14 YOGAJOURNAL.COM YOUR 6-WEEK YOGA GUIDE TO BUILD STRENGTH
STRENGTH
One of the most obvious benefits of
yoga is strength. The practice has a
uniquely holistic effect on muscles. Put
a yoga practitioner next to a football
player, and it’s clear that the two activi-
ties tax muscles differently. Football
demands explosive speed and brute
strength; players build short, tense
muscles with concentric contractions.
A concentric contraction stimulates as
it shortens— picture the biceps bulging
as dumbbells curl toward the chest.
Then they put the dumbbells down,
resisting the pull of gravity in what
is called eccentric contraction. Few
exercises work the muscles equally in
both ways.
But both are key in yoga—often atthe same time. Nearly every single yoga
posture simultaneously lengthens and
strengthens complementary muscles.
For instance, as you bend the front knee
to 90 degrees in Virabhadrasana I (War-
rior Pose I), the quadriceps on the front
of the flexed thigh resist gravity and
lengthen eccentrically. Meanwhile, in
the upper body, the arm muscles shorten
concentrically to pull the biceps back
and alongside the ears. This balanced
contraction and elongation creates long,
lean muscles that may, ultimately, be
more durable and injury proof than
short, tight ones.
The first Western medical study todirectly examine muscle strength and
yoga appeared in 2001 in the journal
Preventive Cardiology. Researchers at
the University of California, Davis, re-
cruited 10 yoga newbies and took base-
line measurements of their strength,
flexibility, and lung function. After eight
weeks of doing yoga, strength and flexi-
bility had grown as much as 31 percent.
That’s a huge gain, but the study isnot without its hiccups, according to
Yoga Journal’s contributing medical editor
INCREASED HAPPINESS
Yoga may lead to brighter, happier thinking all the way around. Though the mechanism
is not fully understood, Yoga Journal’s contributing medical editor Timothy McCall, MD,
notes, one study found that a consistent yoga practice is associated with a decrease in
depression and both a significant increase in serotonin levels and a decrease in mono-
amine oxidase (a substance that breaks down neuro transmitters) and cortisol. Among
meditators, a study by Richard Davidson, PhD, at the University of Wisconsin also found
increased activity in the brain’s left prefrontal cortex, associated with feelings of well-
being and happiness.