***

Pure and unadulterated lifting

• The links you must not miss this week are Jamie Lewis’s meet reports (parts one and two) from his recent powerlifting competition.  Some important lessons to be learned about cutting weight and water, rehydrating properly and mental preparation.

***

Diet, paleo diet and evolutionary adaptations

• Sometimes I just despair at the medical community.  It seems that they can’t even follow their own rules.  Brian St Pierre describes a scenario that he read in Alan Aragon’s research review, where a general practitioner wanted to prescribe some medication because total cholesterol was high, only it was what they call “good” cholesterol!  Of course, whether the cholesterol is high or low is of no interest to me, but the fact that they cannot even follow their own rules suggests that things are completely out of hand now.
• But let’s be clear now.  The research does not support the cholesterol hypothesis.  Check out this recent study at the British Medical Journal that shows that there is no correlation between the consumption of fried food and either heart disease or all-cause mortality.
• But don’t miss the final part of the Randy Roach interview.  If you didn’t catch parts one and two, you can read the whole thing in one go here.

***

Personal training and coaching

• This great research review from Charles Poliquin tells us that in a study of weightlifters doing low (1 set), medium (4 sets) and high volume (8 sets) workouts, the researchers expected there to be diminishing returns.  They expected the low volume to produce substandard results and the medium volume to produce best results, and the high volume to produce either similar results to the medium volume group, or slightly poorer results because of the effects of “overtraining”.  However, the high volume group produced best results.  Charles concludes, somewhat controversially, that “this study disproves the idea promoted by Arthur Jones that performing one set to failure is a superior method of developing strength.”  Ouch.  Don’t pull any punches, Charles!
• And my friend Doug Brignole has some wise words to share about volume and intensity, plus a recent picture of himself to show that you can still look awesome the other side of fifty, although you need some good shirt-ironing skills to pull off the look properly…
• And the amazing Scott Adams tells us how to get everything done on time while maintaining a good mood in the process.  If you are not regularly reading Scott, he is a revelation in thinking properly.
• And Gray Cook is interviewed about the birth of the very popular and effective Functional Movement Screen.

***

Stress, sleep and health

•  One of the biggest criticisms about the healthcare system in any Western country is that they do almost nothing about prevention.  They spend all their time on figuring out how to cure problems once they happen.  However, as this blog at British Medical Journal notes, there may be a positive movement in the pipeline.

***

Other interesting stuff

• I don’t really do politics or economics on this blog but being a finance professional involved in raising funds for companies in the mid-market, I do have quite a few thoughts and views.  If you are interested in this kind of stuff, let me leave you with a problem to solve.  Why, if there is a global shortage of finance, are there asset bubbles in internet stocks and commodities?  Why are banks piling money into risky equities and commodities in the stock market instead of lending it?  No, it’s not a trick question.

***

That’s all folks.  More links next week.

Why would the body would make slower-twitch fibres in response to a low-rep training regimen?  Before we can approach answering that question, we need to figure out whether 3-5 reps (as used in the study yesterday) is too high a rep range.

To help us do that, we could look at athletes using a training regimen that incorporated a lot of singles and see how their fibre characteristics compare with those of normal people.  A good choice might be Olympic weightlifters.

Unfortunately, Hercules was not available for testing                                                            (photo by Littlemisspurps)

***

So what is the study?

The study is called Muscle Fiber Characteristics and Performance Correlates of Male Olympic-Style Weightlifters, Fry, Schilling, Staron, Hagerman, Hikida and Thrush, Journal of Strength and Conditioning Research, 2003.

The researchers looked at six national level Olympic weightlifters in the male 94kg weight class.  Seven male exercise science students were used as controls.  During the experiment, the exercise science students were kept in a separate cage from the weightlifters to prevent them from being eaten.

The researchers took muscle biopsies from the vastus lateralis of both weightlifters (WL) and exercise science students (ESS) and compared them.

***

What happened?

Looking at the table of results in the study, we can see that the muscle biopsies revealed the following figures of muscle fibre percentage composition:

• Type I – WL – 46.5%, ESS – 43.8%
• Type IC – WL – 1.2%, ESS – 0.2%
• Type IIC – WL – 0.6%, ESS – 2.4%
• Type IIA – WL – 46.5%, ESS – 26.9%
• Type IIAB – WL – 2.8%, ESS – 5.7%
• Type IIB – WL – 2.4%, ESS – 21.0%

The interesting things here are:

• The type IIB fibres in the weightlifters were found in very small proportions.  In fact, the study notes that there were so few type IIB fibres in some of the weightlifters that they couldn’t measure them accurately.
• The weightlifters had much greater type IIA fibre percentages instead instead.

This is slightly different from our study yesterday, where we noted that beginners showed a movement from type IIB to type IIAB fibres over an eight-week period of introductory strength training, but basically, we are still dealing with the same shift from fast to slower twitch muscle fibres.

***

What do the researchers make of all of this?

The researchers observe that “the percentage of fibre types observed for the weightlifters in the present study are similar to what has been previously reported for other resistance-trained athletes, including powerlifters.”

This corresponds to what we noted yesterday, which was that  resistance training using low, medium and high repetitions did not influence the resulting muscle fibre type.

In addition, regarding the apparent switch from type IIB (active but not trained) to type IIA, the researchers note that “such large percentages of type IIA fibres are apparent in both strength/power athletes and endurance athletes and appear to be a natural adaptation to the recruitment of the high threshold motor units comprising the type IIB population, ultimately causing an apparent IIB to IIA transformation.”

However, I would note that there may be a small amount of evidence that plyometrics does not cause such shifts but I will look into this and revert back.

So essentially, the researchers are saying that the change in muscle fibre type is a normal activity of the body, irrespective of training techniques.  This suggests, of course, that strength and power abilities developed by athletes such as weightlifters must be created by different neuromuscular changes than the fibre type change.

***

Anything else?

