The aim of this study was to analyze supraspinatus (SS) and infraspinatus (IS) muscle size and quality before and after a 6-week exercise intervention. The aim of this study was to analyze supraspinatus (SS) and infraspinatus (IS) muscle size and quality before and after a 6-week exercise intervention.
This abstract includes a preliminary analysis on 10 patients with shoulder tendinopathy (mean age 38.7 (12.7) 5F/5M). Both SS and IS muscle size of both shoulders was obtained using US. Multiple scans were performed at baseline and post a 6-week exercise program. Supraspinatus cross-sectional area (CSA) images were captured in the transverse view. The IS muscle CSA was determined with subject in prone position. Using bony landmarks and a custom-made template to standardize the measurement location, serial images of the muscle were obtained and spliced to calculate the CSA. Size measurements (mm2 and pixels) were performed using ImageJ. To assess intra-rater reliability, images were measured by a single rater and re-measured 6-10 days later with the previous measurement blinded.
Intra Class coefficient (ICC) reliability values were all above 0.95 for measures of size, thickness, and echo intensity for both the SS and IS muscles. Between baseline (T1) to post-exercise (T3), there were no statistically significant changes in the painful shoulders; however, the mean gray scale analysis i.e. muscle quality changes decreased by 7-15%, change exceeded the MDC values, for all measures on the painful and non-painful shoulders.
The ICC analysis reveals excellent intra-rater test-retest reliability across all measures assessed by a single rater. Analysis revealed no significant change in CSA SS or IS musculature between timepoints for the painful shoulders; however mean grayscale analysis exceeded the MDC values for all measures on the painful and non-painful shoulders implying a possible increase in muscle quality following 6 weeks of exercise intervention.
Future steps include a similar analysis utilizing a larger data set and involvement of a control group. Understanding response of muscle size and quality to exercises will be useful in identifying the mechanisms of how exercise works. In this study, we used simple resistance band exercises; future research should focus on determining the effects of appropriate overload training. Additionally, examining the relationship between strength changes, muscle size and quality and functional changes may provide more insight into future treatment directions.
exercise
Ultrasound
