Introduction

Wrist range of motion (ROM) supports coordinated upper-limb function during self-feeding. Wrist restriction may induce proximal compensation, yet the kinematic consequences of discrete wrist positions remain underexplored.

Methods

Ten healthy young women performed a standardized eating task under four wrist positions: free (FP), palmar-flexed (PFP; 20°), intermediate (IP; 0°), and dorsiflexed (DFP; 20°). Upper-limb kinematics were recorded with a wearable IMU system (100 Hz). Discrete outcomes included maximum/minimum joint angles and event-based angles at the end of scooping and mouth reaching. Parametric data were analyzed using repeated-measures ANOVA with Dunnett comparisons versus FP; non-parametric data used Friedman tests with Bonferroni correction (η²). Statistical Parametric Mapping (SPM) was applied to time-normalized waveforms to localize condition effects across the movement cycle.

Results

Wrist position systematically altered kinematics. Compared with FP, PFP produced the largest deviations, including reduced maximum elbow flexion (108 ± 8° vs 124 ± 8°) and forearm supination (68 ± 12° vs 93 ± 12°; η² up to 0.44). At mouth reaching, PFP similarly reduced elbow flexion (108 ± 8° vs 123 ± 9°) and supination (67 ± 12° vs 93 ± 12°) and shifted wrist posture toward palmar flexion. IP and DFP showed smaller departures from FP. SPM indicated the largest effects mainly during late transport/mouth reaching for elbow flexion and supination, and near movement initiation/termination for wrist radial/ulnar deviation.

Conclusion

Non-neutral wrist positioning—particularly palmar flexion—disrupts self-feeding coordination and elicits proximal compensation. Findings may inform orthosis positioning and exercise progression; confirmation in patient cohorts is warranted.