Does scapular positioning predict shoulder pain in recreational overhead athletes?

The objective of this prospective study is to investigate possible scapular related risk factors for developing shoulder pain. Therefore, a 2-year follow-up study in a general community sports centre setting was conducted. A sample of convenience of 113 recreational overhead athletes (59 women and 54 men) with a mean age of 34 (17-64; SD 12) years were recruited. At baseline, visual observation for scapular dyskinesis, measured scapular protraction, upward scapular rotation and dynamic scapular control were evaluated. 22% (n=25) of all athletes developed shoulder pain during the 24 months following baseline assessment. The Mean Shoulder Disability Questionnaire (SDQ) score for the painful shoulders was 34.8 (6.3-62.5; SD 17.4). None of the scapular characteristics predicted the development of shoulder pain. However, the athletes that developed shoulder pain demonstrated significantly less upward scapular rotation at 45° (p=0.010) and 90° (p=0.016) of shoulder abduction in the frontal plane at baseline in comparison to the athletes that remained pain-free. In conclusion, although these scapular characteristics are not of predictive value for the development of shoulder pain, this study increases our understanding of the importance of a scapular upward rotation assessment among recreational overhead athletes.

Motor control and low back pain in dancers.

Professional dancers suffer a high incidence of injuries, especially to the spine and lower extremities. There is a lack of experimental research addressing low back pain (LBP) in dancers. The aim of this study is to compare lumbopelvic motor control, muscle extensibility and sacroiliac joint pain between dancers with and without a history of LBP. 40 pre-professional dancers (mean age of 20.3 years) underwent a clinical test battery, consisting of an evaluation of lumbopelvic motor control, muscle extensibility, generalized joint hypermobility, and sacroiliac joint pain provocation tests. Also self-reported measurements and standardized questionnaires were used. 41% of the dancers suffered from LBP during at least 2 consecutive days in the previous year. Only one dancer suffered from sacroiliac joint pain. Compared to dancers without a history of LBP, dancers with a history of LBP showed poorer lumbopelvic motor control (p<0.05). No differences in muscle extensibility or joint hypermobility were observed between dancers (p>0.05). Despite their young age, pre-professional dancers suffer from LBP frequently. Sacroiliac joint pain, generalized joint hypermobility or muscle extensibility appears unrelated to LBP in dancers. Motor control is decreased in those with a history of LBP. Further research should examine whether motor control is etiologically involved in LBP in dancers.

Scapular positioning in overhead athletes with and without shoulder pain: a case-control study.

Abnormalities of scapular positioning are considered important risk factors for developing shoulder disorders. This study analyses the scapular positioning pattern in a group of overhead athletes with and without shoulder pain. In a multi-center blinded case-control study, 36 shoulder pain athletes (19 men, 17 women), were compared with 36 unimpaired athletes free of shoulder pain, matched for gender, age, hand dominance and body mass index. The blinded assessor performed visual observation, the measurement of the distance between the acromion and the table, inclinometry and the kinetic medial rotation test for dynamic scapular control in random order. Athletes with shoulder pain demonstrate scapular asymmetry in the sagittal plane, observed visually as anterior tilting on the painful side. Athletes with shoulder pain show a lack of scapular motor control on their painful side in contrast to their pain-free side. No scapular positioning or motor control differences were found in athletes with or without shoulder pain.

Scapular positioning and movement in unimpaired shoulders, shoulder impingement syndrome, and glenohumeral instability.

The purpose of this manuscript is to review the knowledge of scapular positioning at rest and scapular movement in different anatomic planes in asymptomatic subjects and patients with shoulder impingement syndrome (SIS) and glenohumeral shoulder instability. We reviewed the literature for all biomechanical and kinematic studies using keywords for impingement syndrome, shoulder instability, and scapular movement published in peer reviewed journal. Based on the predefined inclusion and exclusion criteria, 30 articles were selected for inclusion in the review. The literature is inconsistent regarding the scapular resting position. At rest, the scapula is positioned approximately horizontal, 35° of internal rotation and 10° anterior tilt. During shoulder elevation, most researchers agree that the scapula tilts posteriorly and rotates both upward and externally. It appears that during shoulder elevation, patients with SIS demonstrate a decreased upward scapular rotation, a decreased posterior tilt, and a decrease in external rotation. In patients with glenohumeral shoulder instability, a decreased scapular upward rotation and increased internal rotation is seen. This literature overview provides clinicians with insight into scapular kinematics in unimpaired shoulders and shoulders with impingement syndrome and instability.

