Touch and Go #14

Lastly, a new study yet to be published by Storen et al. (here)  found that peak forces were inversely related to running economy. Meaning, the better running economy, the lower peak forces. In their paper, one of the key suggestions was to minimize horizontal braking forces. How do you do that? Forefoot striking.

Given these conclusions, what should you actually do with your own running?

Goal #1: Change Footstrike
The Lieberman studies demonstrated an important point. Barefoot runners can still hit heel first and when they do, their ground reaction force graph looks remarkably similar to if you had a 1 pound stability shoe on your foot. Thus, it doesn't do us a lot of good to go run barefoot without changing the foot strike. Do not run barefoot hoping that it changes your footstrike. It may alter it slightly and maybe eventually change it, but for most unless you are doing a massive amount of barefoot running, the foot strike change needs to be helped along. For an example, here's a blog that shows a runner running in shoes, vibrams, and barefoot who has done a decent amount of minimalist running, yet still lands heel first. (link here)

Step 1-Regain the feedback
Your body is so used having a heavy shoe on your foot that, heel striking has become second nature. The first step is to slowly regain the proprioception and feedback and let your body figure out how to interpret that data. What happens most of the time when you try and switch foot strikes is that the runner can't feel what they are doing. They can't really tell how their foot is striking.

To fix this, you need to see what you are doing. Grab a video camera and have someone film you doing easy strides. Take a look at how your foot is striking, then take the shoes off and do another short stride barefoot. Again, look at the video and see how you are striking.

If you strike more forefoot barefoot then the process is simple. Simply do some more easy strides barefoot trying to focus on the feeling you are getting and what your legs are actually doing. Then, put shoes on and try and mimic this feeling, being sure to video tape it to see if you are translating that barefoot feeling to running with shoes.

If you strike heel first barefoot then the process is a little longer. You need to try out a variety of cues running while barefoot. By cues, I mean things you think of doing while running. The best way to do it is try one cue out, then watch the video and see if anything changed. If it doesn't work try another cue. Repeat the process until you find something that works.

Possible cues include:
-put your feet down sooner
-drop your foot as soon as knee comes through,
-feel like you're striking behind you.
-Shorten your stride

Barefoot running should be used as an aid to learning how to change your footstrike initially. It's easier to feel how you strike barefoot. Once you've got the feeling down, we move to the next step. It's important that you periodically go through this video taping exercise throughout the process to see if the changes you are making are actually working.

Lastly, remember that footstrike is not only a result of what your lower leg is doing. The entire body is connected and works in a connected way. The lower leg does not act in isolation. Look at the entire body to see if something else might be throwing off your foot strike. Everything has an equal and opposite reaction

Some things to consider:
- Watch the opposite shoulder. If the opposite shoulder is turning inwards too much, that makes the lower leg extend out.
- Watch the opposite side arm stroke. If the arms keep going (i.e. upwards too much or across the body), then the leg keeps going.
- Look at body position. Leaning back causes the lower leg to go out.

 Step 2- Strengthen
The next step is to prepare your body for the foot strike changes its about to make. If you look at the different stress patterns of the foot strikes, the most problematic area will be the achilles tendon. We have to prepare it to take the stress that it's supposed to take but hasn't in years because of how you run.

We do this via two ways. First, the problem with the achilles is that it needs to handle a good deal of eccentric stress while running. Research has shown that the best way to actually strengthen and remodel the tendon itself is through eccentric calf lowering exercises. These exercises consist of basically the lowering portion of calf raises. The difference, obviously, is that we are concerned only with the lowering portion of that exercise. To do these, find a step, or use a calf raising machine, and raise up high with both feet. Once you've gotten up high, take one foot away and lower slowly all the way with only one foot. Then, come back up with both feet. Repeat this approximately 10-15 times for each foot. The goal is actually to do these with a good amount of weight. The high weight is partially what triggers the tendon remodelling. Start with body weight only, and progressively add weight, either by machine, or by holding dumbbells or a barbell or any other technique you can think of.

The second way to prepare for the foot strike change is the obvious one, start doing some walking/jogging barefoot and/or start introducing a minimalist shoe to your training. Not much, just get used to being barefoot. Start with walking around and including barefoot running as part of a cool down after a run.

Step 3- Think about it and practice! Forget Drills!
This step is probably the most obvious but hardest to do. You have to actually practice changing your foot strike. Start with focusing it only on strides following runs. Then progress to thinking about it on cool downs. The next step is to think about your form during normal easy runs. It is impossible to focus on form for a whole run. You won't accomplish anything. Instead, pick out certain time periods during the run in which you REALLY focus on it. Start with maybe 30sec every mile spent concentrating on it. The goal is to extend these periods of focus until it starts to translate into being automatic.

Forget about drills. Running form drills don't change foot strike. Forget them.

SPRINT! Most people will change their foot strike to at least a bit more forefoot when sprinting. You'd be surprised on how much actually sprinting helps change foot strike. In particular spring uphill. Why? Because it's almost impossible to sprint uphill and land heel first. Use these uphill sprints to get the feeling right on how to land and then progress to getting that same landing on the flat ground.

Step 4- Go minimalist
The fun part is finally here. Go minimalist!
At this point, your body should be prepared mechanically to deal with the change in foot strike. So, start introducing actually minimalist running. How much will depend on your background. Most high level runners already do some minimalist running on a regular basis. They run faster workouts in flats or spikes. This is a great way to transition. If you haven't already done so, do your faster runs each week in flats.

