Saturday, February 27, 2016

Knees Over Toes Lunges

There exists a common piece of wisdom in fencing training that the knee should not extend in front of the toes while lunging. My friend Max asked about this recently. One part of the question is that both a limited lunge and lunge with the knee more flexed show up in historical manuals.

A "perfect" lunge with the knee behind the toes.

A lunge with the knee well past the toes.
And both kinds of lunge can also be seen in high-level competitors in modern sport fencing.

The Principles

The concern is generally phrased that letting the knee go past the toes will damage the knee in the long run. Others will argue instead that as long as the knee is strong enough that it shouldn't matter.

From a technical terminology standpoint we are talking about the amount of flexion at the knee joint. The top picture shows about 110° of knee flexion (0° is the knee straight). The bottom picture would be closer to 130° if the thigh were parallel to the ground - as it is the angle looks similar but this fencer has their hips higher than the other.

The forces on the various structures of the knee change throughout the range of motion. The ligaments are tightest around 90°, so the lunge differences we are discussing won't matter since both options flex the knee past 90°.

Compressive forces on the  cartilage and articular surfaces increase with knee flexion. Forces between the underside of the patella and the femur are larger than the forces between the femur and the tibia and menisci. Theoretically this means the kneecap would be at greater risk, but really there are enough differences between the ways an injury can occur that a simple comparison of the numbers is not compelling.

The Research

Well, I couldn't find any published research on this question. But since all the peer-reviewed research on fencing could fit on a 3.5" floppy disk, that isn't surprising. The closest research I could find was on squat depth, such as, "Are Deep Squats a Safe and Viable Exercise?"[1] This is a commentary article where a for and against position are presented by different exercise scientists. The article summarizes a large number of relevant studies. I'm going to extrapolate from this to our question about lunges - any time conclusions are extrapolated or generalized from separate research we should be aware that we could easily be wrong. There could be any number of unaccounted for factors in our lunge question that just don't show up in squat research.

There is ambiguity in the research regarding the risk of injury from deep squats. Overall it would seem that there is no clear correlation in population studies between injury and squat depth. But this could be explained by self-selection. That is, those individuals who continue and/or do well with deep squat exercises are those whose knees would not have been injured - for whatever reason, perhaps some natural advantage of their joint architecture. While those who refrain from deep squats, even for unconscious reasons, may  be more susceptible.

Biomechanics studies clearly show greater compressive forces from deep squats. And greater forces do mean greater likelihood of both acute and chronic injury. So the concern is certainly plausible.

The above is for healthy individuals. In those with known knee problems we can be confident that limiting squat depth, and by extension the knee position in lunges, will reduce pain. The safe generalization is that the motion - squat or lunge - should remain within a pain free range. Whether that is sudden pain during the motion or the ache afterwards doesn't matter, pain is our indication to avoid that extreme.


There is also, of course, the tactical considerations of lunge length. The more the knee is flexed the longer the lunge that can be obtained. A longer reach is it's own tactical advantage. However, a longer lunge is also a longer recovery. So there is a trade-off - higher risk of getting hit by the riposte or afterblow. As a technical coach I would counsel a more conservative lunge, but that is based on my study of Hope's system.

As a fencer I will sometimes take much longer lunges, when I feel the opportunity is right. Sometimes I am wrong and my opponent gets the afterblow. Sometimes I still fall short, but don't get hit either, in which case I was still wrong, just not as wrong. And sometimes I hit where otherwise I would not have and do so safely.

The ability to recover quickly from a long lunge is dependent on the strength of the lead leg, and I think this is where the biggest component of strength actually plays into our question. A strong leg is less likely to suffer many kinds of injuries, but not really the kinds of injuries that occur from deep knee flexion. There are legitimate exceptions though. One of the fencers I train has healthy knees that can withstand a long lunge, but her strength in balance is lacking and she falls too often. I'd tell her to limit her lunge length to reduce injury and falls (but she's 14 so I don't expect it to take).

