaking pitches early in life as oppose to pitch counts

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Pitchers use more elbow throwing than they did before. Pitchers used to use their body to step into a delivery and throw with their shoulder. It was much slower; if a pitcher threw like that today he would never make it out of A ball Hitting has become more advanced. The pitching has to keep up.

A very ridiculous 'rule' that managers follow is not having their closer pitch more than one inning. A guy could put out a fire in the 8th inning in a few pitches and still come out for the 9th, but noooo--that would be more than an inning.