If you are already at that step, then steadily increase the amount of mileage done in a minimalist shoe. Keep track of it in your log and make sure it's progressive and steady. The best ways to do this are if you run once per day, then alternate a minimal shoe and your old shoes every other day.

Step 5- Extend barefoot running
The last step is to extend the amount of barefoot running you do. If you are at this step, you should have already been doing strides and/or cool down jogs barefoot. Now, the goal is to extend these.

Once again, steady progression is the key.

I suggest, and did, the following:
- Think of your barefoot running as if it were hard interval training. That means start with a relatively small amount (1mi) and progressively increase that as you adapt. Also, this means that you need recovery after this "hard training". Start with 2-3 days 'recovery' where you run in flats or regular shoes before you attempt your next barefoot running session. Then cut the recovery to one day, and so on, for however long you want to go.

- Have a mileage limit. Have a mileage cap on how much barefoot running you can do per day and per week. This can progressively increase but should start relatively low.

- It's best to start with including a short amount of barefoot running at the end of regular runs. Meaning if you have a 9 mile run, then run 8 miles of it and then throw off the shoes and do an easy 1mi barefoot. Progress this to where now you are doing 1.5mi, then 2mi, then 3mi barefoot at the end of that run.

Remember:
- Barefoot running is done to support the foot strike

There you have, that's my quick guide to transitioning to a forefoot strike and some barefoot running. How far you want to go is up to you.

Just remember that going barefoot without the foot strike change is pretty much pointless. They have to complement each other.

from Science of Running by Steve Magness. That’s all folks...

Julia

Touch and Go #13

How to go from heel striking/orthotics wearing to forefoot strike/ barefoot running
Should you train barefoot?
This concluding post on the barefoot vs. shoe debate will look at some of the practical applications to all the research that we've discussed. In part 1, I questioned whether cushioning or pronation even mattered. In part 2, I looked at the new study by Lieberman on barefoot running and footstrike, and finally in part 3 I discussed foot strike in relation to performance. With all of this information at your disposal, what do you do? Let's look at some relevant conclusions that were established in the other parts of this series:

- Cushioning may not matter for injury prevention as the body adjusts using feeback.
- Pronation may not be relevant for injury prevention.
- Your body has a complex system of adjusting for whatever surface you land on and whatever is on your foot.
- Footstrike matters for performance.
- Footstrike, not necessarily barefoot running, affects impact forces and energy storage.
- Footstrike is more important than barefoot vs. shod in a number of conditions. In other words, it does little good to run barefoot if your footstrike does not also change.

from Science of Running by Steve Magness. To be continued... one more section to go!

Liz

Touch and Go #12

Practical Implications: What do we learn from all of these studies?
 It lends credence to the idea that footstrike is important when we are concerned with speed and speed only. There is a tendency for faster runners to adopt a non-heel strike in a variety of events. In addition, these foot strike types allow for shorter ground contact times, which also correlate well with speed. One other variable to consider is how that foot strike occured? It's impossible to know but where the heel strike took place is incredibly important. There is a big difference between striking close to under your hips to striking way out in front of you. Perhaps we should consider looking at foot strike in terms of where it occurs in relation to your center of mass, instead of where it occurs on the foot.

Using this data, I’d recommend a switch to a more midfoot or forefoot running style if speed is your main concern.

Secondly, these studies provide some interesting data on fatigue and foot strike. Seeing that ground contact times lengthen, some training should be done to avoid this decrease. I’ve written an entire article (and done a presentation, which I have not posted yet) on a related phenomenon, Strength endurance work, that explains some of the ways to combat this fatigue. We need to train the body to maintain force production (and muscle fiber recruitment) under heavy fatigue. This means start off with being able to increase force production, move to being able to produce force quickly, then move to being able to produce force in heavy fatigued conditions.

Basically, strength endurance work combined with plyometric and power training would seem the best way to train for this type of fatigue resistance. In practical terms:

- Strength Training -> Power training/ Sprint training -> Strength Endurance (Circuits/hills) -> Strength Endurance under fatigued conditions (hard circuits/ 200m reps at 800m pace w/ bounding in between)

from Science of Running by Steve Magness. To be continued...

It is I

Touch and Go #11

Ground contact time and footstrike related to running speed. What it all means:
What does this all mean? It’s hard to make a lot of conclusions since the hard data on the British studies could not be evaluated yet. The preliminary observations are very interesting though.

In regards to foot strike, there is a relationship between running speed and footstrike. Do all fast runners forefoot strike? No, but there is a tendency for the faster runners to forefoot/midfoot strike more so than the slower runners.

Is this a function solely of the speed that they are running? Speed of running certainly plays a role in where you strike to an extent but it’s unlikely that it plays as much of a role as people make it out to. Meaning that someone is not going from a straight heel strike while running easy to a forefoot strike while running 800m pace. The Lieberman study provided the first evidence showing that forefoot strikers struck forefoot regardless of condition. Similarly, if we look at the data in the studies above, you can see that the percentage of footstrike types is remarkably similar despite the significant increase in average running speed (from 63-64sec per lap down to 57.5sec per lap). Even though these are different people running each event, if foot strike was solely a function of speed, like many have claimed, then you would expect to see a definite trend away from heel striking as the group got faster.

