Videos are an accessible form of media for analyzing sports postures and providing feedback to athletes. Existing sport-specific systems embed bespoke human pose attributes and thus can be hard to scale for new attributes, especially for users without programming experiences. Some systems retain scalability by directly showing the differences between two poses, but they might not clearly visualize the key differences that viewers would like to pursue. Besides, video-based coaching systems often present feedback on the correctness of poses by augmenting videos with visual markers or reference poses. However, previewing and augmenting videos limit the analysis and visualization of human poses due to the fixed viewpoints in videos, which confine the observation of captured human movements and cause ambiguity in the augmented feedback. To address these issues, we study customizable human pose data analysis and visualization in the context of running pose attributes, such as joint angles and step distances. Based on existing literature and a formative study, we have designed and implemented a system, PoseCoach, to provide feedback on running poses for amateurs by comparing the running poses between a novice and an expert. PoseCoach adopts a customizable data analysis model to allow users' controllability in defining pose attributes of their interests through our interface. To avoid the influence of viewpoint differences and provide intuitive feedback, PoseCoach visualizes the pose differences as part-based 3D animations on a human model to imitate the demonstration of a human coach. We conduct a user study to verify our design components and conduct expert interviews to evaluate the usefulness of the system.

翻译：视频作为一种易于获取的媒介，常用于分析运动姿态并向运动员提供反馈。现有体育专项系统嵌入了针对特定的人体姿态属性，因此难以扩展至新属性，尤其对于无编程经验的用户。部分系统通过直接展示两种姿态间的差异来保持可扩展性，但可能无法清晰可视化用户希望关注的关键差异。此外，基于视频的指导系统常通过叠加视觉标记或参考姿态来呈现姿态正确性反馈。然而，视频预览与增强受限于固定视点，这既限制了捕捉到的人体运动观测，也导致增强反馈存在歧义。为解决这些问题，我们以跑步姿态属性（如关节角度、步长）为背景，研究可定制化的人体姿态数据分析与可视化方法。基于现有文献与形成性研究，我们设计并实现了PoseCoach系统，通过对比新手与专家的跑步姿态，为业余爱好者提供跑步姿态反馈。PoseCoach采用可定制化数据分析模型，允许用户通过界面自主定义其关注的姿态属性。为避免视点差异的影响并提供直观反馈，PoseCoach将姿态差异可视化为基于人体模型的分部位三维动画，模拟真人教练的示范方式。我们开展用户研究验证设计组件，并通过专家访谈评估系统的实用性。