Muscle Use During Exercise:
A Comparison of Conventional
Weight Equipment to Pilates With
and Without a Resistive Exercise
Device
Jerrold S. Petrofsky, PhD, JD
Amy Morris, BS
Julie Bonacci, BS
Ashley Hanson
Rachel Jorritsma, BS
Jennifer Hill, BS
Department of Physical Therapy, Azusa Pacific University, Azusa, California
Department of Physical Therapy, Loma Linda University, Loma Linda, California
160 Vol. 5, No. 1, 2005 • The Journal of Applied Research
endurance training, resulted in only
minimal muscle activity in core muscles
(abdominal and paraspinal muscles)
compared to exercise on commercial
weight lifting equipment. However, the
addition of the resistive device to
Pilates exercise, increased the workload
substantially, such that exercise during
Pilates was equivalent to a medium
intensity workout on commercial weight
lifting equipment. However, unlike commercial
exercise equipment, Pilates and
the resistive device exercised multiple
muscle groups simultaneously and
thereby provided a more efficient workout
than commercial weight lifting
equipment. The resistive device also
restricted adverse movement at the
joints during exercise making exercise
smoother and safer.
INTRODUCTION
Physical inactivity is a predisposing factor
to obesity. A key issue in obesity is
KEY WORDS: exercise, exertion,
Pilates, EMG, muscle
ABSTRACT
Six subjects between the ages of 18 and
30 years old were examined to compare
use of the quadriceps, hamstring, gluteus
maximus, hip abductor, hip adductor,
abdominal, gastrocnemius and
paraspinal muscles as assessed by electromyogram
(EMG). Muscle use was
measured during all forms of exercise
and exercise using conventional weight
lifting equipment was compared to exercise
during Pilates with and without a
resistive device called the “Zone Pilates
Sculpter” (Savvier LP, Santa Fe Springs,
Calif).The ability of the Pilates device
to restrict movement in adverse directions
and thereby, reduce potential
injuries during exercise was also
assessed. The results of the experiments
showed that Pilates, while good for
The Journal of Applied Research • Vol. 5, No. 1, 2005 161
that it is highly correlated with inflammation
in the entire body.2 Adipogenesis
is a highly regulated process and, with
excess adipose tissue in the body, hormonal
responses increase inflammatory
cytokines.3-5 Chronic inflammation associated
with obesity eventually leads to
disorders such as diabetes.6,7
Simply reducing weight through
dieting, while increasing the uptake of
glucose in muscle,8 is not the best
answer to the problem of obesity.While
dieting increases thermogenesis9 and
oxygen consumption,10 exercise and dieting
together cause a twenty-four hour
increase in metabolism and a reduction
in inflammation in the body.10-13
Unfortunately, for people with disabilities
or the elderly, reducing caloric
intake coupled with heavy exercise for
weight loss14-16 is difficult due to physical
limitations.17 Because of the limitations
in rehabilitation due to age, back and
knee injuries, a number of investigators
have used Pilates as an exercise modality.
18,19 Pilates is a form of exercise that
originally involved low-impact floor and
mat exercises without equipment.
Subsequently, while some Pilates have
remained in this pure form, others have
modified Pilates exercise with the use
equipment. Pilates has been used both in
outpatient settings and in acute hospital
settings.17 Pilates has been tried alone
and in combination with manipulation.20
While Pilates has increased in popularity
(10 years ago 5,000 people were
involved in Pilates; today the number is
over 5 million),21 muscle strengthening
with Pilates, while acceptable, is not as
extensive as that seen after weight lifting
exercise.22
Thus, while strength-training exercise
is useful for building muscle
strength, and aerobic exercise is useful
for building endurance, in many cases,
people with disabilities are unable to
perform either of these exercises. In contrast,
Pilates, without the use of equipment,
increases cardiovascular fitness
and the range of motion of joints, but
does not provide adequate strength
training compared to commercial weight
lifting equipment.
