Regular Season National Football League Research Articles

The Impact of the Helmet-Lowering Rule on Regular Season NFL Injuries

Objectives:The National Football League (NFL) has been under growing scrutiny from the public due to the apparent rise in concussions and head injuries and the subsequent deleterious effects. In efforts to address these concerns, the NFL implemented a new “Helmet-lowering” rule prior to the 2018-2019 season. This rule is defined as “a foul if a player lowers his head to initiate and make contact with his helmet against an opponent.” The purpose of this paper was to compare incidence of injuries in NFL players prior to and after implementation of this new rule.Methods:NFL injury data was retrospectively reviewed from public league records for all players in regular season games played from the 2017 and 2018 NFL seasons. An injury was defined as any player listed on a team’s injury report that was not previously documented on the team’s report one week preceding the index injury. Injury rates were reported as the number of injuries per 1000 athletic exposures (AE’s). Athletic exposures were defined as equal to the sum of the total number of NFL regular-season games played. Relative risk (with 95% CI) was calculated by using the number of injuries per 1000 athletic exposures for the season before and after the new rule implementation. Risk reduction was then calculated for the overall injuries, upper/lower extremity and head injuries.Results:Over the 2 seasons there were a total of 2,774 injuries identified. After rule implementation at the beginning of the 2018 season, there was an overall relative risk (RR) of 0.91 for injury (95% CI 0.88 to 0.95, p<0.0001), with an injury risk reduction of 8.73%. Upper extremity injuries had a RR of 0.76 (95% CI 0.65 to 0.87, p=0.0005) and a risk reduction of 24.10%. Lower extremity injuries had a RR of 0.91 (95% CI 0.87 to 0.96, p=0.0005) with a risk reduction of 8.63%. In concussions and head injuries there was an overall RR of 0.55 for injury (95% CI 0.44 to 0.69, p<0.0001), with an injury risk reduction of 45.10%. Wide receivers and linebackers were most commonly injured players on offense and defense, respectively.Conclusion:Implementation of the new Helmet-Lowering rule seems to have played a role in significantly decreasing the NFL athlete’s risk of injury across all measures, most notably in concussion and head injuries.

Predicting the Winner of Tied National Football League Games

We construct a data set of all 429 tied at the half regular season National Football League (NFL) games between 1994 and 2012. We then examine whether or not the path taken to reach the tie (e.g., rushing yards, turnovers, etc.) has any ability to predict the eventual winner. Our main finding is that only the point spread is significantly predictive, although there is weak evidence to suggest that allowing more sacks reduces the chances of winning. Surprisingly, we find that the team receiving the first possession of the second half does not enjoy a statistically significant advantage. Teams should thus simply try to maximize their first half lead without expecting that first half strategies such as “establishing the run” will pay dividends in the second half.

On the Demand for Live Sport Contests: Insights From the Secondary Market for National Football League Tickets

This study examines the determinants of regular season National Football League (NFL) ticket prices on the secondary, or resale, market. Prices in the secondary market are dynamic and thus particularly useful for evaluating the demand for live NFL contests. A rich dataset is employed that contains information about all transactions conducted by a prominent ticketing site during a full NFL season and allows for a comprehensive investigation of the components of demand in this market. Included in the analysis is a first look at the demand for different seating locations within the stadium. The revealed determinants of demand for resale tickets were largely consistent with studies of the primary market; however, there are notable differences in spectators’ preferences for contest characteristics and uncertainty of outcome across the seating categories. The evidence also suggests that while hometown fans are the primary participants, visiting teams are likely active in the resale market.

