Does Yoga Really Do the Body Good?

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Does Yoga This exclusive ACE-
sponsored study
evaluates the
day body
Yoga may be all the rage at your local gym,
but the truth is—it’s old news. Experts can
trace the origins of yoga all the way back to
2250 B.C. as the Harrapan civilization in
Northern India began to develop postures
and breath-control techniques that they
hoped would enable them to enter an altered conscious-
of the
Body ness and access the spirit realm.
Today, exercise enthusiasts are flocking to yoga studios
and fitness centers in the hopes of reaping more tangible
body benefits like improved muscle tone and strength,
better balance and, of course, pretzel-like flexibility.
“Mind-body exercise” has been the fitness buzzword
Good?du jour for at least five years now and, according to year-old
recent stats from the Sporting Goods Manufacturers
Association, more than 11 million Americans current-
ly practice yoga.
practice of
Yet despite yoga’s long history and the enormous
number of faithful participants, very little real
By Mark Anders
research has been conducted regarding its physical
benefits. That’s where the American Council on
Hatha yoga
Exercise comes in. We know anecdotally, and
from firsthand experience, that yoga is a valuable
fitness activity, but we decided to tap the research
experts at the University of Wisconsin, La Crosse, to
find out just how effective it really is.
Led by Dawn Boehde and John Porcari, Ph.D., researchers
from the University’s Human Performance Laboratory recruited
34 healthy women (average age: 33) for the study. To guarantee an
Continued on page 8
ACE FitnessMatters • September/October 2005

Does Yoga Really Do the Body Good?
Continued from page 7
to the study) to uncover any possible
even playing field, all of the subjects
changes in their fitness levels.
were sedentary and could not have been
involved in a regular exercise program
or yoga training for the six months
prior to the study.
After analyzing the data, researchers
The test subjects were then randomly
found that the regular practice of Hatha
divided into two groups: a yoga group and
yoga significantly improved the subjects’
a non-yoga control group. In an effort to
flexibility, muscular strength and
establish a baseline, all subjects were given
endurance, and balance. After eight
the same battery of tests that evaluated
weeks, the average flexibility of the yoga
their flexibility, muscular strength and
group improved by 13 percent to 35 per-
TESTING PROTOCOL endurance, balance, pulmonary function
cent and the gains were significantly
Each subject was tested prior
and fitness level (see “Testing Protocol”).
greater than the non-yoga group, especial-
Then the yoga group participated in
ly in shoulder and trunk flexibility, and
to and following the two-month
55-minute Hatha yoga classes, three
ankle range of motion (for complete data
study period using this stan-
days a week. During the eight-week
tables, visit
dard battery of tests:
study period each participant complet-
“Focusing on holding the yoga poses
ed an average of about 21 classes.
for 30 seconds helps increase your flexibil-
Back Scratch, Functional
Though there are many forms of yoga,
ity,” says Boehde. “Some poses have you
Reach Test, Trunk Rotation,
Hatha yoga was chosen because it’s
leaning forward so you’re lengthening the
Trunk Flexion and Extension,
beginner-friendly and classes are wide-
back of your body, and the ones where
Trunk Lift, Shoulder Elevation,
ly available throughout the nation.
you’re arching back are stretching out the
Ankle Plantar Flexion and Dorsi-
All of the yoga classes were taught by
front of the body.”
flexion, Modified Sit-and-Reach
Boehde, a certified yoga instructor.
Similarly, the yoga group’s muscular
Each started with five minutes of relax-
strength and endurance was also boosted
ation and yoga breathing (pranaya-
by regular Hatha yoga. In particular, chest
One-Legged Stand
ma), followed by 10 minutes of warm-
and abdominal strength and endurance
up exercises including sun saluta-
was increased significantly, enabling the
ACSM Modified Push-up Test and
tions, 35 minutes of yoga postures
yoga group to perform an average of six
Curl-up Test
(asanas), and, finally, five minutes of
more push-ups and 14 more curl-ups fol-
relaxation and yoga breathing in
lowing the study period (see Tables 1
the corpse pose (savasana).
and 2). “Different yoga poses improve
Forced vital capacity (FVC), forced
Simultaneously, the non-yoga
your muscle endurance because you can’t
expiratory volume in the first second
group was prohibited from partici-
just flop down and do a pose,” Boehde
pating in any form of exercise.
says. “You have to have good posture and
At the end of the eight weeks,
poise, and good core strength to hold

