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ACL Summary

post #1 of 16
Thread Starter 
It has been suggested that the information regarding ACL injury has been spread out into so many topics, that its sort of difficult to get a cohesive, overall view of the entire subject. If you have been following all the threads on this topic religously, then don't waste your time reading this!

But if you are a relatively new bear, you may want to check out the entire thread.

First, you cannot talk about Skiing and ACL injury without mentioning the research of Vermont SKi Safety. Since they put out a video on this topic, I feel it is only fair to put up a direct link to their site, as opposed to simply quoting them.

If you want even more info on Vermont Ski Safety, read this interview with Dr. Carl Ettinger;


What predisposes someone towards an ACL injury, aside from the skiing style described by Vermont Ski Safety?

1. YOU ARE FEMALE: Sorry! Not a sexist statement, but an anatomical truth.
First, there's that Q angle thing. The Q angle refers to the quadricep angle, or the angle between the hip and the knee. Since it is steeper in women, they are more prone to having the knee cap slide, causing injury.

A lack of androgen means that most women are less prone to developing large muscles. Muscle fiber helps protect the joints and connective tissue. Female athletes are subject to the same torque forces in their knee as men. If the muscle is not strong enough to the joint, the knee cap will be even more prone to sliding. That's one of the reasons why strength training is so important for women, and they need to be careful about becoming hyperflexible.

Some factors influencing injury in women:

Women do not bend their knees as much as men when landing from a jump. This increases knee joint pressure.

Women turn and pivot in a more erect position. Bending at the knee and hip reduces ACL stress.

Women use their quads more then their hamstrings when changing direction. As the quads contract, the hamstrings will stretch and relax. A stretched muscle produces less force. So if the knee is not bent enough, there is force on the shin bone to tear the ACL.

IMPORTANT: ANYONE whose quads are significantly more powerful is at risk for an ACL injury.

2. NEUROMUSCULAR COORDINATION: Okay, lets say, you have decent hamstring/quad muscular balance, and reasonably good ski technque. Think your'e immune? Maybe, maybe not. Neuromuscular coordination refers to the firing patterns of the muscular system. Even if the hamstrings are strong, if they don't fire at the EXACT right moment to protect the ACL, its no go. This is why activities that require fast reflexes are being added to sports conditioning programs. The weight training by itself may not cause enough of a reflex reaction to protect the ligament.


Okay, this theory is contraversial, but I thought I'd throw it out anyway. The interconylar notch is at the end of the thigh. This is where the anterior and paoterior cruciate ligaments form an x. It has been SPECULATED that a narrow notch may predispose someone to ACL injury.

4. LOOK AT YOUR FEET: Pronators are susceptible to ACL injury. Also, consider the concept of the kinetic chain, where ski movements start. You need to look at the lower leg; the gastronemius and the peroneals. If someone cannot dorsi flex their foot [curl the toes towards the shin] the tibia can become misaligned, which can effect the alignment of the femur, in turn affecting the integrity of the knee. Landing flat footed while jumping can also make you mor susceptible. The proper progression is toe, ball, heel, squat.

5. WEAK ECCENTRIC STRENGTH: Since ACL injuries happen in the eccentric {lengthening } phase of a contraction, its a good idea to incorporate eccentric training into your routine.

6. BALANCE, STABILITY, PROPRIOCEPTION: Prior to any foot strike, your transverse abdominal muscle must activate the stabilze the sacro illiac joint. If this does NOT happen, the SI joint will destabilize, causing a misalignment of the femurs connection to the pelvis, which in turn misaiigns the knee. BOING!!!
Keep you transverse active by engaging in balance related activities, and practicing your KEGELS.

7. POOR KNEE TRACKING due to weak vastus medialis, the muscle above the knee, responsible for the last 20 degrees of extension.

8. TIGHT HIP FLEXORS: If a muscle group such as your hip flexors are tight, it can inhibit the actions of an assisting muscle group, such as the gluteals. If the glutes are not doing their job, the quads will have to work harder, leading to a hamstring/quad muscle imbalance, which can set you up for an ACL injury. This is called reciporocal inhibition, in case you are interested.

9. TIGHT ILLIOTIBIAL BAND: If the IT band is tight, the vastus medialis will not be able to perform its function of tracking the knee.

This is often a "female issue", but being excessively flexible means that the muscles surrounding the joints and ligaments will be in an overly relaxed state, unables to stabilize and react to stress.


Follow the advice of our illustrious pros in the technique forum, and engage in good technique.