Changing between fibre types only possible in sub-types

I was interested to see that the researchers note that there is little evidence to support the idea that muscle fibres can change from either I to IIA or from IIA to I in humans as a result of exercise.

In this context, the researchers note that the percent fibre type profile for the exercise science students indicated a similar percent of type I fibres as the weightlifters and that the differences in muscle fibre type by percentage are only obvious when the sub-types of the type II fibres are analysed.

***

Titin isoforms

I first wrote about titin isoforms when thinking about running economy and muscle structure.  In that study, the researchers were interested in the role of the large protein called titin, which has significant elastic characteristics and acts as an anchor between the Z-line and myosin within a single sarcomere (you can read more about the role of the protein titin in Bret’s post on the subject).

Titin is partly responsible for the elastic strength of a muscle and it has several isoforms, which are either more or less elastic than each other.  As I noted in my review on running economy and muscle structure, different distributions of titin forms could have an impact on running economy.

In the running economy study, the researchers found that all ten of their national middle-distance runners expressed the faster-mobility titin band and only one subject expressed the lower-mobility titin band as well.

In this study, all of the weightlifters exhibited only the titin-1 isoform (I think this is the same as the faster-mobility titin isoform referred to above), whereas the control subjects were more heterogeneous.  As the researchers in this study note, two physiological possibilities exist:

• Genetics
• Adaptations

Either way, something is going on that is changing the force productive abilities of the weightlifters and it isn’t fibre-type composition.

***

Wrapping up

With many of my research reviews, I end up with more questions than answers but at least I got to the bottom of one question today.  Muscle fibre type does appear to be independent of training routine.

However, that doesn’t mean that training routines can be considered interchangeable!  Low reps still builds strength fastest and higher reps still build endurance fastest.  But saying that low reps build faster twitch muscles than higher reps just isn’t true.  Exactly what they do is the subject for another day.

So here is the main study I referred to back then.  It is called Muscular adaptations in response to three different resistance-training regimens: specificity of repetition maximum training zones, Campos, Luecke, Wendeln, Toma, Hagerman, Murray, Ragg, Ratamess, Kraemer and Staron, European Journal of Applied Physiology, 2002.

Let’s dive straight into what the researchers did.

***

What did the researchers do?

The researchers took 27 healthy strength training beginners and divided them into three training groups for an eight week, lower-body resistance training programme, performing the squat, leg extension and the leg press as follows:

• Low repetition – 4 sets of 3-5 reps with 3 mins rest
• Medium repetition – 3 sets of 9-11 reps with 2 mins rest
• High repetition – 2 sets of 20-28 reps with 1 min rest

There was also a control group that just sat around on their asses doing nothing.  Amusingly, one of the control group couldn’t sit on his ass for eight weeks and started going to the gym, after which he was summarily dropped from the study…  Anyway, the subjects carried out two workouts per week for the first four weeks and three workouts per week for the second four weeks.

And directly after this extremely arduous strength training programme, they looked exactly like this (minus the majestic beard, obviously)… or maybe not.

Hercules probably didn’t take a low-volume approach (photo by Averain)

***

So our bold and hard-working researchers took quite a few different measurements before and after the eight-week lower-body strength training programme.  The measurements before and after were:

• Body mass
• Lean body mass
• Body fat percentage
• VO2-max
• Aerobic power (W)
• 1RM
• Repetition max at 60% of 1RM
• Fibre type analysis (from a muscle biopsy)
• Cross-sectional area (from a muscle biopsy)
• Myosin heavy chain analysis (from a muscle biopsy)
• Capillary density (from a muscle biopsy)

That must have been quite a lot of work for all of those subjects!  Let’s take a look at the results now.

***

OK, what were the results?

Well, to summarise the results very quickly, without getting into too much detail where we don’t need to, this is what happened:

Body mass – all groups increased body mass (control – 0.6kg, low – 2.3kg, medium – 1.7kg, high – 1.3kg).  The researchers did not judge these changes to be significant.

Body fat percentage – the strength training groups all increased body fat percentages (low – 0.4%, medium – 1.3%, high – 0.2%).  Again, these changes were not viewed to be significant.

VO2-max – VO2-max did not really change significantly for any of the groups.  However, this fact is interesting in light of the change in aerobic power below.

Aerobic power (W) – despite there being no changes in VO2-max, aerobic power increased significantly in the resistance training groups (low – 10W, medium – 3W, high – 43W).  Bearing in mind that this study was done back in 2002, the researchers found this result a little troubling and justified it by noting that “although this may seem to contradict the basic principles of training specificity, enhanced long-term work capacity also requires muscular strength and anaerobic power.” They also noted a study that showed resistance training improved running economy and wondered whether it could also improve cycling economy.  Of course, we now know that this is possible thanks to more recent research.

1RM – maximum strength increased just like you’d expect, most for the low rep group, least for the high rep group and somewhere in the middle for the medium rep group.

Repetition max at 60% of 1RM – similarly, the rep max improvements were the inverse of the 1RM improvements.

Fibre type analysis – so in all three resistance training groups, the only really significant movements in fibre composition between pre- and post- eight week training period occured between type IIAB and type IIB fibres.  For all three groups, the percentage of type IIB fibres reduced greatly and the percentage of type IIAB fibres increased significantly.  And we are not talking about small movements here, either.  In only eight weeks, the percentage of type IIB fibres halved and the percentage of type IIAB fibres doubled for all groups.

So the two key points here are: (1) the three protocols all led to the same changes in fibre type, (2) the fibre type changes on the fast-slow continuum were in the slower direction.

Cross-sectional area – the cross-sectional area of the muscles increased only for the low and medium rep groups.  For these two training groups, the cross-sectional areas of all three major fibre types (I, IIA, and IIB) were significantly larger after training (c. 12.5% for type I, 19.5% for type IIA, and 26% for type IIB).

So despite the percentage fibre composition changes being the same as the other two groups, the high rep group didn’t experience the same hypertrophy changes.

