TITLE: Effect of pelvic floor muscle exercises on pulmonary function

  ABSTRACT:
[Purpose] This study aimed to determine the correlation between pelvic floor muscle
strength and pulmonary function. In particular, we examined whether pelvic floor muscle
exercises can improve pulmonary function. [Subjects] Thirty female college students aged
19–21 with no history of nervous or musculoskeletal system injury were randomly divided
into experimental and control groups. [Methods] For the pulmonary function test,
spirometry items included forced vital capacity and maximal voluntary ventilation. Pelvic
floor muscle exercises consisted of Kegel exercises performed three times daily for 4
weeks. [Results] Kegel exercises performed in the experimental group significantly
improved forced vital capacity, forced expiratory volume in 1 second, PER, FEF 25–75%, IC,
and maximum voluntary ventilation compared to no improvement in the control group.
[Conclusion] Kegel exercises significantly improved pulmonary function. When abdominal
pressure increased, pelvic floor muscles performed contraction at the same time.
Therefore, we recommend that the use of pelvic floor muscle exercises be considered for
improving pulmonary function.

BODY.INTRODUCTION:
The pelvic floor muscles (PFM) primarily protect the endopelvic organs but are also
involved in breathing during speaking, deep breathing, and coughing1). Speaking, deep breathing, and coughing occur as the
diaphragm rises due to increased abdominal pressure. Here the abdominal and PFM generate
pressure through their co-contraction2).
PFM contraction protects the endopelvic organs against increased abdominal pressure under
the body's certain reactions such as deep breathing and coughing and helps breathing by
relieving anal and urethral obstructions3).
Therefore, PFM exercises should be included in efforts to improve pulmonary function.
Although the PFM have breathing-related functions, most related studies have investigated
urological diseases4, 5). However, a few studies have examined the effects of PFM
reinforcement on pulmonary function. Most studies have reported that Kegel exercises
reinforce the PFM6). Meanwhile, a recent
study by Park7) attempted to identify the
effects of one-time Kegel exercises on pulmonary function and reported that the vital
capacity was improved in certain categories. However, one-time Kegel exercises may not be
sufficient for reinforcing the PFM. Therefore, the purpose of this study was to examine the
effects of self-disciplined Kegel exercises performed for 4 weeks on PFM strength and
determine whether PFM reinforcement could improve pulmonary function.

BODY.SUBJECTS AND METHODS:
The subjects of this study were 30 female students at S University in Busan City who fully
understood the study's purpose and methods and agreed to participate in it. This study
complied with the ethical standards of the Declaration of Helsinki, and written informed
consent was obtained from each participant. Selection criteria were: no past history of
nervous, musculoskeletal, or heart-lung system disease (any of which could affect our
experiment); no history of participating in pulmonary function promotion exercise programs;
and agreeing not to perform any other exercises during the experiment. The subjects were
randomly divided into a Kegel exercise group and a control group that received no treatment
(n = 15 each). Two individuals in both the test and control groups did not participate in
the second round of measurements; therefore, their measured values were excluded from the
collected data. The control group had an age of 20.23 ± 0.78 years, height of 159.13 ±
3.62 cm, and weight of 55.20 ± 6.67 kg, while the experimental group had an age of 20.41 ±
0.84 years, height of 158.30 ± 4.70 cm, and weight of 54.14 ± 5.88 kg. A digital Pony FX
microspirometer (Cosmed Inc, Italy) was used to measure pulmonary function by determining
the amount and velocity of air that enters and exits the lung. This study measured forced
vital capacity (FVC) and maximal voluntary ventilation (MVV).  The FVC measurement was made while the subjects were sitting on a chair with their limbs
and shoulders straight and legs spread shoulder-width apart and perpendicular to the ground.
They were then instructed to close their nose using a nose clamp and hold the measuring
instrument with one hand and let it nip the mouth. Measurements were taken while the
subjects breathed normally three or four times and then took a deep and fast inspiration
followed by a fast expiration. The expiratory breath was maintained for 6 seconds. The MVV
was then measured with the subjects in the same position. The subjects were led to perform
inspiration and expiration for 12 seconds in the deepest and fastest manner. Each
measurement was taken three times, and the average value of each was used in the analysis.
The first round of measurements was taken before the start of the Kegel exercises, while the
second round of measurements was taken after the end of the 4-week Kegel exercises course.
Kegel exercises have been shown to help reinforce the PFM8). The ready position of Kegel exercises was lying on the floor with
the knees bent and the soles touching (frog position). Next, without contracting the
abdominal, lumbar, gluteal, and lower-limb muscles, the subjects slowly contracted only the
PFM for 5 seconds; at the fifth second, they performed a maximum contraction of the muscle.
The subjects relaxed at the sixth second and performed a fast contraction and relaxation
between the seventh and ninth seconds, then rested at the tenth second. One set of exercises
included performing ten sets of the above exercise twice. A 40-second break was provided
between sets.  The statistical program SSPWIN (ver 21.0) was used for the analysis, and the statistical
significance level was set at α = 0.05. This study used paired t-tests to compare the test
and control groups before and after the exercises, and an analysis of covariance test was
conducted to identify differences in variations between the two groups.