On the other hand one of my frequent opponents has a nice technically perfect lunge length and knee angle, but her strength-to-weight ratio isn't as good so she has a slow recovery. Which I can exploit when we fence.


If the historical system you study shows a deep lunge then I would feel free suggesting a person train that, as long as it's pain free.  In general, I will always counsel a conservative approach; it is easy for young, healthy athletes, or simply highly competitive adults, to overtax themselves in ways that they will regret years later.

And there is a component of individualization, rather than a one size fits all answer. This is the responsibility of the coach and requires time, observation, experience and thought to answer

1. Schoenfeld, B., & Williams, M. (2012). Are Deep Squats a Safe and Viable Exercise?: Strength and Conditioning Journal, 34(2), 34–36.

Friday, February 12, 2016

FALSE: "If you can't do it slow, you can't do it fast."

The title of this post is the text from an image meme I saw today on Facebook. In it some Asian Martial Arts looking dude is about to shoot fireballs from his hand.


This is a common meme in martial arts training. And martial arts training is pretty much the only realm of physical training where someone might say this. And let's be clear, we mean Asian martial arts when we say this. A boxing coach isn't going to say this. A wrestling coach isn't going to say this. That fact is the first thing I brought up in the discussion thread where this popped up.

Muscle Memory

On the thread from the original image source we see this comment:

Here we get to one of the two key components of this: the idea of how muscle memory works. Muscle memory is the creation of motor programs in our brain: connections of all the various nerves involved in a particular action are formed and strengthened. Timing components are tied together so that everything happens at just the right moment. The timing of doing something slowly is clearly not the same as the timing for doing it fast. So the motor program for fast is not the same as the motor program for slow.

Each individual motor unit in our muscles is supplied by a single nerve from our brain, through the spine, to the muscle. Each motor unit is comprised primarily of either Type I or Type II fibers. Type I are the slow, weak fibers and they are used to move slowly. Type II fibers are the fast, strong fibers and they are used to move at fighting speed. As such the neurons for fast and slow movement are not even the same neurons in the brain. And, so the motor program for fast is not the same as the motor program for slow. It cannot be.

Running is just fast walking

One of the other points brought up in this thread is the assertion that "running is just fast walking."

This statement is false. We can see it merely in the definitions of the words.
to go quickly by moving the legs more rapidly than at a walk and in such a manner that for an instant in each step all or both feet are off the ground. (
to advance or travel on foot at a moderate speed or pace; proceed by steps; move by advancing the feet alternately so that there is always one foot on the ground in bipedal locomotion. (
Emphasis added to make clear the difference. That's not even bringing up the volumes of data from gait studies, especially myography studies. Myography studies show that different muscles are used at different times and in different ways (such as eccentric vs. concentric).

One cannot get good at running a race simply by walking a lot. They aren't the same activity.

And we see the same thing in martial training, especially with weapons. If I perform a descending cut slowly versus quickly there is a clear difference. Slowly I have to battle gravity, I have to keep my weapon from falling faster. Quickly and I outpace gravity by a significant margin.

Cut slowly and my muscles that pull upwards are actually doing most of the work with an eccentric (lengthening) activation. Quickly and the opposite muscle groups are doing most of the work with a concentric (shortening) activation. Different muscles used differently. So the motor program for fast is not the same as the motor program for slow.

Furthermore, as I train a given motor program the myelination of the neurons increases. Myelin is  the insulation on the "wires". It makes the signals go faster. And it means that one motor program influences another less and less the more it is trained.

Doesn't this contradict "slow" strength training?

Sure. If I had ever said that all we need is strength training. But I have repeatedly said otherwise. The key neurological benefit of strength training is that it teaches the motor units near each other to fire in sync. Also, muscles can better synchronize when they are better myelinated.

There is a speed below which strength training becomes less useful but that's only when it you are aiming to move at less than one or two seconds for the motion. That timing is for each of up and down. So two to five seconds (with a pause at either end), total per rep, is still good training for a 300 ms strike.

But slow training is useful!