Functional stability re-training: principles and strategies for managing mechanical dysfunction.

Functional stability is dependent on integrated local and global muscle function. Mechanical stability dysfunction presents as segmental (articular) and multi-segmental (myofascial) dysfunction. These dysfunctions present as combinations of restriction of normal motion and associated compensations (give) to maintain function. Stability dysfunction is diagnosed by the site and direction of give or compensation that relates to symptomatic pathology. Strategies to manage mechanical stabililty dysfunction require specific mobilization of articular and connective tissue restrictions, regaining myofascial extensibility, retraining global stability muscle control of myofascial compensations and local stability muscle recruitment to control segmental motion. Stability re-training targets both the local and global stability systems. Activation of the local stability system to increase muscle stiffness along with functional low-load integration in the neutral joint position controls segmental or articular give. Global muscle retraining is required to correct multisegmental or myofascial dysfunction in terms of controlling the site and direction of load that relates to provocation. The strategy here is to train low-load recruitment to control and limit motion at the site of pathology and then actively move the adjacent restriction, regain through range control of motion with the global stability muscles and regain sufficient extensibility in the global mobility muscles to allow normal function. Individual strategies for integrating local and global recruitment retraining back into normal function are suggested.

Movement and stability dysfunction--contemporary developments.

A good understanding of the control processes used to maintain stability in functional movements is essential for clinicians who attempt to treat or manage musculoskeletal pain problems. There is evidence of muscle dysfunction related to the control of the movement system. There is a clear link between reduced proprioceptive input, altered slow motor unit recruitment and the development of chronic pain states. Dysfunction in the global and local muscle systems is presented to support the development of a system of classification of muscle function and development of dysfunction related to musculoskeletal pain. The global muscles control range of movement and alignment, and evidence of dysfunction is presented in terms of imbalance in recruitment and length between the global stability muscles and the global mobility muscles. Direction related restriction and compensation to maintain function is identified and related to pathology. The local stability muscles demonstrate evidence of failure of adequate segmental control in terms of allowing excessive uncontrolled translation or specific loss of cross-sectional area at the site of pathology. Motor recruitment deficits present as altered timing and patterns of recruitment. The evidence of local and global dysfunction allows the development of an integrated model of movement dysfunction.

An optical technique for the measurement of thoracic wall movement during high-frequency jet ventilation.

Instrumentation for use in high-frequency jet ventilation is not currently capable of providing information suitable for predicting gas exchange. Whilst techniques for the accurate measurement of tidal volume during jet ventilation are now available, the relationship between tidal volume and the efficiency of gas exchange varies with frequency and inspiratory/expiratory time (I:E) ratio. We report technical details of a new non-invasive instrument capable of accurately measuring displacement of the thoracic wall at high frequencies and without electrical connection to the patient. It is hoped that use of this instrument will allow the calculation of an efficiency index for the transduction of airway pressure changes into peripheral expansion. It is also hoped that this index may be of value in predicting the gas exchange response to changes in jet parameters.

Scapular-focused treatment in patients with shoulder impingement syndrome: a randomized clinical trial.

The purpose of this clinical trial is to compare the effectiveness of a scapular-focused treatment with a control therapy in patients with shoulder impingement syndrome. Therefore, a randomized clinical trial with a blinded assessor was used in 22 patients with shoulder impingement syndrome. The primary outcome measures included self-reported shoulder disability and pain. Next, patients were evaluated regarding scapular positioning and shoulder muscle strength. The scapular-focused treatment included stretching and scapular motor control training. The control therapy included stretching, muscle friction, and eccentric rotator cuff training. Main outcome measures were the shoulder disability questionnaire, diagnostic tests for shoulder impingement syndrome, clinical tests for scapular positioning, shoulder pain (visual analog scale; VAS), and muscle strength. A large clinically important treatment effect in favor of scapular motor control training was found in self-reported disability (Cohen's d = 0.93, p = 0.025), and a moderate to large clinically important improvement in pain during the Neer test, Hawkins test, and empty can test (Cohen's d 0.76, 1.04, and 0.92, respectively). In addition, the experimental group demonstrated a moderate (Cohen's d = 0.67) improvement in self-experienced pain at rest (VAS), whereas the control group did not change. The effects were maintained at three months follow-up.

Dynamic stability of the scapula.

