When both arms are moved together by a robot while watching a screen, healthy people’s muscles work harder than when only one arm is moved, even if they’re not trying to move it themselves.

Scientific Claim

In healthy adults, bilateral passive robot-assisted training with visual feedback is associated with significantly higher muscle activation levels (0.77 ± 0.13) in upper limb muscles compared to unilateral passive training with visual feedback (0.24 ± 0.05) during circular and S-shaped virtual tasks, suggesting that bilateral coordination may enhance neuromuscular engagement even without voluntary effort.

Original Statement

“Results revealed that BPT-visual (0.63 ± 0.26) significantly increased muscle activation level when compared to those of BPT-none (0.45 ± 0.27) and UPT-visual (0.24 ± 0.05) (p < 0.01).”

From study:Effective unilateral/bilateral robot-assisted training for upper limb motor function rehabilitation: a cross-sectional study

Evidence Quality Assessment

Claim Status

overstated

Study Design Support

Design supports claim

Appropriate Language Strength

association

Can only show association/correlation

Assessment Explanation

The authors imply causation by suggesting this finding informs clinical protocols, but the study only measured healthy adults without clinical outcomes. The verb 'increased' implies causation; 'associated with' is appropriate.

Evidence from Studies

Supporting (1)

Effective unilateral/bilateral robot-assisted training for upper limb motor function rehabilitation: a cross-sectional study

Cross-Sectional Study

Human

2025

The study found that when both arms are moved together by a robot with visual cues, muscles work harder than when only one arm is moved—even without the person trying to move on their own. This matches the claim that using both arms at once boosts muscle activity.

Contradicting (0)

No contradicting evidence found

Source Study

Effective unilateral/bilateral robot-assisted training for upper limb motor function rehabilitation: a cross-sectional study

Score: 33

DOI: 10.3389/fnhum.2025.1571624

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