Goalkeeper: A Zero-Sum Exergame for Motivating Physical Activity

Evangelos Niforatos*, Camilla Tran, Ilias Pappas, Michail Giannakos

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedings/Edited volumeConference contributionScientificpeer-review

1 Citation (Scopus)


Incentives and peer competition have so far been employed independently for increasing physical activity. In this paper, we introduce Goalkeeper, a mobile application that utilizes deposit contracts for motivating physical activity in group settings. Goalkeeper enables one to set up a physical exercise challenge with a group of peers that deposit a fixed amount of money for participating. If a peer fails to complete the challenge, Goalkeeper redistributes their deposit to those who managed to complete it (i.e., zero-sum game). We evaluated the potential of Goalkeeper in increasing physical activity with a total of 50 participants over the course of 2 months. Our findings suggest that deposit contracts induce a loss-aversion bias, that in combination with peer competition, is effective in increasing exercise motivation. Ultimately, we generate a set of design principles for exergames that utilize deposit contracts for increasing physical activity in group settings.

Original languageEnglish
Title of host publicationHuman-Computer Interaction – INTERACT 2021 - 18th IFIP TC 13 International Conference, Proceedings
EditorsCarmelo Ardito, Rosa Lanzilotti, Alessio Malizia, Alessio Malizia, Helen Petrie, Antonio Piccinno, Giuseppe Desolda, Kori Inkpen
Number of pages22
ISBN (Print)9783030856120
Publication statusPublished - 2021
Event18th IFIP TC 13 International Conference on Human-Computer Interaction, INTERACT 2021 - Virtual, Online
Duration: 30 Aug 20213 Sep 2021

Publication series

NameLecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics)
Volume12934 LNCS
ISSN (Print)0302-9743
ISSN (Electronic)1611-3349


Conference18th IFIP TC 13 International Conference on Human-Computer Interaction, INTERACT 2021
CityVirtual, Online


  • Exercise contracts
  • Motivation
  • Peer competition
  • Physical activity
  • Zero-sum game


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