Closer Look at the Nature of Adrian Peterson's Sports Hernia

Dave Siebert, M.D.@DaveMSiebertFeatured ColumnistFebruary 10, 2013

GREEN BAY, WI - JANUARY 05:  Running back Adrian Peterson #28 of the Minnesota Vikings runs the ball against the Green Bay Packers during the NFC Wild Card Playoff game at Lambeau Field on January 5, 2013 in Green Bay, Wisconsin.  (Photo by Andy Lyons/Getty Images)
Andy Lyons/Getty Images

When the Minnesota Vikings announced that Adrian Peterson underwent offseason sports hernia repair surgery for an abdominal strain he had been secretly battling for weeks, the MVP running back's already jaw-dropping season became downright incomprehensible.

Not only did AP fall just nine yards short of the all-time single-season rushing record while winning both the NFL Most Valuable Player and Offensive Player of the Year awards, he did so just one year following surgical reconstruction of his left ACL.

Now a sports hernia, too? It's just a flesh wound, apparently.

In an interview with ESPN's Josina Anderson, Peterson stated he suffered the injury all the way back in Week 10. How did he do since? Let's recap his rushing totals following Minnesota's Week 11 bye (h/t official NFL statistics):

  • Week 12: 108 yards
  • Week 13: 210 yards
  • Week 14: 154 yards
  • Week 15: 212 yards
  • Week 16: 86 yards
  • Week 17: 199 yards


It is difficult to wrap one's head around those numbers under normal circumstances. Add a sports hernia to the mix, and it becomes nearly impossible.

The term "sports hernia" is an umbrella term for a number of different injuries involving tears or weakness in the muscle and connective tissue in the lower abdomen or groin. On Feb. 7, a statement on the Vikings' official website shed some light on what, exactly, was going on in Peterson's case:

Adrian Peterson had a surgical procedure done today by Dr. William Meyers, in Philadelphia, Pennsylvania. Dr. Meyers was able to successfully repair Adrian's abdominal core muscle injury (sports hernia). We expect a speedy recovery with no long-term concerns.

The statement is consistent with a December report in the Los Angeles Times that stated Peterson had a strained abdominal muscle—another way to describe some types of sports hernias.

Muscle strains can be classified as grade-one, grade-two or grade-three. Grade-one strains constitute over-stretches of the muscle, while grade-two and grade-three strains represent partial and complete tears, respectively.

During his interview with Anderson, AP recalls when the injury took place:

I just remember getting twisted up pretty bad in an awkward position. My jersey never moves like that. I don't know if it was from a tackle or from me pulling away from someone. I just remember thinking when I saw my jersey like that, that I must've gotten twisted up pretty bad.

AP's description is a classic sports hernia mechanism of injury. By being abnormally and forcefully twisted at the core, AP's abdominal muscles were stretched and stressed in a way they are not used to. The result was a strain.

There are many individual abdominal core muscles. The most well-known is the rectus abdominis—the muscle that makes up the "six pack" and the same muscle Green Bay Packers wide receiver Greg Jennings had surgically repaired earlier this season. Others include the transversus abdominis, internal oblique and external oblique muscles. Each includes an area of connective tissue that can be stretched or torn to cause a sports hernia, as well.

Abdominal muscles are used primarily to stabilize the body's core while turning, twisting and bending. They are also used for forced exhalation—something that can be felt by placing a hand on the abdomen while blowing as if to put out birthday candles.

Strained muscles produce extreme pain when they are used, and if one makes their career as a professional running back, the abdominal muscles are used a lot. Every time Peterson bent, changed directions, cut or breathed deeply, he risked feeling a jolt of severe pain and adding to the inflammation surrounding the injury.

At one point, AP thought he might not be able to finish the season.

Referring to the numeric pain scale physicians and therapists use to gauge patients' pain, Peterson told Josina Anderson the pain was a "10 out of 10" during the Vikings' Week 16 game against the Houston Texans. The pain was so severe that he received a cortisone injection to the groin—a type of steroid that reduces inflammation—in hopes of controlling it.

Since Peterson's injury never saw more than a few days of rest at any one time, it did not have a chance to heal—he had to fight through the pain week after week. "It was mind over matter," AP told Anderson. "It was just about doing what I had to do to push myself every week."

After the season came to a close, Peterson finally had the opportunity to undergo surgery for definitive repair.

The surgery is a relatively simple one—I have personally assisted on several. Using previous MRIs as guidance to locate the injury, Dr. Meyers likely simply exposed the muscle tear and stitched it back together.

In some hernia repair surgeries, a waffle-like mesh material is stitched over the tear to provide additional support and act as a foundation to guide the body's healing. Whether or not a mesh is placed depends on the extent and size of the tear and whether or not the tissues under the tear are protruding through the defect.

Only AP can know how much pain he was in prior to the operation. That said, it was certainly substantial. To play through it for eight weeks, AP had to draw upon the superhuman willpower and determination he already demonstrated during his return from an ACL tear.

Yet perhaps more jaw-dropping is the fact that until he popped up on the Vikings' injury report in Week 15, no one even knew he had the injury. He looked just like his regular old, tackle-shredding self.

As he recovers from surgery over the next few weeks, AP will continue to be in pain when he uses the injured muscle. However, it will certainly be nothing compared to what he dealt with during the season—one of the greatest offensive seasons ever.

What can he possibly have in store for us next?

Dave Siebert is a medical/injury Featured Columnist for Bleacher Report who will graduate from medical school in June. He plans to specialize in both Family Medicine and Primary Care (non-operative) Sports Medicine. Anatomical and injury information discussed above is based on his own knowledge.