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REHABILITATION SHOULDER IMPINGEMENT
highlighted as a main cause of dysfunction in the shoulder, are now commonly assessed in patients with impingement (9,10).
Ellenbecker
(11), Mottram (9) and Host (12) recognise the inability to control the movement of the scapula during upper limb movements and note this frequently accompanies the development of shoulder pain.
SCAPULA
DYSKINESIA AND SHOULDER IMPINGEMENT – WHAT IS THE EVIDENCE?
BY COLIN PATERSON, MCSP INTRODUCTION
N COLIN PATERSON, MCSP umerous treatment options are
available for the treatment of shoulder impingement. Donatelli (1) discusses the use of manual therapy, myofascial treatment, graduated exercise and strengthening programmes. However taping has become a popular adjunct to physiotherapy practice, popularised by McConnell (2,3). Due to this popularity there has been a steady growth in published research, but it must be noted that the majority concentrate on the effects on lower limb pathologies. Clinically the use of taping is usually combined with a specific exercise programme. However this article will concentrate solely on the use of taping for shoulder impingement, its effect on scapula muscle activity and its efficacy.
According to Kamkar, Irrgang and Whitney (4) shoulder impingement refers to the signs and symptoms of pain and dysfunction, which are a consequence of pathology that either decreases the volume of the subacromial space or increases the size of its contents. Bigliani et al (5) categorised impingement into two groups: primary and
14
Shoulder impingement is a common dysfunction presenting to therapists clinically. Altered scapula movement, or scapula dyskinesia, is now regularly implicated as a contributing factor to shoulder impingement due to growing research evidence highlighting alterations in muscle activity of the scapula rotators. Numerous treatment options for scapula dyskinesia are available including exercise therapy, postural awareness and taping. The use of taping techniques to improve the activity of muscles around the shoulder girdle has in recent years grown in popularity. With the growing need for research evidence to support clinical practice, this paper provides a review of the current evidence on both scapular muscle activity in subjects with impingement. The second paper reviews the use of taping techniques to alter muscle activity around the scapula.
secondary impingement. They defined primary impingement as an outlet stenosis of the subacromial space due to anatomical factors such as a hooked acromion. Secondary impingement was considered to be due to physiological factors. These factors could include glenohumeral instability, scapulothoracic
dyskinesia and posture (6-8) and are considered to be associated with altered motor recruitment and are common in over- head athletes (8).
SCAPULA STABILITY Scapula mechanics, which research has
sportEX medicine 2008:36(Apr):14-17 The scapula has numerous functions
contributing to both stability and mobility of the shoulder complex. It provides a base for muscle attachment and its appropriate orientation optimises the length tension relationships of these muscles (9). Kibler (8) commented that when the scapula loses its stability, the orientation of the glenoid fossa is compromised, preventing optimum function of both the glenohumeral joint and supporting musculature, namely the rotator cuff. Coordinated scapula movement is therefore essential and force couples exist to produce this smooth movement. It is when these force couples become dysfunctional that problems are thought to arise (13). The primary scapula force couple associated with shoulder elevation is between serratus anterior and trapezius; resulting in lateral rotation of the scapula (10). In the early range of elevation both the upper fibres of trapezius and serratus anterior are active. Later in range, when the axis of rotation moves towards the acromioclavicular joint, the lower fibres of trapezius and serratus anterior are dominant (1,14,15).
MOTOR CONTROL DYSFUNCTION
It is commonly accepted that many factors influence movement of the human body, including soft tissues, bone, joints and also the nervous system. It is the nervous system that controls the coordination of muscle activity that allows effective and efficient movement patterns to occur (16). A reduction in this control of motor activity can contribute to pain and dysfunction. Alternatively it is proposed that pain and dysfunction can cause an alteration in motor control.
