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Paper text:
commonly , the muscles of the pelvic floor ( pfm ) support the abdomen and pelvic viscera . 
 during periods of increased intra - abdominal pressure ( iap ) , such as coughing or breathing , 

the pfm are engaged to maintain the position of the bladder neck and assist with urethral 
 and anal closure1 . additionally ,
when iap 
 is increased , the pfm play a significant role in the maintenance of iap .
contractions of the pfm are always combined with activity of the 
 abdominal muscles because the abdominal cavity acts like a  balloon3 .
thus , the pfm work in synergy with the anterolateral 
 abdominal muscles and diaphragm to modulate and respond to changes in iap4 .
hodges et al.5 reported that when iap is increased by talking , deep breathing , and 
 coughing , pressure is distributed in all directions due to the organs and ascites in the 
 abdominal cavity .
therefore , the pfm , diaphragm , and abdominal muscles contract together to 
 protect the organs against the pressure and thus contribute to respiration .
these muscles 
 also act as one unit at the center of functional kinetic chains6 .
sapsford and hodges3 confirmed that the increases in vaginal electromyography ( emg ) and 
 pressure during this strong abdominal maneuver were the same as the increases that occur 
 during a maximal pfm contraction . as a result ,
co - activation of the abdominal muscles and pfm is consistent with the pattern 
 that they work together in a coordinated manner to increase pressure in the abdomen and 
 support the pelvic organs .
in addition , co - activation of these muscles has been reported 
 during lifting , coughing , and forced expiratory efforts3 , 4 .
therefore , contraction of 
 the pfm modulates breathing and is involved in changes of iap with the diaphragm5 . in other words , both the diaphragm and pfm 
 move caudally during inspiration and cranially during expiration7 , however , even though the pfm are related to breathing , most 
 studies of the pfm have investigated urinary system diseases , and there is a lack of studies 
 regarding the pfm and the respiratory system .
the present study therefore attempted to 
 identify the effect of respiratory muscle activity and maximal voluntary ventilation ( mvv ) 
 on the contraction of the pfm .
the subjects were 19 female adults in their 20s who consented to participate in the present 
 study .
they were provided with detailed instructions about the purpose and method of the 
 present study , and written informed consent was received from each participant .
the 
 characteristics of the subjects were as follows : age , 23.3  0.9  years ; height , 163.6  
 4.8  cm ; weight , 55.1  5.4  kg .
subjects were excluded if they had a history of major 
 abdominal or pelvic surgery , any neurological or respiratory condition , smoking , and low 
 back pain .
the present study was approved by the daegu university institutional review board 
 and in accordance with the ethical principles of the declaration of helsinki .
all the experiments were conducted under 2 conditions during randomized trials : before and 
 during contraction of the pfm during mvv .
in the present study , a spirometer ( spiropalm , a - m systems , usa ) was used to examine vital 
 capacity .
the subjects were asked to sit comfortably on a chair and place their hands on 
 their shoulders to reduce compensation by the trunk .
a clip was placed on the bridge of the 
 nose to prevent breathing through the nose .
the subjects were then asked to breathe out 
 through their mouth carefully while holding a mouthpiece to prevent air from leaking . for 
 the mvv measurement ,
the subjects were asked to breathe as quickly and deeply as possible at 
 a ratio of 90110 times / min for 12 seconds .
an emg ( telemyo dts , noraxon , usa ) was used to measure the activities of the respiratory 
 muscles during mvv .
the emg data were band - pass filtered between 20  hz and 400  hz . the notch 
 filter was set at 60  hz .
the sampling rate for the signals was set to 1,000  hz . the 
 collected data were analyzed after calculating the root mean square ( rms ) values . the 
 reference voluntary contraction ( rvc ) was used for the standardization of the emg .
the baseline 
 emg activity was recorded for 3 seconds in a sitting position before the performance of the 
 pfm activity .
the emg data for the mvv were recorded for 12 seconds . to reduce skin 
 resistance ,
excessive hair was removed from the skin , the corneum was removed by rubbing the 
 skin with a piece of sandpaper , and the skin was cleaned with disinfectant alcohol .
the transverse 
 abdominis / internal abdominal oblique ( tra / io ) electrode was placed 2  cm medial and superior 
 to the anterior superior iliac spine ; the external abdominal oblique ( eo ) electrode was 
 positioned halfway between the iliac crest and the rib cage in the midaxillary line ; the 
 rectus abdominis ( ra ) electrode was situated 2  cm lateral to the midline at the level of the 
 anterior superior iliac spine8 ; and the 
 sternocleidomastoid ( scm ) electrode was put over the muscle s belly9 .
all the participants listened to an explanation of the pfm 
 activity method before the measurement was performed .
empty the bladder before performing the exercises ; 2 . wear 
 comfortable clothing ; 3 . take a deep breath first and focus on relaxing the body and 
 concentrate on the muscles in the vagina - anus area ; 4 .
contract the muscles around the 
 vagina - anus as if you are trying to prevent yourself from urinating or breaking wind and 
 pull the muscles inward ( consisted of 68 seconds of contraction with 6 seconds rest in 
 between ) ; 5 . do not hold your breath during the contractions , do not contract your buttocks 
 or abdominal muscles10 .
wilcoxon s signed rank test was used to compare the contraction of the pfm and respiratory 
 muscle activity or vital capacity .
there were statistically significant differences during contraction of the pfm both 
 respiratory muscles activity and vital capacity .
activation of the scm , ra , eo and tra / io 
 significantly increased during contraction of the pfm ( p<0.05 ) , and mvv significantly 
 increased during contraction of the pfm ( p<0.05 ) ( table 1table 1.the changes in respiratory muscles activity and vital capacity between before 
 contraction and during contraction of the pfm during mvv ( n=19)variablesbefore contractionduring contractionmuscle activity of mvv ( % rvc)scm741.1259.91,084.4397.8*ra285.896.8354.2193.0*eo458.594.0675.3199.4*tra / io559.1353.0682.9554.8*mvv ( l / min)101.320.2110.421.3*meansd * p<0.05 .
scm : sternocleidomastoid , ra : rectus abdominis , eo : 
 external abdominal oblique , tra / io : transverse abdominis / internal abdominal oblique , 
 mvv : maximum voluntary ventilation . ) . meansd
scm : sternocleidomastoid , ra : rectus abdominis , eo : 
 external abdominal oblique , tra / io : transverse abdominis / internal abdominal oblique , 
 mvv : maximum voluntary ventilation .
the diaphragm , the principal muscle 
 of respiration , has been reported to act as one of the spinal stability muscles , and the io , 
 eo , and pfm are also activated to increase respiratory capacity with the diaphragm . the 
 spinal stability provided by these muscles
is generated from their co - contraction , which 
 increases iap ; these muscles also function as respiratory muscles by increasing their 
 activities when respiratory demand increases11 .
the present study examined the effect of contraction of the pfm 
 ( act as respiratory muscles or stabilize the trunk ) on respiratory muscle activity and vital 
 capacity .
a significant increase in muscle activity in ra , eo , tra / io ( expiration muscles ) 
 and in scm ( an accessory muscle for inspiration ) was seen during contraction of the pfm . 

