Shoulder muscle coordination in young controls, elderly controls and degenerative rotator cuff tears
In 106 participants, elderly controls and patients with degenerative rotator cuff tears both showed reduced muscle synergy dimensionality compared with young controls, with no significant difference between the two older groups. The authors interpret the tear group's patterns as altered coordination on top of age-related neuromuscular changes. [1]
Automatic summary · not editorially reviewed
The key findings
The study recorded surface electromyography from eight shoulder-related muscles during maximal shoulder abduction and flexion in 106 participants: 24 young controls, 24 elderly controls and 58 patients with degenerative rotator cuff tear. [1]
Compared with young controls, both elderly controls and patients with degenerative rotator cuff tear showed reduced muscle synergy dimensionality, with no significant difference between the elderly control and tear groups. [1]
The authors suggest that degenerative rotator cuff tear is associated with altered muscle coordination patterns superimposed on age-related neuromuscular changes, and that the combined analyses may support future individualized rehabilitation strategies. [1]
The source at a glance
- Study type / format
- Abstract of a cross-sectional group-comparison study using surface electromyography
- Population / context
- 106 participants: 24 young controls, 24 elderly controls and 58 patients with degenerative rotator cuff tear.
- Summary based on
- Study abstract
- Original publication
- September 25, 2026
Young, elderly and rotator cuff tear groups compared
The study asked whether altered shoulder neuromuscular coordination in degenerative rotator cuff tear reflects aging-related changes or changes linked to the pathology. Surface electromyography was recorded from eight shoulder-related muscles during maximal shoulder abduction and flexion tasks in 106 participants: 24 young controls, 24 elderly controls and 58 patients with degenerative rotator cuff tear. Muscle synergies were quantified with non-negative matrix factorization, intermuscular coordination with beta-band coherence analysis, and muscle interaction patterns with network topology metrics.
Supporting source [1]
Reduced synergy dimensionality in both older groups
Compared with young controls, both the elderly control and rotator cuff tear groups showed reduced muscle synergy dimensionality, with no significant differences between the elderly control and tear groups. Synergy structure differed between groups depending on the task, and tear participants showed coordination patterns partly similar to those of elderly controls. Intermuscular coherence and network analyses showed group-specific alterations mainly during shoulder abduction, involving deltoid-related and deltoid-scapular muscle interactions.
Supporting source [1]
Interpretation as age-related plus pathology-associated changes
The authors conclude that degenerative rotator cuff tear is associated with altered muscle coordination patterns superimposed on age-related neuromuscular changes. They describe the combined synergy, coherence and network analyses as possibly giving quantitative insight into mechanisms of functional impairment in degenerative rotator cuff tear and as support for future development of individualized rehabilitation strategies. These are proposed future uses, not tested rehabilitation outcomes.
Supporting source [1]
How to interpret this
Abstract only; the full text was not reviewed. The abstract reports group comparisons and associations, not causes, and does not report effect sizes, follow-up or rehabilitation outcomes. The rehabilitation use is described as a future possibility.
Based on the study abstract; the full paper, tables and supplementary data were not reviewed.
Source & supporting passages
Sun JN, Dong CB, Zhan MQ, Chen L, Hu DQ, Zheng N, Li H, Ma YR, Li YR, Chen P. · europepmc.org · September 25, 2026