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

Pose Walking

how to walk......

Captain Barclay's Gait

I was reading recently about the amazing Captain Barclay.  His most famous exploit was the walking of 1,000 miles (1,600 km) in 1000 hours for 1000 guineas in 1809.  There is good analysis here.

I thought that the way in which his gait was described was interesting.  It is essentially POSE walking.

Walter Thom attributes Captain Barclay's pedestrian powers to his great strength and his walking style that involved bending the body forward to throw the weight on the knees, taking short steps and raising his feet only a few inches from the ground. (from here)

When walking, the Captain took comparatively short steps and had an air of leaning more than slightly forward. (from this book)

Walking poles

Another quick thought.

If you are into hillwalking / hiking / backpacking you will have seen people walking with poles.  The usual justification is that it takes pressure off the knees.  My observation is that it seems to mess up people's gait, especially in climbing or descending.

My current theory is that it impacts on proprioception.  This is the way in which the brain senses the body's position in space, through various sensors - propriceptors - throughout the body in nerve endings in muscles, tendons and joints. The brain relies on complex and rich sensory data from across the body to maintain balance and posture as we move.

Perhaps using poles diminishes the way in which weight is carried through the feet and so the sensory input is also diminished ...... and this has a negative impact on balance and gait.

It is similar to the way in which shoes and stiff soled boots blunt the sensory impact and damage gait.

Just a thought.

Grannies on the prowler

we need more old ladies pushing prowlers......

Gait....

I am thinking a lot about walking at the moment in preparation for an article I am writing for TGO magazine. 

There are several journal articles I've been reading but particularly useful has been:

Dynamic Principles of Gait and Their Clinical Implications

which is a review of the biomechanics of walking.

Most of my thought is shaped by the principles of POSE though and Romanov's key fundamental that we are mainly trying to deal with and work under gravity.  His piece on Pose walking technique has been useful and is similar to the ideas of MovNat. 

Mark Sisson's piece is valuable too.

It all builds together - a more efficient gait will allow you to go further with less effort and with less potential for injury.

I FORGOT - This ebook is phenomenal 

Here are a couple of videos on technique too:

Maffetone on walking

Phil Maffetone was ahead of the pack in some ways - he was talking about a low carb diet for endurance and getting barefoot years ago.

Anyway, still thinking of the upcoming Hillfit articles, he had a good piece on the walking gait the other day:

I'll copy all of it here but all his articles are worth checking out.

More on Gait
Dr. Phil Maffetone

The two-part article on gait (May 2011) was very popular. Among the reader’s questions were those about walking gait. Walking is an ideal workout for fat burning and overall fitness for millions of people. Runners often walk too, as warm up or cool down, as a method to develop more endurance (i.e., longer runs), and even during marathons, often unplanned. It’s actually not unusual to see the walking gait of runners as abnormal.

As discussed in the article on gait, there’s an obvious difference between walking and proper running, especially in how the foot strikes the ground (on the heel for walkers and more forward in runners). The walking body, which always has one foot in contract with the ground, functions like an inverted pendulum, swinging along step-by-step, literally vaulting over stiff legs with locked knees. Running should not involve locking the knee, as each is always slightly flexed while the foot is on the ground. Herein lies one problem with many runners who walk, and even those who don’t run. When walking, many people keep their knee slightly flexed instead of locked. It’s as if their knee is in a running gait pattern while the rest of the body is walking. This poses a potential physical problem—stress on the knee joint and in the muscles around it.

When walking, you should gently be locking your knee with each step, as you “vault over your foot and start pushing off. That doesn’t mean thrusting the knee joint into extension. But naturally allowing it to go into full extension and lock momentarily before continuing the normal gait cycle. This should never cause pain in the knee—if it does it means something is wrong somewhere (such as muscle imbalance, poor foot mechanics, or bad shoes).

In competitors performing the Olympic walk, in addition to making sure there is always contact with the ground, locking the knee is a requirement—otherwise they may be disqualified.

All other walkers need not be so concerned other than to avoid unnatural gait movements. Improper shoes promote this more than anything else. For runners, the problem may be they’re used to a slightly flexed knee during running and somehow this gets translated into a walking gait.