Capillary density – despite this being a staple question for basic personal training muscular adaptations to resistance training course material, the researchers did not note any significant changes to capillary density in any of the subjects.

 The subjects became unstoppable after their eight weeks hard training                      (photo by RobinElaine) 

***

What’s all that about type IIAB and type IIB?

It’s really nothing that complicated although if you get into the research methods of how they figure out what each fibre is classified as, it can get horrible in a hurry (a good summary can be found here).  Anyway, briefly, originally, muscle fibre types were divided into three classifications:

• Type I – slow
• Type IIA – intermediate
• Type IIB – fast

However, scientific advances have now resulted in seven fibre types being differentiated, as follows:

• Type I
• Type IC
• Type IIC
• Type IIAC
• Type IIA
• Type IIAB
•  Type IIB

Essentially, the same rules apply as for the three types.  The further down the list you go, the faster-twitch the fibre and the more powerful it is.  The interesting thing is that the resistance training methods seems to make the fibre composition less powerful rather than more powerful.

***

Wrapping up

So the things that interest me here are:

• Why do the three different protocols lead to the same fibre type changes?  Are we looking in the wrong place when it comes to differentiating the muscle types of different athletes?
• Why does the body do something that is counter-intuitive for strength gains when tested with low repetitions such as 3-5 reps?  Is the protocol too high rep?  Would the same fibre-type change happen with singles or plyometrics, for example?  Fortunately, I have a study up my sleeve for tomorrow that should help us answer this question.

In the early 1900s, Eugen Sandow showed the world that it was possible to be as powerful as the circus strongmen and still have the body of a Greek god.  He changed the public perception of strength completely.  Previously, they associated strength with large, fat men competing on stage.  Following Sandow, they associated it with the appearance of a bodybuilder.

Fast forward 100 years and, on a smaller scale, Jamie Lewis at ChAoS and PAin is doing much the same thing.  He is demonstrating by competing successfully in raw powerlifting and by his frequent photo updates, that he is capable of being both extremely strong and extremely lean at the same time.  Issuances of Training Insanity is his first e-book and you can go and buy it here (not an affiliate link).

Really?  So what is so special about the e-book?

The e-book is all of Jamie’s training-related rants blog posts from 2009 to 2011 condensed into one tome.  For those of you who have not yet come across Jamie’s training methodologies, he suggests you should:

• Build up your work capacity to do a lot more lifting than others might lead you to believe is necessary
• Aim for a higher volume of training
• Don’t fear overtraining
• Use heavier weights, meaning higher sets of fewer repetitions (10 x 3, 15 x 1 etc.)
• Use shorter rest periods (45s – 1min)
• Use compound lifts almost exclusively
• Try partial lifts for variety and building tendon strength
• Train more frequently (at least five days a week)

The e-book contains over 100 chapters of information about how to modify your training to get exceptional, rather than average results.  You can get hold of a copy here.

***

Pure and unadulterated lifting

• Sumoman explains his rate of strength gain over a four and a half year period, showing how the calculations work.  You have to remember that Sumoman is already very strong to begin with so you would not expect big improvements as you would with a beginner.  I will be interested to do the same calculation for myself at the end of this year, after two years on a Hepburn cycle.  My year one was clearly showing beginner gains on this lift.  Before starting, last year, my back squat was 124kg for 8 x 3 and at the end it was 165kg for 8 x 3, which is a 33% improvement.  Since I am aiming to put 30kg on the lift in 2012, I would hope to gain 18%.  After that, it will no doubt be a lot lower.
• Chad Waterbury proposes a paradoxical lift for shoulder health and strength.  It is dumbbell upright row to external rotation that is designed to develop proper strength in the external rotators.  I am not completely convinced by it myself but it looks interesting…

Personal training and coaching

• One of the things I really like about Rory at Chiron is the way that he thinks about everything that matters very carefully.  You should not miss this very thought-provoking post.  In it, he argues that people devote very little thinking time to actually making decisions and quite a lot of thinking time to justifying those decisions once they have been made.  I see this all the time both at work and socially and I would add that some people are much worse than others…
• And a perfect follow-on from this post is Lyle McDonald’s research review of a paper that investigates cognitive bias and the perception of healthy and unhealthy foods.  Paraphrasing a little, the study found that people tend to overestimate the calorie content of unhealthy foods when the foods are served alone and underestimate the calorie content of the same foods when the same foods are combined with a healthy option.  And this is the interesting bit.  The more people were concerned with dieting and losing weight, the bigger the difference was in their perceptions!  So the more you care about dieting, the more you will convince yourself that eating a biscuit is OK because you ate an apple at the same time! 
• If you’re interested in how the best endurance coaches work, it is probably worth checking out this article on Chris Carmichael.  Not interested?  If you’re a personal trainer interested in working with athletes, it might behove you to consider changing your mind.  The article notes how interest in endurance sports is booming (again) and popular marathons are selling out this year in minutes or hours, not days as last year.
• One of the interesting phenomena about the fitness industry is the continuum that runs from physiotherapy at one end to true strength and conditioning at the other.  My take is that there is a big difference between the point on that continuum where strength coaches need to operate and the point where personal trainers need to operate.  Generally, the people who I see come into my studio would be treated as candidates for quite serious rehabilitation if they were an athlete.  So I was very interested in Mike Reinold’s comments in this post about a kneeling glute bridge variation, as they rang completely true with me.  I do often find that my clients struggle with hip extension on a glute bridge.  However, cues about heel placement and pelvis alignment tend to help.      

Diet, paleo diet and evolutionary adaptations

• I find that I read quite a lot faster than other people can talk, so I dislike podcasts unless I am driving somewhere and need something to do on the way.  So I was delighted to see that Chris Kresser’s podcast is now being transcribed.  In this edition, he discusses why it is so hard to lose weight and then keep it off.
• If you need a reason to stop eating pretend foods, like margarine and other horrible concoctions, read this post from Healthy Diets and Science, which points to a study showing that margarine increases prostate cancer risk in men by 30%.