a previous study by sapsford4 suggested that voluntary contraction of the 
 pfm increases iap and brings about contraction of io , resulting in stability of the spine 
 and an increase in expiration .
in addition , a study of the thickness of the abdominal 
 muscles through precise contraction of the pfm confirmed that pfm ` contraction increased the 
 thickness of tra and io12 .
some studies 
 have observed that contraction of the pfm prompts activation of the tra and io13 , and that the scm is progressively 
 activated during incremental static and dynamic maneuvers to maximal ventilation in healthy 
 adults .
thus , the scm is an important accessory muscle of inspiration and becomes active 
 during ventilation at high lung volumes and elevated levels of inspiration tasks14 .
therefore , the present study confirmed 
 that contraction of the pfm in breathing causes cooperative contraction of the surrounding 
 abdominal muscles and the accessory muscle of inspiration .
thus , an effect was expected on 
 vital capacity due to the increase in iap .
the present study identified a significant increase in mvv measured during contraction of 
 the pfm .
mvv is an important indicator in evaluating motor capacity and it depends on vital 
 capacity ( maximum breathing capacity of the lung at a given time ) and the speed at which 
 that amount of air is inhaled and exhaled .
it also depends on the elasticity of the lung , 
 thorax and on the strength of the breathing muscle and resistance of the airway and 
 thorax15 .
contraction of the pfm 
 resulted in an increase in mvv , suggesting that contraction of the pfm is very important in 
 maintaining dynamic breathing capacity during exercise ; that is , contraction of the pfm 
 resulted in an increase in muscle recruitment of the respiratory muscles and diaphragm4 , thereby affecting the strength of the 
 breathing muscles and increasing the speed at which air is inhaled and exhaled .
this brings 
 about an increase in mvv , which requires constant activity of the breathing muscles . 

therefore , contraction of the pfm helps postural stability of the lumbopelvic region as well 
 as ventilation16 .
consequently , it is 
 necessary to breathe make advantage of contraction for the pfm .
however , vital capacity and 
 respiratory muscles activity were only observed during a temporary contraction of the pfm , 
 so the correlation between pfm strengthening exercise and respiratory muscles and vital 
 capacity remains undefined .
therefore , invigoration of breathing exercise programs using pfm 
 is necessary and further studies are required on activity of respiratory muscles and vital 
 capacity through the pfm strengthening exercise .
[ purpose ] the aim of the present study was to examine the impact of the pelvic floor 
 muscles ( pfm ) on dynamic ventilation maneuvers . [ subjects and methods ] the subjects were 
 19 healthy female adults in their 20s who consented to participate in the present study . 
 
 electromyography ( emg ) was used to examine respiratory muscle activity , and a spirometer 
 was used to examine vital capacity before and during contraction of the pfm . 
 [ results ] 
 there were statistically significant differences in the sternocleidomastoid ( scm ) , rectus 
 abdominis ( ra ) , external oblique ( eo ) , transverse abdominis / internal oblique ( tra / io ) , and 
 maximal voluntary ventilation ( mvv ) when the pfm was contracted . 
 [ conclusion ] contraction 
 of the pfm can be effective in promoting activation of the respiratory muscles and vital 
 capacity . 
 therefore , the pfm should be considered to improve the effects of respiratory 
 activity .