Screening the athlete's shoulder for impingement symptoms: a clinical reasoning algorithm for early detection of shoulder pathology.

Chronic shoulder pain and dysfunction are common complaints among overhead athletes seeking care from physical medicine and rehabilitation. Impingement is a frequently described pathological condition in the overhead athlete. Impingement symptoms may be the result of rotator cuff pathology, shoulder instability, scapular dyskinesis or muscle dysfunction, biceps pathology, SLAP lesions and chronic stiffness of the posterior capsule. At present, numerous different shoulder tests have been described in literature and discussed with respect to their individual diagnostic accuracy. However, in view of the number of shoulder tests, it is often a challenge for the clinician to select the appropriate tests for diagnosing the underlying pathology. The purpose of this paper is to present and discuss a clinical algorithm which may be used in the early detection of the underlying causes of impingement symptoms. In this algorithm, a specific chronology and selection of diagnostic tests may offer the clinician a guideline in his physical examination of the athlete with shoulder pain.

Internal impingement in the tennis player: rehabilitation guidelines.

Internal impingement is a commonly described cause of shoulder pain in the overhead athlete, particularly in tennis players. Three shoulder dysfunctions, often correlated with internal impingement symptoms, require attention in the rehabilitation strategy of internal impingement in the tennis player: (1) acquired glenohumeral anterior instability, (2) loss of internal rotation range of motion, and (3) lack of retraction strength. Based on recent literature, the following guidelines are proposed in the rehabilitation of the tennis player with internal impingement symptoms: (1) shoulder rehabilitation should be integrated into kinetic chain training, not only in the advanced phases of the athlete's rehabilitation, but from the initial phases; (2) both angular and translational mobilisations can be used in the treatment of acquired loss of glenohumeral internal rotation range of motion to stretch the posterior structures of the glenohumeral joint; and 3) in the rehabilitation of scapular dyskinesis, the therapist should focus on restoration of intramuscular trapezius muscle balance in the scapular exercises, with special attention to strength training of the retractors.

Trapezius activity and intramuscular balance during isokinetic exercise in overhead athletes with impingement symptoms.

We compared normalized trapezius muscle activity and intramuscular balance ratios between overhead athletes with impingement symptoms and non-injured athletes during isokinetic abduction and external rotation movements. Thirty-nine overhead athletes with chronic impingement symptoms and 30 non-injured athletes participated in the study. Electromyographic activity of upper, middle, and lower trapezius was measured during isokinetic abduction and external rotation, using surface electrodes. The results show a significant increase of upper trapezius activity during both movements in the patient group, with decreased activity in the lower trapezius during abduction, and in the middle trapezius during external rotation. Analysis of the intramuscular activity ratios revealed muscle imbalance on the injured side of the patient group for upper/middle trapezius and upper/lower trapezius during abduction, and for all three muscle activity ratios during external rotation. These results confirm the presence of scapular muscle imbalances in patients with impingement symptoms and emphasize the relevance of restoration of scapular muscle balance in shoulder rehabilitation.

Evaluation of isokinetic force production and associated muscle activity in the scapular rotators during a protraction-retraction movement in overhead athletes with impingement symptoms.

OBJECTIVES: To determine if the muscle force and electromyographic activity in the scapular rotators of overhead athletes with impingement symptoms showed differences between the injured and non-injured sides. METHODS: Isokinetic peak force was evaluated during protraction and retraction of the shoulder girdle, with simultaneous recording of electromyographic activity of the three trapezius muscles and the serratus anterior muscle, in 19 overhead athletes with impingement symptoms. RESULTS: Paired t tests showed significantly lower peak force during isokinetic protraction at high velocity (p<0.05), a significantly lower protraction/retraction ratio (p<0.01), and significantly lower electromyographic activity in the lower trapezius muscle during isokinetic retraction on the injured side than on the non-injured side (p<0.05). CONCLUSION: These results confirm that patients with impingement symptoms show abnormal muscle performance at the scapulothoracic joint.

Does taping influence electromyographic muscle activity in the scapular rotators in healthy shoulders?