Sleep, stress and health

• You might think that this link would be better placed in the diet section but I think it sits best as a stress-related link.  Matt Metzgar points out a study that shows that people who ate at their desks suffered distractions from their meals and were less full as a result.  I think this line of questioning is a very fruitful one, as I suspect mindful eating will become something that is shown to improve health and body composition.  And if you need an incentive to get away from your desk, you could always be inspired by Jason’s lunchtime workouts!
• And more from Matt Metzgar, in this post, where he notes that recent research shows that the amount of television you watch is directly correlated with your life expectancy.  In an Australian study, it was found that for every hour of TV you watch, your life is reduced by 22 minutes.  I watch on average, one film a week, on a Sunday evening.  So I am reducing my lifespan by 38 hours every year, or roughly 1.5 days.  So over the next 50 years, I could reduce my lifespan by 75 days, or 2.5 months!  What is your calculation?
• Mad in America points out that a recent study shows that stress causes brain shrinkage in otherwise healthy people.    The study abstract reads: “Current results demonstrate that increasing cumulative exposure to adverse life events is associated with smaller gray matter volume in key prefrontal and limbic regions involved in stress, emotion and reward regulation, and impulse control. These differences found in community participants may serve to mediate vulnerability to depression, addiction, and other stress-related psychopathology.”  In my opinion, in the fitness industry, we need to get with the programme and stop obsessing so much about which type of oily fish is healthiest or which tubers paleolithic people might have eaten.  Stress is vastly more important than micromanaging already good nutrition.
• If you take as pessimistic a view of the UK healthcare system as I do, you won’t be surprised by this Telegraph article noting that more than half of healthcare professionals are unaware that high numbers of children and elderly people are Vitamin D deficient.  Interestingly (perhaps unsurprisingly) there is no comment about sun exposure or the fact that people don’t seem capable of going outside anymore.

***

That’s all folks.  More links next week.

Today, I’m going to carry on with the biomechanics of gait theme but move on from old people to talk about barefoot running.

I talked a bit about barefoot running a while back, when I reviewed an article called Running-related injury prevention through barefoot adaptations.

In that study, we found that millions are spent on developing running shoes with “better” shock absorption every year.  However, the more padding you apply to the shoe, the less well the foot uses its own internal shock absorbing capabilities and the more injuries you are likely to get.

Barefoot people passed this way (photo by Draenen)

***

This time, we’re just going to look at how barefoot running differs from shod running.  In other words, just the facts…

***

So what’s the study?

It’s called Biomechanical analysis of the stance phase during barefoot and shod running, by De Wit, De Clercq, and Peter Aerts, Journal of Biomechanics, 2000.

The aims of the study were to provide a comprehensive description of barefoot running and to compare barefoot with shod running.

***

What did they do?

The researchers took nine male long distance runners and tested them while running barefoot and shod at three different speeds.  The researchers used force plates and video cameras as in the study we looked at yesterday to take the various measurements.

As with yesterday’s study, the researchers put markers on the skin at the hip, the knee joint and at the ankle joint at the lateral malleolus. In this study, the researchers also put a marker at the shoulder, at the height of the acromion.

In the barefoot condition, foot markers were placed at the tuber calcaneum and at the fifth metatarsal joint.  In the shod condition, markers were placed on the shoe at the height of those landmarks.

***

So what happened?

The researchers noted the following key points:

Shorter strides - for all the tested speeds, the runners took significantly smaller step while running barefoot.

Higher cadence – for all the tested speeds, the runners ran using a higher cadence (strides per minute) for the barefoot condition.

Shorter contact time – for all the tested speeds, the runners feet were in contact with the ground for a shorter period of time when barefoot running.

Vertical ground reaction forces – barefoot running is characterised by a significantly larger loading rate than in shod running (but not greater forces at the maximum point) and, in general, more than one impact peak was found for the barefoot condition.  The following chart is taken from the study and shows the difference between the forces experienced barefoot and experienced using a running shoe.  You can see clearly how the barefoot runner gets a sharp shock immediately at the outset and then a secondary shock that is larger, whereas the shod runner gets his initial shock later and less sharply, followed by the same secondary shock.

Figure 3, taken from Biomechanical analysis of the stance phase during barefoot and shod running, by De Wit, De Clercq, and Peter Aerts, Journal of Biomechanics, 2000

***

Running kinematics – both the occurrence of the impact peak and the end of midstance are reached significantly faster for barefoot running than for shod running.  Looking at the diagrams of how the runners are hitting the ground, this is because the barefoot running strikes with a flatter foot rather than a heel strike, as the shod runner does.

***

So how do the researchers interpret their results?

Thinking about the loading rate

The researchers found that when the subjects were barefoot running, a significantly larger loading rate during impact was found.  They noted that this agreed with results of previous studies.

Previous studies had assumed that the initial sharp shock that runners felt when barefoot running was the driving force behind the change in gait.  In other words, the runners experienced the jolt and therefore modified their running pattern.  The running pattern caused a flatter foot placement, rather than a heel strike.

Using their video recordings, however, the researchers noted that the more horizontal foot placement of the runners  was prepared well before touchdown.  In the barefoot condition, the ankle was already significantly more plantar flexed at 0.03s before touchdown.  This seems a bit odd, as you would expect the initial shock to be the driver of the changed kinematics.

However, the researchers did some more work and realised that the flatter foot placement in barefoot running could be explained by the fact that previous research had found that heel striking creates forces that approach the maximum physiological deformation that is possible for the fatty heel tissue.  The theory then is that once you have done heel striking once, you don’t do it again.

And in this study, the researchers found that, in the barefoot running condition, the maximal local pressure underneath the heel is negatively correlated with the foot angle at touchdown.  Or, in other words, the more horizontal the foot, the smaller the maximum pressure acting on the heel.

