Download Etiology of low back pain in athletes

Etiology of Low Back Pain in Athletes
Timothy J. Trainor, MD and Michael A. Trainor, DO
Address
Spine Institute/University of Louisville Leatherman Spine Center,
210 East Gray Street, Suite 900, Louisville, KY 40202, USA.
E-mail: [email protected]
Current Sports Medicine Reports 2004, 3:41–46
Current Science Inc. ISSN 1537-890x
Copyright © 2004 by Current Science Inc.
Low back pain and injury is a common affliction for patients
involved in athletic endeavors. For this reason, the health
care professional should be cognizant of age-related and
sports-specific considerations when evaluating athletes with
low back complaints. An elevated index of suspicion with
regard to specific etiologies of back pain proves invaluable in
order to avoid the misdiagnosis of a more serious problem.
Although a number of conditions exist that require more
aggressive evaluation and treatment, the majority of low back
pain in athletes is self-limiting. In this context, a treatment
plan designed to increase low back and abdominal muscle
strength, flexibility, and range of motion often proves beneficial not only in returning the athlete to competition, but also
in preventing injury recurrence.
Introduction
Lumbar spinal pain and related pathology cause significant
patient disability, as well as a tremendous socioeconomic
strain to society. A review of the orthopedic literature
reveals a 70% to 90% lifetime incidence of low back pain
in the general population, with up to 4% of that population undergoing lumbar spine surgical intervention [1–4].
Although not as commonly affected as adults, children
also frequently experience low back pain. Back pain causes
more disability in persons under age 45 than any other
entity. Furthermore, spine trauma typically afflicts 30-yearold men with a sports-related cause in 6% to 13% of
instances [5]. With such a large portion of young persons
troubled by this malady, it is not surprising to learn that
the incidence of back pain in athletes is as high as 30% [6].
Moreover, certain sports, and particular positions within
those sports, have an incidence of back injury approaching
50% [7•].
Although back pain is such a pervasive condition in our
society, it is most often a self-limiting problem that is easily managed with conservative measures. Fortunately for
the athlete, the majority of back ailments in this subpopulation also respond well to noninvasive therapy. Despite
similar results obtained with analogous treatments, many
differences in the epidemiology of back pain exist between
athletes and nonathletes. Athletic endeavors subject the
spine to forces not often encountered by the nonathlete.
Furthermore, distinctions between various age groups
within the athletic population must be recognized. Children are not “miniature adults” and have unique anatomic
and physiologic considerations that cannot be overlooked.
The many unique causes of back pain in athletes must be
appreciated in order to prevent inaccurate diagnosis of
more serious conditions that may require specific treatments. Ultimately, however, the most common back ailments affecting athletes can be prevented by recognizing
the epidemiologic patterns that contribute to their development and by implementing programs to combat them.
Adolescent and Adult Athletes
The differential diagnosis of back pain in the young athlete
differs from that of the adult athlete. Micheli and Wood [8]
have reported spondylolysis (a defect in the pars interarticularis) as the most common cause of low back pain in the
adolescent athlete. More recently, Kraft [9•] has stressed
the frequency of low back complaints in adolescents as a
result of pathology to the pars interarticularis. These pars
defects are thought to be most commonly caused by stress
fractures. Sports requiring repetitive hyperextension of the
low back, such as gymnastics, figure skating, diving, and
football, have been proven to be a risk factor for the development of spondylolysis [9•,10•]. Pars stress fractures
most commonly occur in children between the ages of 6
and 10 years, with a reported prevalence of 4%. The defect
in the pars can lead to spondylolisthesis, or slipping of one
vertebral body on the other. The physician must recognize
the diagnostic possibility of spondylolysis in order to initiate the appropriate evaluation of an adolescent athlete.
Radiographic studies are often unnecessary in the evaluation of an atraumatic injury, especially in the adult athlete.
Spondylotic defects, however, often occur in the absence of
a specific traumatic event. Early identification of the fracture by radiographic means may prove crucial in order to
initiate the appropriate treatment allowing bony union of
the fracture.