Return to Play in National Football League Players After Operative Jones Fracture Treatment

Jones fractures commonly occur in professional athletes and operative treatment remains the standard of care in this patient population. In our clinical experience, an aggressive postoperative rehabilitation protocol for National Football League (NFL) players with an average return to play (RTP) between 8 and 10 weeks can have successful outcomes with few complications. The purpose of this study was to quantify RTP and rate of complications, including nonunion, refracture, and reoperation among a cohort of NFL players with operatively treated Jones fractures. Between 2004 and 2014, 25 consecutive NFL players who underwent acute Jones fracture fixation by a single surgeon were reviewed. Operative treatment for the majority of patients involved fixation with a Jones-specific intramedullary screw and iliac crest bone marrow aspirate with demineralized bone matrix injected at the fracture site. Additionally, our protocol involved the use of noninvasive bone stimulators, application of customized orthoses, and an aggressive patient-specific rehabilitation protocol. Patient demographics were recorded along with position played, seasons played after surgery, RTP, and complications. RTP was defined as the ability to play in a single regular-season NFL game after surgery. At the time of surgery, average age for all patients was 24.0 years and BMI 31.0. Player positions included 8 wide receivers, 4 linebackers, 4 tight ends, 2 defensive tackles, 2 cornerbacks, 1 offensive tackle, 1 center, 1 tackle, 1 defensive end, and 1 quarterback. Seventy-six percent of players underwent operative fixation during their first 3 seasons. Forty-eight percent were diagnosed before or during their rookie (first) season.RTP was 100% for all players and 80% were still playing at time of publication. Three patients (12.0%) refractured and required revision surgery. Time until RTP was influenced by other variables and difficult to measure because many surgeries were performed early in the offseason. All 9 players who underwent surgery between July and October, and were therefore eligible to return to play in the same season, had an average RTP of 8.7 weeks (range 5.9-13.6). With an appropriately placed intramedullary screw and an aggressive rehabilitation protocol, early RTP was achievable with a low refracture rate in professional athletes. All NFL players in this series were able to return to play after surgery. We observed that these injuries were more likely to occur in the first 3 seasons of play and in wide receivers, linebackers, and tight ends. This at-risk subset of players may benefit from improved preventative measures. Level IV, retrospective case series.

Repair of Acute Superficial Deltoid Complex Avulsion During Ankle Fracture Fixation in National Football League Players.

Infolding and retraction of an avulsed deltoid complex after ankle fracture can be a source of persistent increased medial clear space, malreduction, and postoperative pain and medial instability. The purpose of this descriptive case series was to analyze the preliminary outcomes of acute superficial deltoid complex avulsion repair during ankle fracture fixation in a cohort of National Football League (NFL) players. We found that there is often complete avulsion of the superficial deltoid complex off the proximal aspect of the medial malleolus during high-energy ankle fractures in athletes. Between 2004 and 2014, the cases of 14 NFL players who underwent ankle fracture fixation with open deltoid complex repair were reviewed. Patients with chronic deltoid ligament injuries or ankle fractures more than 2 months old were excluded. Average age for all patients was 25 years and body mass index 34.4. Player positions included 1 wide receiver, 1 tight end, 1 safety, 1 running back, 1 linebacker, and 9 offensive linemen. Average time from injury to surgery was 7.5 days. Surgical treatment for all patients consisted of ankle arthroscopy and debridement, followed by fibula fixation with plate and screws, syndesmotic fixation with suture-button devices, and open deltoid complex repair with suture anchors. Patient demographics were recorded with position played, time from injury to surgery, games played before and after surgery, ability to return to play, and postoperative complications. Return to play was defined as the ability to successfully participate in at least 1 full regular-season NFL game after surgery. All NFL players were able to return to running and cutting maneuvers by 6 months after surgery. There were no significant differences in playing experience before surgery versus after surgery. Average playing experience before surgery was 3.3 seasons, 39 games played, and 22 games started. Average playing experience after surgery was 1.6 seasons, 16 games played, and 15 games started. Return to play was 86% for all players. There were no intraoperative or postoperative complications noted, and no players had clinical evidence of medial pain or instability at final follow-up with radiographic maintenance of anatomic mortise alignment. Superficial deltoid complex avulsion during high-energy ankle fractures in athletes is a distinct injury pattern that should be recognized and may benefit from primary open repair. The majority of NFL players treated surgically for this injury pattern are able to return to play after surgery with no reported complications or persistent medial ankle pain or instability. Level IV, retrospective case series.