An intermediary between the two
types of exercise (Pilates and commercial
weight lifting equipment) is a type
of Pilates called Zone Pilates. In Zone
Pilates, a light resistive band is used to
keep the joints in alignment during exercise
and to provide resistance.The present
investigation was conducted to
examine the effects of such a resistive
band on muscle use compared to Pilates
without a resistive band and to commercial
exercise equipment.
SUBJECTS
The 6 subjects were male (4) and female
(2) aged 18 to 35 years old. All subjects
were fit and free of any cardiovascular,
neuromuscular, or orthopedic injuries.
All methods and procedures were
explained to each subject who then
signed a statement of Informed Consent
approved by the Human Review
Table 1. General Characteristics of Subjects (group average)
Age (years) Height (cm) Weight (kg)
Mean 25.3 169.9 69.8
SD 1.5 6.7 9.6
Male, n = 4; female, n=2
Committee at Azusa Pacific University.
The general characteristics of the subjects
are shown in Table 1 including their
average age, height, and weight.
METHODS
Determination of Muscle Activity
Muscle activity was determined through
the use of the electromyogram (EMG).
The electromyogram represents an
interference pattern that reflects the
activity of the underlying muscle.23 Since
the relationship between tension and
EMG is linear,24,25 the electromyogram
was used to assess movement. Muscle
activity was assessed by determining the
maximum EMG of the muscle during a
maximal effort and then, during any
exercise, assessing the percent of maximum
EMG to calculate the percent of
maximum muscle activity that was
used.25,26 Two electrodes were applied,
one on the belly of the muscle and one 2
cm distal to the belly for any given muscle.
A third electrode, the ground, was
attached within 4 cm of the 2 active
electrodes.The electrical output from
the muscle was amplified with a biopotential
amplifier whose frequency
response was flat from DC to 1000 Hz
and amplified with a gain of 5000
(Biopac Incorporated, Santa Barbara,
Calif).The amplified EMG was digitized
with an analog to digital converter (12
bit) and sampled at a frequency of 2000
162 Vol. 5, No. 1, 2005 • The Journal of Applied Research
Figure 1. Measurement of maximum muscle
strength in the hip adductors during manual
resistance applied by one of the research
personnel.
Figure 2. A study participant engaged in
squatting exercises with the resistive device
placed around the knees. EMG activity was
measured from 8 muscle groups.
Figure 3. A study participant engaged in hip
adduction against the resistive device used
in the study. EMG was measured from 8 muscle
groups.
The Journal of Applied Research • Vol. 5, No. 1, 2005 163
samples per second and stored on an
IBM Pentium 4 Digital Computer. The
digitizer was an MP100 (Biopac
Incorporated, Santa Barbara, Calif). The
amplitude of the EMG was analyzed by
taking the absolute value of the digitized
data and then calculating the root mean
square value of the EMG.
Maximum strength was measured
over a three second period by asking the
subject to exert a maximal effort with
the body in a position to isolate each
muscle being studied (Figure 1).27 Three
such contractions were exerted with 1
minute between contractions.The maximum
EMG recorded during the 3 contractions
was recorded to normalize all
EMG data. During exercise, EMG was
sampled over a one second period and
the percent of muscle activity was
assessed by dividing the EMG during
exercise by the maximum EMG during a
maximal effort. This technique is
described elsewhere.28
Resistive Device During Pilates
The resistive device used during Pilates
is an oblong ring with a resistive band
included. On one part of the band there
is a hinge and by opening the other end
of the band, resistance is applied to the
body (Figures 2 and 3). The relationship
between band separation and tension is
shown in the graph in Figure 4. As seen
in Figure 4, the relationship between
tension and stretch obeys Hook’s Law
and provides a linear change in resistance
with the degree of expansion of the
band. To exercise a given muscle, such as
the hip adductors, the band was placed
in position on the body (as shown in
Figure 3), and the legs would be adducted
while EMG was measured.
