# Why Women suffer more Knee Injuries



## Lisa (Mar 25, 2007)

> Female athletes are up to eight times more likely to suffer knee injuries during their careers than males, and now researchers may be closer to understanding why.
> 
> A recent study of 10 female and 10 male NCAA athletes completed within the Department of Biomedical Engineering at the Cleveland Clinic found that female athletes tend to land from a jump with a more flexed ankle, the foot rolling outward with an elevated arch, and more knee abduction and knee internal rotation compared to male athletes.
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> When fatigued, differences between women and men in these movements and loads were even larger, possibly explaining why females may be at greater risk of non-contact anterior cruciate ligament (ACL) injury during landing



FULL STORY


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## exile (Mar 25, 2007)

Very interesting and important result if it can be sustained. 

But then the question is, why are women more likely to land in that configuration? The article didn't even speculate, so far as I can tell...


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## Kacey (Mar 25, 2007)

I'm not overly surprised - I did some research in the past when I've injured my own ACL, and here are some of the things I've found:



> Young Women at Greater Risk of ACL Tears
> "Women are anywhere between two and eight times more commonly injured in regards to their ACL than males are. There's several suspected answers, but the most common reason where the research is heading right now, is what are known as neuromuscular differences. In other words, the way women's muscles fire around the knee  the quadriceps or hamstring muscles in response to a stress to the knee joint. And there's been shown to be several differences between males and females."


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## exile (Mar 25, 2007)

This is very interesting, Kacey, but it is also a bit troubling, because the information in your post suggests that the problem is due to neuroanatomical differences between men and women so far as the ACL itself is concerned, whereas the study Lisa posted seems to locate the primary difference in the way female athletes land from a jump&#8212;foot position. It could be both are right, but the material in your post seems to identify the crucial difference in angle not at the foot but again, at the knee. So it looks like there's something additional going on...

Also, I'm confused by the point made about weaker leg strength in female athletes. Is that supposed to be relative to body weight? Because if so, it conflicts with results I've seen repeatedly confirmed, which is that women have the same number of fast-twitch muscles below the waist per lb of body weight as men do. And it's the fast-twitch muscles which are developed by strength training. So there looks like a contradiction of sorts here...?

It's so hard to get a unified story out of these exercise physiology types!


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## Shaderon (Mar 25, 2007)

That's really interesting, thanks Kacey.


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## Kacey (Mar 25, 2007)

exile said:


> This is very interesting, Kacey, but it is also a bit troubling, because the information in your post suggests that the problem is due to neuroanatomical differences between men and women so far as the ACL itself is concerned, whereas the study Lisa posted seems to locate the primary difference in the way female athletes land from a jumpfoot position. It could be both are right, but the material in your post seems to identify the crucial difference in angle not at the foot but again, at the knee. So it looks like there's something additional going on...



I've seen some of each... I can only speculate that the different configuration of the knee joint and the angle of the thigh from the hip due to the width of the pelvis combine to change the landing angle - thus leading to greater injury from the jump foot position in addition to greater physiological risk.  But that's pure speculation on my part.



exile said:


> Also, I'm confused by the point made about weaker leg strength in female athletes. Is that supposed to be relative to body weight? Because if so, it conflicts with results I've seen repeatedly confirmed, which is that women have the same number of fast-twitch muscles below the waist per lb of body weight as men do. And it's the fast-twitch muscles which are developed by strength training. So there looks like a contradiction of sorts here...?
> 
> It's so hard to get a unified story out of these exercise physiology types!



As far as that potential contradiction goes - although the proportion of fast-twitch fibers may be the same by weight, women are generally less muscular than men - women who lift weights are often aiming for a sleeker, less bulky look than men, and therefore tend to complete more reps at lighter weights, which changes the build-up of muscle tissue, and therefore overall strength.  Also, in general, women weigh less than men, so while they may have the same potential number of fast-twitch fibers per pound, the average woman will still less overall strength.


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## Brian R. VanCise (Mar 25, 2007)

Fascinating posts by everyone.  Thanks for the info.


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## Lisa (Mar 25, 2007)

Kacey's post is great.  Exile you, yet again, bring up some excellent points as well.  

I can't find the study, I read it years ago while in nursing school.  It related the injuries to women's knees not only to weaker/smaller leg muscles, wider pelvis' but also on the fact that women have a lower center of gravity then men because we carry a larger amount of our body weight in our hips.


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## exile (Mar 25, 2007)

Kacey said:


> I've seen some of each... I can only speculate that the different configuration of the knee joint and the angle of the thigh from the hip due to the width of the pelvis combine to change the landing angle - thus leading to greater injury from the jump foot position in addition to greater physiological risk.  But that's pure speculation on my part.



Yes... that has the ring of truth. Makes much senseLisa's original study didn't address the point, but it's true that the difference in the landing angle her study talks about is fixed at the moment of landing. They probably haven't gotten to the point of tracking it all the way through the jump, lol!





			
				Kacey said:
			
		

> As far as that potential contradiction goes - although the proportion of fast-twitch fibers may be the same by weight, women are generally less muscular than men - women who lift weights are often aiming for a sleeker, less bulky look than men, and therefore tend to complete more reps at lighter weights, which changes the build-up of muscle tissue, and therefore overall strength.  Also, in general, women weigh less than men, so while they may have the same potential number of fast-twitch fibers per pound, the average woman will still less overall strength.



You're right, that's bound to be the case, actuallymen tend to weight-train for bulk. Women very possibly train more for endurance (except for women shot-putters, discus throwers and other athletes who _must_ train for explosive lower-body strength). 

What you say makes very good sense all round...


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## Ping898 (Mar 26, 2007)

I was just reading an article the other day in an old Runner's World and it mentioned that your shoes may also contribute to the problem.  That a lot of manufacturer's will just take a men's shoe and slap "women's colors" on it and sell the shoe as a woman's shoe, but that that can cause problems cause it assumes things like the location of arches and the amount of pronantion between men's and women's feet are the same...


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## Kembudo-Kai Kempoka (Mar 26, 2007)

It's not really news for geeks in sports physio land. Wider pelvis requires a steeper incline toward the midline to get the feet under the body, which requires a greater valgus angle at the knee.

In general, women are also more flexible than men...even men who stretch; if Lisa and I start the same yoga program at the same time, she'll be at a 3 year landmark when I'm at my year mark, and we'll both have the same number of mat hours. 

Bigger valgus with more flexible muscles = that funny angle that's hard on the ladies' knees. One researcher who noted an increase with knee problems among college volleyball players practicing plyometric box jumps recommended landing with the feet wider than natural, so as to decrease the load on an increased valgus knee. Knee complaints dropped by over half.

Take care of your knees; you need them.

D.


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## exile (Mar 26, 2007)

Kembudo-Kai Kempoka said:


> It's not really news for geeks in sports physio land. Wider pelvis requires a steeper incline toward the midline to get the feet under the body, which requires a greater valgus angle at the knee.
> 
> In general, women are also more flexible than men...even men who stretch; if Lisa and I start the same yoga program at the same time, she'll be at a 3 year landmark when I'm at my year mark, and we'll both have the same number of mat hours.
> 
> ...



This is _very_ interesting... what strikes me is that if you just look at a number of men and women at random, it isn't especially clear that women's hips are all _that_ much wider in relation to their height, say, then men's are. I'd be interested in seeing this difference quantified, but if it were any larger than 10% overall I'd be surprised. But apparently, that small difference, and the consequent small difference in angular alignment that Dave has commented on, is enough to make a major impact on the numbers distinguishing men's ACL injury rate from women's. These very small differences seem to get leveraged into major outcomes...


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