Changes in sensory feedback, abnormal
reflex activation and reduced coordination have all been identified as contributing to deficits in the sensory control of movement (16). The basis of closed-loop motor control is accurate sensory feedback to the central nervous system (CNS). A reduced ability to detect movement and a reduced repositioning sense have occurred in populations with musculoskeletal dysfunction; for example subjects with low back pain (LBP) (17), post ankle sprain (18), subjects with shoulder instability (19) and subjects with osteoarthritis of the knee (20). Reduced sensory input to
the CNS can lead to delayed reflex responses, impaired coordination of voluntary movements and faulty movement error detection and correction (16). In addition any change in muscle activity affects the sensation of movement. Therefore factors such as fatigue, antalgic movement patterns and pain-induced muscle inhibition could all result in altered motor control strategies that could potentially exacerbate the initial dysfunction. Hence a negative cycle is continually being reinforced (16).
Dysfunction of the scapula stabilisers has been highlighted clinically in subjects with impingement (9). This is consistent with studies in other anatomical regions that demonstrate stability muscle dysfunction associated with pain (16,21,22). Increased anterior glenohumeral laxity has been
associated with poor scapula stability (4,23). Glenohumeral instability has also been associated with reduced firing of the rotator cuff (24), amplifying the joint instability further. The scapula stabilising muscles have been studied in both normal and painful shoulders to determine alterations in firing patterns with pain. An EMG study of 15 throwing athletes by Glousman et al (24) observed reduced serratus anterior activity in the group with unstable shoulders, although caution should be applied in extrapolating this data to
impingement patients, despite instability being a potential cause of secondary impingement (5).
Ludewig and Cook (25) investigated the scapular muscle activity of 52 impingement diagnosed subjects. Their results support those of Glousman et al (24) by demonstrating statistically significant alterations in scapula muscle activation in impingement subjects. Ludewig and Cook (25) also measured the resulting effect on scapula positioning. The impingement subjects demonstrated a statistically significant reduction in serratus anterior activity with a resulting reduction in posterior tipping of the acromion and initial upward rotation of the scapula, accentuating the risk of subacromial impingement. Increased activity in both the upper and lower portions of trapezius also reached statistical significance from mid-range elevation upwards. However the reliability of using skin markers for
kinematic analysis of true scapula positioning was not discussed in the above studies. Studies by Cools et al (26-28) have
also found altered scapular muscle activity in impingement populations. Cools et al (27) found overhead athletes with shoulder pathology to exhibit decreased force output of serratus anterior, resulting in an altered muscle balance between serratus anterior and trapezius. In the same study they
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Figure 1: Right scapular winging 15
SERRATUS ANTERIOR CAN AFFECT THE SCAPULA FORCE COUPLE AND RESULT IN DYSFUNCTION AND PAIN
AN OVERALL IMBALANCE IN MUSCLE ACTIVITY BETWEEN TRAPEZIUS AND
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STRAPLINE ONE FEATURE SUBJECT
BIOMECHANICS SUPPORT FOR BRITISH WORLD CLASS DISABILITY SWIMMING
In disability swimming competitions, athletes with conditions such as limb loss, spinal cord injury, cerebral palsy or other physical impairments, may compete against each other, depending on which classification they are given. Swimmers with a functional impairment are allocated a class from 1-10, according to the extent of their impairment. Athletes in class S1 will have severe impairment, such as extremely limited coordination in all four limbs; those in the S10 class will have a minor impairment, such as a restriction of movement at the hip. Three separate classes (S11-S13) exist for swimmers with a visual impairment.
Great Britain has, for some time, been one of the world leaders in disability swimming at elite level and is the current International Paralympic Committee (IPC) World Champion. As a result of significant funding from UK
BY CARL J. PAYTON, PH.D
BIOMECHANICS SUPPORT Biomechanics support for British Disability Swimming is led by the author, but involves a significant input from a number of other specialists. The aim is to deliver a comprehensive programme of support to Britain’s elite disabled competitive swimmers and their coaches, to enhance performance at elite level. To achieve this aim, the programme involves:
■ Analysing starting, turning &
stroking techniques in training, and in competition, to identify strengths and weaknesses
■ Developing new testing protocols and equipment to provide rapid
feedback of relevant information, in a user-friendly format
■ Creating strategies for modifying technique and regularly monitoring each swimmer’s progress
■ Providing coach support through seminars, workshops, articles etc
■ Conducting applied research projects to underpin the support work. There are three distinct
components of support: 1)
biomechanical assessment and intervention; 2) applied research projects, and 3) coach mentoring and support. This section will provide more detail on each of these.
