22 May 2011

The Science of Baseball: May 22, 2011

I will be starting a new feature that seems unique based on what I have seen out in the internet and is something I may be more in tune with than most.  That would be a review of scientific literature about baseball.  Each Sunday night I plan to post on three recent journal articles that deal with baseball.  I have reviewed the literature in the past for this blog, but it has always been very much directed.  For example, a few weeks ago I wrote about hGH and how it is unlikely that it affects performance in baseball.  This column will be not be as focused on a single issue.  Here we go:

Fleisig et al. 2011. Risk of serious injury for young baseball pitchers: a 10 year prospective study. Am J Sport Med 39:253-257

The study focused on 481 youths aged between 9 and 14.  Injury incidence was simply defined as elbow/shoulder injuries and retirement due to injuries.  The study also looked at how throwing more than 100 innings a year, throwing curveballs at age 13, and spending three years at catcher affected injury rates.  They found that 5% of young pitchers will suffer a major arm injury within ten years and that this probability increases by 3.5x if the pitcher throws more than 100 innings per year.  I could not tell if 100 innings per year is causation or mere correlation.  I write this because very good young pitchers tend to pitch a lot into their high school years.  In such a situation, they will have more opportunity to be injured.  Additionally, the study suggests that young pitchers should not double as catchers.

Fry et al. 2011. Relationships between muscular strength and batting performances in collegiate baseball. J Strength Cond Res 25

Thirty one members of a Division I baseball team volunteered for this study.  Muscular strength was measured as grip strength, parallel barbell back squat, and incline bench press, and ball velocity off tee.  Performance metrics were batting average and slugging percentage. [If you cannot tell already, I would have completely overhauled this experimental design.]  The study concluded that motor coordination is certainly important, but that muscular strength is a factor in batting performance and they suggest all programs need a weight training component.  I do not think the study entirely shows that, but it is certainly an idea that would have been ground breaking back in 1975 when it is was thought that flexibility and thin lean muscle was ideal.  Nowadays . . . not so much.  I included this study to show that not all science being released in ground breaking.  A lot of it tries to substantiate common sense.

Kaplan et al. 2011. Comparison of shoulder range of motion, strength, and playing time in uninjured high school baseball pitchers who reside in warm- and cold-weather climates. Am J Sports Med 39:320-328.

In this study, the researchers were trying to determine whether there were physical differences between the shoulders of pitchers in warm weather climates when compared to cold weather climates.  The idea being that warm weather pitchers will pitch more and that this increased workload results in destabilizing the shoulder, which is thought to lead to arm injury.  50 pitchers were included from warm weather climates and another 50 were selected from cold weather climates.  None of these pitchers had a significant history of injury.  Rotational range and strength tests were conducted for each population and then the two groups were compared.  Cold weather pitchers had less of a range of motion in comparison to the warm weather pitchers.  They also had more external rotation strength.  It is generally considered a tighter shoulder (resulting in less range of motion) and a stronger shoulder results in fewer injuries.  It was also verified that these issues were related to playing time in a dose dependent manner (this means motion and strength are incrementally affected with time played).  This suggests that a healthy pitcher pitches less.  However, there is also considerable data suggesting that the number of repetitions correlates to future success.  As such, there needs to be a happy medium between being overworked and getting in enough experience.  There is probably no bright line criteria for determining what that level is as arms vary in their resiliency.


Unknown said...

Hey Jon, love this idea of bringing new science into baseball discussion. As you say, the experimental design is sometimes flawed; but at least we have more data to go along with our more subjective opinions! ; )

Jon Shepherd said...

Indeed, the study certainly has merit. I just wish they would have thought about it a little bit longer. I think the experimental design could have been sharper and more elegant. As it is, they chose too few metrics and selected from within a population that is likely to have quite similar training methods.

Nick J Faleris said...

Love the series, Jon. Looking forward to more.

steve said...

Great idea for a series.

"I could not tell if 100 innings per year is causation or mere correlation."

It depends on the type of statistical modeling used. And causation is sort of a dirty word when it comes to this type of work because it assert a degree of certainty most researchers aren't comfortable with.

Jon Shepherd said...

@steve . . . Right, I am completely using causation in terms of having enough certainty to assume it to be so.

@Nick . . . This is certainly something I am very much interested in. I hope others will enjoy it as much as you do. It certainly speaks to my training.