THE RELATIONSHIP BETWEEN PELVIS INCLINATION , EXERCISE AND LOW BACK PAIN ( LBP ) DURING PREGNANCY

The relatively short period of pregnancy constitutes a time of major somatic, mental, functional and also so cial changes in a womanʼs life. A signifi cant part of the health and discomfort issues experienced during pregnancy is related to the muscularskeletal system. According to many authors (e.g. Wang, Dezinno, Maranets, & Berman, 2004; Mens & Damen, 2006), the majority of complaints of pain by pregnant women can be classed as “Low Back Pain” (LBP). Until recently the term “low back pain” bore the meaning of non-specifi c pain, involving both lumbar spine pain and also pain on the posterior side of the pelvis. But lately some researchers have begun to diff erentiate between the diagnostics and therapy of the lumbar and pelvic area (e.g. Albert, Godskesen, & Westergaard, 2002). Pregnancy related LBP may be defi ned as any idiopathic pain between the 12 rib and the gluteal crease. It does not involve any situations in which the pain could be connected to specifi c pathological phenomenon, e.g. disc herniation (Sneag, 2007). LBP problems usually originate in the period before pregnancy, due to minimal adjustment of daily non-physiological movement routines. The incidence of LBP discomfort is present in nearly fi fty percent of the pregnant population (Mens & Damen, 2006) and it is a frequent cause of mental and physical discomfort. Although both types of pain are usually referred to as Low Back Pain, their symptoms, diagnostics and therefore therapy have to be diff erentiated (TABLE 1). THE RELATIONSHIP BETWEEN PELVIS INCLINATION, EXERCISE AND LOW BACK PAIN (LBP) DURING PREGNANCY


INTRODUCTION
The relatively short period of pregnancy constitutes a time of major somatic, mental, functional and also so cial changes in a womanʼs life.
A signifi cant part of the health and discomfort issues experienced during pregnancy is related to the muscularskeletal system.According to many authors (e.g.Wang, Dezinno, Maranets, & Berman, 2004;Mens & Damen, 2006), the majority of complaints of pain by pregnant women can be classed as "Low Back Pain" (LBP).Until recently the term "low back pain" bore the meaning of non-specifi c pain, involving both lumbar spine pain and also pain on the posterior side of the pelvis.But lately some researchers have begun to diff erentiate between the diagnostics and therapy of the lumbar and pelvic area (e.g.Albert, Godskesen, & Westergaard, 2002).Pregnancy related LBP may be defi ned as any idiopathic pain between the 12 th rib and the gluteal crease.It does not involve any situations in which the pain could be connected to specifi c pathological phenomenon, e.g.disc herniation (Sneag, 2007).LBP problems usually originate in the period before pregnancy, due to minimal adjustment of daily non-physiological movement routines.The incidence of LBP discomfort is present in nearly fi fty percent of the pregnant population (Mens & Damen, 2006) and it is a frequent cause of mental and physical discomfort.
Although both types of pain are usually referred to as Low Back Pain, their symptoms, diagnostics and therefore therapy have to be diff erentiated (TABLE 1).
From a biomechanical point of view, os sacrum and os ilium form an anatomically and functionally tight com plex.Mechanical forces of the growing uterus and other factors occurring during pregnancy could infl uence the axial system and therefore enhance the develop ment of LBP.Pelvis inclination and spinal curvatures may be infl uenced not only by the mechanical forces occuring during pregnancy but also by improper activity (weakness or coordination) of the so called deep spinal stabilisation system (Neumann, 2002).
Todayʼs therapy involves, above all, rest, sometimes complemented by the active building of the pelvic and spinal muscular corset or passive fi xation using a pelvic belt.The importance of exercise activating the postural muscles prior to pregnancy in order to prevent future LBP is not clear yet.There is no evidence as to whether the biochemical and biomechanical changes occurring during pregnancy have a more excessive impact on the female body than the state of her muscular apparatus itself.However, we believe that proper exercise prior to pregnancy helps pregnant women deal with the discomfort in their lower back area.This alleviation of pain should occur thanks to better support for the growing uterus and also thanks to a higher awareness of the body helping to prevent the pain by avoiding certain kinds of movements.
Despite the high incidence of LBP occurrence during pregnancy, our knowledge of pathogenesis, clinical demonstrations and therapy is insuffi cient so far.Foreign literature does contain some articles on the topic of LBP during pregnancy, Czech scientifi c journals present very few related articles and there are virtually no study materials for obstetricians at all.

