The American Sports Medicine Institute kicks off its 22nd annual “Injuries in Baseball” course Jan. 29 in Orlando. Today we continue from Part I of our discussion with ASMI’s Smith and Nephew Chair of Research, Dr. Glenn Fleisig.

Baseball Prospectus: Do teams tend to send more major league pitchers or minor leaguers? What are some of the differences between the two groups?

Dr. Glenn Fleisig: Teams look at it from both perspectives. Obviously they have a major interest in getting their major league pitchers healthy and performing at peak efficiency. But they also have a great deal invested in their better minor league prospects, where they may have a big career in front of them, but face a lot of uncertainty. The minor leaguers that we see, some have it, some don’t. Teams can use our input to try and identify who’ll be the major leaguers of tomorrow, but also to help refine the mechanics and performance of their raw gems; at a younger level, there’s more opportunity to adjust flaws, if we can diagnose them. Major leaguers tend to be very professional. They’re focused on what it is they need to do, they have the intelligence and experience to understand the limits of their bodies, and they’re generally better students of their profession.

It’s funny…we didn’t know when we got into this if there’d be hesitation from teams, in sending either their prospects or major leaguers over. But everybody who’s used our services has been very open-minded, optimistic, and from what we’ve been told, pleased with the results.

BP: Talking about younger pitchers and some of the injuries that can really derail a young career–are they susceptible to injury because their mechanics and approach aren’t as refined, or because pitching arms are more fragile while they’re still maturing?

Fleisig: We’re very interested in injury prevention on the younger side–Dr. Andrews and I are on the USA Baseball Medical and Safety Advisory Committee. USA Baseball is the governing body of amateur baseball in the U.S., which means picking and overseeing the Olympic team, but also governing youth leagues and high school ball. When we’ve found some answers, through USA Baseball we’ve been able to get those answers out there to young pitchers and their coaches.

Around 1996, we started looking at the epidemiology of youth baseball (which includes Little League, Dixie League, Dizzy Dean League–different names in different parts of the country). USA Baseball asked ASMI to look at whether or not kids should throw curve balls, and how many innings they should throw. So we did our own research, and we also surveyed many top coaches and doctors about those questions. That led to some interesting findings: Although every youth organization was limiting the number of innings a kid could throw, the experts all felt we should be counting pitches, not innings, and paying particular attention to high-stress innings, where a young pitcher has to throw a lot of pitches to escape from a jam. The consensus on curveballs was have kids throw them once they’ve started to reach an age of maturity. So age 10 no, 13 to 17 is better. But these are largely opinions–educated opinions, but still opinions–at this point.

Anyway, this all leads back to injury risk being a major factor more because the young pitchers’ bodies are still developing, not necessarily because of bad mechanics–we’ve actually seen plenty of youth league pitchers with good, repeatable deliveries, which is an encouraging sign of the quality of teaching out there. To be a successful baseball pitcher for the long run, you don’t want to have any overuse injuries obviously. But if you can’t underuse a pitcher and have him throw one pitch a year, or he won’t develop the technique and strength he needs to be successful. We’re looking for that fine line, what’s too much, and what’s too little.

BP: Sounds like there’s still a ton of work to be done to get from educated theories to hard data. Has ASMI been able to do any controlled, longitudinal studies, looking at the effects of different levels of usage over time, with different groups of young pitchers?

Fleisig: What we’ve done, through a USA Baseball grant, is watch youth league baseball throughout Alabama. We counted how many pitches pitchers threw every game, which ones were throwing curves and other pitches, and which ones reported arm pain–these were 9- to 14-year-olds. This wasn’t kids breaking down and having surgery, more like unusual arm pain. We weren’t able to set up our own specially-designed control groups, but we will be seeing how these 500 kids or so play out. We’ll see how many drop out because they want to chase girls, how many have injuries, how many lack the ability to advance further.

The study’s been going on for years, and we’ve published the results so far. In general, we found that the more pitches thrown a game and in a season, the higher the risk of arm pain. We found the threshold in youth baseball to be about 70 pitches in a game, but it can vary quite a bit from pitcher to pitcher. It’s hard to point to one magic number, for either amateur or professional pitchers.

