Eighteen older women (mean age: 85.4 years; s.d.: 5.4 years) participated in the study. According to the self-report survey, all the participants used their right hand to turn lids when performing jar opening tasks, and 89% experienced hand discomfort or pain in the month prior to the study. Overall, the mean hand dysfunction score of the participants was 5.8 out of 10 (s d.: 1.8) (distribution is presented in Fig. 1.). Participants whose scores exceeded 5.5 were categorized into the more severe hand-dysfunction group (n = 11), and participants with lower scores were categorized as the hand-healthier group (n = 7).