Association between shoulder external rotation strength and real-world arm use in patients with mild post-stroke hemiparesis: a cross-sectional study.
Shuichi Sasaki, Atsuko Karube, Akari Kobayashi and 6 others
In 17 stroke survivors with mild arm weakness, stronger shoulder external rotation was linked to more and better use of the affected arm in daily life.
Those with movement-induced shoulder pain had weaker external rotation and less shoulder range of motion.
Key findings
1The affected-to-unaffected external rotation strength ratio was positively correlated with both amount of use (r = 0.65, p = 0.009) and quality of movement (r = 0.70, p = 0.004) on the Motor Activity Log, and these associations persisted after controlling for overall motor impairment (FMA-UE) and spasticity (MAS).
2Four of the 17 participants reported movement-induced shoulder pain; this group had a lower external rotation strength ratio (0.58 ± 0.12 vs 0.75 ± 0.17) and reduced shoulder flexion range of motion (132.5° ± 15.3 vs 165.2° ± 18.6) compared with the 13 without pain, both reaching statistical significance.
3Grip strength ratio correlated with external rotation strength ratio (r = 0.73, p = 0.001), and the authors suggest grip strength may serve as a practical screening indicator of overall upper-limb strength when hand-held dynamometry is not available, while cautioning it is not a direct substitute for external rotation assessment.
Still to come
How it was doneWhat they foundWhat it means for PTsWhat it means for OTs
Read the rest of this summary
You get three full summaries a month, free, and we do not ask for a card. Search, the TL;DRs and your library stay unlimited either way.
What it does not show
Only 17 participants, and the pain subgroup contained just 4 people; the authors explicitly call the study exploratory. All participants came from a single convalescent rehabilitation ward, so the findings may not generalise to acute inpatient settings, outpatient clinics, or home-based rehabilitation. The cross-sectional design means the direction of the relationship is unknown: weak external rotators may lead to less arm use, or disuse may lead to weaker rotators. Movement-induced pain was assessed by clinical observation rather than a validated pain scale, so it may reflect subjective or inconsistent reporting. All participants had mild impairment (Brunnstrom IV–VI, FMA-UE mean 53.4), so the findings say nothing about patients with more severe hemiparesis. Although partial correlations controlled for FMA-UE and MAS, other unmeasured confounders (e.g., cognition, motivation, comorbidities) cannot be excluded.
Declared interests
Funded by a research grant from the Kanagawa Occupational Therapy Association. The authors declare no conflict of interest.
The easy way to misread this
Do not read the pain-subgroup differences as a robust finding: only 4 of 17 participants reported pain, the authors call the study exploratory, and the MAL difference between the pain and no-pain groups did not reach significance. The cross-sectional design also means the link between external rotation strength and arm use could run in either direction — weak rotators may cause less arm use, or less arm use may lead to weaker rotators — so this is not evidence that strengthening external rotators will increase a patient's daily arm use.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →