# Comparison of Upper Body Joint and Hand Motions in Eating Solid Foods With Chopsticks and Semisolid Foods With a Spoon in Healthy Males and Females: Observational Study

## TL;DR

This study compares body movements when eating solid foods with chopsticks and semisolid foods with a spoon in healthy men and women.

## Contribution

The study provides detailed kinematic data on chopstick and spoon use for different food types in East Asian eating contexts.

## Key findings

- Chopsticks led to smaller shoulder flexion angles in all eating phases for both males and females.
- Chopstick use resulted in shorter hand movement distances and slower speeds during food transport.
- Elbow and forearm movements were more pronounced with chopsticks during specific phases compared to spoons.

## Abstract

Foods are not only masticated and swallowed but they also influence the choice of utensils and their use. Comparing the contexts in which different utensils are used with each food form could help in the assessment of individuals experiencing eating difficulties in the food culture unique to East Asian countries.

Considering East Asian rehabilitation practices, in this study, we evaluated upper body movements involved in eating pickles (solid food) and yogurt (semisolid food) using chopsticks and a spoon, respectively.

Upper body kinematics, including joint and hand spatiotemporal parameters, were quantified using a 3D inertial motion-capturing system and analyzed in healthy males (n=22; mean age 27.9, SD 5.5 years) and females (n=21; mean age 26.9, SD 4.7 years) across 4 feeding phases (reaching, picking it up, transporting, and inserting food into the mouth) by comparing utensils for eating respective food forms using the Wilcoxon signed rank test.

Both sexes showed smaller maximum shoulder flexion angles with chopsticks for eating solid food across all phases (Males: reaching phase, P<.001; picking foods up phase, P=.04; transport phase, P<.001; and mouth phase, P<.001. Females: reaching phase, P<.001; picking foods up phase, P=.007; transport phase, P<.001; and mouth phase, P<.001.). Elbow, forearm, and wrist ulnar deviation angle changes were smaller using chopsticks during the “picking up” phase (in both sexes, P<.001) compared with using a spoon. However, greater elbow joint angle changes were found during the “reaching” phase (males, P=.002; females, P=.03) and greater forearm angle changes were found during the “transporting” phase (males, P=.01; females, P=.001) with chopsticks than with spoons. Regarding hand spatiotemporal parameters, the chopstick condition involved shorter actual distances (males, P<.001; females, P<.001), lower distance efficiency (males, P=.04; females, P=.001), and slower speed (males, P=.001; females, P<.001) during food transport.

The joint angle and hand spatiotemporal parameter characteristics observed during chopstick use for eating solid foods and spoon use for eating semisolid foods in healthy individuals could serve as reference movements in individuals with sensorimotor dysfunctions and inform the selection of adaptive utensils in rehabilitation practice.