BP: This could be hugely valuable information for a major league team to have, if you could do the same thing with groups of prospects, and follow them from the low minors all the way to the big leagues. Or follow high school and college pitchers, especially given some of the horror stories you hear about managers riding their aces hard in tournaments and damaging their arms. Have you tried approaching schools and teams about doing this? Would any be willing to try?

Fleisig: We’re hoping to do something to that effect. We’ve studied professional pitchers and youth league pitchers, the natural next step would be to go to the middle. USA Baseball has talked to MLB about studying players that get drafted. It’s tough though. In the NFL, you have the NFL combine, where everyone shows up to do physical evaluations, skills evaluations, medical evaluations. There’s no such equivalent in baseball. They say it’s because of scheduling: When a pitcher is drafted out of high school or college, he has to show up to pitch in the minors right away, and there’s no central depository of people to look at them before that.

We’ve suggested conducting a retrospective study of what kind of conditions players are showing up with. If they show up having already had major surgery, we can look to determine if they pitched a lot at a younger age. For the healthy ones, was their usage more moderated? There’s a proposal on (MLB Vice President of Baseball Operations) Sandy Alderson’s table. We could help set up a structure where drafted players are greeted, given comprehensive medical exams and questionnaires, and teams could improve their drafting success as time goes on. We would need permission from MLB, as well as a research grant, with the expenses going to all 30 teams–don’t forget, we’re a non-profit. But we think MLB would be interested in something like this. It’s one thing to want to help youth baseball, but this can have an immediate effect on teams’ bottom line, save them millions of dollars.

BP: Could this become a contentious issue, where some teams are willing to invest in new ways to improve their on-field performance, and other don’t?

Fleisig: I know first-hand that this could be an issue, because when we offered to do biomechanical studies for all pitchers, the response was that they’d rather we do it team-by-team with whoever’s interested. We could modify the study’s design so that it doesn’t have to include all 30 teams. But that raises some issues with the accuracy of the study. The sample size would be smaller, and it may not be as randomized, in that teams that agree to participate may already be doing a better job than most of identifying healthy pitchers with better odds of future success. But like anything else, in the end this will be a business decision for teams to make.

At the major league level, there’s an insurance company/underwriter group called American Specialty that’s already doing risk analysis. They compile what’s called the Redbook to track many of the things we want to look at. We help them with data analysis, interpreting injury trends at the major league level. They have charts that’ll say things like ‘this team spends this dealing with injuries,’ or ‘here’s how old players compare to young players.’ They’re an insurance company, but they view themselves as more of a risk management company. When a baseball player gets injured, they pay out the salary–if it’s insured–they charge the premiums. So they’ve approached MLB, not just in terms of collecting bills, but trying to reduce the bills. The data covers how much teams pay in insurance and disability, things like that. It’s a good start as far as the major leagues go, but we feel there’s a lot more knowledge out there to be gained by looking at draftees and minor league players.

BP: The big trend among hitters has been to hit the weight room hard, to work on strength training, and try to add power through increased bat speed. Do the same principles hold true for pitchers–get stronger, throw hard, and you’ll have more success?

Fleisig: Not necessarily, no. We’ve compared body types of pitchers, even pitchers who haven’t been to ASMI like Pedro Martinez. What we’ve seen is that different pitchers can be successful with different body types. Being in good playing shape for a long career differs for a pitcher compared to, say an NFL offensive lineman. The most important factors for a pitcher are range of motion, flexibility, explosive strength, and stable joints. Strength in the legs is extremely important as power generators; long before we were around, pitchers were jogging, doing roadwork. A pitcher like Pedro may be thin in the upper body, but he’ll have that lower body strength that allows him to generate velocity. When there’s a flaw, like the arm getting up too early or too late and causing performance and injury risks, that’s often just a teaching flaw, not a strength flaw.

BP: What about just injury risks? Is it a bigger risk to draft a small pitcher over a big guy, the way conventional wisdom suggests?

