National Football League Players Have Higher Rates of Knee Extensor Mechanism Tears During Short and Normal Rest Weeks versus Long Rest Weeks

Warren G. Haralson; Ashwin R. Garlapaty; John Baumann; Garrett R. Jackson; James L. Cook; Steven F. DeFroda

doi:10.1055/a-2585-5099

The Journal of Knee Surgery, Table of Contents

J Knee Surg
DOI: 10.1055/a-2585-5099

Original Article

National Football League Players Have Higher Rates of Knee Extensor Mechanism Tears During Short and Normal Rest Weeks versus Long Rest Weeks

Warren G. Haralson

¹Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri

²Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri

,

Ashwin R. Garlapaty

¹Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri

²Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri

,

John Baumann

¹Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri

²Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri

,

Garrett R. Jackson

¹Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri

²Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri

,

James L. Cook

¹Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri

²Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri

,

Steven F. DeFroda

¹Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri

²Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri

› Author Affiliations

Abstract

Lower extremity injuries, particularly knee injuries, in National Football League (NFL) players are common. Extensor mechanism ruptures often require season-ending surgery. These ruptures, involving structures like the quadriceps and patellar tendons, are caused by powerful movements that overload the knee. Research on NFL injury risk factors, including time between games, is growing, but studies on rest periods and knee injuries have shown mixed results and are limited in scope. No prior research has specifically examined extensor mechanism tears in relation to short, normal, or long rest periods between games.

Using publicly accessible resources (NFL injury reports, Pro-Football-Reference.com, and ESPN.com), an online search was conducted to identify NFL players who tore their quadriceps tendon or patellar tendon between the 2009 and 2023 seasons. Only regular season injuries after week 1 were included. The date of injury and prior game date were collected in order to calculate the length of rest. Next, each injury was categorized as a short (<7 days), normal (7 days), or long (>7 days) week injury. Other factors, such as age, football position, and playing surface (natural grass or artificial turf), were also collected.

A total of 58 players met inclusion criteria. There was no difference in extensor mechanism injury rates between short weeks and normal weeks. Players were 4.7 times more likely to tear their extensor mechanism during normal weeks than long weeks (p = 0.0039) and 3.7 times more likely to tear their extensor mechanism during short weeks than long weeks (p = 0.0385). Regarding playing surface, extensor mechanism tears were more likely to occur on artificial turf than natural grass (p = 0.0324).

During the 2009–2023 NFL seasons, players were found to have 4.7 times higher rates of knee extensor mechanism tears during short (<7 days) rest weeks and 3.7 times higher rates during normal (7 days) rest weeks between games, when compared to long (>7 days) rest weeks. There was no difference in knee extensor mechanism injury rates between the short and normal rest weeks.

Level of Evidence Level III.

Keywords

lower extremity injuries - knee injuries - knee extensor mechanism injury - National Football League - rest week analysis

