Here is a little more information about what Jon Niese thinks he is experiencing, and why the Mets are sending him back to New York for a MRI. The following is taken from Wikipedia:
Dead arm syndrome starts with repetitive motion and forces on the posterior capsule of the shoulder. The posterior capsule is a band of fibrous tissue that interconnects with tendons of the rotator cuff of the shoulder. Four muscles and their tendons make up the rotator cuff. They cover the outside of the shoulder to hold, protect and move the joint.
Overuse can lead to a build up of tissue around the posterior capsule called hypertrophy. The next step is tightness of the posterior capsule called posterior capsular contracture. This type of problem reduces the amount the shoulder can rotate inwardly.
Over time, with enough force, a tear may develop in the labrum. The labrum is a rim of cartilage around the shoulder socket to help hold the head of the humerus (upper arm) in the joint. This condition is called a superior labrum anterior posterior (SLAP) lesion. The final outcome in all these steps is the dead arm phenomenon.
The shoulder is unstable and dislocation may come next. Dead arm syndrome won’t go away on its own with rest—it must be treated. If there’s a SLAP lesion, then surgery is needed to repair the problem. If the injury is caught before a SLAP tear, then physical therapy with stretching and exercise can restore it.
Here is an excerpt from a piece that was on MLB.com, back in 2009, on Dead arm syndrome:
For Seattle starter Ryan Rowland-Smith and many other Major League pitchers, it’s mostly a Spring Training thing.
“You’re coming off an offseason where you have your own throwing program,” Rowland-Smith says.
“All of a sudden you get to camp and you’re throwing to bases, doing extra stuff. You’re on your legs all day, and that’s when you get that dead arm. You’re in the heat, with day games after day games. You’re up early in the morning. All those things factor into it.”
And when the dog days of August hit and teams are plowing ahead in the latter stages of a 162-game regular-season grind, dead arm can resurface and potentially taint a pennant race.
The key, most veterans agree, is to do the only thing you can do to get rid of it.
“Just pitch through it,” C.C. Sabathia says.
Easier said than done for a 6-foot-7, 280-pound perennial Cy Young candidate, but Linebrink says Sabathia’s dead-on about curing dead arm.
“You absolutely have to just keep going and pitching and you know it’ll come back,” Linebrink says.
And here is an excerpt from a piece written in the Wall Street Journal back in 2011:
Still, “dead-arm syndrome” varies so much in its degrees and its causes that even its name “has become sort of a bucket term,” said Dr. Michael Hausman, the vice-chairman of orthopedics at Mount Sinai Hospital. “It’s not a precise diagnosis.”
Usually, Hausman said, a pitcher who has a “dead arm” has a slight injury to his labrum, the rim of cartilage that keeps the shoulder’s ball-and-socket joint stable. The injury and the shoulder’s resulting instability might be so subtle that the pitcher wouldn’t sense any pain at all. “The brain is trying to protect your body,” Hausman said, “and it basically lowers your fastball in order to prevent you from damaging your arm.”
My experiences with pitchers and players experiencing dead arm (it’s not just isolated to pitchers), is that there generally isn’t pain involved with dead arm. As you can see from the Wikipedia description, nowhere is the word pain used in the explanation. Dead arm is simply fatigue—the ball doesn’t come out with the same snap as usual. It’s fairly common in pitchers early in camp as they do extra throwing due to fielding practice and adjust to the Florida heat…
But the pain scares me. Pitching coaches and trainers know the signs of dead arm, so to be sent for a MRI means there may be more to it. Let’s hope that Niese’s dead arm is not a result of an underlying injury, and his body’s way of protecting itself from further injury by lowering his arm strength, as Dr. Michael Hausman pointed out in the WSJ article.
Keep checking back with MMO for updates on the Niese situation.