Consequences to athletic performance
Low back injury in athletes may be of further significance as Nadler et al. documented that athletes with resolved low back pain from a history of low back injury demonstrate significantly diminished athletic performance in a 20m shuttle run test compared with a healthy group (Nadler et al., 2002). Despite this study, there is very little scientific literature investigating the consequences of current or resolved low back pain and injury on athletic performance. Research findings have demonstrated that weak hip extensors have been associated with the presence of low back pain, and in female athletes, the presence of hip weakness identified at the time of the pre-participation physical has been shown to be predictive of the subsequent development of low back pain (Kankaanpaa et al., 1998; Leinonen et al. 2000; Nadler et al., 2001; Nadler et al., 2002). Gluteus maximus should be the primary hip extensor during sprinting (Simonsen et al. 1985). During sprinting, the hamstrings should act as a transducer of power between the knee and hip joint and contribute little to hip extension (Jacobs et al., 1996). This transfer of power is essential in the execution of explosive movements like sprinting (Gregoire et al., 1984).
Significant alterations to hip extensor recruitment have been shown to occur with chronic low back pain during walking, causing the gluteus maximus to be inhibited and hamstrings overactive (Vogt et al., 2003). Hypothetically, gluteus maximus inhibition during sprinting may impact power development and sprinting performance and may require the hamstrings to contribute more force to hip extension rather than acting in its transducer role, potentially predisposing hamstring injury. This fits with the often talked about, but poorly researched syndrome proposed by Janda, the lower crossed syndrome, where decreased hip joint range of motion leads to hypermobility of the lumbosacral region (Janda, 1996), which may be another potential mechanism for low back pain. It also fits with models of overactivity of the global muscle system and a compromise in the local spinal muscle system, predisposing excess force directed at unprotected spinal structures and further back injury.
Given the consequences of low back pain on the lumbar-pelvic muscular system discussed earlier in this topic, it is highly likely that other measures of athletic ability may be reduced in athletes with a history of low back injury. If objective deficits are documented in research, further research is also required to document that rehabilitation and management protocols are successfully able to reverse the decline in athletic performance, not just resolve symptoms.
Association of low back pain with other injuries
Given that evidence exists documenting that low back pain produces changes in the neuromuscular control of the lumbopelvis (Demoulin et al., 2007) and in athletes, it produces altered muscle response patterns required for lumbar-pelvic stabilization during sudden trunk loading following clinical recovery from low back pain (Cholewicki et al., 2002), it is reasonable to hypothesize that low back pain could increase the risk an athlete has of suffering other injuries. A prospective study by Nadler et al. showed a correlation between the prevalence of low back pain in athletes and lower extremity overuse syndromes, through an unclear mechanism (Nadler et al., 1998). In community level Australian Rules footballers, a history of low back pain has been shown to be a risk factor for other injuries, producing a 19% increased risk of overall injury rates (McManus et al., 2004). Changes in lumbar-pelvic stabilisation and neuromuscular control could explain the high rates of injuries such as hamstring injuries, groin injuries and other lower limb muscle strains which occur in the various football codes, cricket and track and field to name a few sports.
Using magnetic resonance imaging to confirm diagnosis of hamstring injury, 14% to 19% of all hamstring injuries are without muscle damage (Verrall et al., 2001; Verrall et al., 2003; Woods et al., 2004), suggesting no local muscle pathology. A recent study found this figure could be as high as 45% (Gibbs et al., 2004). Injury in such cases could possibly be related to altered functional biomechanics or pain referral that does not appear on cross sectional imaging. It is known that referred myotomal pain from lumbar-pelvic structures, the sciatic nerve and the gluteal or piriformis muscles can mimic hamstring strains (Verrall et al., 2001). The term ‘back related hamstring injury’ has been coined and is used to classify injuries as having both local hamstring signs and positive lumbar signs (Bennell et al., 1998, Orchard, 2001).
