More Barefoot Research....

Thanks to Adam Dean for pointing this out.

Almost a year ago I had a couple of posts (here and here) about a Harvard Professor who was doing research into barefoot running.  The research continues, and Wired Magazine had a feature on his two latest studies which have been published just this month.  Their piece is called More Evidence Supports Barefoot Running and points to Daniel Lieberman's latest work:

If you’re a runner, start striking with your forefoot. And wear those goofy minimalist shoes while you’re at it. Your body will thank you.

Those are the findings of a pair of studies by Daniel Lieberman, a professor of human evolutionary biology at Harvard University. He found runners who use a forefoot strike face a significantly lower risk of repetitive stress injuries, and barely there running shoes produce more efficient movement than conventional kicks.

The two studies are:



Foot Strike and Injury Rates in Endurance Runners: a retrospective study.

PURPOSE:
This retrospective study tests if runners who habitually forefoot strike have different rates of injury than runners who habitually rearfoot strike.
METHODS:
We measured the strike characteristics of middle and long distance runners from a collegiate cross country team and quantified their history of injury, including the incidence and rate of specific injuries, the severity of each injury, and the rate of mild, moderate and severe injuries per mile run.
RESULTS:
Of the 52 runners studied, 36 (59%) primarily used a rearfoot strike and 16 (31%) primarily used a forefoot strike. Approximately 74% of runners experienced a moderate or severe injury each year, but those who habitually rearfoot strike had approximately twice the rate of repetitive stress injuries than individuals who habitually forefoot strike. Traumatic injury rates were not significantly different between the two groups. A generalized linear model showed that strike type, sex, race distance, and average miles per week each correlate significantly (p<0.01) with repetitive injury rates.
CONCLUSIONS:
Competitive cross country runners on a college team incur high injury rates, but runners who habitually rearfoot strike have significantly higher rates of repetitive stress injury than those who mostly forefoot strike. This study does not test the causal bases for this general difference. One hypothesis, which requires further research, is that the absence of a marked impact peak in the ground reaction force during a forefoot strike compared to a rearfoot strike may contribute to lower rates of injuries in habitual forefoot strikers.

(interesting that cross country running seems risky whatever you do!)


Effects of Footwear and Strike Type on Running Economy.

PURPOSE:
This study tests if running economy differs in minimal shoes versus standard running shoes with cushioned, elevated heels and arch supports, and in forefoot versus rearfoot strike gaits.
METHODS:
We measured the cost of transport (mlO2/kg/m) in subjects who habitually run in minimal shoes or barefoot while they were running at 3.0 m/s on a treadmill during forefoot and rearfoot striking while wearing minimal and standard shoes, controlling for shoe mass and stride frequency. Force and kinematic data were collected when shod and barefoot to quantify differences in knee flexion, arch strain, plantarflexor force production, and Achilles tendon-triceps surae strain.
RESULTS:
After controlling for stride frequency and shoe mass, runners were 2.41% more economical in the minimal shoe condition when forefoot striking and 3.32% more economical in the minimal shoe condition when rearfoot striking (p<0.05). In contrast, forefoot and rearfoot striking did not differ significantly in cost for either minimal or standard shoe running. Arch strain was not measured in shoes condition but was significantly greater during forefoot than rearfoot striking when barefoot. Plantarflexor force output was significantly higher in forefoot than rearfoot striking, and in barefoot than shod running. Achilles tendon-triceps surae strain and knee flexion were also lower in barefoot than standard shoe running.
CONCLUSIONS:
Minimally shod runners are modestly but significantly more economical than traditionally shod runners regardless of strike type, after controlling for shoe mass and stride frequency. The likely cause of this difference is more elastic energy storage and release in the lower extremity during minimal shoe running.

Lifehacker on the dangers of sitting

I've had stuff here before on the health impact of spending too much time sitting down.  Lifehacker had a good piece on it today too:

Do you sit in an office chair or on your couch for more than six hours a day? Then here are some disturbing facts: Your risk of heart disease has increased by up to 64 percent. You're shaving off seven years of quality life. You're also more at risk for certain types of cancer. Simply put, sitting is killing you. That's the bad news. The good news: It's easy to counteract no matter how lazy you are.

Their prescription was:

Happily, you only need to do two things to counter the effects of sitting all day:

• Remember to stand once an hour.
• Get about 30 minutes of activity per day.

Whether you're a couch potato watching marathons of Firefly or an office worker sitting in front of a computer, an Australian study suggests short breaks from sitting once an hour can alleviate most of the problems described above

Inadequate sleep and obesity

Here is another one on sleep that I saw today in my trawl of the new research.   Nothing that we have not seen before but this is a review that tries to pull together some of the studies:

Does inadequate sleep play a role in vulnerability to obesity?