BIOMECHANICAL ASSESSMENT & INTERVENTION
Both qualitative and quantitative
biomechanical assessment techniques are used to analyse swimmers in training and in competition. Swimmers have the opportunity to be assessed at least three times per year at one of the Disability Swimming High Performance Centres (Stirling, Manchester and Swansea). Four types of assessment are currently available:
■ qualitative & quantitative video analysis
■ race analysis ■ velocity meter analysis
■ tethered and semi-tethered force analysis.
Video analysis (qualitative & quantitative) Above and below water digital video recordings are used to provide
BY ANTHONY SHAW, BSc
SUDDEN CARDIAC DEATH SCD is defined as a non-traumatic, non-violent, unexpected event resulting from sudden cardiac arrest within six hours of a previously witnessed normal heart (1). It has long been established that physical activity significantly improves cardiac health, reducing the risk of atherosclerosis and subsequent SCD in young individuals (2), however, a small but significant number of athletes still die suddenly. These tragic events are often highly
publicised, particularly when they involve high profile sports people. Over the last few years, events such as the deaths of professional footballers Marc Vivian Foe, Miklos Feher and more recently, the young Sevilla player Antonio Puerto and the Motherwell captain, Phil O’Donnell, in conjunction with the cardiac arrest and subsequent resuscitation of Clive Clarke in England, have highlighted the problem. In addition, there have also been a number of exercise related SCDs in high profile events in the UK including the London Marathon and the Great North Run.
THE FACTS
Estimates on the number of people who die of SCD are varied. Research from the USA suggests a figure of between 1 in 200,000 and 1 in 300,000 (3). The true figure however is likely to be higher as there is no systemic national registry for sudden cardiac deaths in sport, and experts in cardiac pathology are rarely responsible for performing post mortem examinations. Furthermore deaths from electrical rather than structural disorders cannot be identified during a post-mortem examination (4). It is thought that approximately 2% of all SCDs fall into this category following testing performed on the first degree relatives of SCD victims (5). The major cause of SCD in athletes can be divided into two groups depending on the athletes’ age. The majority of deaths in athletes over 35 years are due to coronary artery disease, whereas SCD in younger athletes is usually due to inherited or congenital disorders of the heart (5). The majority of these SCDs occur either during or immediately after exercise, suggesting that whilst exercise is not directly responsible for causing SCD, it can act as a trigger
6
CARDIAC SCREENING AS A RESULT OF SUDDEN CARDIAC DEATH IN ATHLETES
Sudden cardiac death (SCD) is an uncommon occurrence but when it happens the consequences are far reaching. The death of young, apparently healthy individuals who are considered to be at the pinnacle of fitness, impacts upon sport, their peers, family and friends and the community as a whole. More often than not, these events occur with little or no prior warning. This article looks at the background of SCD, the principle causes and the number of people it affects as well as examining the principles of cardiac pre-participation screening of athletes as a means of limiting the number of SCDs.
(1). Of 157 young athletes in the United States who suffered SCD between 1986-1995, 90% died during or immediately after a training session (6). The vast majority of SCDs occur in the male population, with a ratio of approximately 10:1. This may be related to the higher participation rates of males in competitive sports and more intensive training loads (7). However it has also been suggested that there may be a greater prevalence and/or phenotypic expression in young males of cardiac disease at risk of arrhythmic cardiac arrest, such as the cardiomyopathies (8-9).
There are a number of conditions that can be attributed to SCD, some of which are summarised in Table 1. Most SCDs are due to inherited structural and functional cardiovascular abnormalities. Hypertrophic cardiomyopathy (HCM), an unexplained or abnormal thickening of the left and/ or right ventricle accounts for 40-50% of all such deaths (1).
CARDIAC SCREENING Cardiac screening is becoming more common and a number of sporting organisations in the United Kingdom currently perform cardiac screening. However there is divided opinion
sportEX medicine 2008:36(Apr):6-8
9
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WHAT IS THE EFFECT OF SCAPULOTHORACIC TAPING ON MUSCLE ACTIVITY?
Based on the previous article, there appears to be an alteration of motor control in subjects with impingement. It is often proposed clinically that taping techniques can alter motor activity (1,2). However, the research surrounding the benefits of tape in this scenario is conflicting.