Commercial Weight Lifting Equipment
Back extensor and flexor, leg abductionadduction
(inner outer thigh machine),
abdominal, quadriceps, and hamstring
strength measurements and muscle
Figure 4. The relationship between the distance of separation of the Pilates’ resistive device and
force is illustrated. The relationship, as predicted by Hook’s Law, is slightly non-linear. The regression
equation with the second order Polynomial fit is y = 0.1204x2 + 0.1235x – 0.1497. In use, however,
the distance used to open the resistive device in actual exercises never exceeded
approximately 20 cm and therefore, the device is used in a fairly linear range of resistance versus
displacement.
164 Vol. 5, No. 1, 2005 • The Journal of Applied Research
activity during submaximal work was
accomplished on a Keiser weight lifting
system (Wilmington, Del). The system
uses compressed air to operate pistons
and to apply resistance during exercise.
PROCEDURES
Three series of
experiments were
performed on each
subject. In the first
series, exercise was
performed during
Pilates and EMG
was sampled. The
exercises chosen are
shown in Table 2.
The exercises were
performed with and without the resistance
device and included (as shown in
Table 2) a variety of leg exercises involving
flexion, extension, abduction, and
adduction of the hip.
Table 2. Exercises Performed in Study
Pilates Exercise Machine Exercise
45° squat Quad machine
90° squat Quad machine
Left leg adduction Inner outer thigh
Right leg adduction Inner outer thigh
Left hip extension Hamstring machine
Right hip extension Hamstring machine
Table 3. Muscle Use Data from Commercial Weight Lifting Equipment as a Percentage of
Maximal Strength*
Exercise Abdominal Paraspinal Quads Hams Hip abs Hip ads Glut Gastroc
Quad low 22.67 24.05 24.85 5.83 8.67 12.19 18.92 3.67
Quad med 18.13 25.54 33.83 7.67 6.83 24.57 20.60 4.83
Quad high 28.60 31.37 49.50 8.67 12.17 27.93 25.48 5.50
Ham low 18.57 30.92 13.00 21.67 15.30 11.46 36.20 11.05
Ham med 26.56 33.40 13.64 29.35 15.75 24.82 40.41 5.50
Ham high 29.17 36.96 16.83 43.57 16.23 29.99 43.76 6.10
Abd low 26.33 6.50 6.00 14.83 8.00 13.12 16.75 6.50
Abd med 34.49 11.87 5.83 9.00 10.00 10.50 7.89 5.83
Abd high 44.00 4.83 4.50 10.00 6.50 7.00 20.89 4.33
Back low 5.00 27.54 7.17 6.50 9.24 8.70 4.67 8.51
Back med 8.50 31.25 6.50 6.50 8.27 7.00 5.83 6.83
Back high 8.83 40.94 7.67 7.47 6.00 7.86 7.50 10.24
*Quads indicates quadriceps; hams, hamstring; hip abs, hip abductor; hip ads, hip adductor; gluts, gluteus maximus;
and gastroc, gastrocnemius.
The Journal of Applied Research • Vol. 5, No. 1, 2005 165
In the second series of experiments
on the same subjects, the same muscles
were exercised and assessed, but with
the addition of the rubber exercise band,
as previously described. Finally, once
EMG was assessed, exercise was performed
in a gymnasium on standard
exercise equipment (ie, quadriceps and
hamstring weight lifting machines) and
the weight applied on each exercise
machine was determined to compare
with the results of EMG activity during
Pilates without resistance and with
resistance. For the quadriceps machine,
the workloads were 9 kg, 15.9 kg, and
22.7 kg for light, medium, and heavy
loads.The loads on the hamstring
machine were set at 9 kg (light), 13.6 kg
(medium), and 18.18 kg (heavy).The
workloads for the abdominal flexion
machine were set somewhat higher at
18.1 kg (light), 36.3 kg (medium), and
54.5 kg (heavy). Finally, workloads were
set at 22.7 kg (light), 29.5 kg (medium),
and 36.3 kg (heavy) for the back extensor
muscles.
Statistical Analysis
Statistical analysis involved the calculations
of means, standard deviations, and
t tests. ANOVA was also used to compare
data between groups.The level of
significance was set at P < 0.05.