Return to Play After Chondroplasty of the Knee in National Football League Athletes

Background: Knee injuries, including articular cartilage damage, are common in football players and are potentially career threatening. The rate of return to play (RTP) as well as the factors affecting return after arthroscopic chondroplasty of the knee is performed in National Football League (NFL) athletes are not known. Purpose: To determine the rate of return to regular season NFL competition after arthroscopic knee surgery including chondroplasty of articular cartilage lesions. In addition, identification of factors that influence successful return was investigated. Study Design: Case series; Level of evidence, 4. Methods: Athletes in the NFL who underwent arthroscopic chondroplasty at a single institution were identified. Retrospective chart review and review of the NFL online database were utilized to determine the rate of RTP and factors affecting an athlete’s ability to return. Chi-square and Student t tests were used to assess differences among players who were and were not able to RTP, and logistic regression was employed to determine a player’s odds of return. Results: There were 52 patients (54 procedures) identified from the surgical database who met the inclusion criteria for the study operated on between August 1, 2001, and March 31, 2011. Of these players, 36 (67%) were able to return to regular season NFL game play at an average of 8.2 months, including 13 (24%) who were still active in the NFL. The average time to follow-up was 5.9 years, and all players were allowed at least 2 years of follow-up. There was no significant correlation of RTP to athlete age, lesion size, lesion location, position played, or round selected in the NFL draft. Players who underwent concomitant microfracture were 4.4 times less likely to return to the NFL than were those who did not undergo this procedure (95% CI, 1.3-15.5). Athletes who played more than 11.6 games per season were 4.7 times more likely to RTP than were those who played fewer games per season (95% CI, 1.4-16.6). Athletes who returned to play competed in 56 fewer games, 3.3 fewer seasons, and played in 3.2 fewer games per season compared with their level of competition before surgery. Conclusion: A majority (67%) of NFL players are able to RTP after arthroscopic knee surgery including chondroplasty of articular cartilage lesions. Athletes who play more games per season are more likely to RTP after chondroplasty of articular cartilage lesions of the knee, but those undergoing concomitant microfracture are less likely to return. No statistical significance was determined when comparing the athletes who returned to play with respect to age at surgery, lesion location, lesion size, lesion grade, position that the athlete played, or draft round.

Return to Play After Shoulder Stabilization in National Football League Athletes

Objectives:Shoulder instability is a common and limiting injury to football players. The return to play (RTP) percentage and factors affecting RTP after shoulder stabilization in National Football League (NFL) players are not defined. The purpose of this study was to determine the rate of return to professional football play in the NFL after shoulder stabilization and to determine what factors may affect RTP in these athletes.Methods:Sixty NFL players who had undergone shoulder stabilization at our institution were followed to determine the rate of RTP and factors predicting RTP. Chart review was performed to glean perioperative data and follow-up was performed by accessing the statistics database maintained by the NFL. Successful RTP was defined as return to play in at least one regular season NFL game following surgery. Chi square and Student’s t-tests were performed to examine differences between perioperative and athletic history variables and a player’s ability to RTP.Results:Ninety percent (54 of 60) of NFL players were able to return to game play following shoulder stabilization. The average time to RTP was 8.6 months. Age, number of games before surgery, and career length were not statistically different between those that returned and those that did not. Eleven of the sixty patients underwent open stabilization. Ninety-two percent (45/49) of the arthroscopically treated and eighty-two percent (9/11) of the openly treated athletes were able to RTP; these rates were not found to be significantly different. Playing history and demographics were similar between the open and arthroscopic groups. Players selected before the fourth round of the NFL draft were 7.6 times more likely to RTP. Circumferential labral tears were found in seven athletes, all of whom were able to RTP following surgery.Conclusion:The RTP rates for NFL players following shoulder stabilization are quite high (90%). There is no difference in RTP rates between open and arthroscopic repairs. Being selected in the first four rounds of the NFL draft is highly predictive of a player’s ability to RTP.