BY COLIN PATERSON, MCSP EXPERIMENTAL STUDIES
he study by Cools et al (3) investigated the effect of taping over the upper trapezius muscle as advocated by McConnell (4) (Figure 1). The aim of this technique is to inhibit the overactive upper fibres of trapezius and thus prevent excessive elevation of the scapula, which can occur in subjects with impingement. The results of their study found no beneficial effect of taping on motor recruitment patterns, the EMG patterns for all of trapezius and serratus anterior were unaltered.
T
Contradicting these results are those by Morin et al (2) who found the same taping technique to decrease the activity in upper trapezius with a concurrent increase in the activity of lower trapezius. They did not assess the activity in serratus anterior in their study, limiting comparisons with other studies. Both Morin et al (2) and Cools et al (3) used a cross-over design with sound internal validity, although neither indicated the time frame between tape and no-tape sessions. Consequently, insufficient knowledge
is available about any potential carry-over after the tape session and the influence this could have on the results. The other difference between the two studies was the activity performed, which could explain the conflicting results. Cools et al (3) used flexion and abduction movements of the shoulder while Morin et al (2) utilised an isometric activity of 90º abduction and 45º internal rotation with elastic tubing. It is known that an isometric muscle contraction produces a more regular electromyographic reading and this would provide more consistent data to analyse, which again could be a factor explaining the differences between the two studies results (5, 6). Unfortunately, the use of pain free subjects without shoulder dysfunction severely limits the external validity of their results. It would appear they were trying to normalise the motor pattern of subjects with normal patterns already and therefore, the significance of their results or lack of, needs to be noted with caution.
The use of normal subjects was used in
TECHNIQUES TO ADDRESS THE REDUCED ACTIVITY IN SERRATUS ANTERIOR MAY HAVE GREATER CLINICAL SIGNIFICANCE YET THIS HAS NOT BEEN ATTEMPTED IN LITERATURE
GREA 18 IT WOULD APPEAR THAT TAPING
the non-clinical study by Alexander et al (7). They utilised a taping technique proposed to facilitate the lower fibres of trapezius, shown in figure 2, and investigated its effect on motor neurone excitability. In line with other studies, the authors chose not to address a functional movement pattern or the effects on scapular positioning. Unexpectedly, the result of the technique was inhibition of the lower fibres of trapezius by an average of 22%. Clinically it is proposed that applying tape parallel to the line of muscle fibres facilitates muscle activity due to an improved length-tension relationship of the actin and myosin cross-bridges (1,4). Alexander et al (8) have further
investigated the issue of taping along and across the orientation of the muscle in relation to facilitating and inhibiting muscle activity respectively. They demonstrated that taping across the line of the muscle fibre failed to have any affect on motor neurone excitability (H-reflex) of gastrocnemius or soleus when taping the calf complex. However, when under tape and sports tape were applied along the line of the muscle fibres of medial and lateral gastrocnemius a resultant reduction in motor neurone excitability was measured. These results support the findings of their previous 2003 study (7). Their study did not directly attempt to explain why these results occur but they hypothesise that taping along the direction of the muscle fibres could shorten the muscle which in turn unloads the intrafusal
sportEX medicine 2008:36(Apr):18-20
muscle fibre which reduces its firing rate and therefore decreases the activity of the motor neurone. Clearly these results have only been investigated on 2 separate muscle groups and further study is needed to consolidate these findings.
The results of the study by Ackerman et al (9) demonstrated that taping the supporting shoulder of professional violinists during pieces requiring more vigorous playing resulted in a statistically significant increase in the activity of upper trapezius and produced a concurrent reduction in performance quality. No other effects of the taping were noted on EMG or performance measures for less demanding musical pieces. The authors explained that the violinist would have needed to elevate her shoulder to a greater extent to support the violin during the more vigorous piece. The tape was applied in a way to prevent elevation and protraction. Therefore, greater activity in the upper trapezius to overcome this resistance would explain the results. Overall, the proposed effects of taping in relation to facilitation and inhibition of activity needs further controlled trials into the long term effects in impaired subjects.