A strength training routine should concentrate on closed chain exercises such as squats and leg presses. Most PT's agree that the leg extension machine creates too much shearing force for the ACL.
Incorporating balance is crucial.
here are some exercises from threads that can only be found in the archives: http://www.bfit.net/secure_members/sports_specific_workout/core_trunk_dev elopment_for_snow_sports.htm

click on the free exercises at http://www.sissel-online.com

SUPER ADVANCED! Please be careful:

From the Stone Clinic in SF:

From OUTSIDE Mag: http://www.outsidemag.com/magazine/2...0101body2.html

Plyometric training is also being used fro prevention of ACL injuries.

A still controversial area is the subject of stretching. In the "old days", we used to believe that stretching was important before any activity.

There has been NO research that ACCEPTABLY proves that pre sport stretching prevent injury!!!!

If you are a hyperflexible female with many of the predisposing factors mentioned, you may want to reconsider doing an hour of hatha yoga prior to skiing.

A relatively new concept that is being researched, is the idea of self myofascial release. The basic philosphy is that you want to release an area that is knotted, without a significantly dangerous increase in muscle length. This is particularly effective if you have tight quads, IT band or hip flexors.
Check this out! http://www.smiweb.org/rehab/guides/roller_guide.pdf

If you do get hurt, find a PT that specializes in sports rehab. The ideal is someone like the one Linda went to, a PT who is also an athletic trainer. Don't forget to do post rehab workouts.

Hope this was useful.

<FONT COLOR="#800080" SIZE="1">[ March 30, 2002 12:57 PM: Message edited 4 times, by Lisamarie ]</font>
post #2 of 16
very useful, thank you.

The number of acl patients I have run into warrants a good hard look at this thread...wether you have been injured or not, this is some good stuff, good to have it all in one place.

prevention is FAR easier than recovery...

happy skiing!
post #3 of 16
Thread Starter 
Cool! Believe it or not, all these posts are a little bit self serving. I'm studying for some extremely "techy" sports med personal training exams. If I just read the texts, it doesn't assimilate. Re writing it and making it applicable to areas that are relevant to me makes the learning easier and more enjoyable.

Okay, this machine is way, way too pricy for a skiers budget, but if people can get their gyms to carry it, this would be the ultimate prevention exercise. Combines the concepts of Skiers edge, Slide Board and Pilates.
post #4 of 16
Nice! Don't forget your cardio. Injuries happen when your tired. People who do lots of aerobic stuff usually have more energy. You should also do some anaerobic training, so that you can tolerate lactic acid buil up better.
post #5 of 16
Thread Starter 
Thanks! I knew there was something I was going to forget!

I mentioned that tight hip flexors can inhibit the action of the glutes, which in turn will put more emphasis on the quads, accentuating the problem.
Check out these hip flexor stretches;

This is an old thread, that I was only able to find in the archives. It explains the underlying philosophy of what we are talking about. Too many people look for specific exercises to work this or that muscle. Again, this is fine for general fitness. But when it comes to injury prevention and sport performance, an integrated system is needed.


<FONT COLOR="#800080" SIZE="1">[ March 31, 2002 10:42 AM: Message edited 2 times, by Lisamarie ]</font>
post #6 of 16
Thread Starter 

Some ACL injuires require surgery, some don't. One of the determining factors is whether or not the synovial membrane rips. Generally, if you hear a "pop" when the injury happens, its the sign that the membrane has ruptured, and basically, your'e toast!

[ August 27, 2002, 07:24 PM: Message edited by: Lisamarie ]
post #7 of 16

*Excellent* summary of much of the info about ACL injuries. I've bookmarked your post(s) to refer back to later.

As an extremely satisfied 1991 ACL-reconstruction (patellar graft) patient, it seems like I'm often asked about the subject. There are so many different theories/myths surrounding this injury that it's really nice to have such a comprehensive explanation of predisposition and prevention.

Well done and thanks much.


(And yes, I did hear the "pop") :
post #8 of 16
Thread Starter 
And thank YOU Bob! I will periodically update this. ACL's have recently become a major focus of sports medicine research. Although we have many ACL threads, this one summarizes all the info.

One more thing. There has been some controversy as to whether ACL patients should do the leg extension machine. Most of the people who know there stuff say you should not.
Recent studies have indicated that even if you have good knees, if you use the leg extension machine AND particpate in sports, you can actually set yourself up for injury.


Remember the kinetic chain thread? Training is essentially, neurological. The leg extension machine moves in a predictable, isolated manner. In sports, the legs do not function that way. So by performing an exercise that isolates an already hypertonic muscle in a stable environment, you are actually DEtraining the reflexes that would help you react to a potential injury!
post #9 of 16
Originally posted by Lisamarie:

One more thing. There has been some controversy as to whether ACL patients should do the leg extension machine. Most of the people who know there stuff say you should not.
Recent studies have indicated that even if you have good knees, if you use the leg extension machine AND particpate in sports, you can actually set yourself up for injury.