The adolescent athlete is prone to some unique etiologies of back pain not encountered in the adult athlete, secondary to the anatomic and physiologic differences
between the adolescent and adult spine. Many of these differences are related to the normal growth process. Hyperlordosis, or lordotic low back pain, has been reported as
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Spine Conditions
the second most common cause of adolescent backache
[7•,8]. During the adolescent growth spurt, the axial skeleton tends to grow more quickly than the surrounding
thoracolumbar fascia and soft tissues. Consequently,
pathologic tightness ensues, stressing the spine and resulting in back pain. Sports requiring strong hamstring muscles can magnify the tension and perpetuate the problem.
Stretching exercises to increase hamstring, pelvic, and thoracolumbar spine flexibility will alleviate the pain. Temporary use of an antilordotic brace may also prove to be
beneficial [7•].
Vertebral endplate fractures occur at the junction
between the vertebral body and the apophysis attached to
the outer annulus fibrosis [10•]. This entity occurs exclusively in the adolescent because the cartilaginous endplate
is weaker than the attached annulus. The avulsed fragment
displaces posteriorly into the spinal canal, resulting in
symptoms mimicking a central herniated nucleus pulposis.
Unlike in the adult spine, blood vessels in the pediatric
spine cross the vertebral body into the vertebral disc
through the endplate. This fact predisposes the adolescent
to discitis, or bacterial infection, of the vertebral disc. The
clinician must be mindful of these physiologic differences
between pediatric and adult populations in order to formulate an appropriate differential diagnosis.
Athletes and the General Population
Muscle strains and ligament sprains comprise as much as
97% of back pain in the general adult population with
more serious etiologies accounting for fewer than 5% of
back problems [5]. Similarly, most back injuries in athletes
are also soft tissue-related. The anatomy of the athlete’s
back is no different from that of the nonathlete’s. The biochemical and physiologic processes that occur when the
back is stressed are identical between these two groups.
Furthermore, studies have not proven the athlete to have
stronger back muscles than those of the general populace.
Despite these many similarities, epidemiologic data
obtained from ordinary people should not be extrapolated
to the athletic population for many reasons. Athletes often
subject their backs to unusually large forces and positions
not commonly encountered by the general populace. Furthermore, the stress they place on their backs often occurs
over long, repetitive cycles and periods of time. Fatigue or
overuse injuries will follow. The spine absorbs and transmits power between the upper and lower extremities
throughout athletic activity. Extreme forces are often generated in various sports, both contact and noncontact, that
will predispose the athlete to back injury. Additionally, the
position and contours the spine must assume for different
athletic events further compromises the athlete’s back. The
high incidence of spondylolysis in gymnasts is well documented [11–15]. Similarly, divers and football linemen
constantly hyperextend their backs, leading to an increased
incidence of spondylolysis [15,16].
Epidemiologic data obtained from athletes versus the
general public must also be viewed cautiously. The number
of injuries and backaches may well be inflated in the nonathletic population and underestimated in the athletic
group. Individuals of the general public may be motivated
to inform superiors of minor backaches in order to obtain
monetary compensation or special working conditions.
The athlete, on the other hand, may avoid reporting back
pain or injury because of unwanted consequences. In a
recent study, Lundin [17•] revealed that despite significantly more radiologic abnormalities among athletes, the
frequency of reported back pain in athletes was no greater
than in nonathletes. Ong [18] examined disc degeneration
in Olympic athletes at the 2000 Sydney Games using magnetic resonance imaging (MRI). Radiographic results from
that study suggested a greater prevalence and degree of
lumbar disc degeneration in elite athletes versus the general population. Athletes may be unwilling to risk losing
playing time, monetary compensation, or scholarship
opportunities by notifying coaches, team physicians, or
managers of their condition. An individual’s response to
treatment will also be influenced by these factors. Athletes
may wish to speed their recovery in order to return to their
sport as soon as possible. They may report quicker recovery
times and better response to treatment than their nonathletic counterparts. These issues must be recognized when
analyzing epidemiologic data and when applying that
information to these different populations.
Degenerative conditions of the spine are a common
entity among the general population; by contrast, these
arthritic disorders are extremely rare in the athlete. Clearly,
the younger age of the athletic population plays a key role
in this distinction. Spondylosis and spinal stenosis are not
part of the differential diagnosis when evaluating the athlete with back pain; on the other hand, these are very common diagnoses in middle aged and older adults. Micheli
and Wood [8] demonstrated these distinctions in a study
comparing the etiology of back pain in athletes and the
general populace. They found a 48% incidence of discogenic back pain in a general adult population versus an
11% incidence in young athletes.
