Keywords
female - quality of life - physical examination - sleep
Introduction
Pilates exercise was invented by Joseph Pilates in the 1920s. Its original name was
“Contrology” because it places emphasis on the control of the body position and movement.[1] Exercises are floor-based, or involve the use of specialized equipment, which provides
adjustable spring resistance. The traditional principles of Pilates exercise include
centering (tightening of the “powerhouse” [trunk muscles]), concentration (cognitive
attention while performing the exercises), control (postural management while performing
the exercises), precision (accuracy of the exercise technique), and flow (smooth transition
of movements within the exercise sequence).[2]
The Pilates method includes several stretching and strengthening exercises, which
can be divided into two categories: mat Pilates, and exercises with the Pilates apparatus.
The first set of exercises is performed on the ground, without any specific equipment,
while Pilates apparatus includes exercises against resistance provided by springs
and pulleys.[3]
Over the last few years, Pilates has become popular as a holistic exercise focused
on respiration, body control, and accuracy of movements.[4] Current evidence suggests the positive effects of Pilates on respiratory muscle
strength, balance, quality of life, and overall physical performance.[5] Moreover, in a recent systematic review and meta-analysis, it was found that Pilates
is an alternative exercise to improve maximal oxygen uptake (VO2max) values.[5]
The aim of the present study was to evaluate the effect on quality of sleep, aerobic
capacity, and anaerobic power of four months of Pilates training in premenopausal
women. Premenopausal women were selected in order to avoid vasomotor (hot flashes,
night sweats, or both) and genitourinary symptoms associated with menopause, which
affect most menopausal women, and could alter the results of the present study, including
sleep quality and quality of life.[6]
[7]
Materials and Methods
Design
The present is a prospective observational study of pre- and postexercise measurement
comparison with a control group that does not follow an exercise program.
Participants
The sample consisted of 53 premenopausal women, 40 of whom formed the intervention
group, and 13 of them were the control group. Premenopausal women were those reporting
normal length of menstrual cycle without any vasomotor or genitourinary symptoms.
Also, the premenopausal period was defined as the period before women begin presenting
signs of menopause, such as variable menstrual cycles (≥ 7 days difference in the
length of consecutive menstrual cycles), or amenorrhea for ≥ 60 days.[8]
We made a call of interest in a Pilates gym, to which 72 women responded; from the
respondents, we selected 40 (55.5%) that fulfilled the enrollment criteria of the
study. In addition, we also invited women to participate in the control group, and
of them, we selected 13 that fulfilled the enrollment criteria, and were mainly not
participating in systematic exercise. This was a convenience sample, based on personal
preference for systematic Pilates exercise or not. The control group received exercise
on demand, or according to their preference, but not systematically or under supervision.
The two groups, however, had similarities in somatometric characteristics. The participants
did not have any specific ability, nor did they have any specific athletic profile.
The inclusion criteria for the participants were: a) voluntary participation; b) being
premenopausal; c) having a healthy physical condition, without contraindications to
exercise by a doctor; d) exclusive performance of exercise through the ground Pilates
method for the intervention group; e) body mass index (BMI) between 20 kg/m2 and 30 kg/m2; and f) no recent or current practice of physical exercise or sports activities.
The exclusion criteria were: a) duration of the previous exercise; b) other exercises
in parallel with this program (not allowed); c) pregnancy; d) serious health issues
(such as cardiorespiratory, systemic, or musculoskeletal issues); e) prohibition of
participation in Pilates exercises by the doctor; and f) taking medication.
Intervention: Pilates Program
Pilates training included at least 16 weeks (4 months) with at least 3 workout sessions
per week. The training lasted 60 minutes. We started with 15 minutes of balance and
proprioceptive exercises to strengthen joints and ligaments, and improve balance.
During these exercises, the participants were in a standing position and trained all
muscle groups in combination. The strength always began from the center of the body
(powerhouse) and lasted 1 minute. Active recovery followed each exercise, with stretching
of the muscle groups that we had worked on ([Table 1]).
