BACKGROUND：Enjoyment, realization of benefi ts, and interaction with peers are important factors in continuing exercise. Although rhythm synchro exercise is designed to incorporate nudges into the program to elicit enjoyment, the enjoyment felt by participants in response to the rhythm synchro exercise program and the effects of implementing the program have not been verifi ed. OBJECTIVE：This study aimed to subjective changes felt by participants of performing rhythm synchro exercise and the factors that promote enjoyment. METHODS：Thirteen elderly people, who participated in a rhythm synchro exercise class for three months, were interviewed individually to determine the factors promoting enjoyment and subjective changes through the class. RESULTS：A categorical analysis of the interview content showed that enjoyment was promoted by four factors: program component, psychological factors, social factors, and environmental factors. Subjective changes were summarized by six factors: psychological changes, physical changes, environmental adaptation, social changes, cognitive changes, and changes in daily life. CONCLUSION：The results suggested that rhythm synchro exercise incorporating nudges may be a program with respect to fun and exercise continuation.
