WATERLOO — Innings limits. Nearly every young pitcher in Major League Baseball — including Toronto Blue Jays rookies Miguel Castro and Roberto Osuna — has been placed under them at some point in their career.
But a new study by a University of Waterloo researcher suggests restricting the number of innings on young arms does not protect them from injury. Those findings contradict the conventional wisdom of pitching coaches across professional baseball.
“We thought we’d see if there was any correlation. But our data shows that these strategies really make no difference in preventing injury,” said Thomas Karakolis, the study’s lead investigator who did the research while earning his PhD in injury biomechanics at Waterloo.
Karakolis started the study after the Washington Nationals famously pulled their flame-throwing prospect Stephen Strasburg out of their rotation before the playoffs in 2012, because he’d reached his innings limit.
Major League teams use innings limits to ease minor league pitchers into the big league’s longer and more intensive season, believing ligaments, tendons, muscles and bone tissues need time to adapt to the heavier workload.
But after using a computer program that sifted through mountains of publicly available pitchers’ stats, including disabled list appearances, Karakolis and his co-authors found that innings limits is too flawed and too simplistic of a method to protect young arms.
They examined 761 pitchers 25 and under who played professional baseball between 2002 and 2007, and had pitched at least a third of an inning in the majors.
Their findings, published in the Journal of Sports Medicine and Physical Fitness, showed pitchers who increased their innings by more than 30 over the previous season — a standard cut-off for major league teams — weren’t any likelier to get hurt.
“Injury is the result of workload exceeding the capacity of the body’s tissues, so while counting innings is a tempting way to measure workload, it’s actually a very flawed method,” said Karakolis.
“If coaches are looking for ways to prevent injury, simply limiting the number of innings is not the answer. They have to look at how hard a pitcher’s body is working during each inning, each pitch.”
For teams, preventing injuries is a pressing issue — statistics suggest about 25 per cent of all pitchers will have a serious arm injury in their career.
Workload is an important factor in injuries, but simply counting innings doesn’t do enough to measure the stress on a pitcher’s arm, Karakolis said. That’s because some pitchers throw in ways that put a lot more demands on their arm than others, he said.
“It tells us how many innings that guy pitched, but it doesn’t tell us how much work he did to pitch those innings,” he said.
Instead of worrying about innings, Karakolis says teams need to study pitchers’ unique throwing mechanics and invest in specialized strength and conditioning programs that build up a pitcher’s arm and elbow tissues in the off season.
One of his co-authors, Ryan Crotin, said many coaches are still drawn to easy solutions, like the arbitrary 100-pitch count limits used for many starting pitchers. Actually protecting pitchers is more complicated than that.
“Baseball is a slow sport in terms of adapting to scientific measures,” said Crotin, a former consultant to the Baltimore Orioles.
“There’s something about the simplicity of it … But there needs to be more complexity. Teams are starting to adapt and change, but it’s a slow process.”
To better understand why so many pitchers are getting hurt, researchers need to look at a broader range of things, he said, from the number of fastballs pitched in a game to decreases in a pitcher’s velocity over time.
That also including how pitchers are used at the college level, and what role weight lifting and other training methods might play in causing later injuries, he said.