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J Knee Surg 2025; 38(11): 549-554
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
1   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
2   Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri
,
Ashwin R. Garlapaty 
1   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
2   Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri
,
John Baumann
1   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
2   Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri
,
Garrett R. Jackson
1   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
2   Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri
,
James L. Cook 
1   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
2   Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri
,
Steven F. DeFroda
1   Department of Orthopaedic Surgery, Missouri Orthopaedic Institute, University of Missouri, Columbia, Missouri
2   Department of Orthopaedic Surgery, School of Medicine, University of Missouri, Columbia, Missouri
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Funding None.
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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

Author Contributions

Conceptualization: W.G.H., A.R.G., J.B., G.R.J., and S.F.D.; Formal analysis: W.G.H., A.R.G., J.B., G.R.J., J.L.C., and S.F.D.; Investigation: W.G.H., A.R.G., J.B., G.R.J., J.L.C., and S.F.D.; Supervision: J.L.C. and S.F.D.; Writing – original draft: W.G.H., A.R.G., J.B., G.R.J., and S.F.D.; Writing – review and editing: W.G.H., A.R.G., J.B., G.R.J., J.L.C., and S.F.D.




Publication History

Received: 10 October 2024

Accepted: 12 April 2025

Accepted Manuscript online:
14 April 2025

Article published online:
09 May 2025

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