Background & Aims
Chronic atraumatic shoulder pain may present a reduction in muscle strength and movement avoidance behavior with an important decrease in the functionality of the upper limb. Several variables such as acceleration and deceleration to reach peak torque can represent some alterations caused by this condition. This confirmation, however, is not documented in the scientific literature available in databases, justifying the present study. Therefore, the aim of this study is to evaluate and compare possible associations between time of acceleration and deceleration to peak torque during external and internal shoulder rotation and avoidance behavior in patients with subacromial pain syndrome (SPS).
Methods
Total rotator cuff tear, fracture or surgery in the upper limb, overhead athletes and participants over 55 years old were excluded. Participants were evaluated on an isokinetic dynamometer (Biodex 4) in a sitting position with 45° of abduction in the scapular plane, 30° of internal rotation (IR) and 30° of external rotation (ER) at 60°/s speed. At the beginning of the evaluation, the participants performed three submaximal repetitions of each movement to familiarize themselves with the equipment. Strength assessment by three concentric isokinetic contractions was stimulated with verbal feedback and the day’s pain intensity was collected with the analogue numeric scale (ANS). Movement avoidance behavior was assessed using the Avoidance Daily Activities Photo (ADAP) Shoulder Scale prior to the muscle test. For the multiple linear regression model, the dependent variable was the total ADAP score and acceleration and deceleration values of ER and IR torque were the variables.
Results
Sixty-seven participants were evaluated (forty-five women and twenty-two men; age 45?9.04 years; body mass index 29.6.3?6.2 kg/m2) with a pain intensity of 5?2.4. The analysis resulted in a significant model [F(4,62) = 8,87; p < 0.05; adjusted R²= 0.323]. IR acceleration (?=0.110; t=3,79; p=<0.001; 95%CI 0,05 to 0,16) and ER acceleration (?=0.076; t=2,03; p=0.0047; 95%IC 0,001 to 0,150) are associated with movement avoidance, while IR deceleration (?=-0.014; t=-1,18; p=0.242) and ER deceleration (?=0.023; t=1,66; p=0.102) were poorly associated with movement avoidance.
Conclusions
Acceleration to reach peak torque of IR and ER of the shoulder movement are capable of being associated with whether people with SDS exhibit movement avoidance behavior. However, deceleration of IR and ER of the shoulder did not have any association with avoidance behavior towards movement.
References
1. Sahin E, Dilek B, Baydar M, et al. Shoulder proprioception in patients with subacromial impingement syndrome. J Back Musculoskelet Rehabil 2017; 30: 857–862.
2. Ansanello W, Dos Reis FJDSJ, Tozzo MC, et al. Development of the Avoidance Daily Activities Photo Scale for Patients with Shoulder Pain. Phys Ther 2022; 102: 1–11.