"My dance instructor said so." Sure, but it's really a matter of how much slow training and how slow. What slow training can do is teach us the proprioception of the correct movement. That is: what does it feel like to move through the correct motion. This feeling is built from the movement sensors in the joints.

But we also have movement sensors in our muscles and they are clearly not getting the correct propriocetive training.

Proprioceptive training doesn't take that long. A few dozens of repetitions max. You can do that in the first few days of learning a new action. Taking a long time to get good at doing an action slowly is a waste of time.

How slow is also worth noting. Jogging can be part of training for running a race, since it is the same gait. But walking is not. Jogging really is slow running. So it can be a (small) portion of your race training.

I've just started learning a new style of dance. And the instructors will have us do new actions fairly slowly. But only a minute or so. Then they turn the music on.


Martial arts training has buckets of old traditions many of whose origin is lost to time or simply forgotten. (Slow training may have been intended for meditative purposes.) And there arises a problem of people who do not critically analyze these traditions. Of people who do not update this "wisdom" based on new facts.

The motor program for fast is not the same as the motor program for slow.

Now there's a part 2.

Wednesday, February 10, 2016

Should you be doing Prehab?

In accordance with Betteridge's Law, if the headline ends with a question mark the answer is almost always "no". However, in our case it is more nuanced than just this.

My post here is going to be a general response to things I see frequently. As with previous times when I do this I am going to use a specific example for illustrative purposes, but in no way should this be taken as an attack on that individual.

There are plenty of examples of videos describing "prehab" exercises suggested for various sports and exercisers. Prehab, short for pre-habilitation, is generally meant to be exercises undertaken by most people intended to prevent injuries and other problems that arise from training. Or to correct pre-existing, underlying problems.

One of my coaches pointed out that part of the appeal of videos and posts like these is the impression that they present an easy fix. "If I just do this one exercise then that will make up for years of bad posture or lack of strength training." etc. There are seldom easy fixes. I can't think of any in this field.


Are there specific exercises that you should be doing for that specific problem that you have? Quite possibly. But . . .

The internet is not a good place to figure this out. I get quite bothered by any blog post that aims to diagnose what's wrong with you. Diagnosing a physical problem without hands-on work and direct observation by a trained professional is usually just not doable.

Furthermore, anyone with a license in what they are doing cannot say that they diagnose a problem unless they have a corresponding clinical doctorate. Diagnosing problems without such training and licensure is usually against the law. Plus it normally violates your professional organizations standards of conduct and ethics.

And so help me the phrase, "self-diagnose". Please understand that medical professionals use people who say this as the butt of jokes because of how often they are wrong. Google University is not the same as years of education and a residency.

Don't over-estimate your knowledge in a topic.

What do I do instead?

I don't claim to diagnose people. I won't until I finish my doctorate and pass my boards. Instead I say things like, "I think you have X but I can't be sure." And then I follow it up with, "you can do A, and I feel comfortable recommending it because it might help, and it's unlikely to make things worse."

And I will only do this on a case by case basis with people that I work with regularly in-person.

Plenty of times I just say, "I don't know."

Lack of Specificity

One of the big problems with any pre-hab recommendation, especially one from the internet that doesn't involve an exam, is that it lacks specificity. Videos will frequently contain elements that are a "test" for a problem. But, if you get a positive result on a test for a particular problem and that test is correct 60% of the time, then it is right more often than it is wrong. But it's still wrong for plenty of people. A complete exam will use multiple overlapping tests to reach a result with a high likelihood of being positive, but that's not doable without that in-person exam and expertise.

Also, frequently, great big assumptions are being made about people. A video may suggest back exercises for everybody based on the assumption that everybody works a desk job. And has bad posture. And has done so long enough that they've suffered structural changes. Those three assumptions are progressively less obvious - the viewer, or the speaker, may not know they are making the assumption. A foam roller for your back is only pre-hab if you have structural changes leading to a fixed kyphotic spine.

Why am I Writing this Post?

Let's be honest here, a big part of my objection is basically to amateurs acting like experts.

There exists a strain of resistance to experts in our culture. The idea that people who have education, knowledge, and experience gained from other such professionals is overrated. Or out of touch with reality etc. That one's gut can provide just as accurate an understanding as years of study.