The association between low back ailments and hamstring injuries has been recognised for some time (Baquie & Reid, 1999). However, this relationship has not received as much recognition in the scientific literature as what is suggested anecdotally. Verrall et al. have performed a prospective study which showed that that a past history of low back injury approached significance for being a predictor for hamstring injury (p=0.06), without reaching the statistically significant level (Verrall et al., 2001). Further specific research has not followed on from this 114 participant study. A strong correlation between common lower limb soft tissue injuries, including hamstring and calf injuries, that involve L5 and S1 nerve supply, with increasing player age has been clearly demonstrated in the AFL’s injury survey (Orchard & Seward, 2002). Orchard et al. suggest that on the basis that low back injuries are very common in elite athletes with increased levels of lumbar degenerative changes at the L4/L5 and L5/S1 levels (Ong et al., 2003), that subtle pathology may be present, which increases with age and which predisposes hamstring and calf injury (Orchard et al., 2004). The association between low back injury and pathology and hamstring injury has extended into treatment approaches with authors documenting the use of mobilisation (Baquie & Reid, 1999) and slump stretching protocols (Kornberg & Lew, 1989; Turl & George, 1998) in the management of hamstring injured athletes with signs of lumbar injury.
Post career low back pain
Questions need to be raised regarding whether low back pain normalizes following a career of athletic participation. It is known that former elite athletes are more likely to receive hospital care suffering from musculoskeletal complaints in general (Kujala et al., 1996). However, in the largest study performed using self-reported questionnaires, it appears that low back pain is less common in former elite athletes (29.3% of 937) than in non-athletes (44% of 620) (Videman et al., 1995). This is despite an increase in degenerative radiological findings in former elite athletes (Videman et al., 1995; Lundin et al., 2001). It is unclear whether participation in certain sports will affect post career pain or the intensity of low back pain experienced (Lundin et al., 2001).
Diagnosis
Although most low back pain is non-specific and mechanical in nature (Burton et al., 1996), athletes presenting to a sports clinician with back pain may have a pathological cause. It is important to initially consider a broad differential diagnosis list. A sports clinician looking after athletic patients is responsible for performing a diagnostic triage to rule out red flag conditions, diagnose the condition and either referring out, or being responsible themselves for treating symptomatic tissues and recognising and evaluating functional deficiencies and aetiological factors responsible for factors causing the low back injury. Dealing with an athlete can often be a challenge when compared with the general population. A sports clinician must assimilate a large body of clinical information unique to the diagnosis and management of the special needs of those who participate in sport. This includes being highly familiar with the vast array of sports and the potential injury mechanisms for low back pain that could occur in a particular sport.
Whilst most back pain will be mechanical in nature it is important to exclude other diagnoses such rheumatological or inflammatory conditions, infection, fracture and neoplasm. This is particularly the case when adolescent athletes present with low back pain as they are more likely to potentially have a pathologic cause for their symptoms (Micheli et al., 1995). For this reason, it is important for those caring for younger athletes to maintain a high index of suspicion for some of the more common pathologic causes of low back pain in this population. Sports-related diagnoses that have been said to be considered include discrelated back pain, atypical Scheuermann’s kyphosis, spondylolysis, spondylolisthesis and other stress fractures of the pelvis, especially in female athletes (Waicus & Smith, 2002). Other research has documented that junior athletes with chronic low back pain form a population of adolescents who have degenerative disc disease identified on magnetic resonance imaging (Dimar et al., 2007). For adolescent athletes with degenerative disc disease, the relative risk of reporting recurrent low back pain up to the age of 23 years is 16 compared with those having no disc degeneration (McManus et al., 2004). Furthermore, disc protrusion and Scheuermann-type changes also contribute to the risk of persistently recurrent low back pain at a later age (Salminen et al., 1999). How this should alter management approaches remains unclear as there is also a large proportion of adolescent athletes with signs of degeneration present on imaging who remain symptom free. Low back pain in adolescent athletes is a problem that should not be ignored but instead fully evaluated.
The challenge with diagnosis of back pain is that the tissue diagnosis model is mostly not relevant, despite advances in imaging techniques. Whether a sporting population or not, history must identify and eliminate potential red flag conditions that may be present that would indicate more serious pathology. Red flags are clinical indicators of possible serious underlying conditions requiring further medical intervention. Red flags were designed for use in acute low back pain, but the underlying concept can be applied more broadly in the search for serious underlying pathology in any pain presentation. Red flag conditions are listed in Table 1, and should be enquired about in all patients. The presence of red flags in acute low back pain suggests the need for further investigation and possible specialist referral as part of the overall strategy. If there are no red flags present it is safe to reassure the patient and move ahead with the diagnosis process.
|
Red flag conditions |
History or examination findings |
|
Possible fracture |
Major trauma |
|
Minor trauma in elderly, osteoporotic or those taking long term corticosteroids |
|
|
Possible infection |
Symptoms and signs of infection such as fever or chills |
|
Recent bacterial infection |
|
|
Risk factors for infection such as underlying disease process, immunosuppression or intravenous drug use |
|
|
Possible tumour |
Age >50 or <20 years |
|
History of cancer |
|
|
Constitutional symptoms such as weight loss |
|
|
Pain at multiple sites |
|
|
Pain worse at rest |
|
|
Pain worsening at night |
|
|
Failure to improve with treatment |
|
|
Pain persists for more than 4-6 weeks |
|
|
Possible significant neurological deficit |
Severe or progressive sensory alteration or weakness |
|
Bladder or bowel dysfunction |
|
|
Evidence of neurological deficit (in legs or perineum in the case of low back pain) |
Table 1. Red flag conditions for back pain
A focus should be made on the patients age and the age related differential diagnoses prior to full characterisation of the symptoms in history taking. As with all medical diagnosis, it is important to find out key information including the site of pain, whether any pain referral or radiation exists, associated symptoms in particular neurological deficit and systemic features of illness potentially leading to back pain, when the onset of pain began, the course of the pain, quality of pain, the severity, aggravating and relieving factors and movements, previous history of back pain and back injuries and treatment approaches used and their various success. History should also include questioning of the mechanism of injury or the inciting event. This mechanism of injury allows the clinician to predict what potential injuries may have occurred with the force transmitted and facilitates developing a rehabilitation program and implementing preventive measures through technique or training alterations if applicable.
Lawrence et al. state that the patient’s athletic background should be explored (Lawrence et al., 2006). This includes types of sports played, duration of involvement, the level of competition along with what stage of the season the athlete is at, upcoming competition and future goals. This is relevant as it may impact upon the management approaches to be used and their success if an athlete is unwilling to miss a period of training or competition or is going to be uncooperative with management recommendations. It is also important to get an idea of what multidisciplinary management team and coaching staff the athlete has surrounding them as co-management is typically necessary and often mandatory when dealing with the high level elite and professional athlete. These multidisciplinary resources should be embraced and a good working relationship developed as cooperation is often required to implement management programs in an athlete centre approach to care.
In low back pain research performed on the general population, guidelines recommend early identification of psychosocial factors that could prevent recovery from acute low back pain (Ramond et al., 2011). As discussed earlier in this topic it is unclear whether the yellow flag model is applicable to the sporting population. The presence of yellow flags may highlight the need to address specific psychosocial factors as part of a multimodal management approach. Yellow flags are psychosocial indicators suggesting increased risk of progression to long-term distress, disability and pain. Yellow flags were designed for use in acute low back pain. In principle they can be applied more broadly to assess the likelihood of development of persistent problems from any acute pain presentation. Yellow flags can relate to the patient’s attitudes and beliefs, emotions, behaviors, family, and workplace. The behavior of health professionals can also have a major influence. Key factors in low back pain are: the belief that pain is harmful or severely disabling; fear-avoidance behavior (avoiding activity because of fear of pain); low mood and social withdrawal; and expectation that passive treatment rather than active participation will help (New Zealand Low Back Pain Guide, 1997). Future research is required to investigate the relevance of these factors in athletic populations.
Following history taking, physical examination should be equally as thorough and incorporate standard observations and structural analysis, range of motion assessment, palpation and traditional orthopaedic and neurological testing procedures to inform possible investigations if required. The single-leg hyperextension test has been described and is a useful provocative test when differential diagnosis includes spondylolysis (Jackson et al., 1976).