Maximal heart rate and VO
both groups were given another
yourself up in the poses.” Poses such as the
2 max.
battery of tests (the same as prior
plank, half moon, boat, camel and
Table 1.
Table 2.
Changes in push-ups as a result of yoga training.
Changes in curl-ups as a result of yoga training.
? Pre-testing
? Pre-testing
? Post-testing
? Post-testing
Number of Push-ups
Number of Curl-ups
* Significantly different from pretesting (p < .05)
* Significantly different from pretesting (p < .05)
September/October 2005 • ACE FitnessMatters

revolved triangle may be among the best for
improvements should have very good car-
improving strength because they require one
ryover to everyday life.”
to support his or her upper body.
But Porcari advises exercisers to
As for balance, the yoga group experi-
assess their fitness goals and make sure
enced a 17-second increase in their one-
that yoga can indeed help them meet
legged stand time and a modest boost in
those goals, especially if they’re look-
ACE study analyzes calorie-
their functional reach scores. Besides the
ing to lose weight, build significant
burn and aerobic benefits of
obvious improvements yielded by simply
strength or get a good cardiovascular
Hatha and Power yogas
practicing the variety of one-legged moves
As a companion to the Hatha
that are common in Hatha yoga,
“People’s expected benefits need
yoga study, Porcari and Stefanie
researchers point to increased proprio-
to be in-line with reality,” suggests
Spilde analyzed the exercise intensity
ception and strengthening of the muscle
Porcari. “People often try to make
and caloric expenditure of two types
in the ankles and legs as part of the rea-
yoga into this all-encompassing
of yoga. For this study, researchers
son for the better balance scores.
thing. Americans have changed
recruited 15 participants, with at least
However, with regards to aerobic fitness
yoga and tried to morph it into
an intermediate level of yoga experi-
improvements, there were no significant
programs that will hit every aspect

ence, and monitored their exercise
changes in VO2 max or maximal heart rate
of fitness but it was never designed
intensity as they participated in two
in the yoga group over the course of the
that way.”
50-minute yoga sessions (one
study (see Table 3). “You get changes in
Sure, Hatha yoga will improve
Hatha yoga, one Power yoga) fol-
strength and muscular endurance, flexibili-
your strength, but you’ll get much
ty, balance—all those types of things—but
stronger, more quickly, by simply lift-
lowing a videotaped routine for
in order to improve aerobic capacity you
ing weights, he says. As for a cardiovas-
really have to be working in the aerobic
cular workout, yoga isn’t the answer for
Researchers found that a 50-
training zone,” says Porcari. “Based on
that either. In fact, you’d have to jog
minute session of Hatha yoga burns
what we found, the intensity just wasn’t
or cycle to the yoga studio if you’re
144 calories, equivalent to a slow
there.” (For more details, see Yoga
looking to improve your cardio fit-
walk, and provides no substantial
Intensity sidebar.)
ness level.
aerobic benefit (see Table 4). As for
That said, the researchers stress
Power yoga, it burns about 237 calo-
that Hatha yoga is still an excellent
ries in 50 minutes and boosts heart
addition to any fitness routine, par-
rates to 62 percent of heartrate max
“For the average person off-the-street
ticularly because it targets those
(HRmax), providing just a mild aerobic
who doesn’t have a fitness program, this
aspects of fitness—flexibility, bal-
workout. “It’s a great muscular work-
study shows what would happen if you did
ance and relaxation—that are
out and you certainly sweat, but it’s not
eight weeks of Hatha yoga,” explains
most often skipped or over-
an aerobic workout,” says Porcari.
Boehde. And good things would happen
Beyond that, researchers warn that
indeed—including increased strength and
efforts to boost the cardio benefits of
endurance, improved balance, and of
This study was funded solely by the
yoga will only result in reduced flexibility
course, better flexibility.
American Council on Exercise (ACE)
and balance benefits. “It’s always a trade-
“We saw very nice changes in flexibility
and conducted by Dawn Boehde and
off,” says Porcari. “Yoga was designed for
of the entire body, the shoulder girdle,
John P. Porcari, Ph.D., at the La
relaxation, primarily. The more aerobic you
Crosse Exercise and Health
twisting, bending, reaching, good low-back
Program of the University of
make yoga, the less improvements you’ll see
flexibility—all those types of flexibility
Wisconsin, La Crosse.
in those other areas.”
improved,” says Porcari. “And those
Table 3.
Table 4.
Changes in aerobic capacity and maximal
Average physiological responses to
heart rate as a result of yoga training.
Hatha and Power yoga.
Hatha Yoga
Power Yoga
X ± SD
X ± SD
HR (bpm)

% HRmax
2 max (ml/kg/min)

32.8 ± 7.1
35.5 ± 7.2
VO2 (ml/kg/min)
33.4 ± 7.2
35.4 ± 8.3

% VO2 max
Maximal heart rate (bpm)
178.6 ± 11.3
179.7 ± 14.4
182.5 ± 11.9
181.3 ± 12.9
ACE FitnessMatters • September/October 2005