Many other factors discussed in the running gait article also apply to walkers. These include an upright posture, which promotes the use of the abdominal and gluteus maximus muscles, a slightly forward center of gravity (but not bending forward), allowing the pelvis to lead the way, and a level head. And, the wearing of flat shoes, which, while landing on your heels, you don’t remain there very long as your muscles and body’s forward motion quickly move you through the mid-foot and toe-off phase of gait.

Another question about gait was regarding children, and how shoes can interfere with it. This requires more discussion and is the topic of an upcoming article.

Phil's piece on hiking is also worth  reflecting on.

POSE walking

I am still thinking through the material for the Hillfit series I am writing for TGO.  One of the topics is the skill of walking.  For this I think there is a lot to learn from POSE.  We know of POSE mainly from running style  but they also have an approach to walking:

Walking in this case is no different from running. Despite the fact that in walking we always have a ground contact with one or two feet we still need to fall forward in order to move forward and change the support during falling from one leg to the other. So our speed of walking depends on the degree of falling (leaning forward, which is the degree of deviation of the GCM of the body from the point of support) and the frequency of changing supports (stride frequency).

The following premises basically define the major requirements to efficient walking technique.

• Fall forward only from the ball of the foot.
• Don’t push off with the support leg or foot.
• Keep knees very slightly bent or just not locked.
• Touch the ground with the rear part of the foot, but then quickly transfer the body weight on the ball of the foot.
• Pull the support foot from the ground and bring the swing leg to midstance (Walking Pose) to fall forward again.

Increase your walking speed by leaning forward more and more often by changing support quicker.
Keep your body straight, arms bent in elbows according to your speed and stride frequency.
Avoid efforts beyond necessary to keep your body on support and to change support.
Do not bend in your hips. Strong and formed hips (position and strength) are the base of efficient falling and changing support.
Do not worry about stride length – it is a function of leaning forward.
In walking, even at the fastest speed, you can’t bring your cardio-vascular system to the level of exhaustion as in running, but it gives a good load on the body and could be a good base for your further conditioning. The PW technique allows you to avoid an unnecessary load on your joints and muscles, but gives you all the benefits of an aerobic exercise.

Exercise is good for the brain....

This is an interesting looking study.

The plasticity of the brain is something that I've been thinking on a little bit recently after reading The Shallows which details how too much internet use can change the way in which you brain is wired. (Basically it sets you up to be more easily distracted and less of a deep reader/thinker)

Anyway, this study sees exercise improving the brain's cognitive performance.  Basic walking is good for your brain.


Plasticity of brain networks in a randomized intervention trial of exercise training in older adults.
Abstract
Research has shown the human brain is organized into separable functional networks during rest and varied states of cognition, and that aging is associated with specific network dysfunctions. The present study used functional magnetic resonance imaging (fMRI) to examine low-frequency (0.008 < f < 0.08 Hz) coherence of cognitively relevant and sensory brain networks in older adults who participated in a 1-year intervention trial, comparing the effects of aerobic and non-aerobic fitness training on brain function and cognition. Results showed that aerobic training improved the aging brain's resting functional efficiency in higher-level cognitive networks. One year of walking increased functional connectivity between aspects of the frontal, posterior, and temporal cortices within the Default Mode Network and a Frontal Executive Network, two brain networks central to brain dysfunction in aging. Length of training was also an important factor. Effects in favor of the walking group were observed only after 12 months of training, compared to non-significant trends after 6 months. A non-aerobic stretching and toning group also showed increased functional connectivity in the DMN after 6 months and in a Frontal Parietal Network after 12 months, possibly reflecting experience-dependent plasticity. Finally, we found that changes in functional connectivity were behaviorally relevant. Increased functional connectivity was associated with greater improvement in executive function. Therefore the study provides the first evidence for exercise-induced functional plasticity in large-scale brain systems in the aging brain, using functional connectivity techniques, and offers new insight into the role of aerobic fitness in attenuating age-related brain dysfunction.

Walk or Run

I'd rather be a good walker than a bad runner.