Table 1
Example of a daily workout session in a Pilates training program
|
Type of exercise
|
Duration (min)
|
Exercise intensity (beats/min)
|
|
Balance and proprioceptive exercise
|
15
|
120
|
|
(1 min per drill with 10 s of recovery)
|
|
|
|
Body weight and alternative instruments exercises
|
25
|
150
|
|
(1–3 min per drill with 10 s of recovery)
|
|
|
|
Support exercises for the whole body and all muscle groups
|
10
|
160–180
|
|
(1–2 min per drill with 10 s of recovery)
|
|
|
|
Full body stretching exercise
|
10
|
< 100
|
Then, from a stable position and based on the principles of coaching, the time and
intensity of the exercises progressively increased. For 25 minutes, we chose exercises
using the weight of the body and alternative instruments, with the weight not exceeding
1 kg (based on the principle of Pilates), while the heartbeats reached 150 b/min,
thus improving along with the strengthening of the muscles and the aerobic capacity
of the trainees. The duration of each exercise ranged from 1 to 3 minutes, with a
break of 10 seconds, always followed by active recovery (stretching of the corresponding
muscle group after each exercise). We worked with concentric and isometric exercises
for the rectus and lateral abdominal muscles, lower transverse muscles, perineal muscles,
cervical thoracic lumbar spine, arms, and legs. Strength always started from the center
of the body, whilst we aimed for a good lumbopelvic control. For the next 10 minutes,
we were working with support exercises, from 1 to 2 minutes, for the whole body and
all muscle groups, with active recovery at 160-180 b/min, thus exercising on anaerobic
power. We always ended our Pilates workout with stretching (full body stretches) for
the last 10 minutes, focusing on the lumbar spine. All exercises were performed free
of charge, with alternative instruments (balls, ring, tires, and straps).
Instrumentation
The examined variables were muscle strength, aerobic capacity, anaerobic endurance
(cardiorespiratory endurance), balance, flexibility, and quality of sleep, in premenopausal
women. More specifically, the following tests were performed before and after the
intervention:
-
the Harvard Step test, which is a test of aerobic fitness. The participant steps up
and down on the platform at a rate of 30 steps per minute (every 2 seconds) for 5 minutes
or until exhaustion. Exhaustion is defined as when the participant cannot maintain
the stepping rate for 15 seconds. The participant immediately sits down on completion
of the test, and the total number of heartbeats is counted between 1 to 1.5 minutes
after finishing, between 2 to 2.5 minutes, and between 3 to 3.5 minutes. The fitness
index is equal to the following equation: (100 x test duration in seconds) divided
by (2 x the sum of heartbeats in the recovery periods).[9]
-
the Bosco Repeat Jump, which is a test for anaerobic power. The aim is to perform
the highest number of jumps with maximum height in the set time. Jump height is calculated
using a timing mat, which measures the time the feet are off the mat (flight time)
and time on mat (contact time).[10]
-
the Flamingo Balance Test for balance assessment. The participants stood upright on
their fully stretched leg on a special wooden beam (50 × 3 × 4 cm), flexed the free
leg at the knee, and gripped the foot with the hand on the same side. We recorded
the number of falls that occurred in 1 minute of balancing.[11]
-
the Sit and Reach test for flexibility assessment. The participants sat on the floor
with their legs stretched out in front of them, with knees straight and feet flat
against the front end of the test box. With the palms facing downwards, and the hands
side by side, the participants reached forward along the measuring line, as far as
possible. We recorded the nearest centimeter as the distance reached by the hand.[12]
For the assessment of sleep quality, the SOMNOcheck micro-CARDIO (Weinmann Emergency
Medical Technology, Hamburg, Germany) was used, which was administered to each participant
for overnight use at home. This device is routinely used by sleep units for screening
patients against sleep apnea. Each participant was trained as far as the device usage
was concerned, regarding both continuous overnight oximeter and pulse measurement,
and nasal cannula for inspiration expiration recording. This machine is suitable for
identifying apneas and hypopneas, awakenings and arousals, as well as desaturations
for medical use.[13]
[14]
Moreover, insomnia was measured using the Athens Insomnia Scale (AIS)[15] and sleepiness (somnolence) was measured using the Epworth Sleepiness Scale (ESS).[16] The measurements were performed before and after the intervention in the intervention
group.
Ethical Approval
The protocol was approved by the Ethics Committee of the Department of Nursing of
National and Kapodistrian University of Athens (register number: 258-20/5/2019). The
participants were informed in writing and orally about the purpose of the study, and
their written consent was obtained. Personal data of the patients remained anonymous
at all stages of the study.
Statistical Analysis
Data were analyzed using the IBM SPSS Statistics for Windows, version 26.0 (IBM Corp.,
Armonk, NY, United States). Variables were tested for normality, and descriptive statistics
(mean ± standard deviation [SD], frequencies) were reported. For the comparison between
the control group and the intervention group, the t-test for independent samples and
the Mann-Whitney test were performed. For the comparison between the pre- and postexercise
measurements, the t-test for dependent samples and Wilcoxon test were performed. The alpha level was
set at 0.05.
