Visual analysis of users’ performance data in fitness activities

Abstract

This paper presents a tool for the visual analysis of fitness performance data, such as running speed and heart rate. The tool, called MOPET Analyzer, provides a set of interactive visualizations that allow the user to analyze the relations among the different parameters of a fitness session. We developed two versions of MOPET Analyzer: one for desktop systems and one for mobile devices. The desktop version allows for an analysis of sets of different fitness sessions, also providing details for each single fitness session. The mobile version provides very simple visualizations that can be useful on the field. MOPET Analyzer allows the user to monitor her fitness activity and to analyze her fitness progress, helping her to continuously improve the quality of her training.

Introduction

Scientific evidence shows that the regular practice of physical activity and sports provides people of all ages with physical, social and mental health benefits. Physical activity enhances functional capacity and promotes social interaction and integration. Physical activity also has economic benefits especially in terms of reduced health care costs, increased productivity, healthier physical and social environments. In particular, open-air physical activity is characterized by additional valuable aspects, such as natural environments, air quality and sunlight. On the contrary, physical inactivity is a common and avoidable risk factor for some chronic diseases. However, people may perform physical activity improperly, wasting its benefits. Typical errors consist in starting with too intensive exercises or performing them in an uncorrect way. These errors, in general, arise because people generally start to perform physical activity without the assistance of a professional trainer or using mobile devices or software that help them in correctly performing physical activity. People that use mobile devices or software for their physical activities can also make errors, which are generally due to:

• Limitations of the current commercial products [1], [2], [3], [4] for helping users in fitness activities. These products have limited user interfaces (digital-clock style), are often not easy-to-use, and do not focus much on user's motivation. For example, Polar devices can give only a basic motivational feedback, called “calorie bullet”: every time a certain amount of calories is burnt, the device beeps, inciting the user to run more and burn other calories. Moreover, current products do not help users in performing exercises correctly.

• Limitations of current visualizations tools for analyzing users’ performance data. The post session visualization tools offered by the heart rate monitors for fitness currently on the market [1], [4] are in general plots of the user's heart rate or running speed as a function of time. These visualizations allow only for a superficial analysis of the performance and usually and do not offer tools for querying data and comparing data of different sessions. Moreover, current tools do not allow the user to find relations between her performance data and her position.

To tackle the first problem, we introduced MOPET (MObile PErsonal Trainer) [5], a mobile application for supporting users in fitness trails. MOPET currently helps users in:

• training: MOPET employs a 3D embodied agent that shows the user how to correctly perform fitness exercises;

• navigation: MOPET helps users to follow the right path, constantly monitoring her position with a GPS device and providing visual and audio instructions;

• motivation: the embodied agent verbally incites the user to maintain an adequate fitness intensity during the sessions.

This paper focuses instead on the second problem. MOPET Analyzer is a visual tool we propose to help the user in analyzing her performance data. The tool generates its visualizations from the data recorded by the MOPET application. MOPET indeed logs user's position and heart rate during each fitness session. MOPET Analyzer is able to produce interactive visualizations to answer questions such as:

• Where did the user run faster in a single session and over a number of sessions?

• Was the heart rate optimal for the user's physical fitness in a single session and over a number of sessions?

• Has the user's physical fitness improved with training? And how much?

Two versions of MOPET Analyzer have been developed. The first version is for mobile devices and shows a set of aggregated data (e.g., percentage of time during which heart rate was optimal for the user's physical fitness, total energy consumption) which can be quickly explored by the user on the field. The second is for desktop systems and allows for a deeper analysis of user's performance in a single session and over a number of sessions.

The paper is organized as follows. Section 2 describes the related work, covering different aspects of visual analysis of fitness performance and physiological parameters on desktop systems and on mobile devices. Section 3 presents the MOPET Analyzer tool and its visualizations. Section 4 demonstrates how the visualizations can help in analyzing fitness performance data, considering two case studies. Conclusions and future work are presented in Section 5.