Concentric vs eccentric training and SSP muscle architecture
The supraspinatus muscle accounts for a substantial part of subacromial pain syndromes, tendinopathies and, ultimately, rotator cuff tears. Conservative treatment of supraspinatus tendinopathies includes among others concentric and/ or eccentric strengthening exercises. Besides strength gains and hypertrophy, eccentric training leads to improved tendon healing.
This study sought to determine the effect of concentric vs. eccentric strength training on muscle architecture and strength parameters. Fourteen participants completed sonographic and isokinetic assessment procedures and were then randomly assigned to an 8-week training programme consisting of either concentric or eccentric strengthening exercises.
A significant difference in fiber bundle length (FBL) between the concentric and eccentric group was found – in the concentric group FBL decreased, whereas no significant changes were present pre and post training. Pennation angles, muscle thickness and strength parameters increased equally in both groups. A longer FBL may be beneficial, as it helps in sustaining force over greater ranges and, in the case of an eventual surgical repair, increases the change of success.
> From: Kim et al., J Sci Med Sport (2014) . All rights reserved to Elsevier Ltd.. (ePub ahead of print).