Fatigue:
Perhaps most interesting is what seems to happen during fatigue. Ground contact times increase in both studies, regardless of footstrike. If we look back at what typically impacts ground contact time, it provides some interesting clues. Ground contact changed even when footstrike did not, so we can eliminate that possibility. The other two possibilities are that leg stiffness and use of elastic energy changed, which is entirely possible, but impossible to know. There is some research showing fatigue changes leg stiffness and stretch shortening cycle fatigue. Lastly, the most likely scenario is that fatigue is impacting the body’s ability to produce force in as short a time period.

Lastly, in the 1500m study it was interesting to see a change in footstrike pattern. During the last lap, you saw an increase in heel striking. This would seem surprising as generally one of the faster laps in the race as people try and kick it in. The question is why do runners switch to a heel strike under heavy fatigue? I’m not sure I have the answer. One possibility is that stride length tends to decrease with fatigue and runners are trying to compensate by lengthening their stride, but instead of doing it by pushing off and covering more distance, they simply let their lower leg reach out. Another possibility is that fatigue may impact fine control of the lower leg.

from Science of Running by Steve Magness. To be continued...

Michelle

Touch and Go #10

New studies on footstrike. Do faster runners heel strike?
Perhaps the most interesting finding in Lieberman’s work is that it may not be so much the barefoot vs. shod but the footstrike that is the important part. Barefoot running allows for the footstrike to happen properly, so they are interconnected.

Let’s leave behind injury prevention for a bit here and focus on speed. Is one footstrike better for speed in distance events? There are several theoretical arguments that point towards yes.

The role of elastic energy storage and return is one such factor. I’ve already mentioned this quiet a bit, but the Achilles tendon and the arch of the foot store a large amount of energy upon footstrike and then that energy is subsequently used upon take off. A forefoot strike has shown that it potentially uses this mechanism much better. One reason is that upon initial contact the foot is in better position to store the energy from the ground strike. In heel running, a great deal of the initial strike energy is lost. On a similar note, it is possible that a forefoot strike utilizes the stretch reflex mechanism better due to the position of the foot upon contact. With a forefoot strike the whole calf complex is in better position to be stretched and subsequently respond than in a heel strike.

Another potential performance enhancement is that it allows for shorter ground contact time while applying the same amount of force. Several different studies have shown the importance of ground contact time in running. In two separate studies, shorter ground contact time was correlated with top running speed and better economy. This shouldn’t be a surprise when you think about it. Ground contact time is going to be a result of mainly the person’s ability to produce force quickly, footstrike, and the ability to use the elastic energy mentioned above. Obviously footstrike plays a role in the latter two.

Let’s look at a couple of studies on footstrike. Several of which have yet to be published.

In the one study that everyone quotes, Hasewage 2007, they looked at footstrike at the 15km mark in a half marathon. The anti-forefoot strike people use this as justification in their decry of changing running mechanics. However, there are several problems with this view. First, let’s look at what the study said. In the study, out of the 283 runners, 74,9% were rearfoot strikers. The rest were midfoot and forefoot strikers. That leads many to conclude that rearfoot strike may be the way to go. However, if we look at a couple of other factors the picture gets a little more cloudy. When you separate out the top 50 instead of using the entire group, those who midfoot or forefoot strike jumps from ~25% to 38%. That significant difference showed that there was a tendency for more mid/forefoot strikers to be faster.

Secondly, if we look at ground contact time, there was a linear relationship with the faster runners having less ground contact time and GC increasing as you got slower and slower. Basically, the faster the runner, the lower the GC, this isn’t unexpected. In addition, forefoot/midfoot strikers spent significantly less time on the ground than their heel strike counterparts (183ms vs 199ms). These findings led the researchers to conclude:

“The percentage of RFS increases with the decreasing of the running speed; conversely, the percentage of MFS increases as the running speed increases. A shorter contact time and a higher frequency of inversion at the foot contact might contribute to higher running economy.”

There are still two other factors that no one takes into account. First off, the video was taken at ~9.3mi into a 13.1mi race. In other words it takes place pretty late in the race when fatigue has already set in. Studies have shown that footstrike changes with fatigue. What happens is that more midfoot and forefoot strikers become heelstrikers. Thus, when you look this deep into a race, that potentially skews the percentages.

Secondly, the study was done in a large Japanese road race. While there were several elite Kenyans and other nationalities, of the top 283, the vast majority were Japanese. This is very significant. This means that technically, the results are only generalisable mostly to Japanese runners. Why is this significant? Because of how the Japanese historically train and how they historically run. Due to the heavy emphasis on very high mileage and moving everyone to the longer distances (half marathon and marathon) with neglect to the shorter distance races (1500,5k), the running style of Japanese runners is much different than Americans, Europeans, and even Africans. Similarly, the traditional ideas taught by Japanese coaches at the time favoured a running style that was more flat/scoot around type running. Researchers and scientists will probably scoff at this idea, but go watch any video of top Japanese running and you will notice a visual difference. In addition, one of my coaching mentors started spending time going to Japan educating Japanese coaches on running mechanics at around the time of this study. We’ve spent many hours discussing what their views were, what the runners were being taught, and how their athletes were running.

Due to these factors, it’s impossible to take this study and generalize it to anyone except Japanese runners. In addition, the study shows that speed is correlated with both footstrike and ground contact time.

British studies:
In all of the British studies they looked at semi-elite/competitive runners during 800 and 1500m competitions. They looked at foot strike and ground contact time on each lap. This will not only give us an idea on foot strike implications but also on fatigue. The conclusions that can be drawn based on the research about fatigue and training are very interesting!