SUMMARY. The ability to position and control movements of the scapula is essential for optimal upper limb function. The inability to achieve this stable base frequently accompanies the development of shoulder and upper limb pain and pathology. Unlike other joints the bony, capsular and ligamentous constraints are minimal at the scapulothoracic 'joint' so stability is dependant on active control. Clinically, it is noted that patients presenting with shoulder and arm symptoms demonstrate poor dynamic scapula control. Scapula setting is an exercise taught by physiotherapists to correct movement dysfunction associated with abnormal scapula positioning and dynamic control. Addressing the dynamic stabilization of the scapula is an essential part of the management of neuromusculoskeletal dysfunction of the shoulder girdle and an appropriate rehabilitation programme is necessary if this issue is to be addressed. Copyright 1997 Harcourt Publishers Ltd.

Measurement of entrainment ratio during high frequency jet ventilation.

We have measured tidal (VT), entrained (Ve) and "blowback" (Vbb) volumes during high frequency jet ventilation (HFJV) through a Mallinckrodt Hi-Lo Jet tracheal tube in anaesthetized patients. The above volumes were calculated by digital integration of the appropriate regions of flow curves derived from a pneumotachograph placed between the bias flow tubing and the tracheal tube. At a driving pressure of 1 bar, lung minute ventilation increased with increasing ventilatory frequency, whilst tidal volumes decreased. The contribution of entrainment to tidal volume (Ve/VT) remained constant, although the volumes entrained were relatively small and varied widely from subject to subject. Blowback volumes were considerable, especially at ventilatory frequencies used clinically (1-2 Hz). We conclude that it is not possible to entrain predictable concentrations of volatile agents from the low pressure bias flow during HFJV.

Relationship between resonance and gas exchange during high frequency jet ventilation.

We have studied the relationship between gas exchange and mechanical frequency response during high frequency jet ventilation (HFJV) at 0.5-5.0 Hz in anaesthetized pigs. The mechanical gain curve showed a minimal "anti-resonant" response at 0.8 Hz (f1) and a maximal "resonant" response at 5.0 Hz (f2). This finding may be explained by modelling the thorax and abdomen as a system of coupled masses and compliances which undergo two different modes of forced oscillation in the frequency range studied. Gas exchange was optimal in the frequency range between the minimal and maximal responses. The tidal volumes produced were greater than anatomical deadspace, suggesting that gas transport was mainly convective in this range.

Emergency presentation and mortality from colorectal cancer in the elderly.

We have assessed the influence of age on the mode of presentation and perioperative mortality in 1033 patients with colorectal cancer. There were 522 patients (51 per cent) over 70 years (group I) and 511 patients (49 per cent) under 70 (group II). In group I, 301 patients (58 per cent) were admitted as emergencies compared with only 222 (43 per cent) in group II (P less than 0.001). Perioperative mortality was especially high in the elderly emergencies, 38 per cent, compared with 18 per cent for elective operations. Of the patients presenting as emergencies in either age group 66 per cent had localized "potentially curable' disease. The incidence of colorectal cancer is highest in the elderly. A larger number of these elderly patients present as emergencies and die from the consequences of complications of localized disease. Earlier diagnosis by pre-symptomatic screening is therefore especially desirable in these old patients.

Effects of 3 MAC of halothane, enflurane and isoflurane on cilia beat frequency of human nasal epithelium in vitro.

We have measured the effects of three times the minimum alveolar concentration (MAC) of halothane, enflurane and isoflurane on cilia beat frequency of human nasal epithelial brushings from 18 healthy adult patients. Using the transmitted light technique and paired perfusion chambers, the cilia were exposed to 2.25% halothane, 5% enflurane or 3.6% isoflurane in air, or air alone, in a controlled and blinded manner. Over a 4-h observation period, cilia beat frequency of the samples exposed to inhalation anaesthetic agents demonstrated a significant reduction in frequency compared with controls exposed to air alone. Mean cilia beat frequency for the samples exposed to halothane was 9.3 (SEM 1.3) compared with its controls of 11.4 (1.0); for the samples exposed to enflurane, 10.9 (1.3) compared with its controls of 11.6 (1.2); and for the samples exposed to isoflurane, 10.8 (1.1) compared with its controls of 11.6 (1.2). There was a statistically significant difference between the samples exposed to all three volatile agents and their associated controls (halothane, P = 0.01; enflurane, P = 0.03; isoflurane, P = 0.01; nested repeated measures analysis of variance utilizing polynomial contrasts).