Chris Carmain's fastball reached 94 mph despite sometimes searing pain in his elbow.
Then last summer, he felt a pop in his arm after throwing a pitch.
"I threw another pitch and it felt like someone had shot me in the elbow," he said. "Just excruciating pain."
His hand felt hot, then tingly. Then it began to feel cold and he couldn't feel it anymore.
Carmain, 20, of Methuen, a Northeastern University pitcher, said he had felt pain in his elbow as early as Little League but never told anyone.
"You don't want to come off the field, ever," Carmain said. "There's definitely an aspect of pressure that you don't want to let the team down."
The pop he felt last summer was his ulnar collateral ligament tearing. The ligament connects two bones — the humerus in the upper arm and the ulna in the forearm — stabilizing the elbow joint.
MRI scans showed the ligament had begun to tear in high school, when Carmain was pitching for St. John's Prep in Danvers.
Carmain underwent ulnar collateral ligament reconstruction, better known as Tommy John surgery, on Aug. 18.
He'll miss the 2012 baseball season but has learned an important lesson.
"Definitely, if you're experiencing pain, get it checked out," Carmain said. "Don't wait."
Carmain also learned that he spent his high school years doing the wrong shoulder-strengthening exercises and, as a result, he had an especially weak shoulder.
He got the word when he visited Dr. Luke Oh after his tear. Oh is an orthopedic surgeon who performs about 40 Tommy John surgeries a year at Massachusetts General Hospital.
As the number of Tommy John surgeries grows among adults and teens, shoulder strength is becoming a major issue for young pitchers. The right kind of shoulder strengthening exercises can help avoid Tommy John surgery, or recover from it.
"I have yet to see a young athlete that needs a Tommy John surgery that came in with a very sturdy and strong shoulder and rotator cuff," Oh said. "If the shoulder is not optimized ... then the elbow sees more load and it's at increased risk of injury."
Carmain's weak shoulder contributed to the development of partial tears in his ulnar collateral ligament during high school.
He now advises other young pitchers to "get on a shoulder rehab program ... Rehab even if you're not hurt."
The torque and force of throwing a pitch off a mound can overwhelm the ulnar collateral ligament, Oh said.
"The ligament cannot withstand the force of a single pitch," Oh added.
But the rotator cuff and shoulder internal rotators, plus the flexor pronator group of tendons in the elbow, can help protect the ligament and prevent it from tearing.
"That's why it's critical to strengthen and optimize all of those muscle groups in addition to paying attention to things like pitching mechanics," Oh said.
Pitchers in their late teens might be the same height as a major league pitcher, but their muscle groups still need time to develop.
"Their rotator cuff muscles and other elbow stabilizers like the muscle group in the flexor pronator mass have not been developed optimally to throw a ball 80 or 90 mph," Oh said.
Carmain never learned the proper shoulder exercises until his sophomore year at Northeastern.
He did overhead presses and shrugs in high school. "Both lead to tightness and overexposed my shoulder," he said.
"You need to (exercise) the small muscle groups with bands and light weights to keep the shoulder stable," he said.
Carmain now undergoes physical therapy three days each week, two hours each day. The other four days each week he exercises on his own for an hour, working on his rotator cuff and his "lats," the major muscles in the back.
"High school coaches should have an idea of how to strengthen a shoulder and should have some kind of regimen for pitchers and position players to follow," Carmain said. "But if you really want to get the strength necessary, then you need to go to a private coach or at least a physical therapist."