Imaging of injuries
Much controversy exists surrounding the utility of plain film, computed tomography, magnetic resonance imaging, and bone scintigraphy in the evaluation of sports-related spine injuries (Hollenberg et al., 2003). Diagnostic imaging should be used in an evidence based and targeted fashion. The evidence to support the use of diagnostic imaging in non-specific, mechanical low back pain without red flags present is lacking and its use is often costly, time consuming and potentially harmful to the patient when radiation doses are considered. The topic of routine screening is also a dated process. In football code players, it is unclear whether they have a greater prevalence of radiographic lumbar spine abnormalities, including spondylolysis and spondylolisthesis, as age-matched controls (Jones et al., 1999).
In a large retrospective study of plain radiographs of the lumbar spine of 4243 athletic men and women with low back symptoms, 14% had a radiologic diagnosis of spondylolysis and 47% of these (or 7% of all athletes with back symptoms) had associated spondylolisthesis (Rossi & Dragoni, 2001). However, the diagnosis of spondylolysis and spondylolisthesis does not always equate to the symptoms present. The prevalence of spondylolysis in the general population has been estimated between 3% and 6% (Bono, 2006). Most commonly spondylolysis and spondylolisthesis occurs at L5 (85% to 95% of cases) and L4 (5% to 15%) (Standaert et al., 2000). Degenerative findings are known to be higher in athletes with low back demands on radiographic imaging (Sward et al., 1991). Again, their presence does not have to equate a source of symptoms in all cases.
When investigating spondylolysis, imaging should commence with plain radiographs, with anteroposterior, lateral and oblique views. Grading of the spondylolisthesis can be made on the lateral film using the Myerding system. Whilst plain films can be diagnostic, CT is superior in the diagnosis and is the imaging modality of choice for the diagnosis of spondylolysis (Teplick et al., 1986). SPECT is sensitive to metabolic bone changes and is positive in acute spondylolisthesis, however it can be normal in chronic pars defects (Lusins et al., 1994), helping to diagnose acute versus chronic injury and in attributing a source of symptoms. SPECT has been shown to have superior sensitivity to standard bone scans for detecting spondylolysis (Bellah et al., 1991). Magnetic resonance imaging can detect early changes in bone marrow oedema but not fracture, however marrow oedema is known to predate a frank pars defect (Gundry & Fritts., 1999). The use of magnetic resonance imaging in the evaluation of spondylosis has mixed opinions in the literature (Hollenburg et al., 2003), but given the lack of radiation its use is increasing particularly when repeated scanning is required for follow up of adolescent athletes.
Other injuries that require imaging to diagnose include disc herniations. Magnetic resonance imaging is the imaging of choice for the diagnosis of disc herniation, foraminal narrowing and other disc injuries. It can also demonstrate degenerative disc disease and facet arthropathy as causes of back pain (Hollenburg et al., 2003). However, the exact correlation between a degenerated disc and low back pain has been described as elusive as high rates of radiographic findings of degenerative discs are found in asymptomatic patients (Boden et al., 1990). Fatigue type sacral stress fractures are a potential cause of low back pain in athletically active premenopausal women (Johnson et al., 2001). Although plain films can be diagnostic, symptoms typically precede radiographic findings by weeks to months (Johnson et al., 2001). Additionally there is difficulty interpreting radiological findings in the sacral area. Bones scans are very sensitive for stress fractures, but non-specific: a normal scan virtually excludes the diagnosis. CT is sensitive and specific for most stress fractures (Hollenburg et al., 2003). More recently magnetic resonance imaging has been used for the diagnosis of stress fractures (Major et al., 2000) despite previously being thought of sensitive but not specific. In the very early stages magnetic resonance imaging can detect medullary oedema but is insensitive for detecting a fracture line.