In the 1500m, the range of times went from 3:45 to 4:22 with the average being 3:56.
Once again, ground contact time-ground contact time was related to foot strike. Forefoot strikers spent 161ms on the ground compared to 169ms for midfoot and 192ms for heel strike. The difference between heel strike and the other two are pretty remarkable. What is interesting is that ground contact increase basically on every lap.

Footstrike also changed based on lap. Initially on lap 1, 34.6% were forefoot striking, 46.2% midfoot, and 19.2% heel striking. On lap 4 the picture changed slightly. More of the midfoot strikers in particular had switched to heel striking (heel striking increase to 27%.)

What this means.
Fatigue: “over the course of a 1500m race, ground contact time increased irrespective of footstrike position. This implies an element of fatigue, with runners presumably requiring longer to generate the same impulse.”

Before delving into the meaning of this, let’s look at the results of the other study on 800m runners quickly:

800m male runners
- 1:47 to 2:01 (avg: 1:55):
- forefoot-35% Ground contact (156ms)
- midfoot-48% Ground contact (161ms)
- Heel-17% Ground Contact (177ms)
- Ground contact lap 1- 156ms lap 2-168ms

from Science of Running by Steve Magness. To be continued...

Craig

Touch and Go #9

Conclusion and Practical implications:
This study provides further evidence to some of the issues discussed previously in regards to barefoot running. For runners, the major implication could be on foot strike. It’s more than just barefoot running, it’s footstrike that matters. A lot of the differences in collision force are due to footstrike variations. For years, shoe companies and others have said that heel striking is the way to go. Elite runner Mark Plaatjes even made the same argument earlier this week in a well written paper. Lieberman’s article helps lend credence to what I and many others have always speculated. It’s not.

The human body was designed to run with a forefoot/midfoot strike and shoes cause us to run barefoot. In one of the nature barefoot articles there is a great picture illustrating this (above). It is of 2 Kenyan boys running on a dirt road. One is barefoot and landing whole foot, one in shoes, slamming his heel into the ground first. Shoes decrease proprioception, change ankle kinematics and allow the body to change its landing habits.

Therefore, the major finding is that footstrike may be more important than running barefoot or not. Granted running midfoot is hard with heavy shoes. The study shows that footstrike was what mattered. Barefoot runners who landed heel first still had much higher impact forces than when striking forefoot/midfoot. Similarly, the rate of loading was still much higher in barefoot heel strikers than barefoot forefoot strikers. This finding that footstrike matters is something that track coaches have been saying for decades. One of my big mentors, Tom Tellez, has been preaching this for a long time.

More focus should be focused on changing footstrike with barefoot/minimalist running used as a way to aid that change.

A change to barefoot running should be accompanied by a change in running style to a midfoot/wholefoot/forefoot one. For information on how you should run read this (here)  and watch these (here and here) (no I don't think Pose or Chi are wonderful...)

Lastly, I think the take away message is that the human body is more complex than we give it credit for. The fact that it alters footstrike and pre-activation and numerous other mechanisms based on what is on the shoe or what ground you are going to strike is amazing. Think about that for a second. A couple years back Adidas tried to sell a shoe with an expensive microchip that adjusted cushioning each stride. The shoe cost several hundred dollars. The problem is, we already have a mechanism that does that for free….ourselves!

Lastly, a word of caution. This study will catch on fire. The major newsgrabbing headline will be the impact forces. However, that is likely a gross oversimplification of the process. Like with other variables (VO2max, lactate,etc.) don't get tied to one while missing the big picture.

If you enjoyed this or any other article, please help get the information out there and pass it on. Much appreciated.

To read more about barefoot running and running shoes read the below article on Why Running shoes do not work:
http://stevemagness.blogspot.com/2010/01/why-running-shoes-do-not-work-looking.html

from Science of Running by Steve Magness. To be continued...

Debbie

Touch and Go #8

What causes heel strike?
“A major factor contributing to the predominance of RFS landings in shod runners is the cushioned sole of most modern running shoes, which is thickest below the heel, orienting the sole of the foot so as to have about 5u less dorsiflexion than does the sole of the shoe, and allowing a runner to RFS comfortably. Thus, RFS runners who dorsiflex the ankle at impact have shoe soles that are more dorsiflexed relative to the ground, and FFS runners who plantarflex the ankle at impact have shoe soles that are flatter (less plantarflexed) relative to the ground, even when knee and ankle angles are not different.”

Evolution:
“Differences between RFS and FFS running make sense from an evolutionary perspective. If endurance running was an important behaviour before the invention of modern shoes, then natural selection is expected to have operated to lower the risk of injury and discomfort when barefoot or in minimal footwear.”

This essentially means, we’ve got millions of years of adjustment and fine tuning that went on to allow us to run barefoot with minimal risk. In addition, Lieberman points out several evolutionary changes that aid running. The development of the arch, which is essential for elastic energy return, is one of them.

from Science of Running by Steve Magness. To be continued...

Bob

Touch and Go #7

Injuries:
In his accompanying article Jungers eloquently stated:

“Although there is no hard proof that running in shoes, especially hitech or PCECH (pronation control, elevated cushioned heel) versions, causes injuries, in my view there is no compelling evidence that it prevents them either. However, there are data that implicate shoes more generally as a plausible source of some types of chronic foot problems.”

