Fight Medicine: Ask the Fight Doctor Mailbag

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With the recent ACL tears of high-profile athletes like UFC welterweight champion Georges St. Pierre and Washington Redskins quarterback Robert Griffin III, I had a question concerning their recovery. How do these athletes in one year regain the same size mass in their quadriceps that had taken them years to develop in the first place? -- Edmund Leong

The Fight Doctor: Edmund, thanks for a great question. What Adrian Peterson and GSP have done is a testament to their great athletic ability. In fact, even to orthopedic surgeons who reconstruct ACLs on a regular basis, what they have done is unique and arguably not the standard to compare even other elite athletes to when returning from ACL surgery.

A study of NFL wide receivers and running backs showed that only 80 percent of those players that tear the ACL actually make it back to play even a single NFL game. This same study calculated a power rating for each player (total yards/10 + 6 x number of touchdowns). The injured players all had higher power ratings than the players to which they were compared, but when they returned to play, they decreased to average or sometimes less than average production as measured by power ratings. Another study showed that only 63 percent of NFL players returned from ACL injuries. Players who were drafted within the first four rounds were more likely to return to play. The reason for this is unclear, but it may be due to their level of talent and athleticism or simply team and organizational support.

As far as quadriceps strength goes, it has been documented that most athletes only regain 80 percent of their original quadriceps strength by one year after ACL reconstruction. As you might imagine, preoperative quadriceps strength is a significant predictor of knee function after ACL reconstruction. Early rehab focuses on regaining range of motion, as limiting the range of motion of the knee after surgery can result in scarring, making it even harder to regain motion later in the rehab phase.

The best methods to gain return in quadriceps strength are controversial, but some methods are considered standard. Initially, just quadriceps contraction is used and can be improved with neuromuscular stimulation devices. After the early weeks of therapy, closed chain exercises such as leg presses are employed, because these place less stress on the graft. After closed chain exercises come open chain exercises, such as leg extensions, which isolate the quadriceps more than closed chain exercises, but those put the graft under more stress.

Once the athlete gains the ability to do things such as single leg hops and squats, then the real training begins. Plyometrics such as box jumps help with muscle strength and coordination, especially when landing. Running drills also help with balance, stability and agility, which can really put the graft under stress. Without sufficient quadriceps strength, the knee will move all over the place and can result in a rupture of the graft. If you have watched GSP training, you know plyometrics and agility drills are a big part of his routine, which may help explain how he was able to rehab from his ACL surgery so well.

In addition, young age and genetics likely play an important role. For someone like GSP, the combination of technology, a great support team and natural athleticism gives him the ability to defy the odds and come back beyond the expectations of even his own doctors.

Want your question answered by The Fight Doctor? You can contact him by email at fightmedicine@sherdog.com or find him on Twitter @fightmedicine. You can also read more about MMA injuries at FightMedicine.net.