The prevalence of obesity is increasing rapidly worldwide, which is cause for concern because obesity increases the risk of cardiovascular disease and diabetes, reduces life expectancy, and impairs quality of life. A better understanding of the risk factors for obesity is therefore a critical global health concern, and human biologists can play an important role in identifying these risk factors in various populations. The objective of this review is to present the evidence that inadequate sleep may be a novel risk factor associated with increased vulnerability to obesity and associated cardiometabolic disease. Experimental studies have found that short-term sleep restriction is associated with impaired glucose metabolism, dysregulation of appetite, and increased blood pressure. Observational studies have observed cross-sectional associations between short sleep duration (generally <6 h per night) and increased body mass index or obesity, prevalent diabetes, and prevalent hypertension. Some studies also reported an association between self-reported long sleep duration (generally >8 h per night) and cardiometabolic disease. A few prospective studies have found a significant increased risk of weight gain, incident diabetes, and incident hypertension associated with inadequate sleep. Given the potential link between inadequate sleep and obesity, a critical next step is to identify the social, cultural, and environmental determinants of sleep, which would help to identify vulnerable populations. Future human biology research should consider variation in sleep characteristics among different populations and determine whether the associations between sleep and obesity observed in Western populations persist elsewhere.

There you go.  We are back to the need for getting enough sleep if you want to be lean.



There was another  related study  today:

Sleep Duration and BMI in a Sample of Young Adults

In multivariable-adjusted linear regression models, an hour increase in sleep was associated with a −0.38 (−0.70, −0.048) BMI in men. Men who slept <7 h had a 1.4 unit higher mean BMI (27.9; 95% confidence interval (CI): 26.9, 28.9) than men who slept 7–9 h/day (26.5; 95% CI: 26.1, 27.0). Prevalence estimates of overweight (BMI ≥25) and obesity (BMI ≥30) were also inversely associated with sleep duration among men.

More on stretching...for Bozos?

I obviously wouldn't go that far seeing as I keep posting videos of Kelly Starret, but I do think that the arguments for indiscriminate stretching are limited.  For some of us at some times to address particular issues i think there is an argument for stretching. 

Anyway, Zero Drop has posted this list of

10 Reasons Why Runners Should Not Stretch

• Stretching is exercise for the muscles like sea water is hydration for the body. When you're desperate for relief, it feels so right but only makes things worse.
• All athletes, especially runners, are so passionate about stretching. They defend it like their political association, religion, or family. I think many of them may have pictures of their kids in their wallets doing all types of cool stretches that they show their coworkers every day at the water cooler.
• Runners will follow any trend they think will make them run faster. Whether it's a new supplement, pair of socks, pair or shoes, custom orthotics, or stretching. They're the first in line for the Kool-Aid.
• Stretching is a conditioned behaviour, not one we are innately born with. I see my kids run, jump, climb, throw things, and carry objects of all sizes. They move well, and efficiently. I've never seen them stretch. Their developing nervous systems know better.
• The day I see my dog holding a stretch is the day I'll start stretching too.
• Flexibility is a reflection of overall health and fitness. Stretching does absolutely nothing for health or fitness. It's not exercise. It's not a warm-up or a cool-down. And it definitely doesn't substitute for restful sleep or a wholesome diet.
• Yoga is not stretching. Stretching is not yoga. Enough of that claim.
• Make sure you stretch if you want to weaken muscles, promote injuries, decrease performance, delay tissue healing, and have absolutely way too much free time.
• Stretching reduces injuries and improves endurance performance just like certain shoes will make you run or jump faster. Neither claim is true.
• I enjoy watching runners stretch. They must stretch because they think they will run faster. I bet they believe in Sasquatch too.

Sock Doc's full article STOP STRETCHING is definitely worth reading

Stretching may increase your flexibility, but you will most likely be weaker and the results are often short-lived. Saying that stretching reduces injuries or improves endurance performance, (the two main reasons given for stretching), is like saying certain shoes will make you run or jump faster. Many continue to make both these claims, yet neither has ever been proven, and many still buy the shoes and stretch with them on. Stretching is not exercise and not a warm-up before a run or any activity. Aerobic activity is the best warm-up as it increases flexibility in a safe way while improving oxygen utilization, lung capacity, and fat burning.
So balance your muscles and your entire body by balancing your life with proper exercise, diet, and other lifestyle factors. Stop drinking that Kool-Aid propaganda and just say “No!” to stretching!

Super Squat Hip Sequence from K Starr

Sleep more and it is easier to lose wieght

Thanks to Matthew Clarke for pointing this out.


There is an interesting study in the International Journal of Obesity this month.  Lots of times in the past I've pointed to things  saying to get more sleep for lots of health reasons - inflammation, stress reduction etc.  I have just drafted up an  article on sleep and I talk about the signals that you give to your body.   Compromised sleep sends a signal that you are under threat....so you produce stress hormones to get you ready for the threat.....and chronically elevated stress hormones (cortisol etc) lead to all sorts of problems....including obesity.

This new study found that those who slept more were better at losing weight!   Lowered stress was also a success factor, although that is linked - sleep more a way of reducing stress.

Anyway, here is the abstract:

Impact of sleep, screen time, depression and stress on weight change in the intensive weight loss phase of the LIFE study

Background:

The LIFE study is a two-phase randomized clinical trial comparing two approaches to maintaining weight loss following guided weight loss. Phase I provided a nonrandomized intensive 6-month behavioral weight loss intervention to 472 obese (body mass index 30–50) adult participants. Phase II is the randomized weight loss maintenance portion of the study. This paper focuses on Phase I measures of sleep, screen time, depression and stress.

