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More ACL Info

post #1 of 54
Thread Starter 
Okay, by now, we've all been "Vermont Ski Saftyed" to death. But today, at a workshop given by Mike Clark of the National Academy of Sports Medicine, http://www.nasm.org at the Perfrom Better seminar, http://www.performbetter.com , a thought occured to me.

Much of what Vermont Ski Safety refers to is prevention through proper technique. At the beginner and intermediate levels of skiing, most ACL tears probably happen due to faulty technique.

But what about the pro skiers, such as Picabo and Janica? It has been speculated, that many athletes may have a structural condition that may make them more likely to experience an ACL tear.

Some scary facts: An estimated 80,000 - 100,000 ACL injuries occur annually in the general population. 70% of these are non contact injuries.

ACL deficient knees or reconstructed acls have 105 times greater chance of developing osteoarthritis.

Women are more susceptible. when landing from a jump, women will activate more of their quadriceps, men will activate more hamstring. It has been speculated that overactive quads can cause acl injuries.

ACl injuries generally occur during eccentric deceleration. Usually, there is a combination of flexion, adduction and internal rotation which add stress to the ligament.

If you weight train, you know that there is a concentric, {shortening} phase of a contraction, and an eccentric [lengthening} phase. Many people will practice great form on the concentric phase, but poor form on the eccentric phase.

Since lack of eccentric strength is ONE of the causes of acl injury, practicing eccentic training techniques may be in order.

Many people train on weight machines, that are designed to "isolate" certain muscle groups. Unfortunately, this trains the synergistic muscles to become deactivated. But in most sports activities, muscle groups need to work together to support the joints. So using more free weight or cable technigue for training is a good idea.

Quite often, when people look at muscle imbalances that contribute to ACL injuries, they look only at the muscles of the upper leg. But 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.

<FONT COLOR="#800080" SIZE="1">[ March 17, 2002 09:11 PM: Message edited 1 time, by Lisamarie ]</font>
post #2 of 54
Great post, Lisamarie! Julie Parisienne's dad is an MD who knows about such things. She told me, based on his advice, that pre-season training neeeds to do more than develop the quads - the hamstrings also need a lot of attention. She said that a combination of over-developed quads with under-developed hamstrings was not good for ACL protection. There was a time when I focused on squats with weights. Then, hearing that advice, I used a device on my weight bench so that I could do "leg curls" while lying on my stomach - that is, lying face down on the bench, hooked amy ankles under the bar, and bent my legs to that my ankles were drawn closer to my butt.

I'm sure that was an improvement. However, my skiing stamina has been even better since I do less weight work and play more tennis during the off season. For some reason, tennis seems to hit those muscles I use a lot in skiing. This year [pathetic as it has been conditions-wise], I last a lot longer on the slopes - so I'm making a connection of skiing stamina with a lot of summer tennis [and swimming laps]. What say, am I on the right track, or is this my imagination at work?
post #3 of 54
OMG, LM, you took a workshop with Mike Clark? He is such a hottie! [img]redface.gif[/img] Oboe, you are on the right track, but be sure you add some exercises for proprioception. Mike Clark is big on one legged balances with your eyes closed. If you think about that in terms of skiing, well you dont want to be LOOKING at your skis when your skiing, so you need to be intuned to the changes in the terrain so your body can make the needed adjustments.
post #4 of 54
Thread Starter 
Bethany, you crack me up! But you are correct about the proprioception exercises. BTW, they are also used diagnostically. The one legged squats are performed to the point of what is called the "balance threshold". Another words, you only bend to the point where you can keep correct postural alignment throughout the entire kinetic chain. Any tenedencies towards misalignment are noted.

Speaking of alignment, just as a skier needs to be properly aligned in their equipment, they need do their workouts displaying good posture. In other words, its not enough to simply do the workout. If you are using poor posture, you will still be predisposed to injury.
post #5 of 54

A serious question.

Are you kidding? can anyone really bring there toes to their shins?

If so I have a whole lot of work to do.

The only time in my life I ever "worked out" was to fix my shoulder injured early this season. I was enjoying my progress until I read that. I try to eat right , control my weight and stay in reasonable shape by climbing my hill during the offseason and walking my many rounds of golf.

