Designing a Somatosensory Interactive Game of Lower Extremity Muscle Rehabilitation for the Elderly Chien-Hsiang Chang 1 , Kao-Hua Liu 2(B ) , Hiroyuki Kajihara 3 , Wei-Chih Lien 4 , Peng-Ting Chen 5 , Atsushi Hiyama 2 , Yang-Cheng Lin 1 , Chien-Hsu Chen 1 , and Masahiko Inami 2 1 Department of Industrial Design, National Cheng Kung University, Tainan 70101, Taiwan {lyc0914,chenhsu}@mail.ncku.edu.tw 2 Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo 153-8904, Japan {maarkliu,hiyama,inami}@star.rcast.u-tokyo.ac.jp 3 Department of Leisure Regimen Management, College of Tourism, Tainan University of Technology, Tainan 710302, Taiwan tq0016@mail.tut.edu.tw 4 Department of Physical Medicine and Rehabilitation, National Cheng Kung University Hospital, Tainan 70403, Taiwan lwclwhab@ms8.hinet.net 5 Department of Biomedical Engineering, National Cheng Kung University, Tainan 70101, Taiwan chen@ncku.edu.tw Abstract. Somatosensory game-based rehabilitation has recently experienced rapid increases in demand and scale in the health promotion market. However, the existing research on this topic mostly focuses on treatment efficacy rather than game usability, experience feedback, and the needs of the elderly when experiencing the games. To fill this knowledge gap, we designed a somatosen- sory interactive game focusing on lower extremity rehabilitation, explored the intention and motivation of elderly patients, and documented the difficulties and needs of these patients in using the game. We enrolled 15 elderly subjects with lower extremity degeneration and collected data using a one-group pre-test and post-test experiment. For the pre-test, the subjects were treated with a traditional lower extremity rehabilitation program for 1 min, followed by a 5-min question- naire survey. Next, the subjects were asked to play the somatosensory interac- tive game for 1 min, followed by 15 min of post-test questionnaire survey and interview. The results showed a significant difference between the two types of rehabilitation in the us-ability constructs of “fun”, “liking”, “self-expression”, “self-understanding”, “intention”, and “fatigue” in elderly subjects with no prior rehabilitation experience, indicating that, compared to the traditional ones, the rehabilitation game performed better in introducing rehabilitation to the elders, enhancing their motivation, intention, and increasing their self-confidence. The results also showed that the status of lower extremity disease in elderly users did not affect gameplay. Lastly, we provide suggestions for further improvements in © Springer Nature Switzerland AG 2021 Q. Gao and J. Zhou (Eds.): HCII 2021, LNCS 12787, pp. 23–37, 2021. https://doi.org/10.1007/978-3-030-78111-8_2