***

Thinking about running kinematics

When the shod runner’s front foot hits the ground, it does so with much less initial knee flexion but as the body catches up with the foot that is placed on the ground, knee flexion in the shod condition becomes much greater than in the barefoot condition.  As the body passes the foot, the knee flexion is still greater in the shod condition and it only coincides again with the barefoot condition once take-off is achieved.

So, when subjects run barefoot, runners do not maintain similar running mechanics, which the researchers note contrasts to the findings of other studies for running on different resilient materials.  The point then, is that running with shoes on is not the same as running on a forgiving surface.  Your shoes are doing something that is changing the way you are running.

And what is that?  Well, the researchers conclude from the above that the adaptations in stride kinematics to barefoot running are primarily due to changes in touchdown geometry and the subsequent joint movements during initial ground contact.

***

So what did the researchers conclude?

The researchers made the following conclusions:

• Running pattern changes – the researchers found a change in running pattern between barefoot and shod running, mainly characterised by a larger external loading rate and a flatter foot placement at touchdown.
• Actively induced adaptation strategy – the researchers found that in barefoot running, the joint configuration of the leg is already prepared in free flight by a larger plantar flexion, by more knee flexion and a larger knee flexion velocity and that this must therefore be actively performed.  I would add that for the avoidance of doubt, barefoot running came first!  Therefore, it is surely more appropriate to say that it is the shoe that is causing an active adaptation and not the other way around.  Better to say that wearing running shoes substantially changes the way that people run, leading to more heel striking and greater knee flexion in the stance position.
• Heel pressure is greater in shod running – the researchers found that in the barefoot condition there is a correlatio between a flatter foot placement and lower peak heel pressures.  Therefore, they assumed that runners adopt a flatter foot placement in barefoot running in an attempt to limit the pressure on the heel.

So to sum up a different way:

• The researchers found that wearing shoes changes the way you run, which running on soft surfaces or uneven surfaces does not.  So running with shoes on is not the same, conceptually, as running on foam or grass or whatever.
• Wearing shoes makes people start heel striking, which is associated with amateur or beginner runners.

Firstly, I reviewed an article about the differences between hormone responses to resistance exercise in younger and older men.  And then, last week, I looked at a review article that covered a range of studies on how resistance exercise helps older people reduce the effects of wha they perceive as ageing (but may actually be primarily inactivity).

And while there are dozens of studies around that talk about how older people can help reduce the effects of inactivity, I have not seen much discussion of how actual their biomechanical walking patterns change.

***

So what’s the study today?

The study today takes us on a journey to look at how the biomechanical walking pattern of people changes as they get older.  See if you can spot why it happens…

The study is rather optimistically called Biomechanical walking pattern changes in the fit and healthy elderly, by Winter, Patia, Frank and Walt, in Physical Therapy, 1990.  I say optimistically because I think they may be making some incorrect assumptions about what “fit” means in the context of older people.

***

So what is the point of the study?

Well, the reason for the study, of course, is to enable the researchers to understand more about why old people seem to fall down a lot as they get older.

In general, the investigation into old people and falls is rewarding quest undertaken by many noble researchers.  In the various studies I have read, some of them seem to really understand the fact that the people they are testing are simply inactive and weak.  Others, unfortunately, do not comprehend this idea at all and from those parties we get somewhat involved hand-wringing about the possibility of balance being harshly affected by age and other strange notions.

So what’s the connection between falls and walking?

***

Walking is falling over

The important thing to note about walking is that the initiation of walking itself from a standing position is fundamentally a destabilising motion.  The body’s centre of gravity is made to fall forward and only the moving forward of a foot stops the body from falling onto the ground.

When a number of steps have been taken with a normal gait, and we are in motion, the body is frequently in an unstable position, in that one foot is in the air.  The researchers note that this takes place 80% of the time.

The only time that there are two feet on the ground, one foot is pushing off the ground with considerable force while the other foot is accepting the full weight of the body.  In the case where the rear foot is pushing off and the front foot is bearing the weight, neither foot is flat on the ground, as the force in the rear foot is on the ball of the foot and the front foot takes much of the weight on the heel.

So, during normal walking, the body is in an inherent state of instability.

***

So what is hard about walking?

Our researchers describe two basic challenges to balance when walking:

• The upper body - since the upper body comprises about two-thirds of the average person’s body mass, and it’s centre of mass is about two-thirds of body-height above the ground, this unstable mass or “odd object” needs to be controlled.
• The foot - the foot presents an interesting challenge during the swing phase of gait, firstly as it needs to pass the other foot safely without hitting it (or the ground).  How many people do you know who have tripped over their own feet?  Quite a few.  And secondly, there needs to be a gentle foot landing so avoid damage to the foot or shock to the body that throws it off balance.

***

So how does the body prevent the upper body from falling forwards?

Well, it’s not the muscles around the ankle

While research has shown that the muscles controlling movement at the ankle are involved to control the upright posture when standing, they do not perform a similar role when walking, as the strength requirement would be too great.  It would look like a free-standing glute-ham raise or something out of the Matrix.

http://www.youtube.com/watch?v=FgbOcSqfGJk

Dodging bullets or forgetting how to walk properly?

***

So rather than require the ankle to do any real work when the upper body tips forward and the hip angle starts to close, the ankle muscles produce a small dorsiflexor moment to lower the foot into the ground, followed by a small plantar-flexor movement to control the forward leg.

***

It must be the hip and knee muscles, then

Indeed, that is correct.  But remember what we said just now about doing a standing glute-ham raise?  It is (or should be) the hip extensor muscles that intervene to prevent the upper body from falling forwards.

The hip extensor muscles are the gluteus maximus and the hamstrings.

***

So how does the body prevent the foot from catching on things?

With difficulty, to be honest.  Our intrepid researchers note that in other studies, the swing phase of gait has been shown to be executed with considerable precision, with average toe clearances of just 1 cm, and this clearance occurs while the horizontal velocity of the foot is at its highest.

So any degeneration in the fine motor control of the foot would naturally result in quite serious problems, including stumbling during the swing of the foot.

***

So what did the researchers do?