The wind is completely out of my sail right now!

post #6 of 54
Thread Starter 
OOPS!!! That was supposed to read "towards the shin"! Just edited it! [img]redface.gif[/img]
post #7 of 54

The wind of change has returned!
post #8 of 54
Thread Starter 
post #9 of 54
Thanks for the information. By "eccentric phase". are you referring to what I hear trainers call "doing negatives"?
post #10 of 54
hammies vs quads:

hammies are MUCH more important. The hamstring prevents the forward shear that is a common vector of ACL tears.

the quads are important, but mainly from the perspective of compression resistance. when your quads cannot continue bearing your body weight AND the compression (knee bend) forces that increase when skiing bumps, skiing fast GS turns, or landing jumps, you can experience strange articulation in the knee, as well as patellar tendonitis.

eccentric weight training/exercises: after extension, slowly lower the weight in a very exaggerated fashion - not just slow enough to prevent the weights from banging, but a VERY slow movement. if an exercise, replace "weight" with "body weight".

another caveat I've given before but bears repeating here:

Quad extensions are a BIG NO-NO for knee injury patients. Replace with squats, leg presses, straight leg raises, cycling.

<FONT COLOR="#800080" SIZE="1">[ March 18, 2002 11:31 AM: Message edited 1 time, by gonzostrike ]</font>
post #11 of 54
<BLOCKQUOTE>quote:</font><HR>Originally posted by gonzostrike:
...you can have experience articulation in the knee...

What is "articulation in the knee"?
post #12 of 54
Thread Starter 
Gonz is correct! Quad extensions for knee patients are a definite no, no! The reason that the leg presses and squats are preferable, is because they are NOT isolation exercises! The hamstrings, quads and gluteals work together.

Eccentric work is in fact sometimes referred to as "negative" training. You can tell if your muscles are weak eccentrically, is if you go hiking, and your quads hurt you on the DOWNHILL. Perhaps the cyclists can comment on this.

Believe it or not, plyometric training is considered eccentric, because the emphasis is on the deceleration. But it is generally only recommended as PREVENTATIVE medicine. And they must be done correctly. As I said in the q angle thread, the landing sequence is toe, ball, heel, squat. If you tend to land flat footed, that could POSSIBLY indicate a predisposition towards ACL injuries. Personaly, I don't teach them to anyone with too many structural anomolies.

Here's another interesting concept: Reciprocal Inhibition! In English. 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.

It all gets very complicated!

<FONT COLOR="#800080" SIZE="1">[ March 18, 2002 11:08 AM: Message edited 1 time, by Lisamarie ]</font>
post #13 of 54
WhosThatGirl - hey thanks, you caught my typo. I've corrected it. re-check my post for the way it should have read.

Strange knee articulation is anything that exceeds the types of forces the knee is designed to withstand - basically, any forces that commonly result in a ligamentous or cartilagenous tear.

LM - the other reason for avoiding quad extensions (also called "leg extensions") is that because they isolate the joint so specifically, they place tremendous shear forces on the ACL - enough to cause sprains/microtears if the athlete isn't careful.
post #14 of 54
Thread Starter 
Uh huh! We spoke about this awhile ago in another thread, the whole open chain/closed chain idea.

Closed chain exercise exercise happens when your foot is in a fixed position, making contact with a surface. In open chain exercise, your foot has free movement, and is not in contact with any surface.

Closed chain exercise causes compression forces which stabilize the joint. They utilize compound muscle groups, which is how the body is used in all activities.

Open chain exercises cause a shearing force. For anyone with an ACL injury, this is a recipe for disaster! The leg extension machine can cause the knee cap to push against the thigh bone. OUCH!!! Since it pretty much only uses the quads, without any assistance from other muscle groups, there is more stress on the knee joint.

Apologies to anyone who's read this before. But some of this stuff is not on the first 2 pages, so new members may not get a chance to read it!
post #15 of 54
For me, after an ACL injury and surgery two years ago, I discovered that the leg extension machine was the ONLY exercise that isolated and developed my vastus medalis muscle (interior quad muscle above the knee)which had badly atrophied.
I placed the roller closest to my knee to improve leaverage and did two sets of single leg extensions on my bad knee and one set on my good. Closed chained exercises (i.e. functional exercises) will not do this!
My PT told me not to do leg extensions and yet, when I informed him that I was not coming back for the rest of his regime, his only response was "Lisa, you're putting me out of business".
I skied 39 days last year and this year, despite the dismal season in NE, I will have skied 40+. And my knee is great!
And, hey, its snowing!!!!
post #16 of 54
Thread Starter 
Actually, you can work the vastus medialis quite efficiently on the leg press. Instead of going to full felexion you simply flex about 15 degrees. That is basically the range of motion that the vastus medialis controls {can't recall the EXACT degree off hand}.
You can also do partial squats on one leg, going only to the point of your balance threshold. These are great because they also work on proprioception, which is usually lost during an injury.