Speed and footstrike:
One other interesting finding was that speed was NOT related to foot strike type or ankle and foot angles. That means, how fast the runner was in the study did not relate to how he struck the ground. That helps to get rid of the old argument that I have heard time and time again that footstrike depends solely on speed and that only fast runners strike midfoot because they run fast. WRONG.

From a range of runners running at speeds varying from about 7minutes per mile to ~4:20 per mile, footstrike didn't depend on speed.

from Science of Running by Steve Magness. To be continued...

Janene

Touch and Go #6

Barefoot/Forefoot runners have a “smoother” ride: Difference in collision forces:
Barefoot runners “take shorter strides and to run with greater vertical leg and ankle compliance (the lowering of the body’s centre of mass relative to the force of the impact). This serves to blunt the transient force and results in a less jarring, ‘smoother ride’.” (Jungers, 2010)

Basically this means that because of the footstrike difference, the body uses the lower leg in a more efficient shock absorbing way. The foot is more plantar flexed and the ankle is more compliant. This creates a situation where the collision is essentially absorbed and spread out better.

In heel striking the collision forces are concentrated in one area, and very sudden. Meaning a large amount of force in one place, very quickly. Meanwhile in a more flat footstrike, as mentioned above, the impact is spread out, absorbed better, and not so sudden. This leads to peak vertical forces 3x lower in barefoot vs. shoe wearing runners and a rate of loading that is half as much for barefoot compared to shoe wearing runners

This difference may lead to injury prevention, as some studies have suggested that it’s not necessarily the total impact forces but the high rate of force in a very short time. (Look at the drawings in my article below and remember that barefoot running doesn’t have the initial peak impact force). Still, the impact force debate can be VERY misleading. Just a word of caution to read my other blog post on running shoes and realize that peak impact forces do not relate to injuries

Concrete vs. Dirt:
Another interesting finding is the adjustment of impact forces that occurs based on the ground you are going to strike. The study found that barefoot running produced less collision forces on a hard surface than a cushioned shoe.

Similar to the conclusions I came to in the Running shoe article (see Steve’s blog), they found that leg stiffness was adjusted to control impact. This created a situation where there was no difference in rate or magnitude of impact loading based on the surface they were running on. As I have said many times, the body has a built in adjustment mechanism. It controls impact via adjustment of several different mechanisms.

So all those people who are worried about the impact forces of running barefoot on concrete should consider that when they stick a cushioning shoe on and heelstrike, there collision forces are higher!

from Science of Running by Steve Magness. To be continued...

Pam

Touch and Go #5

THE first big study on barefoot running in Nature : Death to Heel striking.
The barefoot debate is about to get a little bit hotter.

A new study released this year by Lieberman in Nature takes an evolutionary look at barefoot running. In the study, they compared barefoot and shoe running on a whole variety of factors in both regular shoe wearers, regular barefoot runners, and even Kenyans!

The study is entitled and I HIGHLY recommend it:
Foot strike patterns and collision forces in habitually barefoot versus shod runners

This is a timely piece as it adds more evidence to the article I wrote a couple days ago below. The implications are great as they extend beyond barefoot running to foot strike too (heel vs. forefoot, etc.) I’ll highlight some of the findings.

Foot strike and Elastic response and energy transfer:
 As I speculated in my article, footstrike greatly effects the elastic energy return. In their study, it was found that forefoot and some midfoot strikes “reduces the effective mass of the foot and converts some translational energy into rotational energy; the calf muscles control heel drop, and the FFS runner can take fuller advantage of elastic energy storage in both the Achilles tendon and the longitudinal arch of the foot.”

On this topic, Liberman speculates that the arch plays a key role in reduced oxygen cost of running in barefoot runners. Essentially during a mid/fore foot strike the arch can stretch over the entire first half of the stance phase, while during the rearfoot strike, it has to wait until the last part of this phase, thus decreasing energy storage and return.

Also, forefoot and some midfoot strikes allowed for greater energy transfer. When heel striking a large portion of kinetic energy dissipates. With forefoot striking, some of the translational kinetic energy converts into rotational energy.

from Science of Running by Steve Magness. To be continued...

Thea

Touch and Go #4

Tying it together with elites:
 Looking at elite athletes, when racing and training, they generally have higher turnover, minimal ground contact time, and a foot strike that is under their centre of gravity. Since the majority of elites exhibit these same characteristics while racing, it makes sense that this is the optimal way to run fast. So, why are we wearing footwear that is designed to increase ground contact, decrease turnover, and promote footstrike out in front of the centre of gravity? I have no idea.

Conclusion:
In conclusion, I’m not some fanatic saying everyone ditch shoes now. Chances are you’ve been running in shoes for 20+ years. Your bodies done some adapting during that time. You’ve got to gradually change if you want to undue some of the changes.

