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di/qualisys87
03-25-2010, 01:05 PM
For those that have 6:16 to sit back at watch a video on the same topic.
"The Barefoot Running Professor by Nature Video"

http://www.youtube.com/watch?v=7jrnj-7YKZE



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-----Original Message-----
From: * Biomechanics and Movement Science listserver
[mailto:BIOMCH-L@NIC.SURFNET.NL] On Behalf Of Michael Orendurff
Sent: Tuesday, March 23, 2010 3:25 PM
To: BIOMCH-L@NIC.SURFNET.NL
Subject: [BIOMCH-L] Barefoot running

Dear Subscribers,

Nature is to be congratulated for publishing confirmatory work (Liberman,
DE, et al, Nature, 2010 463:531-535) that the biomechanics field published
more than 20 years ago (Robbins SE, Hanna AM. Med Sci Sports Exerc. 1987
Apr;19(2):148-56) concerning barefoot versus shod running. However, the
conclusions of both studies remain highly speculative and controversial,
highlighting the need for well-controlled randomized clinical trials of
barefoot vs. shod running adaptations before meaningful conclusions can be
drawn.

Running related injuries are diverse, suggesting several different injurious
factors for specific individuals. Injuries from habitual endurance running
span the full range of bones, joints, tendons and muscles from toes to
spine, suggesting that running stresses the entire organism and any one of
many different components may be injured. In general I agree that loading
rate might be important, but the loading rate of muscles, tendons, ligaments
and bones is much more related to injury than ground reaction force loading
rate. The metric of interest is not the forces applied to the ground, but
the frequency content, amplitude and number of impact transients transmitted
to specific anatomic structures over time. Most running injuries are
chronic but a few are acute.

The primary injuries from barefoot running might be plantar puncture,
abrasion and laceration wounds, plantar bruising, stress fractures of the
metatarsals and Achilles tendonitis/tendonosis. We decided to build shoes
for a reason-pain relief. Modern cushioned shoes despite all their hype and
expense and fashionable colors protect the body by reducing the high
frequency content of these transients, regardless of the foot contact
pattern. They are not perfect, but they are reasonably effective.

Liberman argues that the stiffened soles and arch supports in running shoes
may weaken the intrinsic musculature of the foot. "Furthermore, many
running shoes have arch supports and stiffened soles that may lead to weaker
foot muscles, reducing arch strength. This weakness contributes to excessive
pronation and places greater demands on the plantar fascia, which may cause
plantar fasciitis."

This statement suggests that all runners who wear shoes would eventually
become pronated, which is hardly the case; many have varus and/or cavus and
this does not resolve with running, either shod or barefoot. Liberman is
suggesting the mechanism of the increased load on the plantar fascia makes
it weaker. Why does wearing shoes make the post tib weaker? Why would post
tib weakness lead to plantar fascia weakness (midfoot torsion?!) more than
the very high forefoot bending moments that forefoot contact running
elicits? Wouldn't barefoot (forefoot) running load the plantar fascia much
more than shod running? Is this loading a good thing or a bad thing?
Weaker or stronger? It depends on dose (magnitude, duration, frequency,
mode, training history, nutrition.).

Barefoot endurance running is not likely to increase the strength of these
muscles as effectively a performing three sets of 20 plantarflexion motions
barefoot-muscle hypertrophy is best achieved by high-load, low repetition
movements that trigger mTOR molecular signaling cascades that result in
increased contractile protein synthesis. These hypertrophic mechanisms are
partially blocked by TSC2 which is activated during endurance exercise
through the AMPK pathway that results in increased fat metabolizing enzymes
(Coffey, et al, 2005, 2009).

This suggests that "weight training" barefoot might be effective in
strengthening the intrinsic musculature of the foot. Performing an
endurance activity to gain strength is something like that quote by Mao
about fighting for peace.

I would wager that the windlass effect places much higher forces (and
excursion) on the plantar fascia and that MP extension (forefoot
flexibility) is key, but that limited high-force events should be undertaken
for novice barefoot runners, especially at first.

It is exceeding unlikely that endurance running as is currently practiced by
modern humans is anything like our prehistoric hunting practices. Anyone
who has attempted persistence hunting of large game on foot will quickly
realize that they have horns for a reason: if the initial flush to initiate
running in these animals is successful, additional attempts are often met
with charging behavior and panicked sprinting by the hominids in all
directions to avoid a "Pamplona"-type injury.

Having hunted antelope with Africans using a bow and arrow I know this
scenario to be plausible. Our forbearers supposedly hunted like this with
nothing more than long, sharp sticks. There is something valuable in living
one's hypotheses that makes a charred (steer) steak and a cold beer taste
all the better around the fire after total failure. It may be our ability
to excel at endurance running that initially set us apart from other
organisms, but it is our ability to ask why that sets us apart now.

It is much more likely that this persistence hunting activity should be
described as high-intensity intermittent exercise (HIIE) which persists for
long periods at varying intensity levels. For human musculoskeletal health
these HIIE activities resulted in a balance between endurance capacity and
overall musculoskeletal strength. The foot and ankle would have received a
wide array for force-time stimuli resulting in a joint complex that would be
resistant to fatigue and injury, and yet perform at a very high level.

This is an interesting debate, but I hardly think the main thrust of our
efforts should be to help habitual runners run even more. Our efforts would
have a much bigger health and economic impact if we worked to make
habitually inactive people active. For example HIIE activities like
football (soccer) have been shown to be much more effective than running at
providing a training effect in previously sedentary individuals (Bangsbo, et
al, 2009), reducing fracture risk (Helge, et al, 2010) and reducing coronary
risk factors in women (Andersen, et al, 2010) and men (Krustrup, et al,
2010), increasing musculoskeletal strength and balance (Sundstrup, et al,
2010), endurance and well-being (Krustrup, et al, 2010) and reducing
hypertension and coronary risk factors (Andersen, et al 2010). Soccer
players have much higher bone mineral density at their spine, femur and
tibia compared with runners (Fredericson, et al, 2007) and adults who played
ball sports as children have fewer stress fractures as adults, even when
training for national running competitions (Fredericson, 2005).

Forget barefoot running-play soccer instead.

Michael Orendurff
Division Director
Movement Science Laboratory
Texas Scottish Rite Hospital for Children
Dallas



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