Predisposing Factors for Back Pain in Athletes
As previously mentioned, athletes do not innately have
stronger back muscles than nonathletes; however, they do
subject their spines to larger, more prolonged forces. As such,
the poorly conditioned athlete places himself at great risk for
back injury. This situation is often encountered at the beginning of a season when athletes return from periods of inactivity. The erector spinae and the abdominal muscles
stabilize the back during athletic activities. The normal extensor to flexor strength ratio is 1.3 to 1. Foster and Fulton [19]
reported this ratio to be substantially reduced in athletes
with back pain. An off-season back strengthening program
that emphasizes maintenance of this normal ratio proves
Etiology of Low Back Pain in Athletes • Trainor and Trainor
invaluable in preventing back injuries in athletes. These
strength programs should be continued throughout the season as well, in order to avoid injury.
Muscular force is conveyed from the upper body to the
lower extremities through the spine and pelvis. Inflexibility
of the pelvis will heighten the stress placed on the spine.
Tight hip extensors decrease lumbar lordosis, whereas
hamstring stiffness increases the lumbar lordotic curve. A
delicate balance between these structures must be maintained in order to avoid introducing undue strain on the
low back. A flexibility program for the pelvis, hamstrings,
and hip extensors should be initiated in order to maintain
the proper balance of elasticity in these structures.
Despite maintaining the proper strength and flexibility,
athletes still sustain back pain and injury. One of the most
common etiologies relates to changes in normal training
regimens. Sudden increases in the intensity or duration of
workouts can prompt the start of back pain. It is recommended that athletes never initiate abrupt changes in training schedules, but rather, gradually alter workouts to meet
their goals. Additionally, improper technique while performing athletic activities can lead to injury. Many athletes
incorporate weight lifting into their strength training programs. Lifting weights while hyperextending the low back
places immense strain on the spine and results in injury.
Many studies have demonstrated that football linemen
who block from an erect stance are susceptible to low back
injury [20–22]. Poor equipment also predisposes the athlete to injury. Physicians and trainers must be mindful to
check that players are using appropriate gear while participating in both training and games. Athletic footwear can
also contribute to back pain and must not be overlooked.
General Principles of Diagnosis
and Treatment
Fortunately for those athletes suffering from low back pain,
the majority of these disorders are soft tissue insults. Multiple studies demonstrate that approximately 90% of back
pain resolves within 12 weeks of initial presentation.
[23,24•]. A thorough history and physical examination
should be performed on all athletes with low back pain
and should then dictate the direction of further diagnostic
evaluation. An extensive work-up is not necessary for all
athletes with back pain. In fact, plain radiographs are usually unnecessary in the initial evaluation of the athlete. The
physician must be mindful of specific signs that warrant
further investigation. For example, in the setting of an
acute traumatic event, radiographic studies must be
obtained. Patients with neurologic deficit require an extensive evaluation. The athlete with severe pain that has not
responded to several weeks of appropriate conservative
treatment needs further diagnostic assessment. Patients
with night pain and constitutional symptoms also require
further evaluation. Adolescent athletes with a hyperextension mechanism of injury should obtain radiographs to
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assess for spondylolysis. If radiographs are nondiagnostic,
a single photon emission computed tomography (SPECT)
scan is indicated.
If additional diagnostic studies are necessary, these
should be tailored to answer specific questions. Bone scans
are helpful in the setting of a suspected infection, inflammatory process, or malignancy. MRI scans demonstrate vertebral discs, soft tissue abscesses, malignancy, and the
spinal cord. Computed tomography scans illustrate fractures and bone abnormalities quite well. Laboratory tests
may also help with certain diagnoses such as infection, certain inflammatory conditions, and malignancy.
As mentioned, most back pain in athletes is soft-tissue
related; therefore, treatment of the majority of back disorders should be aimed at functional rehabilitation in order
to minimize downtime and deconditioning. In this context, George and Delitto [24•] outline a treatment-based
classification system for the management of low back pain.