The purpose of this article wasn’t to talk about the benefits of barefoot running. Instead it was to point out the problems with Running Shoe classification. It’s based on a cushioning/pronation paradigm that simply is not as true as they want us to believe. That paradigm needs to be reevaluated. It’s not founded on good science but rather initial ideas that made sense with no science behind them, but upon further review may not stand up to testing. A recent study found that using the good old shoe classification system that everyone uses, had little influence on injury prevention in a large group of Army Basic Training participants (Knapik, 2009). They concluded that selecting shoes based on arch height (like all major running magazines suggest) is not necessary if injury prevention is the goal. I guess that means the systems broken…

Where do we go and how do we fix it? I have no idea. Sorry, no genius answers here. My inclination is that we aim for letting the foot function how it is meant to function, or at least come up with some shoe that may alter foot mechanics but while still allowing feedback/functionality of the body. The first step is looking at the foundation on which running shoes are built upon, the motion control, stability, and cushioning paradigm. My take is that it needs to be reevaluated. I’m going to end with something I’ve already said, but it’s an important concept to get across:

The body is more complicated and smarter than we give it credit.
The type of shoe and material of the shoe changes impact or stride characteristics NOT because of alignment of the lower leg or because of changes in cushioning. Instead it changes impact and stride characteristics because it alters the sensory feedback. The brain is a wonderful thing.

If you found this article to be informative, I'd appreciate it If you passed it along. The goal is to get research based data out there so people can be well informed.

from Science of Running by Steve Magness. To be continued...

Warrick

Touch and Go #3

Maria

Underestimating our Body: Impact forces as feedback:
Back to the question I asked earlier: How can impact forces not change based on shoe sole softness and why isn’t running on hard surfaces lead to more injuries?

The problem is, once again, we underestimate the human body! It’s an amazing thing, and we never give it the credit it deserves. The body adapts to the surface that it’s going to strike, if you give it a chance. The body adapts to both shoe and surface adjusting impact forces via changes joint stiffness, the way the foot strikes, and a concept called muscle tuning.
An example of this can be seen with barefoot running, the diminished proprioception (sensory feedback) of wearing a shoe negates the cushioning of the shoe. Studies using minimal shoes/barefoot have shown that the body seems to adapt the impact forces/landing based on feedback and feedforward data. When running or landing from a jump, the body takes in all the sensory info, plus prior experiences, and adjusts to protect itself/land optimally As mentioned above, it does this through a variety of mechanisms. Thus, you stick some cushioned running shoe on the bottom of your foot and the body goes “Oh, we’re okay, we don’t need to worry about impact as much, we’ve got this soft piece of junk on our foot.

One concept that needs to be further discussed is muscle tuning. It’s a concept recently proposed by Nigg et al. in 2000. He sees impact force as a signal or a source of feedback, as I stated earlier. The body then uses this information and adjusts accordingly to minimize soft tissue vibration and/or bone vibration. His contention is that impact force is not the problem, but rather the signal. Muscle tuning is essentially controlling these vibrations via a variety of methods. One potential mechanism is pre-activation. Pre-activation is activation of the muscles prior to impact. In this case it serves as a way of muscle tuning to prepare for impact and in addition can alter muscle stiffness, which is another way to prepare for impact. Pre-activation has been established with multiple EMG studies.

Shoes not only impact this, but surface type does too. As mentioned previously, the change in running surface did not impact injury rates. Why? Probably because the body adapts to running surface. In an interesting study measuring muscle activity, O’Flynn(1996) found that pre-activation changed based on surface. To prepare for impact, and presumably to minimize muscle/bone vibration, when running on concrete pre-activation was very high, when running on a soft track, not so much.

What all of this means is that the body adapts via sensory input. It has several different adaptation methods. A shoe influences how it adapts. The shoe is not doing anything to alter cushioning, it is simply altering how the body responds to impact. It’s a significant mindset jump if you think about it. Here’s the summary:

The type of shoe and material of the shoe changes impact NOT because of alignment of the lower leg or because of changes in cushioning. Instead it changes impact characteristics because it alters the sensory feedback

In conclusion on the cushioning concept. Well, what are we trying to cushion? Heel impact forces have not been shown to relate to injuries, in fact in one study low impact runners had a 30% injury rate compared to a 20% injury rate in high impact runners. Shoe midsoles do not change, or marginally change impact forces anyway. So, not only may cushioning not be the answer, the shoes might not even be doing their job. But what about those shoe cushioning studies showing improved cushioning with their new midsole?! Well, the majority of that testing is done by using a machine to simulate the impact forces that you experience during running. That means, yes it may cushion an impact more, but it doesn’t take into account the role of the body adjusting impact based on feedback.

The reason cushioning doesn’t work? Because the body adapts based on feedback and feedforward information. These results prompted one notable researcher(Nigg,2000) to call for the reconsideration of the cushioning paradigm for running shoes.

Barefoot running?
Quickly, this topic could not be complete without a brief mention of barefoot running. An interesting thing to note is that the initial peak impact force is absent in barefoot running when compared to running with shoes. What this means is that, the impact forces look like (A) for shoes and (B) for barefoot. That initial little blip in A is the initial impact force. There is a hypothesis that this initial impact force is related to injuries.