RESULTS
Analysis of muscle activity was accomplished
on 4 types of commercial exercise
equipment, a quadriceps machine, a
Table 4. Muscle Use Data from Commercial Weight Lifting Equipment—Standard Deviations
Exercise Abdominals Paraspinals Quads Hams Hip Abs Hip Ads Glut Gastroc
Quad low 2.25 16.29 1.95 1.47 3.14 6.40 9.24 1.75
Quad med 10.19 11.08 4.40 2.16 2.48 6.73 6.50 2.64
Quad high 15.43 12.65 6.09 2.58 5.56 9.34 6.16 2.43
Ham low 7.81 16.55 5.10 8.84 11.53 6.37 10.33 5.62
Ham med 11.40 13.75 4.24 3.79 7.85 6.91 10.98 1.87
Ham high 6.55 19.48 5.34 24.68 10.96 12.35 9.47 1.87
Abd low 4.18 1.87 1.41 4.17 3.03 8.94 8.23 3.27
Abd med 10.33 1.73 1.72 2.10 6.99 4.32 6.57 1.94
Abd high 6.36 1.47 1.05 4.65 1.87 4.43 13.56 3.33
Back low 1.79 11.65 3.76 1.87 6.18 2.62 2.50 6.49
Back med 2.88 16.02 1.05 1.87 6.86 1.41 1.72 1.60
Back high 2.32 15.02 2.73 1.03 1.79 4.43 2.43 6.23
*Quads indicates quadriceps; hams, hamstring; hip abs, hip abductor; hip ads, hip adductor; gluts, gluteus maximus;
and gastroc, gastrocnemius.
166 Vol. 5, No. 1, 2005 • The Journal of Applied Research
hamstring machine, an abdominal flexion
machine, and a back extension
machine, as described under methods.
The results of the analysis of EMG of
the abdominals (abs), paraspinal muscles
(erector spinae), quadriceps, hamstring,
hip abductors/adductor, gastrocnemius,
and gluteus maximus muscles are shown
in Tables 3 and 4. Table 3 shows the
average EMG data, whereas Table 4
illustrates the respective standard deviations.
The exercise was somewhat specific
to the type of machine (Table 3). For
example, exercise on the quadriceps
muscles by leg extension with the lowest
weight yielded muscle activity of 24.85%
maximum strength. For the medium
load, the muscle activity was 33.83%,
and for high loads, it averaged 49.5%.
The loads were different on different
machines. Exercise on each machine
showed a progressive increase in muscle
use associated with an increase in the
workload. However, it was surprising
that the abdominals and paraspinals
were also active. For example, to lift a
medium load on the quadriceps
machine, quadriceps activity was 33.8%
of total muscle activity (Table 3). At the
same time, the abdominal flexors were
18.1% active and paraspinals 25.54%
active. Since the abdominal and
paraspinal muscles are agonist/antagonist
pairs, this seems to show an isometric
component of the exercise, stabilizing
the core muscles to extend the quadriceps
muscles.This was also true during
exercise on the quadriceps and hamstring
machines.
The EMG activity of the quadriceps,
hamstring, gluteus maximus, gastrocnemius,
hip adductors, hip abductors, and
the abdominal and paraspinal muscles is
shown in Tables 5 to 9 for exercise using
Pilates.The specific exercises performed
were the 45° squat, 90° squat (Figure 2),
left hip adduction (Figure 3), right hip
adduction, left hip extension, and right
hip extension. Muscle use was minimal
during Pilates exercise as demonstrated
by the EMG activity (Table 5, 6). In particular,
abdominal activity averaged less
than 10% of the strength of the muscles
during any of the activities listed in
Table 5. Muscle Use for subjects with No Resistance Band During Pilates Exercise as
Percentage of Maximum Activity*
Exercise Abdominal Paraspinal Quads Hams Hip abs Hip ads Glut Gastroc
45° squat 23.7 27.7 28.2 4.8 22.1 20.7 27.2 19.1
90° squat 31.2 37.0 37.5 8.2 28.4 30.7 35.2 26.5
Left hip
adduction 28.1 31.0 23.8 13.0 16.0 13.8 24.9 21.7
Right hip
adduction 24.2 35.1 3.7 11.5 3.8 20.7 34.1 5.3
Left hip
extension 29.9 37.4 29.8 12.3 13.0 9.8 24.3 15.2
Right hip
extension 32.2 42.7 21.7 20.6 13.2 12.6 48.5 11.5
*Quads indicates quadriceps; hams, hamstring; hip abs, hip abductor; hip ads, hip adductor; gluts, gluteus maximus;
and gastroc, gastrocnemius.
