BMJ Open Sport Exerc Med: first published as 10.1136/bmjsem-2019-000684 on 5 April 2020. Downloaded from Open access Original research Orthopaedic and brain injuries over last 10 seasons in the National Football League (NFL): number and effect on missed playing time Suril B Sheth,1 Dharun Anandayuvaraj,2 Saumil S Patel,3 Bhavin R Sheth 2 To cite: Sheth SB, ABSTRACT What are the findings Anandayuvaraj D, Patel SS, Objective To examine trends in number and seriousness et al. Orthopaedic and brain of major injuries in the National Football League (NFL) over injuries over last 10 seasons ► There has been no reduction in the number of or- seasons 2010–2019 and the effect of rule changes to in the National Football League thopaedic or brain injuries in the National Football injuries to the leg, back, arm and head. (NFL): number and effect on League (NFL) over the last 10 years. missed playing time. BMJ Open Methods We calculated, from publicly available weekly ► Over the same time period, injuries to the head have Sport & Exercise Medicine injury reports, the number of players that were injured led to increasingly more time spent being unable to 2020;6:e000684. doi:10.1136/ and playing time missed, that is, the number of weeks on play. bmjsem-2019-000684 average that an injured player had to sit out, as a function ► Targeted rule changes tailored to protect the arm of injury to a specific body part. Using classical time series ► Additional material is and head from injury reduce time missed but the analysis techniques, we fitted injury data with linear and published online only. To view effects are not long- lasting. please visit the journal online non- linear functions. ► Overall, NFL’s rule changes have not had a positive (http:// dx. doi. org/ 10. 1136/ Results The number of major injuries to the leg, back, long- term impact on player safety. bmjsem- 2019- 000684). arm and head has not declined over the last 10 years. During this time period, time missed because of injuries to the head has shown a significantly increasing trend. copyright. SBS and DA are joint first Rule changes designed specifically to protect arm or head How might it impact on clinical practice in the authors. have, respectively, succeeded in shortening the time that future? Accepted 8 March 2020 the injured player misses, but the impact lasts only over a single season. ► The NFL season is associated with a significant risk Conclusions Overall, our data support the argument of injury (5.7% of player weeks lost due to injury in that new, well- intentioned rules adopted every season 2018). Player safety has not improved over the last by the NFL have been proven to be too weak to make decade. Risk factors for orthopaedic injury should be iden- the NFL game safer. Broad- based management of brain ► http://bmjopensem.bmj.com/ and orthopaedic injuries and adoption of preventative tified, extant modern technologies to measure and measures to reduce the number of players injured and the test impacts in the game must be used, and risk seriousness of their injuries are required in the modern management strategies and clinically informed ap- NFL. proaches developed and tested in order to reduce the risk of injury, particularly severe injuries. ► Concussions or time missed because of concussion have not gone down in number . Medical staff, the © Author(s) (or their employer(s)) 2020. Re-use NFL and team officials combined can institute pre- permitted under CC BY-NC. No INTRODUCTION ventative measures based on diagnosing changes commercial re- in cognition occurring from multiple subconcussive use. See rights American football has slipped in terms of its on September 28, 2021 by guest. Protected and permissions. Published by hits in a game, and planning appropriate player popularity as compared with nearly a decade BMJ. 1 management such as prophylactically resting the 1 ago and one reason could be the negative University of California Irvine, affected, but not yet clinically concussed, player if Irvine, California, USA publicity football has received regarding inju- 2 found to be at greater risk. 2Department of Electrical ries in general and concussions in particular. & Computer Engineering, As a result, a bright spotlight has been placed University of Houston, Houston, in recent years on steps the National Football supplementary material highlights some of Texas, USA 3 League (NFL)—the premier professional the key safety related changes made each Department of Neuroscience, Baylor College of Medicine, association of American football—has taken season over the last ten years. On the basis of Houston, Texas, USA to enhance player safety. these health and safety related rule changes, The NFL tweaks its rules every year to we would expect sharp declines in the Correspondence to enhance player safety but also to make the number of players who suffered injuries over Dr Bhavin R Sheth; game more exciting, thereby increasing the years and, when injuries do occur, less brsheth@ uh. edu TV viewership and live audiences. Online serious or severe injuries now than in seasons Sheth SB, et al. BMJ Open Sp Ex Med 2020;6:e000684. doi:10.1136/bmjsem-2019-000684 1 BMJ Open Sport Exerc Med: first published as 10.1136/bmjsem-2019-000684 on 5 April 2020. Downloaded from Open access past. In this context, it is imperative to analyse measures to the shoulder, forearm and elbow and head injuries and develop new metrics that will examine the efficacy included injuries to the head and eye. of these rules and/or changes in technology in terms of We studied the most serious injury grade—out, namely limiting player injuries and enhancing player safety. the injured player having to sit out the next game. First, A number of studies have analysed the impact of we counted the number of players across the league who various injuries on player performance, overall short- suffered an injury that caused them to miss at least one term and long- term health,3–6 the player’s postinjury level game of the regular season. Note that irrespective of how of performance7 8 and even the league’s bottom line.9 10 many weeks a given player remains out because of a given However, these aforementioned reports do not discuss injury, he counts as one towards the first measure. This the effectiveness of preventative measures such as rule measure informs on how many individual players suffer changes on the number and extent of injuries (there has a serious injury in a given NFL season. Second, we calcu- been a seminal study demonstrating that concussions lated the number of games the injured player had to are managed more conservatively now as compared with miss, representing the time a player was sidelined. Note 15 years ago, but in collegiate football).11 The NFL has that the NFL does not use existing technology to measure published a now- dated study that gives the total number the impact of hits; note also that teams in the NFL do not of concussions and ACL and MCL injuries in years 2012– provide access to medical reports of any of their players 2015, but no details have been provided, such as how and furthermore, medical injuries and illnesses are typi- many players were injured, whether or not they had to sit cally scaled and discretised by healthcare providers for out any games because of the injuries, and, if they were convenience, that is, the severity of an injury is a contin- out of action, for how many weeks.12 uous variable but is often discretised. Therefore, in this Our study is among the first to address using up- to- context, one interpretation of the number of games date, publicly available data the following question: do missed is as a proxy for severity of injury, although we rule changes reduce injury? In particular, we examined if will discuss alternative interpretations in the Discussion rule changes instituted by the NFL over the past 10 years below. have succeeded in (1) reducing the number of players For both measures, we fitted the time series data (2010– who suffered injuries and (2) affecting the number of 2019) with a straight line and determined its slope, then games the injured player missed. tested whether the slope was significantly different from zero using a two- tailed t- test. This set of analyses addresses copyright. long- term injury trends in the game. In supplementary MatERIALS AND METHODS analysis, we compared a linear model with a non- linear Data collection step function model, with the location of the step a free We collected data on the number of major injuries in parameter, for a statistically better fit of the injury data the NFL from the past 10 full NFL seasons: 2010–2019. (2010–2019; see online supplementary material). Data from regular and postseason playoff games were In a complementary analysis, we looked at the rule combined. For a given season, we obtained the weekly changes to improve player safety that the NFL adopted injury report of each of the 32 NFL teams (see Ref. 13 prior to the beginning of every season, and marked each http://bmjopensem.bmj.com/ for an example. There are 17 such injury reports for each rule for whether it was designed to protect the leg, back, NFL regular season, and 4 injury reports for the NFL arm or head (see online supplementary material). For playoffs) for all of our analyses. We did not include the instance, the new rule (2013) that requires players to wear preseason in the data because so doing would not cast knee and thigh pads clearly protected the leg, whereas an accurate picture.