(actually I mean a bad jogger)


Every day I seem to see people jogging past me with a really poor gait.  I'd rather they walked and sprinted.

The joy of walking

This is a superb piece form the minimalist blog:

the joy of walking

Today I set out from my house and walked. And walked.
I didn’t have a specific destination in mind, but wanted to walk a bit before finding a quiet place to write. So I walked, out of the town where I live and along the tropical, white-sand coastline, to the next town over.
As others drove cocooned in their cars, I walked, and emitted nothing but my breath.
As others spent their lunch hour pounding down fat-laden burgers and greasy fries or some other cheesy fried piled-high dish, I walked, and burned calories.
As others rushed and stressed, I walked, and took my time.
As others sat at their computers, I walked, and got my blood flowing.
As others held power business meetings and made deals, I walked, and had time to think.
As others were productive and got tasks done, I walked and got nothing done, and cleared my head.
As others had the comfort of shelter and air-conditioning, I walked and worked up a light sweat and was buffeted by the wind.
As a white gull floated serenely above a calm bay, I walked, and watched, and loved it.
I walked for an hour, then wrote and read, and then walked for another hour to get back home, tired but happy.
I can’t walk this much every day, but I walk as much as I can, because you need nothing to walk, you spend nothing, you consume nothing, you emit nothing.
And yet you have everything.

kids who walk or cycle to school are fitter

At one level this one comes under the heading of "obvious"!

On another level it is worth reminding the world that everyday exercise - walking, cycling etc - has a substantial effect.

Many people would do well simply to walk more like Nassim. We are meant to walk. As Kurt says:

7) Walking is an excellent evolutionary activity that we are, simply, evolved to do and doing it is nothing but good. I agree with Sisson on this - lots of low intensity rythmic activity can be good.

Anyway here is the study abstract

Aerobic fitness and mode of travel to school in english schoolchildren.

CONCLUSIONS:: These data confirm findings from countries where cycling is very common in showing that cycling to school is positively associated with aerobic fitness. This study adds to the existing literature by showing that walkers and cyclists are more likely to be classified as fit using recognized cut points. Those who walk and cycle to school may, therefore, be at reduced risk for developing chronic diseases in adulthood.

Walking

Excellent piece here by Nassim Taleb - Why I do all this Walking, or How Systems become Fragile

This is another application of the barbell strategy: plenty of idleness, some high intensity. The data shows that long, very long walks combined with high intensity exercise outperforms just running.

After my Aha! flash, under guidance from Art de Vany, I embarked on an Extremistan barbell lifestyle: long, very long, slow meditative (or conversational) walks in a stimulating urban setting, but with occasional (and random) very short sprints, making myself angry imagining I were chasing the bankster Robert Rubin with a big stick trying to catch him to bring him to human justice. I went to the weight lifting rooms in a random way for a completely stochastic workout --typically in a hotel when I was on the road.

Like the Grey Swan event, these were very, very rare, but highly consequential weight lifting periods, after a day of semi- starvation, leaving me completely exhausted, then I would be totally sedentary for weeks and hang around cafés. Even the duration of the workouts remained random --but most often very short, less than fifteen minutes.

hat tip to Seth

1000 miles....in 1000 hours

This is some Challenge, underway as I write.

On 29th May 2009 at 11.30pm, Richard Dunwoody started a 1000 Mile Challenge to walk the same mile 1000 consecutive times (from the Bedford Lodge hotel in Newmarket up the Bury Road to a post half a mile away and back again) for a 1000 consecutive hours with the last mile up the home straight of Newmarket racecourse just before the Ladbrokes Bunbury Cup on 10th July 2009.

In 1809 Captain Robert Barclay Allardice was bet that he couldn’t walk 1000 miles in 1000 hours for 1000 Guineas – meaning he had to walk one mile in every consecutive hour 24 hours a day – the challenge therefore taking 42 days with the maximum an hour and 20 minutes sleep at any one time (if you walk back to back miles in different hours). He completed the challenge on 12th July 1809, losing three stone in the process with his challenge hailed as ‘one of the greatest human feats ever attempted.’