Mechanisms of LBP occurence during pregnancy
The etiology of LBP during pregnancy is still theo retical; there are 3 main occurrence mechanisms men tioned in the literature: biomechanical/muscular-ske letal, hormonal and vascular.
The common goal of many pregnancy and LBP re lated studies is to discover the origin and factors contribut ing to the perception of sensation (e.g.Fast & Shapiro, 1987;Sneag, 2007;Wang, Dezinno, Maranets, & Berman, 2004, etc.).But multiple conclusions drawn from these studies have brought multiple results and the ques tion of risk factors identifi cation still remains unanswered.

Could proper physical activity during pregnancy aff ect LBP?
Sometimes it is diffi cult to directly pinpoint structures as well as factors which cause pain in the lumbosacral region.Ignorance of the etiology makes choosing proper therapy a diffi cult task.In many cases some relief can be obtained by using a pelvic belt which compresses the sacroiliacal joint, and thus replaces passive ligamental fi xation as well as active muscular stabilisation, specifi cally of m. transversus abdominis and mm.multifi di (Richardson, Snijders, & Hides, 2002).But Mens and Damen emphasize that the excessive use of passive support contributes to myoatrophy and therefore to counterproductive consequences (Mens & Damen, 2006).
Theoptimal prevention of LBP consists in deep stabilisation system activation before conception as well as carefully chosen physical activity in the later phase of pregnancy that can lead to decreasing potential pain.There are many publications and videos on the market today about exercises focused on strengthening postural muscles.No matter whether a woman starts exercising during pregnancy or before, she should focus on special pregnancy modifi ed programs which exclude positions not suitable for pregnant women.Inexperienced women should always exercise under an expertʼs supervision.
We present the 3 most frequently used methods for helping to alleviate back pain (not only during pregnan cy): the Pilates method, Yoga and exercises by Mojžíšová.
The Pilates method was inspired by tai-chi and yoga.Individual exercises are focused on the local strengthening and stretching of global muscle groups, thereby contributing to keeping oneʼs bodily balance and learning proper body posture (King & Green, 2006).The main goal of these exercises is, however, the activation of the so called "power house" which, according to the Pilates method, comprises the diaphragm, pelvic fl oor and abdominal wall.Modifi cation of the Pilates method for pregnant women contributes, among other things, to the enhancing of cardiovascular and respiration function, relaxation and well being.In Yoga, the activation of postural muscles is reached through asanas (exercising positions) as well as pranayama (breathing exercises), because there is a close mutual relationship between respiration and postural muscles.Breathing exercises might be facilitated by upper limbs positioned in given poses and gestures.This technique is called "mudra".According to Véle (2006) these exercises aff ect erect body posture and thus support the function of the deep stabilisation system.The Mojžíšová's method is acknowledged in the Czech Re public as an exercise and as therapy for functional female sterility, based on the reflexive effect on the neuro muscular apparatus.The pelvic fl oor is aff ected by means of infl uencing the lumbar spine, sacrum, coccyx, pelvic muscles and their mutual positions.The method consists of education, 10 plus 2 exercises and mobilisation and is used not only as a form of functional sterility therapy, but its elements can be found in functional vertebrogenic issues therapy, juvenile scoliosis therapy, coccyx pain therapy, etc. (Strusková & Novotná, 2003).

OBJECTIVES
The main aim of our research was the objectivisation of the relationship between LBP occurrence, the training level of the postural muscles and the degree of the pelvic inclination of women in the third trimester of pregnancy.That is why the relationship between pelvic inclination and LBP occurrence was compared within the context of two groups -reasonably physically active as opposed to physically inactive women.

HYPOTHESES
1. Regular physical activity focused on the deep stabilisation system before and during pregnancy significantly aff ects the degree of pelvic inclination.2. Regular physical activity focused on the deep stabilisation system before and during pregnancy alleviates pain in lower segments of the lumbar spine and sacroiliacal joint.3. The degree of pelvic inclination correlates with subjective pain sensation in the lower spinal and pelvic segments.