A recent study by Squadrone et al.(2009) compared running shoes, barefoot running, and running in Vibram Five Fingers. They demonstrated reduced impact forces, shorter ground contact and stride length, but increased stride frequency while running barefoot (and in Vibrams) as compared to running with shoes. This is not unexpected, but shows that running shoes do in fact alter our normal strides. An interesting point is the reduction in stride length but increase in stride frequency. Shoes tend to promote this longer stride at a consequence of ground contact times and frequency. This happens because of changes in feedback signalling, increased likelihood to land on heel stretched out, increased weight, all of which lead to longer times on the ground. It’s interesting to note that elite runners all have short ground contacts and high frequencies (as demonstrated by the often quoted Daniels study of 180 strides per minute).
Tying this to the discussion above on the body controlling things based on sensory information, when running barefoot, there is a higher degree of stiffness in the lower leg. Increased stiffness can result in an increased SSC (stretch shortening cycle) response, resulting in greater force on the subsequent push off (2001). Dalleau et al. demonstrated that pre-activation causing increased stiffness improved Running Economy. In his study, the energy cost of running was related to the stiffness of the lower leg (1998)

Another recent study found that knee flexion torque, knee varus torque, and hip internal rotation torque all were significantly greater in shoes compared to barefoot. What does all of this mean? Potentially, this means more stress on the joints in this area. Jay Dicharry put it best when he said:

“The soft materials in modern running shoes allow a contact style that you would not use barefoot. The foot no longer gets the proprioceptive cues that it gets unshod. The foot naturally accommodates to surfaces rapidly, but a midsole can impair the foot’s ability to react to the ground. This can mute or alter feedback the body gets while running. These factors allow a runner to adopt a gait that causes the elevated forces observed above.”

The one thing that non-barefoot/heel strike proponents use to dismiss midfoot striking/barefoot running is the Achilles tendon. They say, correctly, that the load on the Achilles is higher in midfoot striking runners. The Achilles is meant to take a large load. The problem is we’ve weakened the Achilles through years of wearing shoes with their elevated heels. Essentially, we’ve created the Achilles problem with the shoes meant to prevent it. The Achilles is designed to operate in a rubber band like fashion. . During impact such as the braking or contact phase of running, the achilles tendon stores energy and then subsequent releases that energy via recoil during the take off phase of running. The Achilles, can store and return approximately 35% of its kinetic energy (Ker, 1987). Without this elastic storage and return, the oxygen uptake required would be 30-40% higher! So, in terms of performance why are we trying to minimize the tendonous contribution? It’s like giving away free energy.

Running shoes do not utilise the elastic storage and return as well as barefoot or minimal shoes. More energy is lost with shoes than with barefoot running (Alexander and Bennett, 1989). In addition, in some models of shoes, the arch is not allowed to function like a spring. The arch of the foot can store around 17% of kinetic energy (Ker, 1987). Given these results, its not surprising that running barefoot when compared to running with shoes is more efficient. Several studies have shown a decreased VO2 at the same pace with barefoot running, even when weight is taken into account. This should be no surprise as I mentioned above, without elastic recoil VO2 requirement would be 30-40% higher. Running in a minimal shoe allows for better utilization of this system.

So, the take away message is that shoes change natural mechanics to one that creates mechanical changes that are not optimal for running fast (decreased stride frequency, increased ground contact, decreased stiffness of the system, decreased elastic contribution, and on and on).

from Science of Running by Steve Magness. To be continued...

Touch and Go #2

Katherine

Cushioning:
Impact forces are the other major scoundrel of running injuries. The thinking goes like this, the greater the impact force on the lower the leg, the greater stress the foot/leg takes, which could potentially lead to injuries. To combat this fear, running shoes, particular cushioning ones, are to the rescue. Let’s take a look.

The first question is, do cushioning shoes do their job?

Wegener(2008) tested out the Asics Gel-Nimbus and the Brooks Glycerin to see if they reduced plantar pressure. They found that the shoes did their job! But where it reduced pressure varied highly. Meaning that pressure reduction varied between forefoot/rearfoot/etc. This led to the interesting conclusion that there should be a shift in prescribing shoes to one based on where plantar pressure is highest for that individual person. It should be noted that this reduction in pressure was based on a comparison to another shoe, a tennis shoe. I’m not sure that this is a good control. Basically, this study tells us that cushioned running shoes decrease peak pressure when compared to a Tennis shoe.

In a review on the subject, Nigg (2000) found that both external and internal impact force peaks were not or barely influenced by the running shoes midsole. This means that the cushioning type does not change impact forces much, if at all. But how can this be? I mean it’s common sense if you jumped on concrete vs. jumped on a shoe foam like surface, the shoe surface is softer right? We’ll come back to this question in a minute.

Impact Forces: The picture gets cloudier:
But it’s not as simple as described above.

In an interesting study by Scott (1990) they looked at peak loads on the various sites of likely injury for runners (Achilles, knee, etc.). All peak loads occurred during mid-stance and push off. This led to an important finding that “the impact force at heel contact was estimated to have no effect on the peak force seen at the chronic injury sites,” and led to speculation that impact force did not relate injury development.

Further complicating the impact force idea is that when looking at injury rates of those running on hard surfaces or soft surfaces, there appears to be no protective benefit of running on soft surfaces. Why is this? Because of something called pre-activation and muscle tuning which will be discussed below.

Supporting this data, other studies have shown that people who have a low peak impact have the same likelihood of getting injured as those with a high peak impact force (Nigg, 1997). If you want to complicate things even further, impact seems to be the driving force between increased bone density.

As a coach or trainer this should make sense. The bone responds to the stimulus by becoming more resistant to it, IF the stimulus is not too large and there is enough recovery.

from Science of Running by Steve Magness. To be continued...

Touch and Go #1

Jennifer

Why Running shoes do not work: Looking at Pronation, Cushioning, Motion Control and Barefoot running
The running shoe model needs to be fixed. Pronation, Motion Control, Cushioning, and Stability shoes? Get rid of them all.

