Daily life is becoming increasingly sedentary, and physical inactivity is a global pandemic. Applications and wearables have great potential as tools to promote and increase the levels of daily physical activity (23). Although the use of this technology is a promising alternative to combat inactivity, the efficacy of this approach remains to be determined. In a recent multidisciplinary review of 111 studies (24), less than one third were optimized for effectiveness, engagement, and acceptability and the review concluded that guidelines were needed to facilitate the synthesis of evidence across disciplines.
The potential to measure almost every foreseeable parameter with a wearable device is real. However, not every parameter is practical for either the recreational or competitive athlete (17). Using the prior Rugby Union example, monitoring the covered distance during match play and/or training using GNSS may provide some interesting information but knowing the covered distance per se is unlikely to optimize performance and/or reduce the likelihood of injuries. There are increased efforts to understand the relationship between covered distances in different intensity zones and the likelihood of injury (25–28). In this context, it is important not to confuse the association between a parameter (in this case the covered distance) and an outcome (in this case the likelihood of injury) with the predictive power of a parameter as it was shown that despite being associated, parameters are not always good for prediction (29,30).
Research to develop evidence-based algorithms that support the use of specific parameters to predict injuries and potentially aid in injury prevention is needed. It is important to investigate the interaction between monitored parameters and aspects of performance and/or health that wearables may detect. Collaborative efforts between sport practitioners, engineers, data analysts, sports medicine personnel, and other relevant groups will form a science base for the application of this technology. Easy access to raw data from wearable devices would speed advances and benefit the athlete, scientific community, manufacturer, and practitioner. Wearable companies typically work in isolation to safeguard their intellectual property. In the future, if wearable companies are to become more evidence-based in their approach, they will need to develop multidisciplinary teams that place greater value on research and development.
Quality control of the hardware and the data generated is crucial for wearables to improve athlete performance and health. While there are many wearables that claim to deliver reliable and valid data to the user (31,32), few wearables have had rigorous independent testing (1). Independent research institutions should at least test for the validity and reliability of wearable technology before releasing the products on the market (1,33). Recommendations exist for the assessment of reliability, sensitivity, and validity of data provided by wearables (34). Hardware also should be tested to reduce the risk of harm to the user. Third party, independently verified quality assurance, durability (battery life), survivability (water resistance), and data protection would significantly enhance a products reputation and potential use (35,36). Good quality control of the hardware, the safety, and privacy of the data would increase the reliability of the data generated and improve the comparison between devices.
Wearables need to be simple and time-efficient for a high level of compliance and usage (33). Monitoring simple subjective data (e.g., ratings of perceived exertion) can be done with a touch interface and advancements in speech and voice recognition allow more complex data to be gathered verbally (37). Collaboration with athletes is needed to determine the most suitable form of instant feedback, that is, what information do they need to know to improve performance while not being distracted from their surroundings. Regardless of the presentation medium (e.g., smartwatch, smartphone, "hearables," etc.), the information needs to be in an informative and easily understandable format (38). This is critical, especially when the slightest distraction may decrease performance in disciplines where concentration is paramount to success (e.g., Formula 1, MotoGP, cycling, and skiing) and participant safety. In the future, biofeedback that is not provided instantly could possibly be provided in a virtual reality environment allowing the athlete to receive the feedback and implement strategies to improve aspects of performance (39). Future studies are needed to evaluate the most useful and suitable form of feedback for different athletic tasks and disciplines and to present the data in an understandable and attractive format (38).
To enhance high-level performance, a variety of multiple wearables will likely need to be connected to gather the relevant data within a single database for interpretation. Data that are standardized and easy to share will enhance and facilitate collaboration and big data analytics may identify new relationships between the parameters measured, further enhancing sports performance and health (1,40,41). Developing such large databases and the algorithms they may produce will require the collaborative effort of data service providers, exercise scientists, athletes, and data analysts to generate meaningful and useful information. The motivation to use wearables varies between the populations using them. However, if production of the device is not sustainable and the data is not reliable, valid and/or actionable, no one will ever benefit from this technology.
In the future, athletes will have the option to use an increasing number of wearables and each new device should add beneficial information to the training process with the goal of helping sports scientists and health care providers improve their athlete’s or patient’s performance and/or health. Sharing data and knowledge between the athletes, exercise scientists, hardware and software engineers, and other stakeholders has the potential to improve wearable devices and technology for competitive athletes.
PD is an employee of Wearable Technologies AG which is active in consulting to companies and in hosting events specific to the wearable market. CS is the CEO of Wearable Technologies AG. YP is the founding member of the Sub2 project.
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