Full Text

References

References
1 Mack CD, Kent RW, Coughlin MJ. et al. Incidence of lower extremity injury in the National Football League: 2015 to 2018. Am J Sports Med 2020; 48 (09) 2287-2294
2 Dan M, Parr W, Broe D, Cross M, Walsh WR. Biomechanics of the knee extensor mechanism and its relationship to patella tendinopathy: a review. J Orthop Res 2018; 36 (12) 3105-3112
3 Hsu H, Siwiec RM. Patellar Tendon Rupture. In: StatPearls. StatPearls Publishing; 2024. https://www.ncbi.nlm.nih.gov/books/NBK513275/ (Accessed August 29, 2024)
4 Beranger JS, Kajetanek C, Bayoud W, Pascal-Mousselard H, Khiami F. Return to sport after early surgical repair of acute patellar tendon ruptures. Orthop Traumatol Surg Res 2020; 106 (03) 503-507
5 Boublik M, Schlegel TF, Koonce RC, Genuario JW, Kinkartz JD. Quadriceps tendon injuries in national football league players. Am J Sports Med 2013; 41 (08) 1841-1846
6 Kuechle DK, Stuart MJ. Isolated rupture of the patellar tendon in athletes. Am J Sports Med 1994; 22 (05) 692-695
7 NFL Health and Safety Related Rules Changes Since. 2002 . NFL.com.
8 Jacobi J, Wasserman EBD, DMack C. et al. The National Football League concussion protocol: a review. HSS J 2023; 19 (03) 269-276
9 Lawrence DW, Comper P, Hutchison MG. Influence of extrinsic risk factors on National Football League injury rates. Orthop J Sports Med 2016; 4 (03) 2325967116639222
10 Perez JR, Burke J, Zalikha AK. et al. The effect of Thursday night games on in-game injury rates in the National Football League. Am J Sports Med 2020; 48 (08) 1999-2003
11 Garlapaty AR, Scheiderer JA, Rucinski K, DeFroda SF. Risk of anterior cruciate ligament tears in National Football League players by short, normal, or long rest weeks. J Knee Surg 2025; 38 (03) 148-153
12 NFL.com | Official Site of the National Football League.
13 ESPN - Serving Sports Fans. Anytime. Anywhere. ESPN.com (Accessed September 9, 2024
14 Pro Football Stats, History, Scores, Standings, Playoffs, Schedule & Records. Accessed September 9, 2024 at: Pro-Football-Reference.com
15 Mair SD, Seaber AV, Glisson RR, Garrett Jr WE. The role of fatigue in susceptibility to acute muscle strain injury. Am J Sports Med 1996; 24 (02) 137-143
16 Hess GP, Cappiello WL, Poole RM, Hunter SC. Prevention and treatment of overuse tendon injuries. Sports Med 1989; 8 (06) 371-384
17 Silva JR, Rumpf MC, Hertzog M. et al. Acute and residual soccer match-related fatigue: a systematic review and meta-analysis. Sports Med 2018; 48 (03) 539-583
18 Sharma A, Fletcher AN, Shah JK, Akoh CC, Parekh SG. The effect of Thursday night football on injuries in the National Football League. J Orthop Sports Med 2023; 5 (03) 304-310
19 Baker HP, Young-Hoon Lee K, Dayton SR, Terry M, Tjong VK. Thursday Night Football's impact on all-cause injuries in NFL players during 2012 - 2017. Phys Sportsmed 2019; 47 (03) 350-352
20 Konrath GA, Chen D, Lock T. et al. Outcomes following repair of quadriceps tendon ruptures. J Orthop Trauma 1998; 12 (04) 273-279
21 Boublik M, Schlegel T, Koonce R, Genuario J, Lind C, Hamming D. Patellar tendon ruptures in National Football League players. Am J Sports Med 2011; 39 (11) 2436-2440
22 Logerstedt DS, Ebert JR, MacLeod TD, Heiderscheit BC, Gabbett TJ, Eckenrode BJ. Effects of and response to mechanical loading on the knee. Sports Med 2022; 52 (02) 201-235
23 Epro G, Suhr F, Karamanidis K. Human muscle-tendon unit mechanobiological responses to consecutive high strain cyclic loading. J Exp Biol 2023; 226 (20) jeb246507
24 Bengtsson H, Ekstrand J, Waldén M, Hägglund M. Muscle injury rate in professional football is higher in matches played within 5 days since the previous match: a 14-year prospective study with more than 130 000 match observations. Br J Sports Med 2018; 52 (17) 1116-1122
25 Why I Hate Thursday Night Football | By Richard Sherman. The Players' Tribune. December 15, 2016. https://www.theplayerstribune.com/articles/richard-sherman-seahawks-thursday-night-football (Accessed September 9, 2024)
26 A Former Player's Perspective on Thursday Night Football | News, Scores, Highlights, Stats, and Rumors | Bleacher Report. https://bleacherreport.com/articles/1366927-a-former-players-perspective-on-thursday-night-football (Accessed September 9, 2024
27 Smith MR, Zeuwts L, Lenoir M, Hens N, De Jong LMS, Coutts AJ. Mental fatigue impairs soccer-specific decision-making skill. J Sports Sci 2016; 34 (14) 1297-1304
28 Smith MR, Coutts AJ, Merlini M, Deprez D, Lenoir M, Marcora SM. Mental fatigue impairs soccer-specific physical and technical performance. Med Sci Sports Exerc 2016; 48 (02) 267-276
29 Roger Goodell addresses possibility of flexing TNF games, Commanders sale at Annual League Meeting. https://www.nfl.com/news/roger-goodell-addresses-possibility-of-flexing-tnf-games-commanders-sale-at-annu (Accessed September 9, 2024)