Research group
Of the 30 women originally addressed and examined, 27 pregnant probands aged 20-35 years and in the second half of the third trimester were included in the experiment.All of them indicated that they suff ered from pain in the lumbar spine and pelvicregion.The cho sen subjects were limited to those in a good state of health with no present structural pathology of movement apparatus nor any other serious health conditions.They were divided into two groups: A) 13 physically active women, B) 14 physically inactive women.
To be assigned to the active group, physical activity had to be performed for at least 45 minutes, at least 3 times per week for at least 1 year before conception.During pregnancy, the exercise time needed was reduced to 30 minutes for at least 3 times per week, e.g. 90 minutes every week.Asymmetrically body overloading activities were dropped (tennis, squash, etc.) while activities focused on postural muscle activation were gi ven preference (i.e.yoga, Pilates, breath gymnastics, gym ball exercises, etc.).
Into the B group we assigned women who performed no physical activity or did not match the previously mentioned qualitative and quantitative movement conditions.
For the objective evaluation of deep stabilisation system (DSS) status in the third trimester of pregnancy we discovered no clinical test in the academic literature.Distributing probands into two groups and thus the ap pro ximation of their DSSʼs training level took place based on evaluating their medical historical data.This was performed in view of the fact that most women who fulfi lled the condition of regular exercising mentioned pos turalmus cles-activation focused methods in their train ing programs (Pilates, yoga, gym ball exercises, etc.).Data detection and examination took place at a private rehabilitation clinic and at the Clinic of Obstetrics and Gynecology at Charles Universityʼs 1st Faculty of Medicine.

Measuring the inclination of the pelvis
The inclination of the pelvis was de tected using sim ple anthro pomet ric measuring.We used "Do ležal's method" (Doležal & Gutvirth, 1977), i.e. we measured the inclinatio pelvis against a horizontal line.

Fig. 1
From the diff erence (v 1 -v 2 ) we obtained side a and angle α c a sin D (1) To keep measurement error as low as possible all mea surements were performed by one person and standardised external conditions were maintained (room tem perature, lighting, air humidity).

Clinical LBP fi ndings
Lumbar area pain demonstrates itself mainly by a decreased mobility of the lumbar spine and pain, summoned by torso anterofl exion.Posterior pelvic area pain can be detected by specialised tests.Sneag indicates the existence of more than 15 tests to identify pain level in the posterior pelvic area (Sneag, 2007).Research however has discovered that only three of them are highly sensitive and eff ective -the Patrick-Faber test, the Menell test and the posterior pelvic pain provocation test.In this study we used the Patrick-Faber test and the posterior pelvic pain provocation test, mostly because of the supine position of probands during testing.The position of the Menell test is inappropriate for the third pregnancy trimester.
Patrick-Faber test -the patient lies in the supine position.She performs fl exion, abduction and outer rotation of the hip joint and fl exion of the knee joint of one lower limb.The second lower limb is extended, including hip and knee joints.A physiotherapist slowly presses the fl exed knee (tested side) in one direction while holding the pelvis steady on the opposite side.The test is positive if pain is thereby provoked in the sacroiliacal joint or hip joint.
Posterior pelvic pain provocation test -the patient lies in the supine position with fl exion in the hip joint of 90° with a fl exed knee joint.The tester induces sheer tension on the sacroiliacal joint through the femur.It is important to avoid excessive adduction of the hip joint while testing, because it causes pain even to healthy individuals with simultaneous fl exion.The test is declared positive if it causes discomfort to the patient while testing the monitored area.

Subjective classifi cation of pain
As a part of the examination, the probands fi lled in a medical historical survey about their health condition, regular sports activities as well as the character and localisation of their pain.
There is quite an extensive range of standardised LBP related surveys available for the non-pregnant popu lation, e.g.The Quebec Back Pain disability scale, Aberdeen Low Back Pain scale, etc.All of these were, however, found inappropriate for pregnant women, as they included manoeuvres diffi cult to perform even for entirely healthy pregnant women in the 3 rd trimester (such as carrying heavy objects, short track running, etc.).So we used a newly created medical historical survey for the subjective classifi cation of pain.We used the previously mentioned surveys when assembling this survey (The Quebec Back Pain disability scale and Aberdeen Low Back Pain scale).A numeric scale of 1-10 was added to pain related questions (1 -the slightest pain, 10 -the greatest pain) as well as a diagram for mark ing pain localisation.

Statistical analysis
Because both monitored sets were extensive enough, we used standard mathematical statistical methods, the pelvic inclination of exercising and non-exercising women was compared by a t-test for non-pair values, whe reas subjective "pain level" values between both sets were compared using two non-parametric methodsthe common, but weaker median test and the stronger Wilcoxon-White test.The relationship between pelvic inclination and subjective pain sensation was tested by the non-parametric Spearman factor of serial correlations.