Results
The study sample consisted of 53 women, 13 of whom were the control group and 40 of
whom the intervention group. [Table 2] presents the demographic characteristics of the study participants. The two groups
had similarities regarding age, smoking habits, and BMI.
Quality of Sleep
At baseline, the two groups were similar regarding sleep quality, as assessed by the
SOMNOcheck micro-CARDIO. Moreover, the AIS score (2.54 ± 0.88 versus 2.23 ± 1.05;
p =0.336) and the Epworth score (2.46 ± 0.52 versus 2.68 ± 0.97; p = 0.002) did not differ between the control group and the intervention group at baseline.
After 4 months of Pilates, the intervention group had a significantly lower AIS score
(1.73 ± 0.75 versus 2.23 ± 1.05; p < 0.001) and Epworth score (2.05 ± 0.59 versus. 2.68 ± 0.97; p < 0.001) than at baseline. Moreover, the autonomic arousal index (AAI) (26.09 ± 7.80
versus. 30.47 ± 10.44; p = 0.002) and the non-respiratory AAI (24.18 ± 7.57 versus 27.85 ± 11.01; p = 0.018) were significantly improved after 4 months of Pilates ([Table 3]).
Table 2
Demographic characteristics of participants per group
|
Control group
|
Intervention group
|
|
|
n = 13
|
n = 40
|
p-value
|
|
Age (in years): mean( ± standard deviation)
|
34.00(± 6.38)
|
37.65(± 8.28)
|
0.152
|
|
Smoking: n (%)
|
|
|
0.340
|
|
No
|
10 (76.9%)
|
25 (62.5%)
|
|
|
Yes
|
3 (23.1%)
|
15 (37.5%)
|
|
|
Body mass index (kg/m2): mean(± standard deviation)
|
20.82(± 2.09)
|
21.82(± 2.46)
|
0.190
|
Muscle Strength, Aerobic Capacity, Anaerobic Endurance, Balance, Flexibility
At baseline, the two groups had similarities in the fitness index (Harvard Step test),
the Six-Minute Walk test, Sit and Reach test, the Flamingo test, anaerobic power,
muscle strength, and abdominal muscle endurance. After 4 months of Pilates, the intervention
group presented significant improvement in the fitness index (Harvard Step test) (74.8 ± 11.2
versus 59.4 ± 9.66; p < 0.001), in the distance walked in the Six-Minute Walk test (935.00 ± 186.77 m versus
713.58 ± 183.59 m; p < 0.001), in muscle strength (25.91 ± 4.19 N versus 23.59 ± 3.83 N; p < 0.001), in flexibility (29.97 ± 6.56 cm versus 26.79 ± 6.64 cm; p < 0.001], in balance (2.23 ± 1.87 versus 4.20 ± 1.68; p < 0.001) and in abdominal muscle endurance (19.03 ± 2.75 versus 14.76 ± 2.91; p < 0.001) compared to the baseline values ([Table 4]).
Table 3
AIS and ESS scores, AHI, AAI, and sleep characteristics in both groups and after 4
months in the intervention group
|
CG (n = 13)
|
IG (n = 40)
|
CG versus baseline IG
|
IG: baseline versus after
|
CG versus after IG
|
|
Baseline
|
After
|
|
Mean(±SD)
|
Mean(±SD)
|
Mean(±SD)
|
p-value
|
p-value
|
p-value
|
|
AIS
|
2.54 (± 0.88)
|
2.23 (± 1.05)
|
1.73 (± 0.75)
|
0.336
|
< 0.001
|
0.002
|
|
ESS
|
2.46 (± 0.52)
|
2.68 (± 0.97)
|
2.05 (± 0.59)
|
0.454
|
< 0.001
|
0.031
|
|
AHI (apnea- hypopnea/hour ofsleep)
|
3.32(± 2.15)
|
2.61(± 1.95)
|
2.22(± 1.52)
|
