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 Back
pain is a syndrome endemic in industialized countries.
The spreading of this phenomenon can be described either by health
related or socio-economic items.
The Health defined by OMS as “a physical, psychic and social
well-being” is obviously related to Quality of life and
it can be well described in the chapter of “Health related Quality
of Life”(HrQoL).
The financial importance of back pain can be estimated through lost work
days and disability rate increase.
In USA it has been estimated that almost 5 millions of working-age
people are disabled by back pain and that disability rate is still
increasing; back pain is the third cause of disabilty after heart
disease and artritis in people between 45 and 65 years (1).
Moreover many studies show that this pathology involves also
youngest people, even teen-agers ( 2-7 ).
Backache is a clinical picture whose management involves different fields
because of its several causes and its medical, social
and economic weight.
We carried out a review of the current literature about the relationship
among back pain, posture and muscolar behaviour.
First of all, we will report data about the relation between backache
and posture, especially during work and sport activity; then we will
give the definition of “muscular chains” and we'll underline
their importance in holding and keeping the best posture.
As regards work, Mior SA et al. reported 87% of low back
pain in 320 chiropratics investigated , and low back pain was not
related neither to the height of the examination couch nor to
the technique used; Diakow PR et al. evaluated 172 dentists and found
back pain in 35,5% of them.
Finsen L et al.(43) surveyed posture and performed an EMG study
of neck and shoulder muscles in dentists during working activity,
and carried out that neck flexion and upper limb abduction agreed
with increased activity in splenium and trapezii.
Mulomphy M et al. reported 30% of low back pain among 344 physiotherapists,
and found out that backache appeared often in the first four years
of activity.
Pope MH et al. (44) showed that 4-6 Hz vibrations
in truck and tractor drivers can cause low back pain; they also showed
that special vibration-absorbing seats and an ergonomic driver's cabin
situation can reduce risk of relapse; in guinea pig these vibrations
provoke distortion, increase of discal pressure and neuropeptide level
changements in dorsal roots ganglia.
Gyi DE et al.(45) studied policemen in Great Britain and noticed
that low back pain rate is proportional to Km run and
to hours of driving and it is greater in police motorcyclist
than in police car drivers.
Estryn Behar M et al examined 1500 nurses and showed low back pain
in 47%, medical care demand in 27% and pointed out musculoskeletal
pain as the first cause of absence from work.
Van Dieen JH et al. (46) showed the efficacy of short
and frequent breaks, rather than longer but less frequent, in standing
works in order to prevent back pain.
Aagaard Hansen et al suggest ergonomic desks and seats, soft sport activities,
reduction of sedentary habits as prophylaxis of back pain in
young people; Tertti MO et al found out by MRI scan many cases
of discal degeneration in young people with low back pain.
Salminen JJ found 19,7 % of cases of low back pain in a study performed
on 370 pupils between 11 and 17 years old and these symptoms were
found with a greater rate than average also in their parents (19%
mothers, 15,4% fathers).
The spreading of this pathology can be connected with industrial growth
which in certain activities can lead the worker to sustained wrong
posture: it is worth remembering that the damage is often related
to cronic overload in work (8-3) and in some sport activities
(1,14 -16).
With regard to sport activities, Saraceni VM et al said that gymnastics
(especially aerobics), football, weight-lifting, wrestling,
dance and boat-racing have the highest risk of back pain among sports.
Micheli LJ got the same conclusions studying dancers with back pain;
the author suggested that lower limb postural alteration, tendonmuscolar
lack of balance, shoes and floor can be the likely causes.
Howell DW noticed an incidence of 17% in17 agonistic rowers, assuming
as a cause a lumbar hyperextention during activities; low back pain
decreased with regular session of stretching.
Martini G et al said that non agonistic sport could be involved in rehabilitation
of patient with back pain (17).
The aim of this paper is to evaluate different sides of back pain, connected
with changements in posture and in “muscular chains”.
In these last years, the definition of “muscular chains”
entered in rehabilitative jargon; many techniques currently used in
muscular and postural rehabilitation rewind to “muscular chains”
and “kinetic chains”(42).
We could say that sometimes these references are not properly mentioned
and it can often give rise to misunderstandig even among qualified
people; so we need a pressing historical, epistemologic and
critical review of the idea of kinematic, kinetic and muscular chain
and of their therapeutical aspects.