Fleisig: You can see the answer to that just by turning on the TV. Turn on an NFL game, an NBA game, an MLB game. Football and basketball players have a more homogenous look than baseball players do. In baseball, you’ll see some tall and lanky types be successful and injury-free, and some short and stocky guys the same. You do want to have that lower-body strength certainly, and all things being equal, you’d rather have a pitcher in good shape than otherwise.

Where I think part of the misconception comes from is in some of the teaching methods by coaches. We’ve found that most of the key mechanical issues in pitchers are independent of body size, especially when looking at shoulder and elbow angles. The only one that comes into play, and the one that people harp on, is stride ratio. Coaches love to talk about pitchers with long strides, and how that gives them such a big advantage. We say that a stride that’s 80% of your body length is appropriate, regardless of how tall you are. Most people measure stride length from the front toe to the rubber. We look at front ankle to the rubber, so our recommendation is a little less than most coaches might teach. If you think about it though, it makes sense: what size shoe a pitcher has (and thus where his toe ends up) shouldn’t be that important.

BP: Is there any one ideal of pitching? A Platonic form?

Fleisig: There are things we see in pitchers’ mechanics that are because of personal variation and preference. We don’t think there’s an ideal in terms of how a pitcher raises his leg or swings his arms, that’s individual variation. But we do focus on the load a pitcher puts on his shoulder and the sequence that led to that load. My first checkpoint is ‘Is he in the right position to throw?’ If he is, we don’t really care how he got there. When a pitcher releases the ball, his shoulder should be abducted 90 degrees. That is, you should be able to draw a line through the shoulder that should hit the elbow. What’s not important is arm slot, whether it’s overhead, 3/4, sidearm–we don’t care if the trunk is tilted in any of those cases. The angle of the shoulder joint is key, not the trunk.

BP: What can you learn from non-traditional deliveries like Chad Bradford‘s or Byung-Hyun Kim‘s? Could a sidearm or submarine delivery actually reduce injury risk? What about a knuckleball pitcher like Tim Wakefield?

Fleisig: The pitchers we test are pretty much a typical sample of the pitchers who are out there, from pro ball down to youth leagues. The underhand/sidearm/submarine types are rare, so that means it’s hard for us to compile enough data to get to any meaningful conclusions based on what we’re looking at. Anecdotally, people have told me that it seems to be less stressful, but obviously we want harder evidence. It’s the same with knuckleball pitchers. We’ve studied the fastball vs. the curve vs. the change vs. the slider, because those are the pitches most pitchers throw. But knuckleballs and forkballs we haven’t seen enough to get to any meaningful conclusions.

BP: While we’re here, let’s compare the effects of different pitches and how they’re thrown. Which ones cause the most strain on the arm?

Fleisig: We found that with the fastball, curve, and slider, the forces on the elbow and shoulder are similar; the change-up had significantly less strain on both. In terms of mechanics, the slider looks similar to the fastball. The change-up also has similar mechanics to the fastball, just slowed down. The way you teach a change-up, your whole body goes through the same motion, it’s just different from the wrist up. But we found that overall, pitchers tend to move the arm a little slower, and the body moves a little slower as well. So even though coaches teach using the same motion as a way to deceive the batter, the body mechanics end up being a little different.

With a curve, the pitcher has more of a supenated forearm, with the pinky edge rather than the palm going toward home plate. The wrist motion is also different–with a fastball you flip the wrist, with curve you go from thumb to pinkie. What we concluded was that a properly-thrown curveball doesn’t place more or less force than the fastball. But because of the new set of mechanics you’ve had to learn with the curve, and it being the hardest to pick up, it can still put a lot of strain on the arm over time, especially at a young age. We discourage throwing a curve until the bone growth plates have sealed, so a pitcher shouldn’t add a curve until he’s reached puberty basically. ‘Don’t throw a curveball until you can shave,’ is the expression. So for younger pitchers 14 on down, we suggest working on a fastball with good mechanics, control, and velocity, and developing a change-up to go with that. That gives you that second pitch to throw off the timing of the batter. The curve seems sexy, but a good change can be just as effective as an off-speed pitch working off of the fastball.