The Journal of Applied Research • Vol. 5, No. 1, 2005 167
Table 5. However, some muscles did
become active in specific exercises. The
most difficult exercise was the 90° squat,
in which case the quadriceps muscles
were approximately 40% active (Table
5,6). Thus for the 6 subjects shown in
these experiments, normal extension and
rotation of the hip (hip adduction, hip
abduction, and hip extension) showed
little muscle activity during standard
Pilates exercises. Only when there was a
significant load on the muscle, such as
during the 90° squat, did muscle activity
increase to higher levels.
This was not the result when the
resistance band was added.When the
resistive band was stretched from 0 cm
to 40 cm, there was almost a linear relationship
between load and the distance
stretched (Figure 7). There was a slight
non-linearity at higher loads, although
this fits Hooks Law of elasticity.
However, the maximum distance that
was used to stretch the band during normal
exercise was not even half this
amount (Table 7). For example, during
left hip abduction to a 45° angle of the
hip, the total stretch of the bands was
only 21 cm. This puts the band in the linear
range of force versus stretch and
removes the non-linearity’s that are normally
seen with any elastic structure
under Hook’s Law. As shown in this
table, the greatest degree of stretch in
the band was for hip adduction followed
very closely by hip extension. Band
movement was very slight during 45°
and 90° squats.Thus, for example, the
force exerted on the legs during a left
hip abduction for a typical subject is 12
kg, whereas the force averaged approximately
10.5 kg for hip extension. The
force exerted on legs during squats averaged
4.6 kg for a 45° squat and 5.5 kg for
a 90° squat.
Forty-five degree and 90° squats, as
cited above, have their own inherent
workload placed on the body because of
the fact that body alignment is from the
neutral position where weight is born by
Table 6. Standard Deviation of Muscle Use for Subjects with No Resistance Band During
Pilate Exercise*
Exercise Abdominal Paraspinal Quads Hams Hip abs Hip ads Glut Gastroc
45° squat 4.5 6.9 7.4 2.9 9.3 2.8 7.0 3.7
90° squat 4.3 3.2 13.4 4.9 6.7 6.1 3.9 11.8
Left hip
adduction 4.6 6.4 3.6 4.3 3.8 7.2 3.4 2.6
Right hip
adduction 2.6 3.5 2.2 2.5 1.5 3.9 6.9 3.5
Left hip
extension 4.3 4.0 5.2 2.2 3.7 4.1 2.6 4.3
Right hip
extension 2.9 2.6 2.4 2.9 2.2 4.0 6.1 1.0
*Quads indicates quadriceps; hams, hamstring; hip abs, hip abductor; hip ads, hip adductor; gluts, gluteus maximus;
and gastroc, gastrocnemius.
168 Vol. 5, No. 1, 2005 • The Journal of Applied Research
the joints (Table 8).Weight bearing is no
longer down the axis of the bones and
weight must be compensated for at the
hips, knees, abdominal area, and back
through muscle activity. Therefore, this
exercise provides a good form of exercise.
The bands reduce the amount of
abductor/adductor activity; so with
abductor/adductor activity low, the following
conclusion can be drawn: it is
obvious that there is more stability during
the exercise provided by the bands
than was achieved by voluntary control
of joints, since muscles are not necessary
to stabilize the joints (Table 8).