To help them measure the exact walking pattern of older people to see if there was a comon theme, they took 15 elderly subjects and stuck reflective markers on the following joint centers and segments: toe, fifth metatarsal, heel, lateral malleolus (ankle), head of the fibula, lateral epicondyle of the femur (knee), and greater trochanter (hip).

Then they got each subject to walk at their natural cadence on a level walkway a minimum of 10 times.  A video camera recorded the marker trajectories over the stride period.  Also, each subject walked over a force platform.

They used a control group of younger people so that they had a standard to measure against.

***

What did they find?

 The researchers found that:

• Cadence (number of steps per minute) - the natural cadence of these fit and healthy elderly adults was no different than that of the young adults.  This differed from previous studies, in that cadence was found to be lower in older people.  The researchers put this down to the fact that they had screened to find only “healthy” older people.
• Stride length – the stride length of the older people was significantly shorter, independent of whether it was stated in absolute terms or as a fraction of body height.
• Stance time (time spent with both feet on the ground) - associated with the shorter stride length was an increase in the stance time.  This was not large in absolute terms but it was statistically significant.
• Toe clearance - interestingly, the toe clearance for the elderly subjects was not statistically different from that of the younger adults.
• Index of upper body balance – the researchers measured the covariance of the moments about the knee and the hip, which is an index of how able the subjects are to control the upper body.  Ideally, from a mechanical point of view, it should be fairly close to 100%.  They found that the young subjects scored an average of 67% but the elderly subjects only scored 57%.  The researchers suggested that this means that the elderly are less able to make the shifts in the moment patterns on a stride-to-stride basis to control the balance of the upper body in the sagittal plane and at the same time maintain the extensor support moment.  I would suggest it means that the older people had a weaker posterior chain.
• Push off force – the push-off generation of force from the rear foot by the elderly subjects was considerably less than that of the younger subjects, which explains why their cadence was similar but their stride length was much shorter.  The researchers suggest two possible reasons for this: firstly, that it might have been done deliberately to reduce the potential for instability; and secondly, that it might be caused by a decrease in leg strength.

***

So what are the conclusions?

The researchers conclude that the important discoveries here were:

• The natural walking speed of the elderly subjects was significantly reduced but not because of cadence, but rather because of a reduction in stride length.
• Toe clearance in the elderly subjects was not significantly different from that of the younger adults.
• The index of upper body balance was reduced slightly in the elderly subjects.
• The push-off force was lower in the elderly subjects.

The researchers don’t try to conlude anything further from their work so let me paint a picture…

• Toe clearance – the fact that there is no change to toe clearance supports my view that when elderly people trip over, it is for the same reason that a younger person falls over.  It happens from time to time because the clearance is small and the foot is travelling quickly and people are not naturally very co-ordinated any more because we lead sedentary and unathletic lives (even our non-sedentary pursuits tend to be unathletic).  So why do old people fall more often and hurt themselves?  Because they are not strong and athletic enough to recover once they do lose their balance.
• Upper body balance – this is reduced because the hip extensors (gluteus maximus and hamstrings) weaken faster than the hip flexors and knee muscles (old man butt syndrome).
• Fit and healthy subjects – I think the biggest error that these researchers made was to assume that “active” by today’s standards was sufficient to provide an indication of a healthy elderly person.  I don’t agree with that.  I think that the exercise requirements necessry to produce a healthy elderly person are much more stringent and involve resistance training, not just the treadmill.  I believe that these subjects were weak because of a lack of muscle mass and proper exercise and therefore demonstrated poor walking patterns because of this, not because they were old.

So far this year, I’ve looked at Exercise Physiology and Human Physiology and now I’m going to take a look at Basic Biomechanics (affiliate links: UK, US).  But don’t worry if this is all really familiar to you.  As we progress through the year, I’ll get more specific and more focused on strength and power training.

Basic biomechanics on a bicycle

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So what is biomechanics all about?

Biomechanics is simply the application of mechanical (i.e. physics-related) principles to human beings.

Research into biomechanics can be applied to many different areas, including sport, medical rehabilitation, occupations, ageing and age-related illnesses such as osteoporosis.

***

And what does this textbook cover?

 This textbook starts at the very beginning and works through the following topics:

Kinematic concepts – kinematics is concerned with the appearance of human movement.  This chapter introduces the anatomical reference position and outlines the directional terms that specify how to describe parts of the body in relation to other parts of the body (i.e. superior, inferior, anterior, posterior, etc.).  It also explains the planes of movement (sagittal, frontal and transverse) and the terminology for joint movement (abduction, adduction, etc.).

Kinetic concepts – this is an introduction to basic physical mechanics, including F = ma, definitions of force, pressure etc.  If you have a background in engineering or maths or physics you won’t read this chapter but if you have no idea what I have just written then you really need to stop reading this article and buy this book.

Biomechanics of bone growth – you’d be amazed how few people (including a few medical doctors I’ve asked!) know the contents of this chapter, which is simple review of the principles of bone growth, how bone responds to mechanical stress, Wolff’s law and osteoporosis.

Biomechanics of joints – this chapter explains the different types of joint and how they work and then runs through the basic ideas of flexibility and stability in that context.

Biomechanics of skeletal muscle – this is where I go each time I need to remind myself of the properties of muscle and how it is made up.  It’s useful to refresh the basics before diving into something complication, like discussions of myosin or titin etc.

Biomechanics of the upper extremities – for a simple overview of what the scapulae, shoulders, arms, elbows, wrists, hands and fingers are doing when they move, this is the place to go.  Some good information on typical injuries and pathologies here too.

Biomechanics of the lower extremities – and the same applies for the pelvis, legs, knees, shins, ankles feet and toes.

Biomechanics of the spine – obviously, this is not Stuart McGill level material here, but the basics are covered, including lordosis, kyphosis and scoliosis, as well as typical injuries, such as disc herniations and stress fractures.

