Effect of the Multicomponent Exercise Program MoveUS on the Kinematic Fatigue of People With Glenohumeral Instability: A Secondary Analysis From a Randomized Controlled Trial

BACKGROUND AND PURPOSE: Kinematic movement analysis is highly relevant in patients with glenohumeral instability, a pathology characterized by fatigue-induced slowing of repetitive movements. However, the optimal exercise approach for this symptom remains unclear. This study aimed to determine the effect of the MoveUS Program on the improvement of kinematic fatigue in patients with glenohumeral instability. METHODS: This randomized controlled trial was developed at Axarquia Hospital (Spain). The study evaluated 47 adult patients with glenohumeral instability, and 38 patients finished the study. The patients were asked to perform the modified 30-s and 120-s T-Fast Test as well as three tests using analytical movements such as flexion, abduction, and scaption for 30 seconds as quickly as possible. The outcome variables were the reference point, the time to fatigue, and the percentage of fatigue, both in linear acceleration and angular velocity. The main statistical method was linear mixed-effects models. RESULTS: The MoveUS Program Group showed significant improvements in time to fatigue compared with the control group in the 30″ T-Fast Test (β = 5.09-5.12; p = 0.001-0.003), 120″ T-Fast Test (β = 16.62-31.0; p < 0.001), flexion (β = 8.13-9.51; p < 0.001), abduction (β = 12.7-13.53; p < 0.001), and scaption (β = 13.8-14.94; p < 0.001). As for the percentage of fatigue, the MoveUS Program showed significant differences but only in the 120″ T-Fast Test (β = -19.51--28.11; p = 0.001-0.02). In contrast, significant differences were not found between groups regarding the reference point. DISCUSSION: This study suggests that the MoveUS Program may be useful to generate a delay in the time to fatigue in patients with glenohumeral instability. Future research is needed to confirm the results of this study. TRIAL REGISTRATION: NCT05443295. https://clinicaltrials.gov/study/NCT05443295.