Exercise for rotator cuff tendinopathy: Proposed mechanisms of recovery

Abstract

Rotator cuff (RC) tendinopathy is a common recurrent cause of shoulder pain, and resistance exercise is the first-line recommended intervention. Proposed causal mechanisms of resistance exercise for patients with RC tendinopathy consist of four domains: tendon structure, neuromuscular factors, pain and sensorimotor processing, and psychosocial factors. Tendon structure plays a role in RC tendinopathy, with decreased stiffness, increased thickness, and collagen disorganization. Neuromuscular performance deficits of altered kinematics, muscle activation, and force are present in RC tendinopathy, but advanced methods of assessing muscle performance are needed to fully assess these factors. Psychological factors of depression, anxiety, pain catastrophizing, treatment expectations, and self-efficacy are present and predict patient-reported outcomes. Central nervous system dysfunctions also exist, specifically altered pain and sensorimotor processing. Resisted exercise may normalize these factors, but limited evidence exists to explain the relationship of the four proposed domains to trajectory of recovery and defining persistent deficits limiting outcomes. Clinicians and researchers can use this model to understand how exercise mediates change in patient outcomes, develop subgroups to deliver patient-specific approach for treatment and define metrics to track recovery over time. Supporting evidence is limited, indicating the need for future studies characterizing mechanisms of recovery with exercise for RC tendinopathy.

To allow or avoid pain during shoulder rehabilitation exercises for patients with chronic rotator cuff tendinopathy-Study protocol for a randomized controlled trial (the PASE trial)

“…Outcomes in the qualitative sub-study will be interviews which focus on themes such as motivating factors and barriers to training, empowerment, and explanatory factors [ 46 , 47 ]. During the process, the material can be supplemented if important concepts and themes were not included in the developed interview guide and if new facets of the research question arise.…”

“…The PASE program was developed with special emphasis on patient responsibility and self-management. Thus, part of the intervention in both groups is that participants are offered patient education including load management, advice to gain an understanding of the relation between the occupational demands/situation, sport/leisure time activities, and shoulder training including skills to perform specific shoulder exercises [ 46 ]. Finally, patients are provided with knowledge on how to act if shoulder pain occurs during home exercise and activities of daily living.…”

“…Yet, some of these variables are challenging to investigate using quantitative research or questionnaires. An inclusive model with four mechanism domains of exercise-related factors has been proposed: tendon structure, neuromuscular function, psychosocial factors, and pain and sensorimotor processing [ 46 ]. This model can improve knowledge of mechanisms applicable to RC tendinopathy and enable development of patient-specific treatment to deliver individualized rehabilitation.…”

“…When several effective treatment options with different proposed mechanisms are available (e.g., patient education, load management, sport participation, occupational demands, self-efficacy) and several specific factors are impacted by exercise (tendon structure, neuromuscular function, psychosocial factors, and pain and sensorimotor processing) [ 46 , 47 ], it is important to try to understand the mechanisms by which treatments work and for whom it may work. This can be done by looking at both the effect mediators and moderators [ 48 , 49 ].…”

Assessment of Muscle Stiffness Using the MyotonPro: Effects of Fatigue on Vastus Lateralis and Medialis Muscles

“…Furthermore, Evangelidis et al demonstrated that muscle fatigue significantly impacts the stiffness of the biceps femoris long-head muscle more than the semitendinosus and semimembranosus muscles, providing insight into the increased vulnerability to strain injuries within this muscle group [ 8 ]. Additionally, in the context of rehabilitation following Rotator Cuff tendinopathy, there is a manifestation of reduced tendon stiffness [ 9 ].…”