Movement – the latter half of the book comprises various chapters on different types of movement and the mathmatical equations for describing them.  This includes the equations for describing linear movement and angular movement, equations for describing the forces and work done in linear and angular movement, equations for describing equilibrium of forces, torque and travel through a fluid medium.

If you have a background in engineering, physics or maths then you shouldn’t need these chapters except as a reminder (e.g. in the UK, if you did Mechanics 1 and 2 as A-level maths modules you should be OK).  If you don’t have a clue what any of this means then you might need to read this book if you want to understand what any of the biomechanics research I’ll be reviewing means…

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Wrapping up

This is a great one-stop shop for quite a few important elements of sports science.  However, there is a lot of mechanics in it that people with science or engineering degrees will simply not need.  If you are one of those, you’d be better off with a kinetic anatomy book to provide the first half of this book (in better detail).

However, if you’re an arts graduate or you are turning white with horror at the idea of using maths at all, you might want to get hold of a copy of this book, as it is a very gentle introduction to these ideas!

***

Pure and unadulterated lifting

• Donny Shankle gives his view on glute bridging exercises for weightlifters.
• And The Tight Tan Slacks of Dezso Ban has a great article by the original creator of complexes, Istvan Javorek.  I was recently curious about complexes because of the effect that Vasily Alexeyev reported.  Vasily noted that complexes were effective for gaining muscular bodyweight that was useful for weightlifting.  So Javorek writes that complexes are designed to improve and stimulate neuro-muscular coordination, increase the workout load and intensity, stimulate the skeletal muscular system, increase the cardiovascular benefits of the free-weight program and make the program more dynamic and efficient.
• And here’s some amazing stuff on the Olympic press from Charles Poliquin, including lots of history and some great footage of Paul Anderson.

Diet, paleo diet and evolutionary adaptations

• The key posts to check out this week are the first two parts of the Randy Roach interview at Rheo Blair.  Here are parts one and two.  For those not in the know, Randy is possibly the world’s greatest fitness historian and author of the great tome, Muscle, Smoke and Mirrors, a history of physical culture in modern times.  One of the most interesting points he makes in the second part is why he doesn’t use protein powders any more.  This is definitely worth your time.
• And Dr Davis, writing at Wheat Belly, points out that there is an amazingly strong coincidence between the introduction of the modern high-yield, semi-dwarf wheat in 1985 and the explosion in diabetes incidence.  Certainly, the graph of diabetes incidence does rocket upwards from 1985.  So whether it is the wheat strain or something else (HFCS?), I don’t know, but something happened back then…

Personal training and coaching

• Charles Poliquin exhumes the old case of Jim Fixx, the famous fitness fanatic and marathon runner who died of heart attack caused by a blocked artery.  He notes that in the wake of this fascinating incident, various other doctors (including the famous Tim Noakes) noted similar cases.  Charles quotes Dr Solomon, who made the important comment that “cardiovascular health refers to the absence of disease of the heart and blood vessels, not to the ability of an individual to do a certain amount of physical work.”  So I guess we need to be cautious about equating what we might see as “cardiovascular fitness” with “cardiovascular health”.

Stress, sleep and health

Purely about statins, those horrible pharmaceuticals

• Lots on statins this week, starting with this short article from Healthy Diets and Science, explaining some recent research that shows how statins increase the risk of diabetes in post-menopausal women by 48%.
• And another article from Healthy Diets and Science reporting on some slightly older research that concludes that statins show no benefit to the elderly in that they do not extending the life-span of an elderly person by even one day.
• And the statin manufacturers are in the firing line, as this article from Healthy Diets and Science shows.  The famous Jupiter trial of statins has been criticised for having significant holes in it.  The critics note that there were significant conflicts of interest for those involved in the study and despite this, the results demonstrate that the statins did not work.
• And if that list of problems isn’t enough to convince you to have stern conversation with your GP, check out this study reported again by the tenacious Healthy Diets and Science, which notes that statins can cause errectile disfunction!  It’s a French study, it would seem, which is stereotypical…

How sleep, stress and diet are connected

• Conditioning Research has pointed out an interested stress-related study that shows that getting fat increases the stress response, which then makes you fatter through hormonal changes.
• And similar thoughts are contained in Scott Abel’s blog about the psychosomatic effects of dieting.  I liked his coining of a new French Paradox, suggesting that the French are healthier than other nations because they take time over food and enjoy it.  Stress really is much more important for your health than food.
• Scientific American reports on how lack of sleep makes you hungrier.
• And Core Performance suggests some ways to help reduce the effects of stress when your work or boss are responsible for that stress.

Other interesting stuff

• The more I read, the more I realise that there is a strong tendency for medical scientists and medical professionals make out that they know a lot more about the human body than they actually do.  This fascinating report explains how the chemical imbalance theory often quoted in psychiatry is completely torn to pieces in the medical journals but presented as fact to patients.  It ultimately asks what I was wondering the other day.  Why  do we tolerate this kind of behaviour?

***

That’s all folks.  More links next week.

So here is an interesting little study on how muscle architecture affects muscular growth and strength changes following resistance training and ageing.

Not this kind of architecture (photo by CarbonNYC)

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So what’s the study?

The study is called Disproportionate changes in skeletal muscle strength and size with resistance training and ageing, by Degens, Erskine and Morse, in Journal of Musculoskeletal and Neuronal Interactions, 2009.

The study is concerned with trying to understand better what actually affects the ability of a muscle to contract.  What is it that determines strength?  In particular, the researchers are keen to understand how strength relates to size.  After all, as many people are fond of saying “a bigger muscle is a stronger muscle”.

However, as our intrepid researchers point out, there is a problem with connecting strength to size from the very beginning.  Let’s break it down:

• Short-term resistance training has been shown on several occasions to increase muscular strength disproportionately to size increases (and this is supported by similar observations made by gym rats)
• While it has been suggested that increases in neural activation are responsible for this short-term increase without corresponding size increases, studies have not always shown this (this was new to me!)
• Similarly, the idea that short-term resistance training teaches the body to co-contract antagonist muscles to increase the maximum voluntary contraction of the agonist muscle has not been supported by studies.
• Few studies have looked at whether muscle architecture contributes anything to this debtate.

