Custom Smartphone Application to Guide Locomotor-Respiratory Coupling in the Field Using Step-Adaptive Breathing Sounds

We are interested in understanding breathing during exercise. While many runners experience respiratory limitations, few attempts have been made to address this directly during exercise. Locomotor respiratory coupling is one such breathing technique that could help, although it is rather difficult to learn.

Digital solutions, such as smartphone applications, could potentially enable this. Breathing strategies might help to alleviate respiratory pathologies and dysfunction, as well as improve performance. However, altering highly automated processes, such as breathing, are likely to be acutely ineffective.

Therefore, habitation and practice is necessary to realize such benefits. Mobile low friction tools such as smartphone apps, have the potential to provide such benefits in a more accessible and user-friendly manner. We've previously demonstrated that step synchronized sound guidance can effectively support coupling in novice runners within only one or two sessions.

Furthermore, while lab studies have shown mixed results for the benefits of coupling, we were the first to report that coupling in free running conditions is associated with increases in running speed, as well as decreased ventilatory variability. Run rhythm differs from previous solutions since it utilizes generic smartphone and headphones making it easy accessible for longitudinal studies. And furthermore, it uses easily understandable sound feedback, which was optimized throughout various user studies.

Clever solutions such as music integration and temporality improved their user experience during the run. The creation of the application and the related studies paved a way for new research questions, such as how can runners be dynamically supported with these breathing techniques during the run? And how can these breathing techniques be enhanced and integrated in run trainings programs, such as interval training?

To begin, ask the participant to fill out a pre-participation questionnaire with elements such as informed consent, running history and respiratory health. Download the RunRhythm application to a functioning smartphone running Android eight or higher version. Familiarize the runner with coupling and the application.

Before discussing and instructing locomotor respiratory coupling with the app, perform an individual calibration to determine the runner's natural coupling ratio. Choose a simple running task and record their step and breath rate during the trial. Calculate the nearest whole integer ratio from their quotient.

Begin with rhythmic foot tapping and instructions to breathe at a given ratio in sync with the feet. Repeat while walking and then while running in place. In the application, choose the desired soundscape using the horizontal toggle.

Select start run to begin. If using the app for the first time, press allow to permit the device logging of movement and location. Before each run, complete the onscreen questionnaires by pressing on the numbers corresponding to the current feeling experienced by the runner.

Use the up or down toggle to change the desired coupling ratio. Lock the toggle with the lock icon. Then toggle the voiceover feature with the interface toggle at the bottom right.

Set the sound tempo sliders to the desired step rate thresholds. After describing the user interface to the runner, fasten the device to the runner's body using a waist pack fitted firmly to the body. Click start run and begin running.

When the step sounds activate, listen closely and step to the beat. Then match inspiration and expiration precisely to the sound when the breathing guidance is activated. Encourage the runner to keep stepping at their own pace while the sounds adjust to their step rate.

Instruct the runner to breathe according to the breathing sounds. Continue stepping and breathing with the sounds for 30 to 60 seconds. Have the researcher and runner run together while playing the guidance sounds over a Bluetooth speaker to reinforce coupling fundamentals.

Use headphones during outdoor running to improve the delivery of the sound instructions and enable headphone controls on the application. During the run, change the coupling ratio and temporality using the toggles on the onscreen interface. After the run, press and run to stop the application.

A summary screen displays key metrics, including total distance, average pace and average step rate. Finally, download log files to access timestamped data of the run and application parameters. Running with LRC guidance greatly increased LRC adherence in 17 novice runners, exemplified by one participant's increase from 7.9%to 84.1%After a four week intervention, one participant's LRC increased from 39.7%to 53.4%resulting in a lower average breath rate and increased ventilatory efficiency.