Does a SLAP lesion affect shoulder muscle recruitment as measured by EMG activity during a rugby tackle?

Background: The study objective was to assess the influence of a SLAP lesion on onset of EMG activity in shoulder muscles during a front on rugby football tackle within professional rugby players. Methods: Mixed cross-sectional study evaluating between and within group differences in EMG onset times. Testing was carried out within the physiotherapy department of a university sports medicine clinic. The test group consisted of 7 players with clinically diagnosed SLAP lesions, later verified on arthroscopy. The reference group consisted of 15 uninjured and full time professional rugby players from within the same playing squad. Controlled tackles were performed against a tackle dummy. Onset of EMG activity was assessed from surface EMG of Pectorialis Major, Biceps Brachii, Latissimus Dorsi, Serratus Anterior and Infraspinatus muscles relative to time of impact. Analysis of differences in activation timing between muscles and limbs (injured versus non-injured side and non injured side versus matched reference group). Results: Serratus Anterior was activated prior to all other muscles in all (P = 0.001-0.03) subjects. In the SLAP injured shoulder Biceps was activated later than in the non-injured side. Onset times of all muscles of the noninjured shoulder in the injured player were consistently earlier compared with the reference group. Whereas, within the injured shoulder, all muscle activation timings were later than in the reference group. Conclusions: This study shows that in shoulders with a SLAP lesion there is a trend towards delay in activation time of Biceps and other muscles with the exception of an associated earlier onset of activation of Serratus anterior, possibly due to a coping strategy to protect glenohumeral stability and thoraco-scapular stability. This trend was not statistically significant in all cases

Severe aberrant glenohumeral motor patterns in a young female rower: a case report

Background: This case features an 18-year-old female with glenohumeral dysrhythmia and subluxation-relocation patterns. This unusual case highlights the need for careful examination and consideration to the anatomical structures involved. Conventional approaches to shoulder examination include range of motion, orthopaedic tests and manual resistance tests. We also assessed the patient's cognitive ability to coordinate muscle function. With this type of assessment we found that co-contraction of local muscle groups seemed to initially improve the patients abnormal shoulder motion. With this information a rehabilitation method was instituted with a goal to maintain the improvement. Case presentation: An 18-year-old female with no history of trauma, presented with painless kinesiopathology of the left shoulder (in abduction) consisting of dysrhythmia of the glenohumeral joint and early lateral rotation of the scapula. Examination also showed associated muscle atrophy of the lower trapezius and surrounding general muscle weakness. We used an untested functional assessment method in addition to more conventional methods. Exercise rehabilitation interventions were subsequently prescribed and graduated in accordance with what is known as the General Physical Rehabilitation Pyramid. Conclusion: This paper presents an unusual case of aberrant shoulder movement. It highlights the need for careful examination and thought regarding the anatomical structures and normal motor patterns associated with the manoeuvre being tested. It also emphasised the use of co-contraction during examination in an attempt to immediately improve a regional dysrythmia if there is suspicion of a regional aberrant motor pattern. Further research may be warranted to test this approach