It’s not just barefoot running and minimalism versus running shoes, the either/or situation many portray it to be. It’s much deeper than that. It’s not even that running shoe companies are evil and out to make a profit. Shoe companies may be accomplishing the goals they set out for, but maybe the goals their aiming for are not what need to be done. The paradigm that running shoes are built upon is the problem.
Running shoes are built upon two central premises, impact forces and pronation. Their goals are simple, limit impact forces and prevent overpronation. This has led to a classification system based on cushioning, stability, and motion control. The problem is that this system may not have any ground to stand on. Have we been focused on the wrong things for 40+years?

I’ll start with the customary statistic of 33-56% of runners get injured every year (Bruggerman, 2007). That is kind of mind blowing when you think about it. Since there are a ton of injuries going on, let’s look at what shoes are supposed to do.

Pronation:
As said earlier, shoes are built upon the premise that impact forces and pronation are what cause injuries. Pronation, in particular has been constructed as the bane of all runners. We have become inundated with limiting pronation via motion control shoes. The central idea behind pronation is that overpronating causes rotation of the lower leg(i.e. ankle, tibia, knee) putting stress on the joints and therefore leading to injuries. Running shoes are therefore designed to limit this pronation. Essentially, running shoes are developed and designed to put the body in “proper” alignment. But do we really need proper alignment?
This paradigm on pronation relies on two main things: (1)over pronation causes injuries and (2) running shoes can alter pronation.

Looking at the first premise, we can see several studies that do not show a link between pronation and injuries. In an epidemiological study by Wen et al. (1997), he found that lower extremity alignment was not a major risk factor for marathon runners. In another study by Wen et al. (1998), this time a prospective study, he concluded that “Minor variations in lower extremity alignment do not appear conclusively to be major risk factors for overuse injuries in runners.” Other studies have reached similar conclusions. One by Nigg et al. (2000) showed that foot and ankle movement did not predict injuries in a large group of runners.

If foot movement/pronation does not predict injuries or is not a risk factor for injuries, then one has to question whether the concept is sound or working...

Looking at the second premise, do shoes even modify pronation? Motion control shoes are designed to decrease pronation through a variety of mechanisms. Most choose to insert a medial post or a similar device. In a study by Stacoff (2001), they tested several motion control shoe devices and found that they did not alter pronation and did not change the kinematics of the tibia or calcaneus bones either. Similarly, another study by Butler (2007) found that motion control shoes showed no difference in peak pronation when compared to cushioning shoes. Lastly, Dixon (2007) found similar results showing that motion control shoes did not reduce peak eversion (pronation) and didn’t change the concentration of pressure.

This is sort of a double whammy on motion control shoes. If excessive pronation does not cause injuries to the degree that everyone thinks, and if motion control shoes don’t even alter pronation, what’s the point of a motion control shoe?

from Science of Running by Steve Magness. To be continued...

My theme for 2010 - "Touch and Go".

In 2009 the theme was "Transformation" for which I wrote a whole lot of stuff, which you can find via "Labels".

Before that the theme was "180 steps per minute" which I haven't gathered together via "Labels" but now that I have thought to do so, I shall.

2010's theme will be "Touch and Go". I foreshadowed it below in the post entitled "ground time",  where I said I would talk about how to change things so that you and I can run faster!

This time however I am not going to write it myself, I am going to reproduce it from a very good blog written by Steve Magness.

You may have noticed a new link in "My Blog List" called “Science Of Running” in "My Blog List". The author invites us to pass on his research, so I am doing that. I recommend that you read through some of his other articles, and keep an eye out for his new posts. This looks like the most valuable new resource to emerge for some time.

So for the next two weeks (starting on Tuesday) I am going to reproduce some of Steve's work. Please note that Steve Magness writes in his blog: "If you found this article to be informative, I'd appreciate it If you passed it along” and I have taken him at his word.

The three hour pacer

I have heard a lot of positive feedback about the marathon pacers, all three were very much appreciated.

Marathon running styles

With the "Touch and Go" articles, I will be publishing many of the photos of us running the marathon and half marathon. You can decide whether the various running styles look good or not!

ground time

For the last couple of years I have been suggesting that the many of the speedygeese focus on increasing their running tempo, with the goal of moving along at 180 - 190 steps per minute in their races whether they be short, middle, or long distance, and adjusting their stride length accordingly. This year I thought I might approach this from a different direction, and emphasise the desirability of minimising ground time; the amount of time the foot lingers on the ground when running fast. So stay tuned.

Last night we ran at Parliament House with light rain pending but never really arriving. Four of us ran early; Jen & Rachelle, who didn't stay for the later session; and Andy & I. Then we were joined by Bronwyn, Craig, Emma, Helen, Jodie, Julia (new), Karen, Katherine, Kathy, Neil,   & Warrick for a final session of 3 x 950m stopping at one or more exercise stations on the way around. Helen introduced everybody and remembered every single name, not stumbling once. Wow! Though I guess as she is a teacher, she has had practice recalling names.

Tonight is our athletic club's annual general meeting. I am looking forward to that one! I hope all the good guys get elected, it depends on who turns up to do the electing. All being well, you will read here tomorrow a report from my/our perspective.

Speedygeese in the ABS Fun Run Wednesday 19 May
26 Katie Forestier 29:06
46 Ken White 30:34
90 Bronwyn Calver 34:00
147 Neil Boden 37:05
574 finishes
Needless to say, given that I worked in the ABS all my working life and organised many of the first Fun Runs there, I recognised many of the finishers' names!

Brett, Nadine, Craig, Maria. Photo by Janene.