Return to Play After Partial Lateral Meniscectomy in National Football League Athletes

Background: Lateral meniscal injury is a common and possibly career-threatening injury among players in the National Football League (NFL). The rate of return to play (RTP) and factors that affect RTP after lateral meniscal injury in NFL players are currently not defined. Purpose: The aims of this study were to determine the rate of RTP to regular-season NFL game play of NFL players after arthroscopic partial lateral meniscectomy and to identify factors that can predict the ability to return to play. Study Design: Case series; Level of evidence, 4. Methods: Seventy-two patients undergoing 77 arthroscopic lateral partial meniscectomies were followed to determine the rate of RTP (defined as successful RTP in at least 1 regular-season NFL game after meniscectomy) and factors predicting players’ ability to return to play. Perioperative variables were recorded using retrospective chart review. Players’ heights and weights, dates of return, draft rounds, and counts of games, starts, and seasons both before and after meniscectomy were all collected from statistical databases maintained by the NFL. Chi-square and Student t tests were performed to assess differences among covariates with respect to an athlete’s ability to return to play, and odds ratios were calculated as appropriate. All percentages were calculated as percent of total procedures performed (n = 77). Results: Of the 77 partial lateral meniscectomies performed, 61% (n = 47) resulted in the athlete returning to play at his previous level of competition with an average length of time to RTP of 8.5 months; 19 (40%) of those who returned were still active in the NFL at the time of follow-up. Age at time of surgery, games and seasons played before surgery, and individual position were not significantly different between those who did and did not return to play. Undergoing a concomitant procedure did not affect an athlete’s ability to return to play, nor did concurrent arthroscopic anterior cruciate ligament reconstruction affect a player’s likelihood to return to play. Players drafted in the first 4 rounds of the NFL draft were 3.7 times more likely to return to play than players drafted after the fourth round, and players who started more than 46.2% of their games played (the mean value for this population) were 2.8 times more likely to return to play. Speed-position players (running backs, receivers, linebackers, and defensive backs) were 4.0 times less likely to return to play than non–speed position players (linemen and tight ends). Conclusion: The majority of NFL players undergoing arthroscopic lateral meniscectomy are able to return to play. Players selected earlier in the NFL draft and who are listed as starters in more of their games are more likely to return to play, as are linemen and tight ends. It is significantly more difficult for running backs, receivers, linebackers, and defensive backs to return to play.

Quadriceps Tendon Injuries in National Football League Players

Background: Distal quadriceps tendon tears are uncommon injuries that typically occur in patients older than 40 years of age, and they have a guarded prognosis. Predisposing factors, prodromal findings, mechanisms of injury, treatment guidelines, and recovery expectations are not well described in high-level athletes. Hypothesis: Professional American football players with an isolated tear of the quadriceps tendon treated with timely surgical repair will return to their sport. Study Design: Case series; Level of evidence, 4. Methods: Fourteen unilateral distal quadriceps tendon tears were identified in National Football League (NFL) players from 1994 to 2004. Team physicians retrospectively reviewed training room and clinic records, operative notes, and imaging studies for each of these players. Data on each player were analyzed to identify variables predicting return to play. A successful outcome was defined as returning to play in regular-season NFL games. Results: Eccentric contraction of the quadriceps was the most common mechanism of injury, occurring in 10 players. Only 1 player had antecedent ipsilateral extensor mechanism symptoms. Eleven players had a complete rupture of the quadriceps tendon, and 3 had partial tears. There were no associated knee injuries. All ruptures were treated with surgical repair, 1 of which was delayed after failure of nonoperative treatment. Fifty percent of players returned to play in regular-season NFL games. There was a trend toward earlier draft status for those who returned to play compared with those who did not (draft round, 3.1 ± 2.5 vs 6.0 ± 2.9, respectively; P = .073). For those who returned to play, the average number of games after injury was 40.9 (range, 12-92). Conclusion: Quadriceps tendon tears are rare in professional American football players, and they usually occur from eccentric load on the extensor mechanism. Prodromal symptoms and predisposing factors are usually absent. Even with timely surgical repair, there is a low rate of return to play in regular-season games. There is a trend toward early draft rounds for those who successfully return to play.

Practice or Profits

This article investigates whether the outcomes of National Football League (NFL) preseason games are predictors of regular season NFL performance. Using data from the 2002-2010 NFL seasons, the empirical analysis does not find that either a team’s preseason winning percentage or a win in the third preseason game is a significant indicator of the team’s regular season winning percentage. This result contrasts with previous findings that preseason game performance did provide an indicator of regular season performance for the 1970-1991 NFL seasons. Preliminary evidence is presented that suggests that the change in the importance of preseason performance in predicting regular season performance started around 1994.

