Exploring the effects shoulder mobilization on scapular and shoulder muscle activities

INTERVENTION: The participants’ shoulder will be passively mobilized by an experienced musculoskeletal physiotherapist. The mobilizations will consist of 3 sets of 60 seconds of passive movement, at a rate of 2 Hz, with 30 seconds interval between sets. This dosage (grade +IV, 2 Hz, three sets of 60 seconds, with 30 seconds interval between sets) is commonly used clinically. Two different shoulder mobilizations will be performed (each mobilization will be performed on a different day).Data collection will take place in two sessions. The second session must occur within 10 days of the first session, and with at least 24 hours interposed. For each experimental condition, the participants’ shoulder will be positioned such that the gleno‐humeral capsule and ligaments are lengthened. Thus, when the humerus is mobilized, the gleno‐humeral capsule and ligaments will be repetitively stretched through passive mobilization. Each mobilization will be performed on a different day, and the order of the mobilization will be randomized. The inferior mobilization will consist of repeated glides applied at the shoulder, with the participant’s arm positioned at 120 degrees of shoulder abduction. The posterior mobilization will consist of repeated posterior glides applied at the shoulder, with the participant arm positioned in horizontal flexion. CONDITION: Shoulder disorders PRIMARY OUTCOME: Anterior deltoid muscle activity levels will be considered as primary outcome measures for assessing the effect of posterior mobilization on muscle activity levels. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. Middle deltoid muscle activity levels will be considered as primary outcome measures for assessing the effect of inferior mobilization on muscle activity levels. ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. SECONDARY OUTCOME: Pectoralis major muscle activity levels will be considered as primary outcome measures for assessing the effect of posterior mobilization on muscle activity levels. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. Supraspinatus muscle activity levels will be considered as primary outcome measures for assessing the effect of inferior mobilization on muscle activity levels. ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. When assessing the effect of inferior mobilization, latissimus dorsi muscle will be considered as secondary outcome. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. ; When assessing the effect of inferior mobilization, pectoralis major muscle will be considered as secondary outcome. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. ; When assessing the effect of posterior mobilization, infraspinatus muscle will be considered as secondary outcome. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. ; When assessing the effect of posterior mobilization, latissimus dorsi muscle will be considered as secondary outcome. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. ; When assessing the effect of posterior mobilization, posterior deltoid muscle will be considered as secondary outcome. ; ; Muscle activity levels will be measured using surface electromyography, with a frequency sample of 3000 Hz. ; INCLUSION CRITERIA: Participants will be included if they present no current neck and shoulder injuries.