The importance of our shoulders to everyday movement and activity is often not fully appreciated, until we are limited by injury or pain. The shoulder complex allow us to interact with our surroundings while acting as the functional link between our stable trunks and our free moving upper limbs. This is no easy task for highly mobile joints such as the shoulders. A shoulder injury can be functionally devastating to an individual, and can potentially place unnecessary financial stress on our health care system. Shoulder pain is currently among the most common reasons to visit a general practitioner or a physiotherapist today. Shoulder pain is third in prevalence, only to back and neck pain, and nearly two-thirds of adults suffer from shoulder pain at some point during their lives. Despite being an important focus for rehabilitative care, we have yet to confidently establish efficient and potentially cost effective methods for treating shoulder pathologies and pain. Among shoulder disorders, the rotator cuff (RC) muscles are the leading source of shoulder pain. Due to the vast mobility of the shoulder complex, it relies greatly on the stability and control provided by its supportive tissues, notably the rotator cuff muscles; often rendering them highly susceptible to injury. It has been noted that individuals affected by rotator cuff tendinopathies (RCt) often exhibit motor control and shoulder proprioception deficits. As noted by Cools and colleagues, rehabilitative training programs that focus on motor control are greatly needed for rehabilitation as well as to prevent re-injury. Accordingly, rehabilitation interventions should focus on motor (re)learning, targeting a better muscle coordination to reduce motor control impairments, optimize movement control, and improve muscle strength.

Motor control rehabilitation: To address the motor control deficits among individuals affected by an RCt, we have developed a novel, structured, and supervised group exercise-based program focusing on neuromuscular reeducation. It is well documented in the scientific literature that motor control and proprioception exercises are crucial for healing among this population. However, the effectiveness of a group delivery method remains unknown. It is presently unclear how a group exercise program compares to one-on-one physiotherapy care for shoulder dysfunctions. The developed group program allows patients to individually progress their exercises based on their symptoms, while being guided and corrected by the supervising physiotherapist. This model allows several patients to access physiotherapy services simultaneously, while remaining cost and resource effective for the clinics. To appreciate the goal of the proposed exercise program, it is important to understand the physiological and biomechanical factors directly related to shoulder stability.

Underlying mechanisms for shoulder stability: For its joint stability, the glenohumeral (GH) joint heavily depends on muscle strength, adequate synergistic activity between the neuromuscular structures, as well as a strong joint position sense (a subcategory of proprioception). Our ability to detect our limbs in space helps us to interact with our surroundings and contributes to the neuromuscular stability of our joints. A RCt is often associated with a subacromial impingement syndrome, where structures under the acromion become pinched during arm elevation. Such a compression during arm movements can include abnormal shoulder kinematics, as well as RC and scapular muscles performance deficits. This inadequate scapulothoracic muscle control is believed to contribute to a reduction of amplitude in posterior tilting and lateral rotation of the scapula, which causes the acromion to remain in a lower anterolateral position resulting in a dynamic narrowing of the subacromial space. Also, the abnormal muscle control is associated with superior migration of humeral head with respect to the glenoid fossa, which again leads to a dynamic narrowing of the subacromial space. These deficits contribute to the impingement of subacromial structures and often lead to the symptoms associated with an RCt. What makes the investigated approach unique in addressing RC disorders is the resource-effective exercise rehabilitation model the investigators propose; a motor control and strengthening approach well supported in the scientific literature and packaged in a conveniently resource-friendly protocol. This approach maximizes patient autonomy while being matched to a suitable level of physiotherapist supervision. The investigators believe that the Upper Extremity Neuromuscular Training Program (UpEx-NTP) provides a realistic and financially beneficial solution to a costly health care problem.

Research Question: How will a 6-week UpEx-NTP improve shoulder function, pain, and joint position sense (JPS) in individuals affected by a rotator cuff (RC) tendinopathy compared to usual physiotherapy care? The primary objective of this randomized control trial (RTC) is to compare, in terms of symptoms and functional limitations, a group receiving a group-supervised rehabilitation program (UpEx-NTP) centered on strength and motor control training to a group receiving usual one-on-one physiotherapy clinical care in individuals affected by a RC tendinopathy of the shoulder. It is hypothesized that both the UpEx-NTP (Exp) and usual physiotherapy care (Ctl) groups will equally demonstrate statistically (p-value \< 0.05) and clinically (all noted changes above their MCID : DASH questionnaire = 11 points, WORC index = 12 points and the Numeric Rating Scale for pain = 2 points) significant changes in shoulder function and pain over a 6-week period in individuals with an RC tendinopathy and will be maintained over time, notably 12-weeks after the intervention.