Management
Success in dealing with athletes with back injuries likely requires efforts to address both the cause of the injury and the most appropriate rehabilitation therapy (McGill, 2002). In many cases, addressing the cause of low back pain involves the athlete changing technique but without exception, they have to change the way they train (McGill, 2002). However, evidence to support risk factors for the development of athletic low back pain is lacking. Evidence exists showing that coaching aimed at improving technique in cricket fast bowlers decreases the prevalence and progression of disc degeneration measured with magnetic resonance imaging (Elliot & Khangure, 2002). Whether this translates to improved clinical results or to other sports remains unknown. Despite personal opinions that exist in the literature on the benefits of rehabilitation, there is lack of clinical research recruiting subjects with low back pain from athletic populations into randomised controlled trials investigating rehabilitation protocols or other treatment approaches. Apart from one short-term small study (Hanrahan et al., 2005), the author is not aware of other randomised controlled trials for the treatment or rehabilitation of low back pain with subjects drawn from an athletic population. It is not possible to produce evidence based guidelines for the management of back pain in different sports until an adequate literature base is established.
Current published evidence based guidelines for low back pain management for acute pain in non-athletic populations generally advocate an approach to management that includes advice to: remain active, modify activity, remove only those activities that specifically aggravate and potential replace with other non aggravating activity (relative rest) and to stay at work (Koes et al., 2001; Arnau et al., 2006). Simple analgesic pharmacological agents and exercise and manual therapies are often also advised in a multimodal approach. For chronic conditions various exercise-based protocols are often recommended. It may be for an athlete that a too aggressive active approach to management and the tissue loading from incorrectly prescribed ‘stabilization exercises’ (Callaghan et al., 1998; Kavcic et al., 2004) may be aetiological or aggravating factors. In support of this assertion, it has been shown that there is no significant advantage of additional core-strengthening in reducing low back pain occurrence in athletes (Nadler et al., 2002). Future research should investigate different rehabilitation protocols in a range of athletes from different sports.
The core principles of published guidelines should be used in the management of athletes with low back pain until they are replaced with athlete specific research and guidelines. The published guidelines in many ways mirror many of McGill’s suggestions on how to reduce the risk of low back injuries in athletes, which include (McGill, 2002):
• Avoiding end range of spine motion during exertion. Examples of this include golfers sparing the spine from full lateral bend and near full rotation by reducing the back swing and grooving abdominal patterns that lock the rib cage to the pelvis on follow through.
• Use techniques to reduce reaction moments, such as tackling athletes directing force vectors through the lumbar spine to minimize resulting compressive forces.
• Avoid prolonged sitting (or sitting at all) on the bench, as prolonged flexion through sitting exacerbates discogenic back problems together with ligament based syndromes and results in decreased lumbar flexibility after a warm up period (Greene et al., 2002).
• Do not train shortly after rising from bed if a large amount of lumbar motion is required.
• Have athletes capable of stabilizing their lumbar spine irrespective of their phase of ventilation.
• Have the athlete contract musculature to stabilize the spine to more effectively transmit forces, particularly when an athlete might experience an unexpected load, when using combinations of simultaneous moments and after speed and acceleration of body segments are required.
• Practice spine sparing movement patterns and stabilizing motor patterns.
As most low back pain in athletes is likely to result from repetitive micro-trauma and fatigue from the often monotonous and repetitive overuse situations in training, management must include modifications in training (Baranto et al., 2009). Discussions should be made with coaching staff to ensure a period of relative rest, activity modification and if relevant, technique alteration is made to prevent the cycle of recurrent exacerbations and chronic pain.
Given the natural history of low back pain in adolescence involves a significantly increased risk of adult low back pain, it might be counterproductive to postpone treatment of adolescent athletes until the problems become more severe and chronic (Hestbaek et al., 2006). Hestbaek et al. have suggested a change in focus from the adult to the young population in relation to research, prevention, and treatment of low back pain (Hestbaek et al., 2006). However, it remains to be seen whether a greater focus on prevention and treatment can eliminate the risk and consequences of future low back pain episodes and minimise future chronicity.