0.287
|
0.220
|
0.111
|
|
ΑΙ (apnea/hour of sleep)
|
1.06(± 1.20)
|
0.69 (± 0.72)
|
0.66 (± 0.69)
|
0.107
|
0.432
|
0.087
|
|
ΗΙ (hypopnea/hour of sleep)
|
2.35 (± 1.86)
|
2.20 (± 1.59)
|
1.50 (± 1.12)
|
0.286
|
0.241
|
0.24
|
|
OAHI/hour of sleep
|
0.79 (± 0.71)
|
1.11 (± 1.36)
|
0.83 (± 0.84)
|
0.835
|
0.106
|
0.755
|
|
CAHI/hour of sleep
|
1.70 (± 1.83)
|
1.41 (± 1.18)
|
1.20 (± 0.98)
|
0.868
|
0.358
|
0.914
|
|
Snoring
|
4.88 (± 9.06)
|
7.36 (± 4.34)
|
1.78 (± 3.64)
|
0.091
|
0.766
|
0.090
|
|
AAI (arousals/hour of sleep)
|
28.32 (± 13.30)
|
30.47 (± 10.44)
|
26.09 (± 7.80)
|
0.736
|
0.002
|
0.302
|
|
Respiratory AAI (arousals/ hour of sleep)
|
2.73 (± 3.27)
|
3.16 (± 5.81)
|
1.90(± 1.41)
|
0.828
|
0.751
|
0.794
|
|
Non-respiratory AAI (arousals/ hour of sleep)
|
26.87 (± 12.72)
|
27.85 (± 11.01)
|
24.18(± 7.57)
|
0.794
|
0.018
|
0.367
|
|
RERA
|
0.96 (± 1.70)
|
0.49 (± 0.83)
|
0.55 (± 0.98)
|
0.801
|
0.974
|
0.850
|
Abbreviations: AAI, autonomic arousal index; ΑΗΙ, apnea-hypopnea index; AI, apnea
index; CAI, central apnea index; CG, control group; ESS, Epworth Sleepiness Scale;
HI, hypopnea index; IG, intervention group; ΟΑHΙ: obstructive apnea-hypopnea index;
RERA, respiratory effort related arousal; SD, standard deviation.
Quality of Life
After 4 months of Pilates, the intervention group presented significant improvement
in the scores on the general health (79.05 ± 2.12 versus 76.13 ± 2.13; p = 0.005) and social functioning (88.75 ± 2.32 versus 84.38 ± 2.68; p = 0.005) subscales of the 36-Item Short Form Health Survey (SF-36) compared to the
baseline values ([Table 5]).
Table 4
Fitness Index, Six-Minute Walk test, Sit and Reach test, Flamingo test, anaerobic
power, muscle strength, and abdominal muscle endurance in both groups at baseline
and after 4 months
|
CG (n = 13)
|
IG (n = 40)
|
CG versus baseline IG
|
IG: baseline versus after
|
CG versus after IG
|
|
Baseline
|
After
|
|
Mean (± SD)
|
Mean (± SD)
|
Mean (± SD)
|
p-value
|
p-value
|
p-value
|
|
Fitness Index (Harvard Step test)
|
64.1 (± 8.83)
|
59.4 (± 9.66)
|
74.8 (± 11.2)
|
0.120
|
< 0.001
|
0.002
|
|
Six-Minute Walk test:
distance in meters
|
835.6 (± 249.1)
|
713.58 (± 183.59)
|
935.00 (± 186.77)
|
0.063
|
< 0.001
|
0.132
|
|
Bosco Repeat Jump
|
24.00 (± 4.00)
|
23.73 (± 3.90)
|
24.20 (± 3.50)
|
0.701
|
0.084
|
> 0.999
|
|
Muscle strength (Newtons)
|
21.96 (± 2.24)
|
23.59 (± 3.83)
|
25.91 (± 4.19)
|
0.154
|
< 0.001
|
0.002
|
|
Sit and Reach test (cm)
|
26.00 (±7.22)
|
26.79 (± 6.64)
|
29.97 (± 6.56)
|
0.926
|
< 0.001
|
0.093
|
|
Flamingo test (total number of falls or loss of balance in 60 seconds)
|
3.31 (± 1.32)
|
4.20 (± 1.68)
|
2.23 (± 1.87)
|
0. 072
|
< 0.001
|
0.046
|
|
Abdominal muscle endurance (number of correctly performed folds in 30 seconds)
|
16.69 (± 3.15)
|
14.76 (± 2.91)
|
19.03 (± 2.75)
|
0.087
|
< 0.001
|
0.007
|
Abbreviations: CG, Control group; IG, Intervention group; SD, standard deviation.
