Horsley et al. Journal of Orthopaedic Surgery and Research 2010, 5:12 RESEARCH ARTICLE Open Access Does a SLAP lesion affect shoulder muscle recruitment as measured by EMG activity during a rugby tackle? Ian G Horsley1*, Lee C Herrington2, Christer Rolf1 Abstract 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. | Horsley et al. Journal of Orthopaedic Surgery and Research 2010 5 12 http content 5 1 12 JOURNAL OF ORTHOPAEDIC SURGERY AND RESEARCH RESEARCH ARTICLE Open Access Does a SLAP lesion affect shoulder muscle recruitment as measured by EMG activity during a rugby tackle Ian G Horsley1 Lee C Herrington2 Christer Rolf1 Abstract 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 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