200 years on, champion jockey, polar explorer and BBC presenter, Richard Dunwoody MBE is recreating this challenge walking the same mile 1000 times in Newmarket – 1000 miles in 1000 hours but this time to raise a substantial sum for charity – Alzheimer's Society, SPARKS, Racing Welfare and Spinal Research

.

Think about what is going on here - walking 24 miles a day, every day....with no significant sleep......


Barclay is an amazing character.

Sunset

This is not the usual fare for this blog but I thought I'd share last night's sunset.



Beautiful. More photos from the same walk are here.

Short bouts of brisk walking.....

Another interesting new study.

People need to be encouraged to be active. Some people are put off exercise because they might find it hard to find the time for say a 30 minute workout. (I think everyone can find the time for a 30 minute walk but....) However 10 separate 3 minute walks are just as good at giving certain health benefits....

Accumulating short bouts of brisk walking reduces postprandial plasma triacylglycerol concentrations and resting blood pressure in healthy young men


Background: Physical activity recommendations promote the accumulation of aerobic activity in bouts of 10 min. It is important to determine whether shorter bouts of activity can influence health.

Objective: We compared the effects of accumulating ten 3-min bouts of brisk walking with those of one 30-min bout of brisk walking on postprandial plasma triacylglycerol concentrations and resting blood pressure.

Design: Fifteen healthy young men completed three 2-d trials 1 wk apart in a randomized, repeated-measures design. On day 1, subjects rested (no exercise) or walked briskly in either ten 3-min bouts (30 min rest between each) or one 30-min bout (gross energy expenditure: 1.10 MJ/30 min). On day 2, subjects rested and consumed high-fat test meals for breakfast and lunch.

Results: On day 2 area under the plasma triacylglycerol concentration over time curve was 16% lower on the accumulated and continuous brisk walking trials than on the control trial ( ± SEM: 9.98 ± 0.67 compared with 9.99 ± 0.76 compared with 11.90 ± 1.02 mmol·7h/L, respectively; P = 0.005, one-factor ANOVA). Resting systolic blood pressure was 6–7% lower throughout day 2 on the accumulated and continuous trials than on the control trial (109 ± 1 compared with 110 ± 1 compared with 117 ± 2 mm Hg, respectively; P < 0.0005).

Conclusion: Accumulating 30 min of brisk walking in short (3-min) bouts is equally effective in reducing postprandial lipemia and systolic blood pressure as is one continuous 30-min bout.

Walking....

I just read this in "Walking - the Complete Guide to the Complete Exercise" by Casey Myers:

In today's wild animal kingdom, running is used only as a survival gait. Dr Lovejoy said he doesn't know of any animal that runs more than 3 minutes at a time in its natural environment.

....... it is apparent that we are misusing the running gait when we employ it for prolonged periods of exercise.

Gone walking.....

Back in a week

Just keep walking

Just walking will do you a lot of good. Note that intensity - walking pace - is also important.

Walking and primary prevention: a meta-analysis of prospective cohort studies

Objective:
To quantify the association between walking and the risk of cardiovascular disease (CVD) and all-cause mortality in healthy men and women.

Data sources:
Medline, Cochrane Database of Systematic Reviews, and Web of Science databases were searched to May 2007.

Study selection:
Prospective epidemiological studies of walking and CVD and all-cause mortality.

Results:
18 prospective studies were included in the overall analysis, which incorporated 459 833 participants free from CVD at baseline with 19 249 cases at follow-up. From the meta-analysis the pooled hazard ratio of CVD in the highest walking category compared with the lowest was 0.69, (95% CI 0.61 to 0.77, p<0.001), and 0.68 (0.59 to 0.78, p<0.001) for all-cause mortality. These effects were robust among men and women, although there was evidence of publication biases for the associations with CVD risk. Walking pace was a stronger independent predictor of overall risk compared with walking volume (48% versus 26% risk reductions, respectively). There was also evidence of a dose–response relationship across the highest, intermediate, and lowest walking categories in relation to the outcome measures.

Conclusions:
The results suggest walking is inversely associated with clinical disease endpoints and largely support the current guidelines for physical activity. The mechanisms that mediate this relationship remain largely unknown and should be the focus of future research.