BP: There are some different approaches to pitching in other countries. What do you think of recent Japanese teaching methods? What have you been able to observe from other countries?

Fleisig: Well one thing we’ve seen is that in high school, pitchers in Japan seem to pitch much more than they do in America. We talk about concern of overuse in America, but Japanese coaches often have kids practice pitching six days a week. When you’re on the mound almost every day on throwing 50 to 100 pitches, you’re talking about sometimes 500 pitches in a week. In the majors you’re talking maybe 250. So the question that comes up is ‘if they throw much more, do they have much higher injury rates?’ Medical information in Japan isn’t as consolidated as it is in America, and we already talked about how tough it can be to get reliable data across levels here. We’ve had visiting Japanese researchers spend six months to a year at ASMI. We’ve talked about some differences, like how the sidearm motion is much more popular in Asia–every team in Japan seems to have one guy like that. Basically we talk about we know, they talk about what they know, and we both try to learn from the other.

We did do two studies looking at international pitching. In one study, we analyzed pitching mechanics during the 1996 Atlanta Olympics; in the other, we compared professional pitchers from the U.S. and Korean teams tested in our lab. In the Olympic study, we analyzed 48 pitchers from the eight teams in the competition (Australia, Japan, the Netherlands, Cuba, Italy, Korea, Nicaragua, and U.S.A.). In the lab study, we analyzed 11 Americans and eight Koreans. In both studies, the pitchers who generated the greatest ball velocity had the greatest shoulder external rotation (in other words, cocking the arm back so the palm is facing upward) and the greatest shoulder horizontal adduction (in other words, pinching the lifted elbows behind the back). Some countries had pitchers with greater ball velocity, shoulder external rotation, and shoulder horizontal adduction, while others had pitchers with lower values. Overall, we concluded the differences we saw were really differences between good pitchers and great pitchers, not differences due to different backgrounds.

BP: What has been the most surprising thing you’ve learned since you first started doing this?

Fleisig: We did a study comparing how kids pitch to how adults pitch. We compared youth leagues, high school, college, and pro. We had a preconceived notion that kids would have different mechanics than adults do. My thought was that kids would show more range of motion and flexibility, that they would be like little Gumby boys, bending all over the place. I also thought force would be proportional to height and weight. So I figured a 100-pound kid would throw at about half the force of a 200-pound adult, just with more flexibility. We were totally wrong. With successful pitchers at all levels, they all had virtually the same mechanics. Force and torque wasn’t just proportional by weight at all. The rate of increase of force went up much faster than body weight and body height did.

For any pitcher, as you try to pitch, your arm is trying to come out of the shoulder socket, and your arm muscles hopefully keep it in the socket. The force pros needed to keep the shoulder from pulling out was 120%–as if someone was pulling with 240 pounds on the 200-pound pitcher to try and force the arm out of the shoulder socket. For kids younger than high school level, the proportion of force was 90% of the pitcher’s weight. The data encouraged our belief that learning proper mechanics as early as possible can help you keep them throughout your pitching life. When you get to high school, it then becomes important to add a good conditioning program as the body matures and strengthens. But good mechanics, especially early, is the most important factor to successful, healthy pitching.

BP: At what point will you be able to predict injury?

Fleisig: I think we’re closer than you think. Mechanics is one issue, pitch counts and physical conditioning are others, and we’re making great strides in all those areas. Teams, through ASMI, really do have red flags when they come see us. They can say ‘this guy is a higher risk for injury,’ and be able to back that up. The real challenge is at the youth level. The information exists for teaching proper mechanics and proper nutrition for kids. The challenge is getting information to those levels; you’re dealing with moms and dads who volunteer as coaches. Most of them have good intentions–they try to teach kids pitching mechanics, and they’ll make them throw a lot to practice. Good intentions, just the wrong approach. It’s up to organizations like Baseball Prospectus, like ASMI, to get the answers out there.

Thank you for reading

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