RESULTS
The numeric values measured are displayed in TABLE 2. As we expected, at signifi cance level 0.01 there is a sta tistically signifi cant diff erence between the pelvic inclination of physically active and inactive women (n = 27, the counted t-test value is 3.396, the table value is 2.086).Based on this proven diff erence we can assume that the regular physical activity of women reduces the creation of excessive pelvic anteversion during pregnancy.
The calculations also proved a signifi cant diff erence between the subjective pain sensations felt by regularly exercising and non-exercising women.This diff erence is statistically signifi cant on a signifi cance level of 001 for both non-parametric tests we used -the median test (the calculated value of the chi squared test criterion is 9.258, the table value being 6.635) and the Wilcoxon--White test (the calcuated testing criterion was U = 72.5, whereas the table value was 53).
Using a non-parametric correlation factor, we have proven a statistically signifi cant relationship between pelvic inclination and the sensation of pain classifi ed in a survey by a 1-10 scale (n = 27, counted correlation coeffi cient 0.563, table value 0.465, signifi cance level 0.01).
We have proven all three hypotheses.

DISCUSSION
We consider the defi nite confi rmation of all three hypotheses using mathematical statistical methods to be very important.Our study contributes to the significance of appropriate physical activity before gestation as a form of prevention of LBP during pregnancy.There are increased demands placed on a pregnant womanʼs body due to the increase in abdominal volume and also increased elasticity of the supportive muscular and liga mental apparatus caused by increased relaxin and estrogen production.Accordingly, activated postural mus cles become a supporting pillar during pregnancy.The cooperation of all parts of the postural system is especially important during pregnancy, because it leads to uncomplicated delivery and lessens the probability of LBP in the motherʼs future life.
Regular sport activity had an eff ect on the subjective sensation of LBP in our study.We assume that this conclusion was not only caused by the physiological eff ect of sport activity but also its proven infl uence on the psyche of the exercising person (Křivohlavý, 1992).LBP aff ected persons do not enjoy either physical nor mental comfort, which is a defi nition of health according to the WHO.Pregnancy LBP is a topic of many foreign studies, but the results have not been very coherent (e.g.Vařeka, 1996;Sneag, 2007;Bastiaenen, 2004;Sturreson, Uden, & Uden, 1997).That is why there is still a lack of clear conclusions regarding the etiology and therapy of this problem, which causes signifi cant physical and mental discomfort to future mothers.LBP prevention is what should be accentuated.Enough physical activity and procedural precautions like avoiding positions and movements that cause LBP are considered appropriate prevention.There are few cases of the complete "healing" of LBP during pregnancy, yet therapy is usually successful in reducing pain (its intensity and frequency of occurrence).This therapy consists mostly of exercises for correcting muscular disbalance.Pregnancy should not become an obstacle to active movement, it should moreover be a reason to keep moving or even start doing so.All pregnant women should, however, consult their physical activity with a doctor or physiotherapist.
In addition to other things, the survey contained ques tions about LBP characteristics -levels of pain classifi ed on a 1-10 scale and its localisation.Because we were aware of some degree of subjectivity in the sensation of pain, we also included two clinical tests used for the precise localisation of LBP -the Patrick-Faber and posterior pelvic pain provocation tests.Distinguish ing pain using manual tests almost corresponded to the subjective feelings of the pregnant women and their marks in the picture diagram contained in the survey.Only 4 probands out of 27 had both their clinical tests negative despite the occurrence of subjective pain.Křivohlavý moreover states that scales of painful behaviour are valid methods of pain level detection (Křivohlavý, 1992).
Pelvic inclination evaluation was performed according to Doležal and Gutvirth (1977).The authors say that, in 1977, the average value of pelvic inclination in the 3 rd tri mester in their study was 27.53°.This angle tends to rise with an increasingly anteverted pelvis position.The average presented by the authors almost exactly agrees with the result of our physically inactive group (27.57°), while the physically active group had it 2.28° lower (25.23°).The signifi cance of this diff erence was proven by mathematical statistics.

CONCLUSIONS
Monitoring 27 pregnant probands in the 2 nd half of the 3 rd trimester has proven a statistically signifi cant difference between the pelvic inclination of both re gularly physically active and inactive women.The average value measured on 14 physically inactive women almost perfectly matched average values presented by Doležal and Gutvirth (1977), whose method of detecting pelvic inclination we used.
We further proved that the inclination of the pelvis correlates with pain occurrence in the lower parts of the spine and pelvis.The occurrence of pain was detected by both a survey containing graphical pain localisation and its classifi cation on a 1-10 scale and by two clinical tests for precise LBP localisation.
Using two non-parametric tests we also proved that regular and appropriate physical activity focused on the functioning of the postural system (e.g.Pilates, yoga, swimming, gym ball exercises, exercises by Mojžíšová, etc.) before and during pregnancy reduces pain sensation in the lower segments of the lumbar spine and sacroiliacal joint.We consider these results to be very important mostly from the perspective of LBP prevention during pregnancy.

TABLE 2
Measured data