The precursor of the idea of “kinematic chain “ is Reuleaux
(1875), who described a mechanical system of elements , where
“the movement of a segment has a relation with every other segment
of the system”, and a closed loop allows the forces to flow
according to pre-established directions (18).
This idea is related to an engineering closed loop.
Baeyer (1924) introduced “the joint kinematic system”, that
is not anymore an anatomical series segments but elements involved
in a more complex system: the chain.
The kinematic chain reacts to external forces : “the extremities
of these chains are always closed by resistences; their overcoming
by body activities take place in their own chains” (Baeyer,
1924 and Schmith, 1932,1933).
According to Baeyer the external resistences can be: ground, object hold
in hand, walls.
As regard with resistences produced by the ground , they send the
body back stresses “which allow muscular forces to produce their
effects”(Knoll,1932) (19).
Nowadays, in mechanical engineering the kinematic chain is defined as
“a combination of several elements with kinematic couples in
order to provoke, with a set relative velocity, a setting of the relative
velocities of all the other elements -i.e.appointed one of the elements-
the system has only one degree of freedom”.
According to this discipline, a chain can be considered “open”
if external elements are not connected among them, and consecutively
it cannot be kinematic.
A chain is “closed” if every elements is coupled with the
previous and the following (20). So that, since the above-mentioned
definition of open chain, it is problematic to use the expression
kinematic in the open chains of the human body.
It changed from a kinematic chain (Baeyer), to a kinetic chain (Payr)(19),
where both the energetic and the mechanical side are underlined .
Payr was one of the first to underline the effect on the whole
system caused by a perturbation in only one of the elements of the
chain.
Dempster (1955) (18) was one of the first kinesiologist to resume
Reuleaux's ideas (1875) about the concept of the segment, according
to engineering science where:”in a engineering mechanism the
segments move in connection with a loom which is a part of the system.
So, in order to transmit a force, the segments of the mechanism have
to build up a closed system, where the movement of a system has set
relations with with each other segment of the system”(Reuleaux,
mentioned by Dempster 1955).
We remember that, accoding to engineering science, a “mechanism”is
definite as kinematic chain where one of the segments, which is named
“loom” or “bridge”, is fixed; in this way
from a kinematic chain can result as many mechanism as many segments
there are (20).
Although most of kinematic human chains are open, Brunnstrom (1962)(18)
describes two closed chains in human body.
The first is the pelvis , where three bone segments are joined by the
two sacroiliac and by the pubic synphysis.
The second closed chain is the thorax, where the first ten ribs are joined
with rachis and sternum.
The definition of closed kinematic chain for pelvis will be challenged
by Gowitze (1988), because it found motionless these joints. But what's
about studies of I.A.Kapandji about nutation and contronutation of
sacrum?
Steindler (1973)(21) said that there is a closed chain in a living being
(“kinetic” rather than kinematic) “everytime the
distal free joint of the chain meet a insuperable resistence”.
In daily life, mobilization of more than a joint produces a reciprocal
shifting of different osseus chains; this mechanical system is named
“flat link chain”(22).
Since joint movement is produced by muscles, it is possible to talk about
“muscular kinetic chain”.
Clusters of muscles addressed to a common aim are named “muscular
chains”(19).
This definition strays from engeeniring and its kinematic and kinetic
mechanics, because muscles cannot be referred as a rigid
mechanical system but as a flexible and plastic system.
In a kinematic system it is possible to desume relative velocities of
all members after setting the velocity of a member relative
to another one : muscles cannot do it.
It is not possible indeed, to draw exactly each component of the forces
in every muscular segments.
Explained these discrepancies of definitions and meaning, unfortunately
we have to keep definitions because they are part of biomechanic and
rehabilitation jargon.
“Muscular kinetic chains“are usually divided in open, closed
and braked.
Open kinetic chain: an open muscular kinetic chain is a system whose
distal extremity in free. Exemples are : lower limb during the swinging
period of the gait, the extension of the leg when seated, a gesticulating
upper limb etc..
Close kinetic chain: an extremity of the system is
fixed, on the contrary the close extrmity can move during the action.
Exemples are: Lower limb in charging period of the gait, upper
limb pushing against a wall or lower limb of a person lifting a weight
from the floor.