So let’s have a look at muscle architecture, then.

***

So what is muscle architecture, anyway?

A key aspect of muscle architecture is the pennation angle.  A pennate muscle is a muscle where the fascicles attach to the tendon at an oblique angle, rather than in parallel with the tendon.

In terms of physics, the fact that the fascicles are attaching to the tendon at an oblique angle means that the force they generate is not going to be as effective as if the same muscle were set in parallel.

So the pennation angle is simply the angle between the fascicle and the line coming through the centre of the muscle.  A high pennation angle of the fascicles means that the muscle is going to have to be a lot stronger than a muscle with parallel fascicles to create the same force output at the joint.

In addition, because the fibres are arranged obliquely across the muscle rather than parallel to the centre of the muscle, this means that they are shorter than they would be if they ran all the way through the centre.  In consequence, they have fewer sarcomeres in parallel within the fibres.

Since the speed at which a muscle fibre can shorten is dependent on the number of sarcomeres in parallel it contains, pennate muscles have a slower shortening velocity than parallel fibres.

Finally, it is important to note that there are good reasons that muscle fascicles are arranged in a pennate and not a parallel fashion.  Firstly, note that it is easier to cram more fibres into the muscle in a pennate fashion than in a parallel fashion.  Secondly, the smaller distances that the fascicles contract makes for finer movement control.

***

So why do we care about pennation angle, anyway?

Well, bear in mind that the increase in muscle size in response to strength training is often given as a change in the cross-sectional area of the muscle.  However, the measurement of the muscle cross-sectional area does not take into account any change in the pennation angle of the fascicles.

So if the pennation angle changes as a result of strength training, which it does, then measuring cross-sectional area will underestimate the increase in muscular size and potentially lead to the relationship between strength and size being underestimated.  All other things being equal, this would lead to us seeing that size increases lagged behind strength increases.

However, as the pennation angle increases, strength will be slightly reduced because the angle at which the muscle fibres attach to the tendon is changed for the worse.  All other things being equal, this would have the opposite effect and would lead to us seeing strength increases lagging behind size increases!  However, this factor does not seem to be significant.

Our researchers note that in another study, it has been reported that the increase in pennation angle in the vastus lateralis muscle following resistance training is only 2.7 degrees and such a change would result in a 1% loss of the force at the tendon.  This change was thought to be insignificant in the context of strength inreasing by 16%.

***

Resistance training shifts fast twitch fibres to slow twitch fibres!

Moving away from pennation angle issue, the researchers now note several studies that appear to show that resistance training induces a fast-to-slow fibre type transition, which is also reflected by a shift in myosin heavy chain isoform composition from type IIx to IIa.

(Interestingly, I looked at this from a different perspective a while back when looking at the relationships between muscle structure and running economy.  Back then, it appeared that runners with greater proportions of type IIa and type IIb fibres were more efficient at higher speeds than runners with more type I fibres.  Similarly, differences in titin forms appeared to have an impact on economy.)

I will look at the key study on resistance training and the change in fibre types soon, so don’t get too hung up about this right now.  The main point is that (for beginners) even sets of 3-5 reps lead to a shift from type IIb to type IIa fibres.

(Again, not wanting to get too bogged down in muscle fibre type changes, I will note that this change does not appear to occur with plyometrics, as my article on muscle fibre changes and plyometrics shows.)

So if you consider that fast-twitch fibres are stronger than slower-twitch fibres, then increases in muscular size would come with a decrease in muscle power per fibre, which would lead to strength increases lagging size increases (all other things being equal, which they are clearly not!).

***

Muscle fibre density increases with strength training

The researchers note that some studies show that resistance training leads to a greater myofibrillar packing density of muscle fibres.  All other things being equal, this would lead to size increases lagging behind strength increases.

***

Ageing also changes muscle architecture!

Our intrepid researchers report that there is a decrease in pennation angle and fascicle length during ageing.  This clearly results in a number of changes in size and strength!

The smaller pennation angle in the elderly appears to make very little difference to strength, although technically it should lead to a small increase for the same size of muscle fibres.

Overall, our researchers note that changes in muscle size, neural activation and muscle architecture do not entirely explain the loss of strength during ageing.  The researchers propose that tension in the muscle fibres themselves may be responsible for the reductions.  Again, this reminds me of the study I reviewed about running economy and muscle elasticity and Bret’s post on titin that I referred to in that article.

As an aside here, I did a lot of work last year on trying to understand plyometrics (see a comparison of different plyometrics and muscle fibre changes and plyometrics).  After a lot of study, I got to the point where I respectfully disagreed with the idea that tendons can be trained to store elastic energy in any meaningful way.  They almost certainly do store elastic energy but whether you can train an athlete to increase that storage I think is difficult to show.  However, it does seem that you can train muscles to fulfil that role instead, which is quite exciting.

***

Ageing changes tendon properties

The researchers note that ageing is associated with a decrease in the stiffness of tendons, so the muscles need to contract further to create the same force, as some force is lost in the system.  This could explain the higher losses of strength over size in the elderly.  Fortunately, our researchers note that resistance training has been shown to increase tendon stiffness again (I wonder whether this challenges my idea about plyometrics!).

 ***

Wrapping up

There is a lot here and probably more questions than answers but that can be good from time to time!  The interesting questions that have come out of this for me are:

• How are elastic properties of muscles changing with resistance training and ageing?  Is there anything we can do to maximise these properties?
• How are tendon properties of muscles changing with resistance training and ageing?  Can we manipulate these properties in any way?
• How do different modes of resistance training change fibre types in beginners and experienced athletes?  Is this different from plyometrics?  Can we do anything to generate more fast-twitch hypertrophy rather than slower-twitch hypertrophy?  Does speed of movement make a difference?

Please let me know if you have any thoughts…