The results of muscle use during
Pilates without resistance bands are
shown in Table 6, and the standard deviations
are shown in Table 7. The average
muscle use of the subjects with the
resistance bands for Pilates is shown in
Table 8 and the standard deviations for
these measurements are shown in Table
9. Muscle use during the 45° and 90°
squat showed significantly higher use in
the quadriceps, paraspinals, abdominals,
gluteus maximus, and gastrocnemius
muscles in the 90° squat compared to the
45° squat (P < 0.05) (Tables 8 and 9).
The activity of the quadriceps muscles
Table 7. Forces Applied by a Typical
Subject During Exercise with Resistive Band
Exercise Distance (cm) Force (kg)
45° squat 4.5 4.6
90° squat 6.5 5.5
Left hip
adduction 21.5 12.0
Right hip
adduction 21.0 11.8
Left hip
extension 17.5 10.3
Right hip
extension 18.5 10.7
Table 8. Muscle Use for Subjects with Resistance Band During Pilates Exercise as Percentage
of Muscle Strength*
Exercise Abdominal Paraspinal Quads Hams Hip abs Hip ads Glut Gastroc
45° squat 27.1 29.5 27.2 3.3 11.2 11.3 29.0 22.1
90° squat 36.8 42.1 40.4 4.7 9.6 12.6 39.4 29.4
Left hip
adduction 34.2 40.2 47.0 10.8 44.3 20.5 30.6 28.5
Right hip
adduction 45.0 47.7 4.5 10.5 3.7 32.7 44.4 3.7
Left hip
extension 33.4 45.6 21.7 12.5 11.5 13.5 26.4 13.3
Right hip
extension 41.3 51.0 23.0 43.2 16.3 28.0 71.5 17.3
*Quads indicates quadriceps; hams, hamstring; hip abs, hip abductor; hip ads, hip adductor; gluts, gluteus maximus;
and gastroc, gastrocnemius.
The Journal of Applied Research • Vol. 5, No. 1, 2005 169
corresponded to the load on the quadriceps
leg extension machine (commercial
weight trainer) with equivalent activity
between the low and medium load settings
for the 45° squat and was equivalent
to almost the highest load that we
examined for the 90° squat.Therefore,
abdominal and paraspinal activity, during
the 90° squat without resistance, was
higher than that seen on the commercial
weight lifting equipment during quadriceps
activity, but less than during activity
on the abdominal exercising machine.
When resistance was added during
squat exercises with the Pilates resistance
device, intensity of muscle activity
increased in the abdominal, paraspinal,
and quadriceps muscles, while it did not
affect the hamstring muscles.The activity
in the hip abductors/adductors was
reduced by over 50%. Gluteus maximus
activity and gastrocnemius activity
showed no significant difference (P >
0.05). In other words, the resistive device
increased the workload slightly on the
quadriceps and abdominal muscles and
seemed to stabilize the hip joint, but
lowered activity on the hip abductors
and adductors (Tables 8 and 9).
The muscle use during left and right
hip abduction and adduction with and
without the use of the Pilates resistance
device are also shown (Tables 8 and 9).
For example, when performing Pilates
with no resistance, the muscle use for
the abdominals and paraspinals still
remained somewhat high, but was not
statistically different from that used to
stabilize the core during squats (P >
0.05).With electrodes on the right side
of the body, when the left hip was
adducted, quadriceps activity averaged
23.8% of total muscle activity, this being
equivalent to the lowest workload on
the quadriceps leg extension machine.