They specifically describe modalities for alleviating acute
and chronic low back pain in athletes in order to return the
athlete to daily training schedules and prevent recurrence
of low back injury. Patients initially avoid activity following a back injury. However, long periods of inactivity must
be discouraged in order to minimize loss of strength and
flexibility. Bed rest is occasionally required but must be
limited to 24 to 36 hours. Activities of daily living should
be performed and walking should be recommended. Ice
and nonsteroidal anti-inflammatory medications
(NSAIDs) will help with initial inflammation. Narcotic
medications should be avoided. Stretching exercises
should begin when acute pain and spasm subside, and
usually within 48 to 72 hours of the injury. Hamstring flexibility must be attained. Strengthening exercises are initiated at 1 to 2 weeks following the injury. Flexors or
extensors should be strengthened according to the specific
diagnosis. For example, flexion exercises should be emphasized in patients with spondylolysis, spondylolisthesis, and
facet joint disorders. Athletes with herniated discs must
build up the extensors. With soft tissue strains, both flexors
and extensors should be strengthened in order to achieve
the appropriate balance between the two. Rehabilitation
advances as symptoms subside. When the athlete has
attained normal strength, normal flexibility, and is painfree, return to competition is allowed. The athlete is
encouraged to maintain a strength and flexibility program
after symptoms resolve in order to prevent recurrence of
back pain.
Specific Diagnostic Causes of Low Back Pain
in Athletes
The majority of back pain in athletes results from benign
processes that will never require surgical intervention.
Unfortunately, there are several diagnostic possibilities that
are more serious and must not be misdiagnosed. Because
of the wide range of ages of athletic participants, the differ-
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Spine Conditions
ential diagnosis of low back pain in athletes is rather
exhaustive. It includes soft tissue insults, spondylolysis/
spondylolisthesis, Scheuermann’s kyphosis, fractures, herniated nucleus pulposis, tumors, infections, primary
inflammatory conditions, and non–spine-related referred
pain from various other anatomic locations.
The most common cause of back pain in the athlete
results from a simple low back soft tissue insult. The soft
tissue can be muscle, ligaments, or fascial tissue. In the
adolescent population, this entity is often referred to as
lordotic low back pain or hyperlordosis. The problem can
involve tearing of muscles, ligaments, or fascia, or can
result from stiffness of these structures. These problems
are diagnosed by history and physical examination.
Often, the athlete will not recall a specific traumatic
event. Occasionally, he may recollect a twisting episode.
Paraspinal muscle spasms and point tenderness are common. Radiographs are unnecessary for the diagnosis.
These injuries respond well to conservative therapy as
outlined above. If symptoms persist beyond 2 to 4 weeks
despite appropriate treatment, a more extensive work-up
is warranted.
Spondylolysis and spondylolisthesis may not be diagnosed until adulthood; however, the defect and the slip
typically occur around age 6 [25]. Therefore, these diagnoses should be actively investigated in the adolescent athlete with back pain and a hyperextension mechanism of
injury. The diagnosis of spondylolysis or spondylolisthesis
is most often made based upon plain radiographs. Anteroposterior, lateral, and both right and left oblique views
must be obtained as 20% of defects are unilateral and will
be missed without both oblique radiographs. SPECT scan
is occasionally required to arrive at the diagnosis. Treatment in the acute setting includes restricted activity, analgesics, and bracing.
Scheuermann’s kyphosis is thoracic kyphosis with
anterior wedging of at least 5º in three consecutive vertebrae. Obviously, classic Scheuermann’s involves the thoracic spine and not the low back; atypical Scheuermann’s,
however, occurs at the thoracolumbar junction. The diagnosis is easily made with radiographs. Tall and DeVault
[11] reported an increased incidence in water skiers. Treatment includes postural exercises for mild curves less than
60º. Curves greater than 60º require bracing, and those
greater than 75º become surgical candidates.
There are many different types and severities of fractures of the spine, a discussion of which is beyond the
scope of this article. Major fractures occur in the setting of
high-energy trauma and will be evident on plain films.