Braked chain: when the external resistence of a kinetic chain is
lower than 15% of the maximal resistence that it can move, we could
have an open or hardly braked chain; if this resistence is more than
15%, the chain is close or widely braked.
From a “biomechanical” point of view muscular chains follow
the skeletal bone arrangement, mainly the series arrangement (rachis
and limbs) whereas the paralleling (hand and foot) and the grouping
(carpus and tarsus) arrangement is less important. As the paralleling
arrangement regards eleven liberty degrees of articulation movement
in upper limbs and seven in lower limbs, there are several kinds of
muscle chains.
Each liberty degree regards the activation of some muscles, which spreads
to the nearest ones thus involving the whole system.
Both, upper and lower limbs, show a decrease of liberty degrees
from the close articulations to the distal ones, probably because
the realization of movement needs the maximum accuracy. Open
chains are necessary for balistic movements, which occur with an increasing
rise of speed from the close to the distal articulations. For not
balistic movements, slow but precise, it is necessary the steady control
of the close segment, by involving the stability muscles. In the open
chains muscular activation is from the close to the distal articulation.
The biomechanics of closed muscle chains is the opposite: the stabilizing
articulation is at the distal end, and the direction of the activation
is from the distal to the close articulation. In the closed chains
the steady ring of the chain is the articulation that links the limb
with the external resistance.
Staindler (21) says that a closed chain occurs only in the isometric
exercise, because during this exercise neither the close segment nor
the distal one change their position. As a result, we can assert that
the movement is more dynamic for open chains, and more static
for closed chains. An important biomechanical consequence is that
the same muscle can have different functions according to the kind
of chain in which it works; for example from the squat (closed
chain) to the upright position the soleus extends the tibia, the gastrocnemii
pull backwards the femoral condyles, the posterior muscles of thigh
extend the hip and pull backwards the tibial plate; as a result the
gastrocnemii and the posterior muscles of thigh, which are knee flexors
in an open chain, become agonists of the quadriceps in a closed
chain.
These principles have conditioned the terapeutical exercise in the orthopaedic
rehabilitation; for instance, for the knee rehabilitation it's possible
to tell the open chain exercises ( in sitting position) from the closed
chain ones, in which feet are stopped by a resistence (squatting).
The rehabilitation for the anterior cruciate ligament it's one of these
cases: the weightbearing exercises, comparable with those with closed
chain, have been tested to give less tension to this ligament than
the ones with open chain. This decrease is likely to be the effect
of co-contraction of posterior muscles in weightbearing exercises.
This co-contraction decreases the anterior translation of tibia caused
by the quadriceps.
Another important fact is the different strenght produced by only one
limb or by two limb exercise; for instance, the knee extension during
the sitting position produces more strenght if only one leg, instead
of two at the same moment, make the movement.
It's probable that this difference is caused by the activation of different
muscle chains, and, as a result, by the different stabilization of
the pelvis-trunk system.
Some well-known and debated authors of ostheopatic school (Mézière, Souchard,
Busquet, Bienfait) and authoritative authors of functional anatomy
(K.Tittel, ecc.) describe very accurately the activation of muscular
chains in several human activities, and only seldom they describe
them in the same way. According to Busquet, muscular chains can be
classified like this:
1.Posterior static chains
2.Anterior straight chains: right and left
3.Posterior straight chains: right and left
4.Anterior crossed chains: right and left
5.Posterior crossed chains: right and left.
Moreover there are important structures related to these chains: fasciae,
aponeurosis,ligaments, ecc.
According to P. Souchard muscle chains are classified:
1. Inspiratory series
2. Posterior series
3. Hip anterior-internal series
4. Arm anterior series
5. Shoulder anterior-internal series
M. Bienfait underlines the importance of the cervico-thoracic-abdominal-pelvic
chain, and mainly the link between paravertebral aponeurosis and
fasciae, ligaments and the diaphragm muscle. Bienfait takes again
the concept of anterior and posterior crossed systems, but he states
, for instance, that the anterior crossed chain is made by rhomboid,
serratus muscle, oblique, whereas L. Busquet states that the left/right
crossed chain is made by left oblique, right oblique,
right external intercostal muscles, serratus posterior muscle.
There are only few experimental studies supporting the existence of these
muscular chains.
In the field of sport medicine some surface EMG studies have been carried
out during some exercises made in kynetic chain, especially during
the rehabilitation of a knee undergone surgery for ligament reconstruction.