BODY.RESULTS:
The changes in pulmonary functions of the test group before and after Kegel exercises were
as follows. Among the lower-level categories of FVC, the FVC increased from 2.75 L to 3.13 L
(p < 0.05), FEV1 increased from 2.39 L to 2.78 L (p < 0.05), PEF increased
from 4.48 L to 5.97 L (p < 0.05), FEF 25–75% increased from 2.83 L to 3.48 L (p <
0.05), and FVC increased from 1.53 L to 1.81 L (p < 0.05). These increases were all
statistically significant. On the other hand, while the FEV1/FVC increased from
87.15% to 89.19%, this result was not statistically significant. The MVV increased from
84.88 L to 112.62 L, a difference that was statistically significant (p < 0.05) (Table 1Table 1.Pulmonary function changes by groupGroupPre-exercisePost-exerciseFVCFVC(L)*Experimental2.75±0.473.13±0.47Control3.06±0.312.98±0.36FEV1 (L)*Experimental2.39±0.512.78±0.38Control2.48±0.252.33±0.49PEF (L/s)*Experimental4.48±1.425.97±1.49Control4.66±0.774.46±1.34FEV1/FVC (%)Experimental87.15±7.9389.19±6.64Control81.32±7.0578.44±14.55FEF 25–75% (L/s)Experimental2.83±0.983.48±0.77Control2.50±0.562.94±0.87IC (L)Experimental1.53±0.371.81±0.30Control1.75±0.211.77±0.28MVVMVV* (L/min)Experimental84.88±13.23112.62±19.92Control92.41±8.8091.48±7.74Mean ± SD, *p < 0.05).  Changes in pulmonary functions of the control group were also examined between the first
and second measurements rounds. The FVC decreased from 3.06 in the first round of
measurements to 2.98 in the second round of measurements, FEV1 declined from 2.48
to 2.33, FEV1/FVC decreased from 82.50 to 75.81, PEF decreased from 4.66 to 4.46,
FEF decreased from 2.57 to 2.50, and FIC decreased from 1.65 to 1.64. However, these changes
were not statistically significant. While the MVV increased from 85.56 to 90.80, this result
was also not statistically significant (p > 0.05) (Table 1).  Comparison of changes in pulmonary functions of the test and control groups showed the
following. The test group showed increases in FVC (p < 0.05), FEV1 (p <
0.05), and PEF (p < 0.05), whereas the control group exhibited decreases in the same
variables. These results were statistically significant. For FEV1/FVC, the test
group showed an increase and the control group exhibited a decrease, but these changes were
not statistically significant. In addition, both the test and control groups revealed
increased FEF 25–75% and FIC without statistical significance. For MVV, the test group
showed an increase and the control group exhibited a decrease. These differences were
statistically significant (p < 0.05) (Table
1).

BODY.DISCUSSION:
In normal breathing, inspiration refers to the entry of external air into the body as the
diaphragm contracts and moves downwards, while expiration refers to the relaxation and
upward movement of the contracted diaphragm. However, when forced expiration or coughing
occurs, the anterior and lateral abdominal muscles contract, thereby generating pressure
that strongly moves the diaphragm upward. Here PFM contraction helps maintain the abdominal
pressure. From this viewpoint, the PFM and deep abdominal muscles are involved in breathing
through their concerted contractions9).  This study used Kegel exercises to reinforce the PFM8). The reinforcement of the PFM through Kegel exercises improved the
lower-level FVC categories. This result verifies that PFM reinforcement through Kegel
exercises has positive effects on improving the FVC, which requires increases in
intra-abdominal pressure. This finding coincides with those of a study by Sapsford10), which showed that PFM contraction
generated forced expiration when conditions requiring increases in abdominal internal
pressure occurred, such as nose blowing, coughing, and sneezing. In addition, the FVC
measured in the present study included the process of forced expiration after maximal
inspiration. Eventually, the PFM that was reinforced when intra-abdominal pressure increased
during the process of forced expiration may have also performed co-contraction, thereby
reinforcing forced expiration, which subsequently increased the FVC. The MVV, another
variable tested in this study, also increased. The MVV is measured after breathing for 12
seconds in the deepest and fastest manner; thus, it increases intra-abdominal pressure.
Since increased intra-abdominal pressure activates the PFM, the MVV may have increased after
Kegel exercises.  This study has a certain limitation. It was conducted based on the assumption that a 4-week
Kegel exercise program reinforced the PFM, but it did not directly confirm this hypothesis.
In other words, this study measured the vital capacity based on the result of preceding
research that Kegel exercises performed for 4 weeks reinforced the PFM. Therefore,
additional studies are required to verify that Kegel exercises directly reinforce the PFM
and then identify the correlation between PFM reinforcement and pulmonary function.

Question: Compared to Control what was the result of Kegel exercises program on Maximum Voluntary Ventilation?
Evidence: The test group showed increases in FVC (p < 0.05), FEV1 (p <
0.05), and PEF (p < 0.05), whereas the control group exhibited decreases in the same
variables. These results were statistically significant. 
Answer: significantly increased