WEST POINT, N.Y. >> A bell clanged and two cadets in boxing gloves surged from their corners in a gym at the U.S. Military Academy last week, throwing jabs and uppercuts while other cadets yelled "Keep working him!" and "Use the hook!"

For more than a century, boxing for male freshmen here has been a rite of passage and an academic requirement — one they share with male cadets at the Air Force Academy and midshipmen of both sexes at the Naval Academy. Officials say there is no better way to teach the grit needed for combat.

"We want to expose them to fear and stress and teach them a confidence to respond," Lt. Col. Nicholas Gist, the director of physical education at West Point, said as he watched the cadets fight. "We’d rather teach that at the academy than in Iraq or Afghanistan."

But data obtained by The New York Times shows that the lesson comes at considerable cost. Boxing accounts for nearly 1 out of every 5 concussions at West Point, and 1 out of 4 at the Air Force Academy. So far this school year, boxing has caused a quarter of all concussions at the Naval Academy — more than twice as many as football.

The injuries sideline cadets from varsity sports, academics and military training, West Point officials said. Cadets too concussed to complete the boxing class are required to repeat it.

The Army delayed releasing concussion data to The Times for months as it discussed ways to draw attention away from the issue, an Army document shows.

Now some parents and policymakers are asking whether the military needs to find better ways to instill perseverance than having its best and brightest repeatedly punched in the head.

"There is an argument that whatever benefit a cadet gains from boxing, the cost of missing studies, of missing training, of becoming more vulnerable to injury down range, are detrimental to military readiness," said Brenda Sue Fulton, a West Point graduate who is the chairwoman of West Point’s civilian advisory committee, known as the Board of Visitors. "It’s possible by trying to prepare our cadets, we are making them less ready."

In the last three academic years, West Point has documented 97 concussions from boxing, more than any other sport, although more cadets box because it is mandatory. The Air Force Academy has reported 72, and the Naval Academy 29.

Boxing is not required training for students in ROTC at other colleges or for those who enlist as infantry troops and will be the most likely to face hand-to-hand combat.

Some medical experts say the risk of the boxing requirement may outweigh the rewards.

"No brain trauma is good brain trauma — even if there are not diagnosable concussions, there can still be lasting damage," said Dr. Robert Cantu of Boston University, a leading neurologist specializing in concussions who has advised the Army and major league sports. "Maybe you could justify it if there is some crucial lifesaving skill that can’t be taught in any other way. But short of that, it’s absolutely stupid."

The sport has a hallowed history at the academies. Together they have won 18 collegiate championships in the past 20 years. And many of today’s top military leaders look back fondly on the pummeling they received as plebes, the West Point nickname for freshmen.

Boxing was made a requirement at West Point in 1905 at the behest of President Theodore Roosevelt, joining horsemanship and swordsmanship as necessary skills for young officers. And although swords and horses were cut long ago, boxing remains.

It has endured even as the military, after 10 years of battling roadside bombs in Iraq and Afghanistan, has become increasingly aware of the seriousness of traumatic brain injury, spending hundreds of millions of dollars on research and treatment.

To some extent, the heightened national concern over concussions in recent years has softened plebe boxing. Cadets at West Point now wear thick padded gloves, headgear and mouth guards. In sparring bouts, fighters can throw only one hook, one cross and one uppercut per round. And after each of the 19 classes and three test bouts, coaches give a short talk, telling cadets to report to the health clinic if they feel symptoms of concussion.

But during a recent class, cadets still took repeated jabs to the head, which, Cantu cautioned, can lead to lasting injury, even if there are no documented concussions.

Minor concussions become major disruptions to cadets’ lives because West Point medical protocols require any cadet with a concussion to rest for at least two days, skipping all academic work, sports and military training. For several days after, cadets are usually ordered to limit athletics and schoolwork, sometimes putting them behind in classes. Professors are notified that such students are on "cognitive profile" and should have a light workload.

Lt. Gen. Robert L. Caslen Jr., the superintendent at West Point, said the protocol was a drastic change from when he played football at the academy in the 1970s.

"I’ve been knocked out, given the smelling salts and shoved back in there — that was our concussion protocol back then," he said in an interview. "I always thought it was a badge of honor when I got a concussion — now you are one of the guys. You get knocked out and keep going."

Now, he said, he has to weigh the costs and benefits of boxing. He said that West Point was working to mitigate injuries and studying the impact of concussions at the academy but that he was unwilling to sacrifice teaching cadets how to overcome the fear of facing an opponent.

That means, for now, boxing is staying.

"We’re the Army. The Army gets stuck in the most dangerous, most ugly situations. Ground combat is a brutal, unforgiving business," Caslen said, speaking in a room filled with mementos from the Iraq War, including a chrome-plated AK-47 owned by Saddam Hussein. "To me it is a huge imperative to prepare our soldiers for battle, and I think it is what America expects of us."

In addition to boxing, West Point requires all cadets to take a hand-to-hand combat class that teaches takedowns and submission holds. Caslen said the class was more effective than boxing in teaching cadets how to defeat an opponent but less so in instilling courage.

Caslen said that he and the Board of Visitors had discussed finding a different kind of combat training that did not entail blows to the head but that nothing had been settled on. He said he was also considering broadening the boxing requirement to include female cadets, who may be able to serve in combat roles beginning next year.

Fulton, the board chairwoman, said tradition-bound academies were loath to abandon long-held customs, especially if they might appear weak to other academies. "I think there is a real feeling that no one wants to be the guy who ends plebe boxing," she said.

Among the parents of cadets, there is steady concern over boxing injuries.

"It comes up on Facebook, social media and in meetings all the time because it’s a perennial problem," said one parent who works in health care policy at the Pentagon.

Her son, a top student and cross-country runner, was sidelined with headaches for two weeks after a concussion, she said. Because he missed so much boxing class, he had to retake it.

"All the research and prevention going on in the Department of Defense right now on this, and we are still forcing kids to give other kids head injuries?" she said. "Have we learned nothing from 10 years of war?"

She and other parents interviewed asked that their names not be used out of concern that the publicity could negatively affect their children’s careers.

Last fall, after getting two black eyes and a concussion from boxing, an Air Force cadet who is a varsity athlete told his mother not to worry because he was taking only body blows in class until he recovered.

In a phone interview, his mother said he had another concussion in a boxing bout a week later and then woke up vomiting in the middle of the night. He was forced to curtail schoolwork as symptoms lingered for more than a week.

"I was livid, beside myself, in a panic," his mother said. "I knew he could be severely impacted, maybe for life, and for what? He is a math and science guy, this is the Air Force. He doesn’t need to know how to box."

Twenty years ago, the Air Force announced plans to end mandatory boxing because of mounting pressure from the medical community. But boxing continues. The Air Force did not respond to questions or make any staff members available for interviews.

After his second concussion, the Air Force cadet was forced to drop boxing class. He has to take it again this year.

"I tried to get him to leave the academy, and he wouldn’t," his mother said. "I don’t know what I’m going to do."