Minor fractures can occur with less impressive mechanisms
and should not be overlooked. Transverse process and
spinous process fractures result from direct trauma. Forced
flexion causes anterior compression fractures. Vertebral
endplate fractures in children can cause herniated disc type
symptoms. Treatment of these minor fractures includes
rest, modified activity, and analgesic medication.
The posterolateral annulus fibrosis is the weakest area
of the intervertebral disc and is the most susceptible area to
herniation of the nucleus pulposis (HNP). HNP results
from repetitive torsional forces with lumbar flexion. Acute
HNP in adolescents is uncommon; however, it still
accounts for approximately 10% of back pain in adolescent
athletes [10•]. Herniated discs in adolescent athletes tend
to be more centrally located, with a smaller volume of
extruded disc than that encountered in adult athletes.
Patients may present with classic tension signs of sciatica,
but many athletes (especially adolescents) will present
with nonspecific buttock, low back, or posterior thigh
pain. MRI is the imaging study of choice for viewing the
extruded disc. Most herniated discs do not require surgical
intervention and will resorb over time. Supportive therapy
with rest, NSAIDs, and extension exercises are the mainstay
of treatment. Athletes usually require a more prolonged
period of activity restriction with HNP than with soft tissue
strains. Occasionally, epidural steroid injections are
employed in treatment. Surgical intervention is indicated if
progressive neurologic deficit ensues or if 6 weeks of conservative therapy fails.
Tumors, infections, and primary inflammatory conditions are rare occurrences in the athlete, but should be suspected when patients manifest unusual symptoms such as
nonmechanical pain, night pain, or constitutional symptoms. A thorough history will often clue the physician to
the likelihood of these more uncommon conditions. The
most likely benign spine tumors in children include
osteoid osteoma, osteoblastoma, and anuerysmal bone
cysts. Malignant neoplasms include osteosarcoma, and
Ewing’s sarcoma. Malignant metastatic lesions are more
common in adults as opposed to primary spine tumors.
Leukemia and lymphoma can occur in both adolescent
and adult athletes. As previously mentioned, discitis is a
diagnosis unique to the pediatric athlete. Adult athletes are
susceptible to vertebral osteomyelitis and soft tissue
abscesses. Work-up for all of these conditions involves
radiographs and laboratory data. Treatment depends on
the specific diagnosis that is made.
Finally, the clinician must be aware of pain referred to
the low back from other areas of the body such as the hip,
the pelvis, or the viscera. Renal disorders, bowel pathology,
or reproductive organ disease may present as low back
pain. The possibility of these disorders should be kept in
mind in the patient whose diagnosis remains elusive.
Referral to other specialists may be necessary if these conditions are suspected.
Sport-specific Causes of Low Back Pain
and Injury
Specific sporting events require particular positions and
body motions of the athlete. Back pain occurs in both contact and noncontact sports, emphasizing the importance
that body position and body movement play in producing
Etiology of Low Back Pain in Athletes • Trainor and Trainor
back injury. In addition, the athlete’s spine experiences different forces depending on the activity in which he or she
is engaged. It is important to recognize the intricacies of
the motions and forces involved with individual sports in
order to understand the particular etiologies of back pain
that occur with specific athletic events.
Contact sports
Low back pain has been reported in a number of contact
sports, but has been most extensively studied in American
football. Catastrophic neurologic spine injuries in football
players are generally related to neck injury and not low back
problems. The much more benign low back strain is extremely
common in football players. Semon and Spengler [22]
reported 27% of 506 college football players experienced low
back pain. Saal [21] found up to 30% of players miss games
because of back pain. Spondylolysis and spondylolisthesis are
more serious conditions seen with an especially high prevalence in football linemen. Shaffer et al. [16] reported that
among college and professional football players with spondylolisthesis lineman accounted for 48% and 50%, respectively.
They also found a 0.9% prevalence of listhesis in college players and a 1.5% prevalence among professional players.
Noncontact sports
Gymnasts and divers are highly susceptible to back injury
because of the constant hyperextension motions involved
with their sports. Garrick and Requa [12] found over 12%
of injuries in gymnasts involved the back. Rossi [15]
reported an incidence of spondylolysis to be 32% in gymnasts and 63% in divers. Athletes who trained greater than
15 hours per week were found to have a higher incidence
of back injury.
