Exploring whole-body kinematics when eating real foods with the dominant hand in healthy adults

Despite the importance of eating movements to the rehabilitation of neurological patients, information regarding the normal kinematics of eating in a realistic setting is limited. We aimed to quantify whole-body three-dimensional kinematics among healthy individuals by assessing movement patterns in defined phases while eating real food with the dominant hand in a seated position. Our cross-sectional study included 45 healthy, right-hand dominant individuals with a mean age of 27.3 ± 5.1 years. Whole-body kinematics (joint angles of the upper limb, hip, neck, and trunk) were captured using an inertial sensor motion system. The eating motion was divided into four phases for analysis: reaching, spooning, transport, and mouth. The mean joint angles were compared among the phases with Friedman’s analysis of variance. The maximum angles through all eating phases were 129.0° of elbow flexion, 32.4° of wrist extension, 50.4° of hip flexion, 6.8° of hip abduction, and 0.2° of hip rotation. The mean shoulder, elbow, and hip joint flexion angles were largest in the mouth phase, with the smallest being the neck flexion angle. By contrast, in the spooning phase, the shoulder, elbow, and hip flexion were the smallest, with the largest being the neck flexion angle. These angles were significantly different between the mouth and spooning phases (p < 0.008, Bonferroni post hoc correction). Our results revealed that characteristic whole-body movements correspond to each phase of realistic eating in healthy individuals. This study provides useful kinematic data regarding normal eating movements, which may inform whole-body positioning and movement, improve the assessment of eating abilities in clinical settings, and provide a basis for future studies.