Exploring the impact of musical feedback systems on physical endurance
Creators: name: Ortega García, Mario
Publisher: name: Zenodo
Year: 2024
Subjects: musical feedback system;
musical agency
physical endurance
exercise

description: Music has been proven to have an ergogenic effect in the context of physical activity. It can reduce one’s perceived level of exertion by mitigating the negative feelings caused by the struggle associated with exercise. However, several studies have shown that these benefits can be amplified by inducing a state of musical agency. Musical agency aims to make the user an active participant in the musical output rather than a passive listener. This can be achieved by implementing what is know as a musical feedback system (MFS). For this project, three different MFS were developed in the form of Android apps, each of which empowers the user by giving them control over their workout music in a unique way.

The first musical feedback system consists on music loops that become increasingly more intense and complex as the fluctuation of the accelerometer values grows. Four instruments play simultaneously on different tracks, with three of them being mapped to a different axis plus percussion being mapped to the average fluctuation of all axes. The variation of accelerometer values is measured both on a long term and short term basis.

The second application that was developed counts movement repetitions by detecting significant sign changes on any axis of the accelerometer values. It sets a target of repetitions within a time window, and depending on the user’s performance, different audio effect parameters are tweaked. The user can select any song or audio clip to play while exercising, and at first very aggressive distortion and a restrictive low-pass filter will be applied. As their performance improves, the audio effects become less intrusive.

The third musical feedback system allows the user to specify up to 5 different positions, which will be used to train a custom K-NN algorithm. Subsequently, each of them is assigned a different audio clip, which is triggered every time the K-NN classification algorithm detects a change in the current smartphone orientation. Different instrument are available and can be selected through the user interface.

Lastly, cooperative versions of the first and second musical feedback systems were also developed. These use a PC as a host, and accelerometer values are sent via OSC protocol. In the cooperative loop-based application, each of the four instruments is assigned to a different participant, with loop intensity being mapped to the overall fluctuation of accelerometer data. In the cooperative version of the repetition counter, two participants are each assigned a different audio effect (distortion and low-pass filter), which they must mitigate by performing exercises at the expected pace.

An experiment was conducted to test the second application (Audio effect modulation  through a movement counter). The physical endurance of 9 different participants was tested under two different conditions: passive listening and musical agency. A quantitative and qualitative data analysis was performed. Results seem to point toward an increase in physical endurance and enjoyment when subjects use the musical feedback system.