A growing body of literature exists suggesting that classification of patients with nonspecific, mechanical low back pain into subgroups for the purpose of directing treatment decision-making is important to improve prognosis, quality of care and patient outcomes (Borkan et al., 1998; Beaton et al., 2001). Various approaches are used to classify patients including the McKenzie or Mechanical Diagnosis and Therapy (MDT) technique and the Delitto or Treatement Based Classification (TBC). An important clinical symptom observed during the MDT examination process is centralization. This is where spinal and referred pain is abolished in a in a distal-to-proximal direction in response to therapeutic movement and positioning strategies (McKenzie & May., 2003; Aina et al., 2004). With the TBC patients are classified into three stages based on condition severity, ranging from the acute to subacute and advanced rehabilitation stage (Delitto et al., 1995). Stage 1, where the goal is symptomatic relief identifies four basic treatment subgroups, i.e. manipulation, exercise, stabilization, and traction, using specific clinical signs and symptoms, has been extensively researched and supported in the literature (Fritz et al., 2003; Fritz et al., 2000; Fritz et al., 2007).
An increased body of literature is also developing to support clinical prediction rules, which are prognostic models aiming to identify patient characteristics and clinical signs and symptoms to assign patients to treatment approaches to predict patient outcomes. Although such models do not exist for athletic populations, their development is encouraged given the multitude of treatment modalities that currently exist for back pain. When looking at clinical prediction rules for low back pain, two separate models have been developed to identify patients who would respond best to manipulation (Flynn et al., 2002; Fritz et al., 2005). The original model used five criteria: no symptoms below the knee, recent onset of symptoms (<16 days), low fear avoidance belief questionnaire score for work, hypo-mobility of the lumbar spine, and hip internal rotation range of motion (>35 degrees for at least one hip) (Flynn et al., 2002). This was modified to two criteria that included no symptoms below the knee and recent onset of symptoms (<16 days), as a pragmatic alternative for identifying patients most likely to positively respond to manipulation (Fritz et al., 2005). The stabilization clinical prediction rule was developed to determine whether patients with low back pain are likely to favorably benefit from stabilization exercises (Hicks et al., 2005). It uses four classification criteria, which include: age <40, positive prone instability test, positive aberrant trunk movements, and average straight leg range of motion >91 degrees. Whether these clinical prediction rules can be applied to athletes or whether new rules are required to be developed for athletic populations remain to be seen.
When specifically looking at exercise based rehabilitation protocols McGill suggests several key principles that should be included when developing exercise programs (McGill, 2002):
• Muscle endurance, not strength is more important.
• Patients should be encouraged to maintain a neutral spine when under load and use abdominal contraction and bracing in a functional way.
• No single abdominal exercise challenges all of the abdominal musculature while sparing the back. Therefore more than one exercise is required and the ‘big three’ is recommended: curl ups, side bridge and leg and arm extensions in the birddog position.
Once the basics are developed, then higher challenges and advanced exercises can be incorporated. When specifically looking at athletes, McGill suggests a five stage paradigm based around an adequate foundation of stabilizing motion/motor patterns (McGill, 2002):
1. Identifying the essential motions and grooving appropriate motion/motor patterns.
2. Ensuring joint and whole body stabilizing patterns.
3. Develop muscle endurance around these patterns.
4. Enhance strength.
5. Establish power.
Non-operative management is the mainstay for athletes with low back injuries. If simple conservative approaches to management fail, therapeutic epidural spinal injections are often the next line of therapy recommended in a trial of therapy. However, there are conditions which will require early surgical opinion and management, whilst failed non-operative management of severe, chronic low back pain may also require surgical management. Typical conditions for surgical referral include spondylolisthesis, disc herniation and traumatic fracture. The natural history and risk of progression and the non-operative and operative treatment of spondylolysis has been extensively covered by Bono (Bono 2006) and other authors (Lennard TA & Crabtree M, 2005). Bono states that indications for early surgical management for spondylolysis are a neurological deficit related to spondylolisthesis, a progressive slip or a grade III or high grade slip at presentation. Other literature also exists discussing the management of disc degeneration and disc herniation (Lennard TA & Crabtree M, 2005; Bono, 2006; Lawrence et al., 2006).