Back pain is also common among those participating in
racquet sports because of the constant rotation of the torso
required in these activities. Chard and Lachmann [26] analyzed 631 injuries in athletes engaged in racquet sports. They
found 12% of the injuries involved the spine, with 20%
related to badminton, 21% related to tennis, and 59%
related to squash. Golf also requires transmission of power
through twisting motion of the low back. Spencer and Jackson [27] found that 90% of tournament golfers have had
back injuries. According to a study by Tall and DeVault [11],
29% of professional golfers have experienced low back pain.
Runners rarely complain of low back pain. Jackson and
Pagliano [28] found a 1.1% incidence of low back pain in
adult runners. Glick and Katch [29] reported a 9% incidence of back pain in middle aged joggers. Track and field
athletes appear to be more susceptible to low back injury.
Rossi [15] reported a 22.5% incidence of spondylolysis in
these competitors.
Weight lifters sustain a number of different back injuries. HNP is quite common in lifters. In weight lifters over
the age of 40 years, disc degeneration occurs in 80% of
men 65% of women. Rossi [15] found that 36% of lifters
have spondylolysis.
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Conclusions
Similar to the general population, back pain occurs frequently in the athlete, both young and old. Fortunately, the
majority of these injuries are soft tissue insults that can be
successfully treated with conservative measures. The nature
of the sport played, and the particular forces and motions
required of its participants, can enlighten the physician
about more serious injuries that may be sustained. Back
strengthening and stretching programs are a mainstay of
treatment for most back injuries. Flexibility of the hamstrings and pelvis are also important. These exercises
should not only be utilized following injury, but must be
incorporated into the athlete’s normal training schedule in
order to prevent recurrence of back pain.
References and Recommended Reading
Papers of particular interest, published recently, have been
highlighted as:
•
Of importance
•• Of major importance
1.
Frymoyer JW, Cats-Baril WL: An overview of the incidences
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2. Frymoyer JW, Pope MH, Clements JH, et al.: Risk factors in low
back pain: an epidemiological survey. J Bone Joint Surg (Am)
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3. Svensson HO, Anderson GB, Johanson S: A retrospective study
of low-back pain in 38- to 64-year old women: frequency of
occurrence and impact on medical services. Spine 1988,
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7.• d’Hemecourt PA, Gerbino II PG, Micheli LJ: Back injuries in
the young athlete. Clin Sports Med 2000, 19:663–679.
Extremely thorough, current article that reviews all aspects of back
injuries in young athletes. This review includes indications for bracing
as well as surgical intervention.
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differences from adults in causes and patterns. Arch Pediatr
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9.• Kraft DE: Low back pain in the adolescent athlete. Pediatr Clin
North Am 2002, 49:643–653.
Most recent review article detailing history, physical examination, and
differential diagnosis, as well as treatment options for low back pain
in adolescent athletes. Particular emphasis is placed on pars interarticularis pathology.
10.• Sassmannshausen G, Smith BG: Back pain in the young athlete. Clin Sports Med 2002, 21:121–132.
A recent article identifying common causes of back pain in the young
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athlete with low back pathology is presented.
11. Tall RL, DeVault W: Spinal injury in sport: epidemiological
considerations. Clin Sports Med 1993, 12:441–448.
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Saal JA: Lumbar injuries in gymnastics. In The Spine in Sports.
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17.• Lundin O: Back pain and radiological changes in the thoracolumbar spine of athletes: a long-term follow-up. Scand J Med
Sci Sports 2001, 11:103–109.
An important recent study emphasizing the trend in athletes to
under-report back symptoms even in the presence of radiographic evidence of pathology. This study included 134 athletes representing
wrestling, gymnastics, soccer, and tennis.
18. Ong A: A pilot study of the prevalence of lumbar disc degeneration in elite athletes with lower back pain at the Sydney
2000 Olympic Games. Br J Sports Med 2003, 37:263–266.
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Semon RL, Spengler D: Significance of lumbar spondylolysis
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Surgeons; 2002:97–107.
24.• George SZ, Delitto A: Management of the athlete with low
back pain. Clin Sports Med 2002, 21:105–119.
Article detailing a treatment-based classification system for the management of athletes with musculoskeletal low back pain. Several clinical scenarios detailing diagnosis and management are presented.
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