That being said, just like ski technique, for every rule, there is an exception to the rule, and if doing leg extensions worked for you, then obviously they were a good idea.
post #17 of 54

won't the straight leg raise with ankle weights, squats with varying toe-in/toe-out degrees, and stationary cycling with resistance also strengthen the vastus medialis?
post #18 of 54
No Lisa, you're wrong.

There are no exceptions to ski technique.

There are primary movements that make up proper skiing technique and the movements can only be done one way.

post #19 of 54
<BLOCKQUOTE>quote:</font><HR>Originally posted by Lisamarie:
... Instead of going to full felexion you simply flex about 15 degrees...<HR></BLOCKQUOTE>

Is this 15 degrees measured from a straight leg or from a fully bent leg? I am guessing from a straight leg, yes?

Am very interested in strengthening excercises for the vastus medialis and have been doing a tremendous amount of leg extensions. Want to make sure I am doing these right! Will also now give equal attention to the hamstrings.
post #20 of 54
Thread Starter 
OOPs again! That should have read FLEXION and its 20 degrees from a straight leg. The vastus medialis oblique is also responsible for the tracking of the knee cap. Tracking is a proprioception related function. If you work the VMO in a highly controlled environment, such as a leg extension machine, you will be strengthening its biomotor functionality {last 20 degrees of extension} but the challenge to proprioception will be insufficient. So for that purpose, a one half squat would be more efficient.

To get an idea of how the VMO works, observe modern skiing. One thing Todd once said in a lesson, "think of the knees as bending and straightening, not as bent or straight". And you may notice, that you don't see as much of an exaggerated bent or straight position. Its more of a fine motor control.

A nice, albeit not too challenging integration exercise is to lie on your back, and place a thera band around your foot. Bend your knee in the 20 degree range, simultaneously flexing your foot, as you extend your leg, point your toe. This will combine work on the VMO, along with range of motion in the foot. You can also track and align the placement of the knee.
post #21 of 54
Thank you. I have kneecap tracking problems, and that is why I am trying to build up the vastus medialis.

Does the 20 degree movement also apply to hamstrings? Can you just work the hamstrings 20 degrees effectively or do you have to do a full 90 degree bend? I just got back from the gym where I did the hamstring "leg curl" machine. If I curl up 90 degrees, my knees are not happy. Is necessary to bend the leg completely in order to build the hamstrings?

<FONT COLOR="#800080" SIZE="1">[ March 18, 2002 08:10 PM: Message edited 1 time, by WhosThatGirl ]</font>
post #22 of 54
Thread Starter 
One of the problems with some machine based equipment, is that no matter how much you tweak with the alignment, it still ends up being in the wrong place, especially for women.

Is there a cable machine? You can lie prone on either a stability ball or a weight bench, with the leg attachment on your ankle, and do your curls that way. Although there's nothing wrong with doing partial ham curls, since they are the weak muscle, you may want to try to find a way to also work them full range.

A few other things to think about in terms of tracking. Take a look at your feet. Do you pronate. are you flat footed? This will affect tracking. Not to get personal, and please don't feel you need to comment about this online, but what about your pelvis? If one pubic bone is higher than the other, the knees will have a problem tracking correctly. One more thing, most women are way, way too flexible in their adductors, anf not strong enough. This will make the knees somewhat wobbly.

Something else we've speak about alot on this board, is the transverse abdominal muscle. A healthy transverse will activate before every foot strike. If it does not, the SI joint may be unstable, which will in turn effect how the femur lines with the pelvis, which in turn effects the alignment of the knee. Also, check out the thread on Q angle to get more info about this.

What I am trying to say in an admittedly long winded way , is that most injuries or misalignments are the result of something out of place in the kinetic chain, which effects the functioning of the entire body. So while there's absolutely nothing whatesoever wrong with doing equipment based exercises as a strengthing routine, to correct alignment, and prevent injury, you may need to use a more functional approach.
post #23 of 54
Thank you again! Very very interesting and useful info.
post #24 of 54
Thread Starter 
You are welcome, and BTW, thank you! [img]smile.gif[/img] One of the things I will have to do for my NASM certification, is write up a case study, so this was good practice.

A couple of points. Keep in mind that I really have no problem with people using equipment such as the leg extension machine. I actually use it myself, and since I have no ligament damage, I do do not have a problem with it.