Hamstring activity was low, but hip
abduction and adduction showed low
levels of activity, while gluteus maximus
activity was high to help stabilize the
body. In contrast, when the opposite leg
was adducted, abdominal and paraspinal
activity again remained at about 25%
with quadriceps activity no longer needed,
while to extend the leg the hip
abductors activity increased to about
20% of total muscle activity. Gluteus
Table 9. Standard Deviation of Muscle Use for Subjects with Resistance Band During
Pilates Exercise*
Exercise Abdominal Paraspinal Quads Hams Hip abs Hip ads Glut Gastroc
45° squat 4.7 5.3 4.3 6.7 5.1 7.3 8.2 5.1
90° squat 7.2 6.4 5.9 5.5 3.7 7.1 5.2 5.3
Left hip
adduction 2.4 2.7 3.7 2.5 2.1 2.5 3.4 5.7
Right hip
adduction 5.5 5.5 1.6 1.4 1.4 2.3 5.5 2.5
Left hip
extension 6.2 13.5 2.2 1.9 3.8 7.8 8.1 5.5
Right hip
extension 9.0 2.3 4.9 4.6 3.2 4.2 7.6 5.4
*Quads indicates quadriceps; hams, hamstring; hip abs, hip abductor; hip ads, hip adductor; gluts, gluteus maximus;
and gastroc, gastrocnemius.
170 Vol. 5, No. 1, 2005 • The Journal of Applied Research
maximus muscle activity also increased
to 34.1% of total muscle activity, whereas
the gastrocnemius muscle was quiescent
because of its lack of use on the
extended leg. In contrast, once the resistive
device was added, muscle activity
changed (Tables 8 and 9). Since the
resistance device provided resistance to
adduction, the increased workload
caused increased activity in the
paraspinals and abdominal muscles
(Tables 8 and 9). For example, during
right hip abduction, (the side the electrodes
were on) muscle activity ranged
from 24% with no resistive device to
45.0% when the resistive device was
used, more than doubling of muscle
activity.This also was true of the
paraspinal muscles. Quadriceps muscles
also worked harder during left hip
abduction, and hip abductors and adductors
doubled their activity during the
exercise. Gluteus maximus muscle activity
increased by approximately 25%, as
did the gastrocnemius muscle.Thus, the
overall effect of adding a resistive device
was to increase workload dramatically
during hip adduction on both the left
and right side of the body. It should be
noted that with the resistance device for
right hip abduction, the abdominal muscle
activity was equal to the highest
abdominal exercise used on the commercial
gym equipment. Thus, the use of
the resistive device provided a substantial
increase in the level of workout
equivalent to that of a heavy workout
on commercial gym equipment, at least
for the abdominal and paraspinal muscles.
Data was also collected showing
muscle activity during left hip extension
and right hip extension. Again here,
electrodes were on the right leg.
Quadriceps were more active during left
hip extension than right hip extension
because when the left hip was extended,
the right quadriceps were used to help
stabilize the body.Therefore, 29.8% of
the quadriceps was active. Further, during
left and right extension, there was
significant activity in the abdominals
and paraspinal muscles, amounting to
about one-third maximum strength of
the muscles as shown in the tables.The
gastrocnemius muscle was slightly active
to stabilize the lower leg but was barely
used during these exercises. The greatest
activity in the gastrocnemius was during
left hip extension since the gastrocnemius
muscle was used to help stabilize
the fixed leg.
The change in muscle use for exercise
involving left and right hip extension
with the Pilates resistance band is
shown in Table 8.With the resistance
band applied, there was a significant (P
< 0.01) increase in activity in the gluteus
maximus, abdominal muscles,
paraspinals, quadriceps muscles, and
hamstring muscles.The hip
abductor/adductors had only a small
increase in activity whereas for the other
muscles, there was a much larger
increase in muscle activity. Obviously,
for the side of body not involved in the
exercise, there was still an increase in
muscle activity but the increase was less
than during active exercise. For example,
when comparing the right hip extension
with no resistance, the EMG activity for
the gluteus maximus muscle on the right
hip was 48.5% of total muscle activity
(Table 6). Muscle activity increased to
71.5% with the resistive band applied.
Abdominal muscle activity, with the
band applied, was over 40% of total
activity. On the commercial weight lifting
equipment, abdominal crunch
machine, this is equivalent to a resistance
of 54.5 kg.Thus, with the resistance
added during Pilates, muscle activity for
the abdominals, paraspinals, gluteus
maximus muscles, and hamstring muscles
was equivalent to workouts exceeding
50 kg on commercial weight lifting
equipment. The difference, however, was
on the weight lifting equipment where
The Journal of Applied Research • Vol. 5, No. 1, 2005 171
the exercise was fairly specific for the
muscle being tested whereas during
Pilates exercise was seen on all 8 muscles
groups examined here.