As stated above, inhibition of the upper fibres of trapezius is often the aim of the investigators. However studies have shown increased scapula elevation to occur in subjects with impingement (10,11) but they have not directly related this to increased upper trapezius activity eg. a tight posterior capsule can cause the scapula to elevate excessively as a compensation strategy. Therefore, to attempt to inhibit a muscle with potentially normal activity lacks reason and needs further clinical studies to examine this issue. It would appear that taping techniques to address the reduced activity in serratus anterior may have greater clinical significance, yet this has not been attempted in the literature.
CLINICAL CASE STUDIES All the above papers investigating the rationale of taping produced conflicting results with the majority not supporting its usage and this could influence the clinician to think twice about using these techniques. However, they all used normal subjects with no history of shoulder dysfunction, which does not reflect clinical practice.
Some published literature supports the use of taping in the clinical setting (1,12,13). These studies utilised a single case study design. All three studies used taping to influence the patients’ ability to stabilise their scapula, which was considered to be at fault. Improved scapula setting (1), reduced winging of the scapula (13) and reduced downward rotation of the scapula (12) were reported immediately
SUBJECTS WITH IMPINGEMENT, BUT ALL HAVE VARIATIONS IN THEIR RESULTS
after tape application. However, these were subjective observations by the authors and were not quantified objectively in any of the studies, which obviously limits the reliability of the studies. Host (12) reported a secondary reduction in pain during functional activities as did Morrissey (1). In all three studies the taping was combined with scapula retraining exercises to improve the force couple relationships and optimise scapula control through range.
Activity modification was also advocated in all the studies (1,12,13) to reduce the inflammatory response. This was combined with stretching of pectoralis minor and
latissimus dorsi (12) and thoracic manipulations, trigger point release to pectoralis minor and local cryotherapy to reduce inflammation (1), to produce a comprehensive treatment package that reflects clinical practice. In all three patient scenarios, tape was used as an adjunct to treatment and the direct effects of the taping can not be clearly identified. However, the observations of the clinicians support the use of tape as a method of improving scapula positioning and control allowing rehabilitation to be progressed more rapidly. The use of single case study designs is often controversial (14). However, they are clinically relevant and reflect the individual nature of physiotherapy practice, but longitudinal controlled experimental studies with larger sample numbers are ultimately needed to support practice (14).
SUMMARY
Studies have consistently shown altered recruitment patterns in subjects with impingement, but all have variations in their
STUDIES HAVE CONSISTENTLY SHOWN ALTERED RECRUITMENT PATTERNS IN
results. The available evidence on the use of taping in patients with shoulder impingement is inconclusive. It must be remembered however that some of these papers had significant external validity issues confounded by differing methodology, making direct comparisons difficult. Controlled clinical trials are needed to provide supportive evidence into the effects of taping on scapular muscle activity in
patients with shoulder impingement to support the anecdotal and clinical claims that taping works (1,4,12,13,15). Studies could also address combining the use of taping techniques with exercise therapy as these treatments are often combined clinically.
Clinicians need supportive evidence to justify the use of taping. Evidence of how taping works to promote rehabilitation in this anatomical region must also be addressed. Future studies could also focus on different outcome measures when combined with motor recruitment. The effect of taping on pain levels and functional ability could be addressed, using scales such as the shoulder pain and disability index or the shoulder disability questionnaire. Both of these questionnaires have been shown to be sensitive and reliable (16,17). Currently, the efficacy of taping as a method of treating shoulder impingement is limited due to the lack of supportive evidence. However, lack of evidence does not necessarily mean there is no clinical benefit, merely that an appropriate measure is required to produce the evidence for or against. Meanwhile, until more evidence is provided, clinicians can only continue to base decisions for using this treatment option on the anecdotal evidence available.
Figure 1: Upper trapezius inhibition taping
Figure 2: Facilitation of lower trapezius taping 19
ISSUE 36 APRIL 2008
exceinllence sports
promoting
HIGHLIGHTS ■ SUDDEN CARDIAC DEATH IN ATHLETES
■ SUPPPORT FOR BRITISH WORLD CLASS DISABLED ATHLETES
medicine
■ SCAPULAR DYSKINESIA AND SHOULDER IMPINGEMENT – WHAT IS THE EVIDENCE?
WIN