Although taping techniques are commonly used in addition to exercise programmes in the rehabilitation of shoulder instability and secondary subacromial or internal impingement, few studies exist on the effect of taping on the muscle activity of the scapular rotators. The purpose of our study was to examine the influence of one particular tape on muscular activity in scapular muscles. Twenty healthy shoulders were examined with surface EMG recordings on the three parts of trapezius and serratus anterior muscle during dynamic full range of motion abduction and forward flexion. The movement direction, and tape and no-tape conditions were randomized. The statistical analyses with ANOVA repeated Measures (GLM model) showed significant differences among the means between the four muscles (P<0.05), two movement directions (P<0.05), applied resistance (P<0.01), and movement period (P<0.01). However, no significant difference was observed based on the application of tape. The results of our investigation revealed no significant influence of tape application on EMG activity in the scapular muscles in healthy subjects. Future research will be necessary to examine other parameters of neuromuscular control in order to determine possible proprioceptive changes in muscle recruitment with tape application.

Differences in electromyographic activity in the multifidus muscle and the iliocostalis lumborum between healthy subjects and patients with sub-acute and chronic low back pain.

The present study was carried out to examine possible mechanisms of back muscle dysfunction by assessing a stabilising and a torque-producing back muscle, the multifidus (MF) and the iliocostalis lumborum pars thoracis (ICLT), respectively, in order to identify whether back pain patients showed altered recruitment patterns during different types of exercise. In a group of healthy subjects (n=77) and patients with sub-acute (n=24) and chronic (51) low back pain, the normalised electromyographic (EMG) activity of the MF and the ICLT (as a percentage of maximal voluntary contraction) were analysed during coordination, stabilisation and strength exercises. The results showed that, in comparison with the healthy subjects, the chronic low back pain patients displayed significantly lower (P=0.013) EMG activity of the MF during the coordination exercises, indicating that, over the long term, back pain patients have a reduced capacity to voluntarily recruit the MF in order to obtain a neutral lordosis. In contrast, during the stabilisation exercises, no significant differences between patients and controls were found for the normalised EMG activity of the two muscles. These findings indicated that, during low-load exercises, no insufficiencies in back muscle recruitment were evident in either subacute or chronic back pain patients. During the strength exercises, the normalised activity of both back muscles was significantly lower in chronic low back pain patients (P=0.017 and 0.003 for the MF and ICLT, respectively) than in healthy controls. Pain, pain avoidance and deconditioning may have contributed to these lower levels of EMG activity during intensive back muscle contraction. The possible dysfunction of the MF during coordination exercises and the altered activity of both muscles during strength exercises may be of importance in symptom generation, recurrence or maintenance of low back pain.

Intra-operator and inter-operator reliability of surface electromyography in the clinical evaluation of back muscles.

As a prerequisite to the use of a test battery based on electromyographic (EMG) analysis of the paraspinal muscles for identifying and remedying back muscle dysfunction, the intra- and inter-operator reliability was assessed. Fifteen volunteers underwent EMG tests on three occasions. The test subjects were asked to perform 22 exercises, subdivided into four categories: coordination, stabilization, balance and strength exercises. The time interval between the tests was one week. The myoelectric signals of the multifidus (MF) and iliocostalis lumborum pars thoracis (ICLT) were analysed with regard to amplitude (averaged EMG) and frequency (zero cross rate). The results indicated that the reliability was better for the MF than for the ICLT, and also for exercises at higher loads (strength exercises). In the intra-operator condition, the reproducibility of the averaged EMG was good (ICC>0.75), except for the balance exercises (ICC = 0.40-0.74). In general, the averaged EMG in the inter-operator condition and the zero cross rate in both the intra- and inter-operator conditions are less or poorly reliable. These results demonstrate that when back muscle function is evaluated during coordination, stabilization and strength exercises, only the averaged EMG parameter has acceptable reproducibility over time when assessed by the same operator.

The effects of three different training modalities on the cross-sectional area of the paravertebral muscles.

The purpose of this study was to determine the effect of different training schedules on the cross-sectional area (CSA) of the paravertebral muscles (PA) in chronic low back pain (CLBP) patients. To achieve this goal 59 patients were randomly assigned to three different 10-week rehabilitation programs: stabilization training (group 1, n=19), stabilization training combined with dynamic resistance training (group 2, n=20) and stabilization training combined with dynamic-static resistance training (group 3, n=20). The CSA of the PA was derived from standard computerized tomography (CT) images at three different levels. The CSA of the PA was found to increase statistically in group 2 (upper end-plate of L4) and group 3 (upper end-plate of L3 and lower end-plate of L4). In contrast, no statistical differences over time were found in group 1. Since stabilization exercises have no effect on the CSA of the PA, intensive lumbar resistance training seems to be necessary to restore the size of the PA in CLBP patients with atrophied back muscles. No systematic difference in hypertrophy between dynamic and dynamic-static strengthening training modes was found.