Angl° is an interactive wearable device which provides an enhanced exercise experience. It creates real-time sound feedback to help recreational athletes prevent injuries and maintain proper training intensity. The device increases the user’s awareness of their posture and tempo through melodic soundscapes. These soundscapes are generated based on sensor information monitored from the user’s natural training rhythm. When their posture collapses, Angl° creates dissonant audio to alert them to their degrading form. The device also guides users to optimal workout intensity, subtly increasing the tempo of the soundscape to motivate them, or slowing it down to protect them from overexertion.

We strove to understand the relationship between training intensity and injuries within recreational sports. Be it running, cycling, weight lifting or stretching, the trickiest sports injuries to prevent are not the abrupt ones, but rather the repetitive strain injuries. These result from long-term overuse due to bad technique and poor body control. In the core of all this is the lack of proper posture. Good upper body posture lets you use your core muscles at their peak, and relaxes your joints so you can make the most of your workout experience. Therefore our aim was to monitor and give feedback on upper body posture for the user.

Proper training intensity, which is reflected by your heartbeat, has a great effect on your workout results and experience. Working too hard may lead to injuries and burnout, while not working hard enough may end in unsatisfying results. Angl° prevents users from training too intensely, reacting to their speed and motions in real time, not based on a pre-set program.

Why we need real-time feedback:
There are numerous devices on the market that help track athletes’ progress and statistics, however all the information has to be processed after the initial exercise has already occurred.

Why sound feedback:
Excluding watching yourself in a ballet studio mirror, it is exceptionally difficult to know and maintain a good posture at all times when doing sports. Here, we explored the possibility of using sound to unobtrusively inform the users of their body posture and exercise intensity as they are actively conducting their workout.

Why we need mutual interaction in sound feedback:
In current sports products the audio interaction only provides a one way communication. Sound is widely used to boost the workout experience by motivating people to follow the beat and the mood of the music. Choosing music with the wrong BPM could result in improperly high or low training intensity which leads to improper cadences and injury prone postures. Instead of music playback, our intent was to let your body movement, heart rate and tempo generate personal soundscapes which would create a unique experience every time. The soundscapes and the user’s behavior affect each other mutually. It is a feedback loop which makes recreational athletes more comfortable and confident in training.

Initial research:
We conducted a round of preliminary research to better understand sports related injuries. This helped us to narrow our focus toward repetitive strain injuries as opposed to sudden and mostly unavoidable accidents. Repetitive stress injuries are caused by athletes practicing bad technique for long periods of time. We worked to create a system that would inform users as soon as their posture or training intensity changes for the worse.

User Research:
We chose recreational athletes as the target for this new training experience. Professional athletes have already acquired a proper technique, so their injuries are harder to predict or avoid (sudden accidents or injuries due to overuse).

Sound Experiments:
We found it effective to use a sound feedback system because it could be integrated into the user’s training routines in real time, without distracting them from their workout experience. The challenge was to create soundscapes that are pleasing over long periods of time, while expressing tension from time to time to raise the athlete's attention.

We experimented with different musical attributes to give meaning to the soundscape. The sound quality transitions from pleasant to tense to show instant changes in posture. To express that, we used climaxing keys (e.g. G to G#) and shifting musical scales (e.g. major to minor). While the tonal quality of the sound is linked to posture, the tempo of the sound was linked to changes in the athlete's cadence as their heart beat increases or decreases.

We also experimented with embodied sound generation. In our final design, the user’s body positioning informs the sounds they create, instead of having the user react to existing music with fixed BPM.

Form and Technology Testing:
We ideated on the form of the device, initially starting with an external back strap worn under the workout equipment. However, through user testing we received valuable feedback that indicated that creating a much more integrated and compact device would help minimize discomfort. This informed our decision to make a t-shirt encasing the sensors and speakers.

We prototyped different sensors to prove the viability of the concept. The integrated technology has to measure whether the posture is correct and relaxed. Stretch sensors measure the distance between shoulder blades, and three points along the shoulder blades and spine triangulate neck tilt. Aside from measuring posture, we also used accelerometers measure the tempo and intensity of movement. All of this is translated into soundscapes which are outputted through directional speakers on the shoulders, which make earphones obsolete.The overall device is compact and contained, holding all the necessary components in an unobtrusive form.

Here is a short video of one of our sensors and generated sounds being user tested: https://vimeo.com/87424860

Within this exploratory design project we found out that sound is an effective modality for giving real-time training feedback, without distracting the user. The device makes valuable information about tempo and posture available instantly, as opposed to something that would be noticed only after the workout, when it might be too late to avoid the injury. The generated soundscapes act as a mirror of the user's body movements. The device makes a conditional relationship between behavior and feedback by mentally linking incorrect posture to a dissonant sound, which builds up the user's confidence to recognize how to keep a good posture and tempo while exercising. Through an enriched experience Angl° aims to motivate more and more people to engage in recreational sports activities in a safe and accessible way.