Table 5
Quality of life parameters in both groups and after 4 months in the intervention group
|
Parameter
|
CG (n = 13)
|
IG (n = 40)
|
CG versus baseline IG
|
IG: baseline versus after
|
CG versus after IG
|
|
Baseline
|
After
|
|
Mean (± SD)
|
Mean (± SD)
|
Mean (± SD)
|
p-value
|
p-value
|
Mean (± SD)
|
|
Physical functioning
|
93.9 (± 12.1)
|
93.38 (± 1.69)
|
93.18 (± 1.38)
|
0.739
|
0.491
|
0.377
|
|
Limiting roles due to physical health
|
78.9 (± 20.0)
|
91.25 (± 3.17)
|
90.63 (± 3.32)
|
0.010
|
0.317
|
0.013
|
|
Physical pain
|
93.1 (± 15.9)
|
83.50 (± 2.05)
|
84.44 (± 2.32)
|
0.006
|
0.572
|
0.008
|
|
General health
|
90.4 (± 11.4)
|
76.13 (± 2.13)
|
79.05 (± 2.12)
|
0.001
|
0.005
|
0.005
|
|
Emotional wellness
|
85.9 (± 15.4)
|
69.60 (± 2.85)
|
69.60 (± 2.85)
|
0.002
|
> 0.999
|
0.002
|
|
Social functioning
|
85.6 (± 15.18)
|
84.38 (± 2.68)
|
88.75 (± 2.32)
|
0.914
|
0.005
|
0.414
|
|
Limiting roles due to emotional problems
|
79.5 (± 21.7)
|
82.50 (± 4.77)
|
82.50 (± 4.77)
|
0.302
|
> 0.999
|
0.302
|
|
Energy - Fatigue
|
78.9 (± 12.4)
|
68.88 (± 2.13)
|
68.88 (± 2.13)
|
0.012
|
> 0.999
|
0.012
|
Abbreviations: CG, control group; IG, intervention group; SD, standard deviation.
Discussion
The goal of the present study was to examine if the regular practice of Pilates exercises
increases the quality of sleep and the general activity level in premenopausal women.
The main findings are that the systematic Pilates exercise improves quality of sleep
(arousals), ESS (somnolence), AIS (insomnia), quality of life, and general physical
activity.
Our study showed that Pilates improved both insomnia and sleepiness, which is particularly
important for good sleep. Similar results were found by Leopoldino et al.;[17] in their study, the level of sleepiness showed significant improvement after 12
weeks of Pilates.[17] The American Sleep Disorders Association has recognized physical activity as a nonpharmacological
intervention that is highly effective for improving sleep patterns, enhancing the
levels of daytime sleepiness,[17] increasing the levels of serotonin, the synchronization of the biological clock,
and the indirect improvement in thermoregulation.[18]
In addition, systematic Pilates exercise improved the AAI, which is the most important
factor to evaluate the quality of sleep. The less the awakenings during sleep, the
better the quality of sleep. In a recent meta-analysis, the autjors[19] found that the Pilates group had significantly lowered the total score on the Pittsburgh
Sleep Quality Index (PSQI) compared with the nonexercising control group, whereas
no significant improvement in use of sleep medication was observed. Ashrafinia et
al.[20] showed that Pilates exercises appeared to improve sleep quality in primigravida
postpartum women. The intervention group showed a significant improvement in subjective
sleep quality, sleep latency, daytime dysfunction, and total PSQI score (p < 0.001); however, there was no difference in sleep duration, habitual sleep efficiency,
and sleep disturbance between the groups.[20]
Moreover, Pilates improves muscle strength, flexibility, balance, and abdominal muscle
endurance in premenopausal women. Kloubec[2] demonstrated that in active middle-aged men and women, exposure to Pilates exercise
for 12 weeks, for two 60-minute sessions per week, was enough to promote statistically
significant increases in abdominal endurance, hamstring flexibility, and upper-body
muscular endurance. Participants did not demonstrate improvements in either posture
or balance when compared with the control group.[2]
In the present study, there was a significant improvement in the general health and
social functioning subscales of the SF-36 in the Pilates group. These results are
similar to other studies, which have reported that the Pilates method increased the
ratings regarding general health, physical aspects, bodily pain, and functional capacity.[17]
[21]
A possible limitation of the present study is the relatively small number of participants;
however, the results are clear, and the involvement of the control group for the baseline
measurements strengthens the results of the study. Nevertheless, these results need
to be further investigated.
Conclusions
Pilates exercises appeared to improve sleep quality (AAI, AIS, and ESS) in premenopausal
women, as well as muscle strength, anaerobic fitness, anaerobic power, balance, flexibility,
general health, and quality of life (SF-36).