That's very interesting.

My surgeon (God, how could it really be eleven years ago?!?!), was adamant about me *not* using a leg extension machine. Particularly during rehab but also just in general.

That reminds me... one rehab exercise he highly recommended was to do the Stairmaster *backwards*. I got very weird looks from many of the other gym patrons, but it sure seemed to help with equalizing overall muscle recovery.

post #10 of 16
LM, two thoughts.

1. Whose notions are those under "ARE YOU SUSCEPTIBLE?" Are they from the interview with that doctor you mention?

2. Emphasize FIRST, and thereafter again and again, that if you suspect you have hurt your knee, NOBODY other than a qualified orthopod with experience in knee injury can tell you what's going on. That also means that your excellent compendium of info is NOT a substitute for an actual in-person physician exam and diagnosis.

Peoples' fear of MDs and/or hospitals should not lead them to trying a self-diagnosis. The knee is far too critical to our skiing!
post #11 of 16
Thread Starter 
The "ARE YOU SUSCEPTIBLE" info is the sum toal of research that has been done in the past few years by the ACSM, NASM, and other medical, orthopedic, physical therapy organizations.

And as I've said time after time in many threads, it is crucial that no one ever, for any reason, tries to get their injury diagnosed over the internet, even by someone who is an orthopedic surgeon.

That being said, prevention is possible, to some degree. Although nothing is fool proof, its a good idea to eliminate the risks. If there are now actual studies that prove that the leg extension machine can leave you susceptible, why do it.

If hyperflexibility puts women at irisk for injury, they need to stop buying into the propaganda set forth by the new age yoga nazis, and get into the weight training room!
post #12 of 16

What about Classic Ballet?

I never was into the hype of aerobics, even when Richard Simmon's(sp?) first came out. I found the aerobics' us girls were made to do in gym class boring and didn't do a thing for me. I always found Formal and Informal types of Dance to be a great way to condition your body. In fact if we had the technology and research we have today back 15 years ago(when I blew my ACL), I would have still been playing soccer.

My doctor was completely surprised on how quickly I was healing from my injury, but because physical therapy wasn't what it is today I feel my body was cheated. (I was in perfect condition)

I have lost much of the muscle I had at 16-18, and I blame it on the fact people didn't know what they know today. I am happy that other young athletes have a better change at getting back after an injury.

Please LM keep up on the information on ACL and recovery. They did make me use those leg extension machine and I always felt it didn't feel right with my leg. Now I will never touch one of those machines again.

post #13 of 16
Thread Starter 
Actually, Becca, although ballet dancers do incur many injuries, ACLS are not that common amongst them. It has been speculated that the reason for this is similar to one of the many reasons martial artists are not particularly prone to ACL injury: Working barefooted increases proprioception.
post #14 of 16
Then that explains why I had such strong legs.

I had lots of bad falls, in skiing, but never had a knee injury till after I stopped ballet training.

With my knee injury I had to stop point, and everything else went down hill after that.

I am seriously thinking of going back to ballet and getting my youngest into it also.
post #15 of 16
Thread Starter 
Becca, you may want to consider a combination of ballet and martial arts, especially for your young ones, with all the stuff that's going on nowadays!

One thing that martial trains that is crucial for injury prevention: Your reflexes! Check out the skiing and martial arts thread: http://www.epicski.com/cgi-bin/ultim...1;t=000137;p=2

I noticed from your photo that you wear glasses. Visual acuity is another important aspect of injury prevention. So anything that trains you to respond quickly to visual stimuli is helpful! I have a slight deviation in my binocular vision. Lately, I have been finding medicine ball drills helpful.

I need to restste the obvious.


They are for post rehab or injury prevention only.
And once again, please refrain from asking for diagnostic advice over the internet. the only thing anyone, even a top orthopedic surgeon can LEGALLY tell you is R.I.C.E.
rest ice compression and elevation
post #16 of 16
Originally posted by Lisamarie:
Becca, you may want to consider a combination of ballet and martial arts, especially for your young ones, with all the stuff that's going on nowadays!
My husband is all for both, so am I. It's really scary with all the child adduction going on. Men become very protective when they have young girls, at least mine is.

Now I have to be careful on what type's of exercise I do with my knee, because I have no brace right now I can feel it's unstableness. Found a local doctor who is recommended by my old doctor. A lot of Farmers(amish) get hurt around here and finally we have one.

Walking, and Biking are the two main exercises I can do reg. But anything with weights is questionable.
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