Do Leg-Focused Exercises Improve Arm and Hand Function for Individuals With Neurologic Disorders? A Scoping Review.

This is a scoping review, not a systematic review with a risk of bias assessment. The authors state that no risk of bias assessment was conducted and that this limits the strength of evidence. Only 12 studies were found across 77 years of searching, most with small samples, and their PEDro quality scores ranged from 5 to 8 out of 10. The studies differed widely in design, exercise type, dose and outcome measures, so the results cannot be pooled or compared directly. Upper limb results were usually an incidental finding rather than the thing the study was designed to test. Only one study specifically hypothesised that leg training would improve arm outcomes. Several individual trials were underpowered: the authors of the 63-person chronic stroke trial said so directly, and the 94-person inpatient trial attributed its lack of significance to being underpowered with poor adherence (5-15 minutes per session on 7 of 28 days in some cases). Despite the review being open to any neurologic condition, the included studies were almost entirely in stroke and Parkinson disease, so nothing here applies to spinal cord injury, multiple sclerosis, ALS or cerebral palsy. The search was restricted to English, inaccessible articles were excluded, and the review was not preregistered.

The investigators declared no financial or nonfinancial disclosures in relation to this project. The review was not preregistered.

Do not read this as evidence that leg exercise is a way to improve arm and hand function. Only one of the 12 studies actually set out to test that question, most of the positive findings were incidental to what the study was designed to measure, and half the studies found no upper limb change at all. In the largest trial leg training and arm training produced similar gains and neither was better than the other, so there is no basis for replacing arm and hand training with leg work.