However, during hip adduction/
abduction and extension/flexion, the
additional load caused substantial
increases in EMG activity.This is not
surprising since the resistance band was
placed halfway between the hip joint
and the knee. As such then, by placing
the resistance further away from the
actual hip, the body had to work against
a lever arm to extend the band.
Therefore, the resistance of the band
was amplified providing average muscle
activity for the hip abductors of 44.3%
(Table 8) compared to 13% with no
band being used (Table 6).Thus exercise
was substantially higher in intensity
using the band for the exercises examined
here.
Probably the best example of the
high work levels being accomplished is
to compare exercise on conventional
weight lifting equipment to exercise with
Pilates. Lifting 3 progressive loads during
quadriceps leg extension, hamstring
flexion, and other exercise, as shown in
Table 4, established an equivalent workload
to compare Pilates against. Muscle
activity during Pilates with the bands
was equivalent to the medium weight
level on commercial exercise equipment.
However, as noted in Table 4, most of
the muscles were quiescent on these
pieces of equipment except for the muscle
being studied, ie, a quadriceps
machine exercised the quadriceps muscle.
In performing Pilates with a resistive
band, all muscles were active, providing
a more balanced workout for more muscle
groups than provided on one piece
of commercial exercise equipment
alone.
DISCUSSION
It has been estimated in a recent magazine
article in Newsweek that over 5 million
people are using Pilates for exercise
in the United States.21 Harvard’s
Women’s Health Watch promotes
Pilates as a good, safe method for exercise
and conditioning.22 Chiropractors
have also promoted Pilates for the treatment
of adult scoliosis.20 Pilates has also
been used with acutely ill hospitalized
adults.17While Pilates has been effective
for treating lower back pain and other
disorders,18 it provides only minimal
resistance exercise.17Without resistance
during exercise, aerobic demand is not
at a high enough level to reduce inflammatory
cytokines, and increase whole
body metabolism for weight control.
29,10,13 Thus to reduce leptin and reduce
cytokines, heavier exercise is necessary.30
In the present investigation, the use of a
resistive device during Pilates increased
the workload dramatically.The workload
for Pilates alone in the present
investigation was very light averaging
20% of the total muscle activity for the
hamstring, quadriceps, and gluteus maximus
muscles respectively.With the addition
of resistive bands, the workload
dramatically increased by at least 50%.
This increase in muscle activity, in turn,
will be beneficial for weight loss, muscle
conditioning (firming, toning, and
strength conditioning), and reducing
inflammatory cytokines associated with
diabetes and obesity.When compared to
conventional weight lifting equipment,
the exercise load is moderate. Much
heavier activity in muscles can be seen
with the use of conventional weight lifting
equipment as shown in the present
investigation, but such heavy loads
would be detrimental to patients with
disabilities or individuals wishing to simply
increase aerobic fitness and muscle
tone. Commercial weight lifting equipment
generally causes an increase in
muscle strength and hypertrophy in
muscle without aerobic conditioning.31
Therefore, the goals of lifting with conventional
weight lifting equipment are
172 Vol. 5, No. 1, 2005 • The Journal of Applied Research
very different than that of aerobic exercise.
By adding a resistive device to
Pilates, aerobic exercise can be done at a
much greater level and should increase
muscle tone more effectively than
Pilates without the resistance device.
An added benefit of the resistive
device is that by using an oblong resistive
device that can circumvent the limb,
the joints are stabilized and kept in
alignment during exercise (ie, helps to
guide the user through the movement).
From an orthopedic standpoint, this
places less stress on knees, hips, and
ankle joints as well as upper body joints,
so that there is less chance of injury. The
present investigation then, showed a
marked advantage in using this device
during Pilates.
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