The great advances of the modern era are a result of study. Of experimentation. Of critical analysis of people's gut intuition. In athletic training, in the 50's there arose a new paradigm that included actual efficacy testing of training methods. After 60 years of published, peer-reviewed research the experts can make very clear, consistent statements about a variety of topics in this field. We can back them up with volumes of data and with the teams and athletes that have won over those who did not know about or use this research.

Professionals using the best scientifically tested methods produce athletes that beat those who don't.

Additionally, these teams have lower injury rates.

In my internship at Boston University the rowing coach for the freshman, lightweight (therefore weight limited) team came to us because the rowers were putting on weight. We knew this was bunk. Freshman college students don't gain weight from the gym. We all know why the really gain weight and it's on the weekends.

The peer-reviewed research clearly shows that the type of program we were running with these athletes is simply incapable of producing significant hypertrophic gains that would make them heavier. The coach's gut intuition was wrong. We used the research to prove it. This let us justify continuing with a well designed program that benefited the athletes. Hooray!

But I've seen this sort of problem even from experts. I am much more inclined to trust a video of this nature when it is highly specific. Of if it just says that this kind of exercise is part of a complete approach without saying that it addresses any specific problem.

But if an expert says something like: "[this is an exercise] you should be doing." without any kind of specification or targeting, then I get cranky.

A specific example for illustrative purposes.

The video that provoked this particular post is Bit #14 over at Valkyrie WMAA. In the video there is the common problem of the benefits or function of an exercise either being mis-categorized or overstated. In it foam rolling and lacrosse ball self-massage is set-up as being good for strength, stability and as a warm-up. Self-massage is not any of these things. Self-massage is a perfectly good thing to do but not to achieve any of those objectives.

Then some ankle exercises with a band are described as increasing strength and flexibility. The resistance only does one of these things - increase strength. There is also an error of exercise specificity. Seated resistance band exercises for the ankle are indicated in those recovering from an injury of the ankle. But it's not a practical, functional exercise. It does not use the ankle in the way that you use it in everyday life or in HEMA. Ankle strengthening should be done while standing or moving with a general population of people who are capable of participating in a HEMA class.

The second "pre-hab" video in the series on Valkyrie contains additional, common errors in the understanding of pre-hab.

In it dynamic stretches are referred to as pre-hab. They are not. Dynamic stretches are simply the opposite of bad exercise program design. So to be clear, I support using dynamic stretches before working out (though I don't like the ones shown in the video), but do not call them pre-hab. They are not intended to increase strength or stability, the benefits of pre-hab noted at the beginning of the series. Nor should they be used to increase range of motion, since stretches that increase ROM are inappropriate before exercise.

The other pre-hab action in the second video is a static stretch. Like many other pre-hab recommendations it makes specific assumptions about people. Furthermore, static stretches are counter-productive before exercise.

This gets to a common problem with pre-hab recommendations. The assumption that everyone has this problem and needs physical therapy style exercises for it. The ankle strengthening is suggested as if everybody will need an injury recovery type of ankle exercises. That's a big, and usually incorrect, assumption. The fact that a random person has some weakness in this particular band exercise, in a single direction of movement, at whatever level of resistance is being generated, is implied to be evidence of it's need and value.

But is there an actual everyday or fencing action that the person has problems with? That's what might be an indication for such an exercise.

What Prehab would I recommend?

  • Scapular movement patterns and stabilizer strengthening, plus external rotator strength for Longsword.
  • The same for Hope's smallsword, but due to different actual positions and with an emphasis on the static position versus dynamic components.
  • External rotator strength for any thrust heavy system.

That's about it. Anything else needs to be specific to the person.

I invite readers to comment with specific questions about pre-hab. I'll use those questions to guide upcoming posts.


Most pre-hab videos and blog posts are either not actually pre-hab but are frequently perfectly good components of an exercise plan; or contain worse errors like "diagnosis". Highly generalized or blanket solutions are unlikely to be right for you.