The Impact of Visiting Team Travel on Game Outcome and Biases in NFL Betting Markets

Using data on regular season National Football League games from 1981-2004, this study examines the impact that travel has on game outcome and whether betting markets fully incorporate this information. A visiting team travelling west to east and crossing at least one time zone is shown to significantly increase the probability of the home team winning. This impact increases with distance, but at a decreasing rate. Evidence on whether betting markets fully account for this travel effect is mixed. While there is evidence that markets do not fully account for the impact of travel and that bettors underestimate the home team’s score whenever the visitor crosses a time zone, the model does not provide a profitable betting strategy out of sample. Thus, any bias is likely too small to profitably exploit.

Patellar Tendon Ruptures in National Football League Players

Background: Although knee injuries are common among professional football players, ruptures of the patellar tendon are relatively rare. Predisposing factors, mechanisms of injury, treatment guidelines, and recovery expectations are not well established in high-level athletes. Hypothesis: Professional football players with isolated rupture of the patellar tendon treated with timely surgical repair will return to their sport. Study Design: Case series; Level of evidence, 4. Methods: Twenty-four ruptures of the patellar tendon in 22 National Football League (NFL) players were identified from 1994 through 2004. Team physicians retrospectively reviewed training room and clinic records, operative notes, and imaging studies for each of these players. Player game statistics and draft status were analyzed to identify return to play predictors. A successful outcome was defined as participating in 1 regular-season NFL game. Results: Eleven of the 24 injuries had antecedent symptoms. The most common mechanism of injury was an eccentric overload to a contracting extensor mechanism. Physical examination demonstrated a palpable defect in all players. Twenty-two were complete ruptures, and 2 were partial injuries. Three of the 24 cases had a concomitant anterior cruciate ligament (ACL) injury. In 19 of the 24 injuries, the player returned to participate in at least 1 game in the NFL. Players who returned were drafted, on average, in the fourth round, while those who failed to return to play were drafted, on average, in the sixth round. Of those players who returned to play, the average number of games played was 45.4, with a range of 1 to 142 games. Conclusion: Patellar tendon ruptures can occur in otherwise healthy professional football players without antecedent symptoms or predisposing factors. The most common mechanism of injury is eccentric overload. Close attention should be paid to stability examination of the knee given the not uncommon occurrence of concomitant ACL injury. Although this is usually a season-ending injury when it occurs in isolation, acute surgical repair generally produces good functional results and allows for return to play the following season. Players chosen earlier in the draft are more likely to return to play.

A Methodology for Evaluating Production in Football: An Armchair Quarterback's Rating System

This paper posits a model of production in football. Applying this model to basic offensive and defensive statistics from regular season National Football League games, one is able to accurately explain variation in points scored, points allowed, and win percentage. One can apply individual player statistics for quarterbacks and running backs to the model parameters to calculate the marginal contribution of specific players to their teams. Therefore, this methodology is not only attractive because it is grounded in statistical analysis, but it also offers a uniform system to compare the production of different players at different positions - properties that the current NFL rating system does not contain. The most obvious use of this model would be to apply it to quarterback and running back salaries to determine if the market for those players is reasonably efficient.

Overreaction in the NFL point spread market

A tendency for individuals to overweigh recent information and underweigh prior data has been discovered by researchers in financial markets, economic forecasting, security analysis and other areas. A study of point spread patterns in the 2264 regular season National Football League (NFL) games over the 1981–;1995 seasons was conducted to investigate the overreaction bias of bettors. Results indicated that bettors tend to overweigh outstanding positive performance when measured over the previous game, over the previous two to five games or over the previous season. In general, the more outstanding the performance, the greater the overreaction. However, bettors did not overreact to unusual negative performance over the same periods. This result is congruent with the tendency for heavy favourites to cover the point spread less than half the time over the 1969–;1995 seasons. The overreaction bias in the NFL betting market provides another example of a violation of the weak form of the Efficient Markets Hypot...