However, the effort of describing several muscular chains during a
sport exercise has effective only a kynesiologic ground but not on
a scientific ground.
Several studies carried out about posture have showed its relationship
with rachialgia.
Mangione P et al. have studied the relationship between the hip extension
and the consequent changes on the pelvis inclination: variations of
this angle might cause pain to the back. Day JW et al. state, by the
utilization of a computerized system, that the lumbar curve is influenced
by the pelvis inclination: the anterior inclination increase
lordosis, whereas its posterior inclination decreases lordosis.
Pelvic inclination is also capable of influencing the orientation of
the head and other parts of the body.
Konno S. et al. have examined the relationship between the pressure registered
inside the paravertebral muscles and rachialgia, finding out that
the compartmental syndrome of posterior lumbar muscles is always associated
with a rise of this pressure; furthermore, changing the lordotic position
into a cifotic one , the pressure rises and the blood flow decreases.
Snjiders CJ et al. have found that the utilization of a pelvic
belt can help against low back pain because of its synergyc action
with the internal oblique abdominal muscle for the stabilization of
sacroiliac joints.
Willliams MM. et al. have examined the effect of a flat foam rubber
cushion over 210 patients with low back pain, in sitting position
behind the lumbar area causing cyphosis, versus the effect of a roller
causing lordosis : the authors have come to the conclusion that in
sitting position the lumbar roller is more effective except for patients
suffering for vertebral stenosis or spondylolistesis. Mjeske
et al. agree that in sitting position the utilization of a lumbar
device like a cushion can modify the posture by modifying the position
of forearm, arm, pelvis and trunk.
Gill KP et al. have compared 20 patients with low back pain and
20 pain-free, testing their proprioceptive abilities: the individuals
with back pain have showed an impairment of this ability.
Luoto et al. have carried out a study on postural control during
externally disturbed one-footed stance among healthy control subjects
and patients with chronic low back pain at the beginning of a functional
back restoration program and 6 months later at follow-up examination,
in order to study their postural control and to evaluate the
effects of the rehabilitation program.
Their results have showed deficits of motor skills and of coordination
in patients with pain, and these deficits are reversible with successfull
low back rehabilitation.
Some authors have studied the influence of height and weight on rachialgia.
Kuh DJ et al. have found that there is no relationship between individuals
taller than average and rachialgia.
Bergenudd
H et al state that both, male and female have no correlations between
height, cyphosis, lordosis and rachialgia, and for women there is
no relationship between menarca, menopause , number of children and
low back pain (study carried out over 575 individuals). Merriam
WF et al. agree with the fact that rachialgia is not linked either
with height or a pelvis height bigger than average ; Hickmott
KC et al. state that height, weight, (obesity included), sex are not
involved in producing low back pain.
Basmajan JV et al.
suggest that the EMG-BFB (electromyographic biofeedback) should
be used during dynamic movements of trunk to relieve pain, by modifying
the wrong posture of patients with low back pain.
According to many
authors, electromyographic anomalies of postural muscles of trunk
are a common feature of patients with back pain.
Nouwen A. has registered
the EMG surface activity of paraspinal muscles in 20 individuals
with chronic low back pain; after the utilization of BFB to relax
these muscles he hasn't found improvement of pain. Cram JR et al.
state that “the difference between EMG activity of right and
left cervical and lumbar paraspinal muscles is very important
for the diagnosis of rachialgia”.
Soderberg GL et al.
affirm that patients with rachialgia have an increase from baseline
EMG activity even after exercise (in this case a lifting exercise);
the EMG activity was recorded from erector spinae muscles (T10, L1,L3)
and from rectus abdominis muscle.
To come to a conclusion
, the evidence is that not all the authors agree with each other about
the posture, the movements and the risk factors capable of producing
rachialgia; furthermore there isn't uniformity about the concept of
muscle chain, and all the methods of postural reeducation need to
be studied more about their clinical results and their relationship
with the theoretic knowledge of muscle chain.
Next aim will be
to involve the concept of muscle chain into the neurophysiology and
the central motor patterns.
Valter Santilli
Primario Unità Spinale
C.T.O.
Roma
Enzo Paris
Silvia Capici
USU Ospedale CTO Andrea
Alesini
Roma
Stefano Finucci
Scuola di specializzazione
in MFR
Tor Vergata
Roma
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