Methods:

The Phase I intervention consisted of 22 group sessions led over 26 weeks by behavioral counselors. Recommendations included reducing dietary intake by 500 calories per day, adopting the Dietary Approaches to Stop Hypertension (DASH) dietary pattern and increasing physical exercise to at least 180 min per week. Measures reported here are sleep time, insomnia, screen time, depression and stress at entry and post-weight loss intervention follow-up.

Results:

The mean weight loss for all participants over the intensive Phase I weight loss intervention was 6.3 kg (s.d. 7.1). Sixty percent (N=285) of participants lost at least 4.5 kg (10 lbs) and were randomized into Phase II. Participants (N=472) attended a mean of 73.1% (s.d. 26.7) of sessions, completed 5.1 (s.d. 1.9) daily food records/week, and reported 195.1 min (s.d. 123.1) of exercise per week. Using logistic regression, sleep time (quadratic trend, P=0.030) and lower stress (P=0.024) at entry predicted success in the weight loss program, and lower stress predicted greater weight loss during Phase I (P=0.021). In addition, weight loss was significantly correlated with declines in stress (P=0.048) and depression (P=0.035).

Conclusion:

Results suggest that clinicians and investigators might consider targeting sleep, depression and stress as part of a behavioral weight loss intervention.

Some MovNat

Although it looks a bit warmer, this is much like the seminar I attended with the great Erwan Le Core back in December 2010.



By the way if you are wondering how this fits with my Hillfit approach, I think High Intensity Training, resistance training can quickly get you the strength that you need in order to practice MovNat Skills.  Without basic strength you will never get far in terms of climbing etc.  I do not discount all these skills, and I think there is value in becoming expert in them.....but strength.....exercise is something else.

Exercise and insulin sensitivity: both hard AND easy training.......

We've had material up here before on the way in which exercise can promote insulin sensitivity - even brief intense exercise.

I spotted this new study that highlights that both endurance and resistance training can have an impact, but on different elements of that sensitivity:

Insulin Sensitivity After Maximal and Endurance Resistance Training

Maximum Resistance Training (MRT) led to a greater increase in glucose uptake capacity (in muscles), whereas Endurance Resistance Training (ERT) led to greater insulin sensitivity, supporting the recommendation of both MRT and ERT as primary intervention approaches for individuals at a risk of developing type 2 diabetes.

It is something that I point to in Hillfit - intense exercise to failure that can tap into all the muscle fibres - slow, intermediate and fast twitch - lets you drain them of glucose in a way in which endurance exercise does not allow....and endurance exercise does have some benefits.

Actually it is pretty much similar to what Mark Sisson has been saying for a while:

• Lift Heavy things
• Move around alot at a slow pace

Or indeed, Clarence Bass "barbell" strategy - 

 I do a combination of high-intensity intervals and low-intensity walking—and very little of the moderate-intensity aerobics that most people do. I call this my barbell aerobics strategy because, like a barbell, it uses both ends of the intensity spectrum—with almost nothing in between. 

which is also of course Nassim Taleb's approach

Warm up?

I have had stuff on here before about warm ups, mainly discouraging static stretching as a warm up since it seems to impair performance and do nothing to prevent injuries or soreness.  Dynamic stretches or mobility work seems to have more promise.

Anyway, there was a post on the excellent Sweat Science blog (reading that blog just makes me want to give up because he does all this stuff so well!) which looked at a recent study about the impact of different warm up protocols on swimming performance - The ideal warm up for swimmers

It is well worth reading the post and it prompted me to search around because initially I could not find the study to which it referred.  I did find the actual thesis from the student who did the work however. 

What is interesting to me is that 37% of the sample performed best with no warm up whatsoever.  It may be specific to the event that was being measured and I am sure that there are confounding factors in the study, but it is something to think on.  I think the conclusion that they reach - individuals differed in their response to different warm-ups is probably pretty accurate!

Dr M C Aldhous - Writer and Editor

Where I was this morning....

 I suppose this is another post about my book  - Hillfit.   The reviews are still coming in and I've collected them on a page here.  As I've said, the reason I train is to get out into the hills, so each trip will be easier, safer and more fun.  This morning was up in my local hills to watch the sunrise.  It was windy but stunning.

Anyway, this post is just to say that a big credit for the quality of the book goes to my editor / proof reader.  Dr M C Aldhous went through the text, proof reading, reference checking and generally tightening up my prose.  Her input was vital in getting the thing together in a decent state such that we were happy to put it up for sale.

It is one thing writing blogs, but pulling together something a bit more substantial and then being audacious enough to try to sell it is a different proposotion, having a proper professional editor was a huge help.

Dr M C Aldhous is an immunologist by profession with a background in HIV and IBD, but she has a sideline in freelance editing, so if you have any writing that you want to have checked over, checked and redrafted, then I would suggest that you get in touch for a quote.  Email her at mcaldhousATgmail.com