Over the course of a season, 30.8 injuries occur for every 100 National Football League players, compared with 38.8 injuries in the National Hockey League, 42 in Major League Baseball and 72.9 in the National Basketball Association, according to a 2021 analysis of injuries across 13 seasons of professional sports from 2007 to 2020. 

Does it mean the concern about football is overblown? Not necessarily: As you will see, football injuries might be less frequent, but they are more severe. Still, this data illustrates the challenges facing sports epidemiologists. For all the attention paid to sports injuries, the nuances in the data get relatively little attention.

The rate of injuries comes from a database of 54,944 injuries over 13 years, compiled by

Garrett Bullock,

a sports epidemiologist at the Wake Forest School of Medicine, and a team of co-authors:

Elizabeth Murray,

Jake Vaughan

and

Stefan Kluzek

at the University of Nottingham.

Injury rate in male professional
North American sports, 2007–19

Lower leg/

achilles tendon

Lower leg/

achilles tendon

“It’s the first step, whether you’re doing injuries in sports, or Covid-19 or malaria,” said Dr. Bullock, who played baseball in the Houston Astros’ farm system before becoming an epidemiologist. “The first thing you need is to understand how many people get sick or injured, and what’s the severity or burden of that disease or injury.”

They looked at injuries per 100 players, per season. Some sports play far more games than others, of course, and that is a key variable in determining the risk of injury. The statistics for football players would be horrible if they played 82-game seasons, which is one reason they don’t.

Basketball injuries are largely to the knee and ankle, each responsible for nearly 14 injuries per 100 players per season, followed by 12 to the groin/hip/thigh area and eight to the trunk, back or buttocks. The sport’s jumping leads to enormous numbers of injuries.

All the throwing in baseball leads to lots of injuries: For every 100 players, nearly nine injuries occur to the groin, hip or thigh; 7.5 to the forearm, wrist or hand; and seven to the arm, shoulder or elbow. The most common injuries in hockey are to the back and groin.

The most common injuries for football players are to the groin, hip or thigh, at 6.5 for every 100 players, and to the knees, at 6. 

These injuries can certainly be severe but make no mistake, none are as severe as what football players commonly face when it comes to concussion. These sports have “more overall injuries but you’re not as much worried about catastrophic injury, compared with a football player,” Dr. Bullock said.

The injury thought to be suffered by Mr. Hamlin of the Bills is known as commotio cordis, when blunt trauma affects the rhythm of the heart. It is extremely rare, generating fewer than 30 cases a year nationwide, across the millions of people who play sports, at all levels of play. It is thought to be most frequent in sports such as baseball, when a player takes a projectile directly to the chest.

Concussion presents a combination of both danger and frequency, and here the NFL has the highest rate, with 3.5 concussions per 100 players per season, compared with 3.2 for hockey, 1.7 for basketball and 0.4 for baseball.

It isn’t clear whether this sort of injury is becoming more common in football. Reported concussions climbed sharply from 2009 to 2015, as the NFL introduced and strengthened its protocols around returning to play after potential head injuries. This is at least partially, perhaps entirely, because of increased reporting and awareness of head injuries that might have been shaken off by earlier generations.

A study of retired players from before 2001 found that 50% said they had suffered head injuries that they didn’t report at the time. Since 2016, concussions have trended downward. (Though concussions might have been underreported in early years, they were likely too rare to affect football’s injury ranking relative to other sports.)

Trends are also unclear at the college and high-school level because efforts to really understand sports injuries are relatively recent and coincide with better data collection—and that means injuries are more likely to be reported. 

Beginning in the 1980s and lasting until the 2004-05 school year, the National Collegiate Athletic Association used a pen-and-paper system. A sample of athletic trainers filled out a pair of injury reports on paper, one for their own files and one they were supposed to fax or mail to the NCAA, where it was entered manually into a database. Though the system was better than nothing, researchers knew it was cumbersome and introduced many opportunities for data-entry errors. 

Only in 2004-05 did the NCAA transition to an online system, now known as the NCAA Injury Surveillance Program. In contrast with many other public information surveys where response rates have been falling, participation in the ISP has increased in recent years, especially after a 2018 push by the NCAA.

A system for high schools—known as High School Reporting Information Online, and modeled after the NCAA’s system—was launched in the 2005-06 school year.

These surveys find the most injuries and worst injuries are in football. In high school, the rate of concussion is highest in football. It is followed closely by girls’ soccer (heading the ball is what does it), where the concussion rate in 2015 actually exceeded football’s. 

The goal of this epidemiology isn’t to bum anyone out but to understand where risks occur, and where equipment, training and rules need improvement. After all, in sports, the agony is meant to be in defeat, not injury.

Write to Josh Zumbrun at josh.zumbrun@wsj.com