This study proposes a harmony generation system designed to enhance motivation for group exercise. The system generates sounds based on the movements of multiple users and enables collaborative musical performance by layering these individual sounds. Additionally, it supports the creation of harmonious output by correcting timing discrepancies in sound generation between users. In the experiment, participants performed various exercise patterns while the presence and degree of sound generation and correction were varied to evaluate the system's effectiveness.The results confirmed that musical collaboration through physical movement can increase the enjoyment of exercise in a group setting. Furthermore, adjusting the timing of each user's sound generation helped create a sense of unity, reduced psychological burden, and suggested an increase in users' motivation to exercise.

This study proposes a virtual reality (VR) system that utilizes the cross-modal effect—an interaction between visual and auditory senses—to create the illusion of reduced training load. The system employs a height-adjustable chair to help prevent users from losing balance during squat exercises and a non-see-through head-mounted display that projects a 3D scene responsive to the user's movements. An evaluation experiment was conducted to explore the relationship between immersion tendency and perceived fatigue. The results indicated that the system's support reduced subjective fatigue while having minimal impact on heart rate. Moreover, a noticeable discrepancy between the avatar's movements and those of the participants suggested that a stronger immersion tendency may contribute to an increase in perceived fatigue. These findings suggest that VR can be effectively used to reduce the subjective feeling of fatigue during exercise, potentially offering a more comfortable and engaging training experience.