But another factor that can POSSIBLY {not always!} set someone up for an ACL injury is lack of proprioception. The tracking on a piece of equipment is predictable. Nothing is predictable on snow, so we need to learn to be spontaneous in the way we correct our alignment.

About 22 years ago, I was hit by a car and fractured my tibial plateau on my right leg. I performed lots of ham curls and leg extensions, including specific machine based exercises for the VMO.

A few years later, I was running marathons, and teaching a schedule of high impact aerobics that would have killed the average 20 year old. Without injury.


At the 23 mile mark in the NYC marathon, I accidentally hooked my right ankle with someone else. Not having the proper righting instincts to keep me upright, I fell and sprained my right ankle. BTW, as a kid, I used to sprain my right ankle alot.

Then, when I first learned to ski, even though I was in phenomenal shape, my balance was atrocious! It gradually got better, but there is an amazing difference between what I can do on my right side, and what I can do on my left.

Back in the "old days", if someone had an injury, we would strengthen the muscles around the injury. Although this method definitely has its benefits, its not always the most efffective way.

Often, its not just a muscle weakness causing the injury, but a recruitment pattern effecting the entire kinetic chain. So, in addition to the muscle strengthening, practicing movement sequences that aid in proprioception and correct the recruitment pattern are a good idea.

One other thing I've been thinking about lately. I do beleive that boot fit and alignment are crucial.
BUT.... I have to wonder sometimes, if we ONLY rely on our boot work, and not correct the structural imbalances, are we still setting ourselves up for injury?

I don't know.

Okay, a little quiz about knee tracking. Two people perform squats. one person's knees track medially, the other's track laterally.
I have to devices that aid in PROPRIOCEPTION
hint, not strength. One is a medicine ball placed between the knee. The other is a thera band that is wrapped above the knee, outside the leg {but not tightly}
Who gets what device? [img]smile.gif[/img]


<FONT COLOR="#800080" SIZE="1">[ March 19, 2002 11:44 AM: Message edited 1 time, by Lisamarie ]</font>
post #25 of 54
Hmmmmm....I may fail this quiz. In fact, I had to look up "proprioception" in Websters. What I think you mean by the use of that word is how the knee instinctively responds to sudden, real-life situations such as those on an ski slope.

To the quiz... the lateral (abnormal) tracker gets the medicine ball and the medial (normal) tracker gets the strap? The lateral tracker uses the ball because the ball requires balance and many tiny spontaneous muscle corrections.

I looked at your website. [img]smile.gif[/img] I wish I still lived in the Boston area, I would take some of your classes! I used to work out religiously at Joy of Movement in Wellesley. Did you teach there? They had the best high-impact aerobic class "Aerobics for Athletes and Dancers". What a workout!

<FONT COLOR="#800080" SIZE="1">[ March 19, 2002 02:06 PM: Message edited 2 times, by WhosThatGirl ]</font>
post #26 of 54
Thread Starter 
Bingo! Great job! Actually, neither is normal, both are a sort of deviation. Very perceptive, though!

As for Joy of Movement, uh oh, we are dating ourselves! I actually worked for the one in NYC. Hope you did not get "screwed" by that false bankrupcy they pulled about 12 years ago!

But you know, one of the reasons I think I never get athletic injuries, is that I never listened when they said teaching high impact aerobics is bad for you!
post #27 of 54

Not all tracking medially or laterally in the knee is due to weak muscles.

My knee cap and therefore the knee were tracking medially because of a combination of pronation in the foot and a tight ITB. That kinetic chain thing. I was tested for muscle strength and the physical therapist was amazed at how strong my leg muscles are. It took her a few sessions to put it together.

Since then I have orthodics in my shoes and have worked on stretching the ITB. The knee now tracks noramlly in a two and one legged squat.

Goes to show you that some things are not what they seem.
post #28 of 54
Thread Starter 
Yep! I brought up the pronation thing in the Q angle thread. http://www.epicski.com/cgi-bin/ultim...&f=11&t=000121

Also, look at my post from 3/18, 9:15

A few other things to think about in terms of tracking. Take a look at your feet. Do you pronate. are you flat footed?

<FONT COLOR="#800080" SIZE="1">[ March 26, 2002 08:01 PM: Message edited 1 time, by Lisamarie ]</font>
post #29 of 54
I'm not sure if this link has been previously posted, but it throws up new theories on the higher incidence of ACL injuries for women: http://www.nature.com/nsu/020325/020325-1.html
post #30 of 54
Thread Starter 
Thanks, David! I've posted similar links, but not that one.
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