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Joined Forces

A playful, interactive tool for Jujutsu practice during the Covid-19 pandemic

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Malmö University


5 weeks (2020)


User research
Workshop Facilitation


Amanda Asplund

Raquel Canete Yaque

Björn Grauers

Karin Härenstam



Motivation and Challenge

In 2020, the Covid-19 pandemic affected every part of lives. For keeping one’s distance, a variety of sports practices needed to be cancelled, including martial arts like Jujutsu. In this project, we explored how we might create a Corona safe way for Jujutsu practitioners to build confidence by putting their skills to test, reflecting on their improvement, and receiving feedback.


The deliverable is a prototype for an interactive, playful tool, consisting of a staff and floor mat equipped with sensors and actuators. While the staff ensures a 2m distance, users can apply strength, footwork, and techniques in line with their habitual Jujutsu practice. The floor mat provides feedback on the users’ performance, tracking their score, to simulate competition and challenge which emerged as important factors throughout the process.


A close combat system

Jujutsu is ‘an art of weaponless fighting employing holds, throws, and paralyzing blows to subdue or disable an opponent’ (Merriam-Webster). As such, it involves close contact which posed a challenge to continue practice during the pandemic.

Judo Tackle

Design Process

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Phase 1: Empathize



To identify central aspects of Jujutsu practice and how the pandemic has affected it, we shared a questionnaire with various Jujutsu-clubs, receiving 19 responses. Here, participants emphasized the importance of testing their strength and skills with an opponent.

Expert Interview

Correlating with the questionnaire, we interviewed a Jujutsu instructor at Malmö Ju-Jutsuklubb. He confirmed the insights from the questionnaire, adding the importance of footwork and transferring the opponent’s force instead of using brute strength.

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Jujutsu Practice

After conducting the interview, we were fortunate to receive a private Jujutsu class. It deepened our understanding of the art and its movements.

Phase 2: Define

Design Synthesis

We analyzed and clustered all gathered insights into four main themes: Building confidence, self-control, engaging mind and body, and motivation through challenge.

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Workshop I

We held a workshop with three different activities that differed in their movements and if an opponent was involved.

For Activity-A, participants each held the end of two elastic bands while standing on a field marked with sticky notes. They were only allowed to step on the sticky notes while trying to make their opponent loose balance by manipulating the bands.


Activity-B resembled the game dodgeball, as participants threw balls at their opponent from a distance, trying to hit targets on each other’s body. This activity emphasized footwork, reflexes, and precision.

During Activity-C, participants were trying to hit targets on a wall by throwing a ball in a movement mimicking a punch. This activity explored the engagement of a challenge without opponent.

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Identifying criteria

For entering the ideation phase, we identified various criteria which should be included in the design:

  • Keep 2m distance

  • Engage in competition

  • Transfer force + affect opponent

  • Afford balance, footwork, strength, strategy

Phase 3: Ideate


Based on the gathered insights, we started sketching initial concepts – either with pen and paper or as physically trying out ideas with makeshift materials.

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Phase 4 + 5: Prototype & Test


Workshop II

We prepared two prototypes, trying them out ourselves and in a workshop session. Participants’ feedback helped us to further refine the concept, such as adjusting the construction and training field as well as the kind of interactive feedback needed during rounds.

Tangible and Digital

Based on the feedback, we created a prototype that combined a wooden construction with Micro:bits that were programmed to emit sound and vibrate. We used the Wizard of OZ technique to simulate the connection between the mat and the stick.

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Finding the right stick proved to be an iterative process as well.

Final Testing

During a final testing session, the design met the criteria previously established. A few critical points were raised concerning technical aspects, such as sensor sensitivity and feedback accuracy.


Final Design: Joined Forces

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How it works

Goal: Get your opponent out of the field while staying in the center.

  • Sound starts and ends rounds

  • Handle vibrates when changing spheres

  • Vibration and sound indicate you’re out of bounds

  • App (future work) tracks the score


  • Allows transferring force without close contact

  • Allows the basic principles in Ju-Jutsu to be practiced

  • Includes interactive feedback

  • Helps building confidence during training

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Future Work

To further improve the design, the sensors and actuators need to be refined and seamlessly implemented into the mat and stick. Furthermore, the next step would be working on the score board and app. The design might also be adaptable to related martial arts practices.

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