Embodying non-human characters and exercising abdominal muscles are both underexplored in exergames. We address this by describing the design and evaluation of a novel human quadruped locomotion exergame, Become the Beast. In the game, the player lies supine on the ground and moves their arms and legs to control a quadrupedal character (a tiger), similar to common bodyweight abdominal muscle exercises such as the Bicycle Crunch. The motion tracking is computer vision-based, utilizing a Kinect sensor placed above the player, which makes our approach suitable for commercial premises such as indoor activity parks where a system needs to run unattended and without any wearable components. Our system extends embodied interaction beyond traditional bipedal or controller-based systems, demonstrating how natural limb movements can generate responsive and immersive quadrupedal motion within virtual environments. We conducted a user study (N=15) and utilized Reflexive Thematic Analysis (RTA) to evaluate the system's intuitiveness, control, and overall player experience. The findings validate that natural body movements effectively control the avatar while delivering an intense core workout. Notably, gameplay immersion masked physical exertion, allowing rigorous core training to be primarily perceived as play.

翻译：在体感游戏（exergames）中，对非人类角色的具身化体验以及腹肌锻炼均属尚未充分探索的领域。本文通过描述一款新型人-四足运动体感游戏《化身猛兽》的设计与评估，对此问题进行探讨。游戏中，玩家仰卧于地面，通过移动四肢控制一个四足角色（虎），其动作类似常见的自重腹肌练习（如自行车卷腹）。动作追踪基于计算机视觉技术，利用置于玩家上方的Kinect传感器实现，这使得我们的方案适用于室内活动乐园等商用场所——系统需自主运行且无需任何可穿戴组件。本系统将具身交互扩展至传统双足或基于控制器的系统之外，展示了自然肢体运动如何在虚拟环境中生成响应式且沉浸式的四足运动。我们开展了一项用户研究（N=15），并采用反思性主题分析法（RTA）评估系统的直观性、操控性及整体玩家体验。研究结果证实，自然身体动作可有效控制虚拟角色，同时提供高强度核心训练。值得注意的是，游戏沉浸感掩盖了生理消耗，使得高强度的核心训练主要被感知为娱乐活动。