Previous studies exploring the effects of wearing high heels have found
that it causes shortening of the medial gastrocnemius muscles and increases
Achilles tendon stiffness, resulting in chronic adaptations in the
muscle-tendon units in the foot. However, few studies have looked at the effect
of these changes on the locomotor and neuromechanical function of muscle-tendon
units, especially in habitual high heel wearers.
In response, researchers from Griffith University in Queensland,
Australia decided to examine the effects of habitual
high heel wearing on the neural and mechanical behavior of
the triceps surae muscles during walking.
“No study before ours had looked at length changes of the muscle
fibers,” lead author Neil J. Cronin, PhD, who is a senior researcher at
the University of Jyväskylä in Finland, told O&P
Business News. “This was a major gap in our knowledge because
movement can only happen when muscles contract, so we need to understand this
process in order to fully comprehend the effects of wearing high heels for a
long time.”
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Methodology
The researchers recruited two groups of participants. The first group
consisted of nine women who habitually wore heels with a minimum height of 5 cm
for at least 40 hours per week and at least 2 years. The 10 women in the
control group wore heels for fewer than 10 hours per week. The average age of
the participants was 25 years.
Both groups walked at a self-selected speed over a level walkway
approximately 8 m long while barefoot 10 times. The test group performed the
task an additional 10 times while wearing heels of their own choice. The
researchers used electromyography to measure the muscle activation, and an
ultrasound probe was used to measure fascicle strains.
The results of the study, which were published in the Journal of
Applied Physiology, showed that while walking in heels, the test group
had shorter
muscle fascicles during standing than the controls,
suggesting that they had already experienced chronic adaptations in
muscle-tendon architecture. The researchers also found that the heel group
demonstrated significantly larger strains in the muscle fascicles when walking
in heels compared with barefoot walking. The heel group also demonstrated
higher muscle activation in the medial gastrocnemius than the control group.
“The high heel group activated their muscles relatively more when
walking overground compared to the control group. There are two implications of
this,” Cronin said. “First, the muscles are likely to fatigue sooner,
because they are being used to a greater extent. Second, using more energy to
achieve a given distance, which seems to be the case in the high heel group, is
less efficient.”
Barefoot results
The researchers also found that the heel group demonstrated higher
muscle activation while walking barefoot compared with the controls, but they
had similar fascicle strains and joint kinematics to the control group. This
partially refuted the researchers’ hypothesis that the heel group would
demonstrate larger fascicle strains than the control group while walking
barefoot.
“We were originally surprised by this finding. Our working
hypothesis, which is currently untested, is that when the high heel group walks
barefoot, it somehow represents a ‘novel’ task as far as the brain is
concerned, since the muscles and tendons, as well as the brain itself, have
adapted to the conditions that are imposed by wearing heels,” Cronin said.
“In response to this, it seems that the high heel group subconsciously
activates their muscles more strongly. We hope to test this idea in the
future.”
This adaptation when walking barefoot poses potentially harmful effects
when women switch from heels to flat shoes.
“We know that the muscles and tendons get used to the position they
are forced into when in heels,” Cronin said. “Therefore, if somebody
switches to only wearing flat shoes, this would represent a change in the way
the muscles and tendons are loaded. Whenever this happens, there is always a
potential for injury.”
The most significant aspect of the study, however, was the young age of
the participants. The participants had already developed chronic adaptations,
suggesting that adaptations can occur more quickly than previously thought. How
these adaptations could affect muscle and tendon structure later in life
remains unknown.
“Unfortunately I only have anecdotal evidence at the moment,”
Cronin said. “I have been told by numerous women that they are unable to
walk in flat shoes anymore because it is too painful. This is probably the same
effect we have seen in the younger women; the tendon becomes very stiff, and
perhaps beyond a certain point, which may be several decades, this is
irreversible.” — by Megan Gilbride
For more information:
- Cronin NJ, Barrett RS, Carty CP. Long-term use of high heeled shoes
alters the neuromechanics of human walking. J Appl Physiol. 2012 Jan 12.
Epub ahead of print.
