A Systematic Review of Fitness Apps and Their Potential Clinical and Sports Utility for Objective and Remote Assessment of Cardiorespiratory Fitness

Key Points The validity and reliability of existing and/or underdevelopment fitness apps should be further investigated. Physiological signals should be incorporated into fitness apps, such as heart rate measures using a smartphone camera, during or after exercise testing. There is a need to develop interoperable fitness apps (e.g., different languages, apps integrated into both app markets, data that is device-independent). Fitness apps should incorporate evidence-based cutpoints of CRF, allowing interpretation of fitness testing resultsWe are grateful to Ms Carmen Sainz-Quinn for assistance with the English language.Background Cardiorespiratory fitness (CRF) assessment provides key information regarding general health status that has high clinical utility. In addition, in the sports setting, CRF testing is needed to establish a baseline level, prescribe an individualized training program and monitor improvement in athletic performance. As such, the assessment of CRF has both clinical and sports utility. Technological advancements have led to increased digitization within healthcare and athletics. Nevertheless, further investigation is needed to enhance the validity and reliability of existing fitness apps for CRF assessment in both contexts. Objectives The present review aimed to (1) systematically review the scientific literature, examining the validity and reliability of apps designed for CRF assessment; and (2) systematically review and qualitatively score available fitness apps in the two main app markets. Lastly, this systematic review outlines evidence-based practical recommendations for developing future apps that measure CRF. Data Sources The following sources were searched for relevant studies: PubMed, Web of Science®, ScopusTM, and SPORTDiscus, and data was also found within app markets (Google Play and the App Store). Study Eligibility Criteria Eligible scientific studies examined the validity and/or reliability of apps for assessing CRF through a field-based fitness test. Criteria for the app markets involved apps that estimated CRF. Study Appraisal and Synthesis Methods The scientific literature search included four major electronic databases and the timeframe was set between 01 January 2000 and 31 October 2018. A total of 2796 articles were identified using a set of fitness-related terms, of which five articles were finally selected and included in this review. The app market search was undertaken by introducing keywords into the search engine of each app market without specified search categories. A total of 691 apps were identified using a set of fitness-related terms, of which 88 apps were finally included in the quantitative and qualitative synthesis. Results Five studies focused on the scientific validity of fitness tests with apps, while only two of these focused on reliability. Four studies used a sub-maximal fitness test via apps. Out of the scientific apps reviewed, the SA-6MWTapp showed the best validity against a criterion measure (r = 0.88), whilst the InterWalk app showed the highest test–retest reliability (ICC range 0.85–0.86). Limitations Levels of evidence based on scientific validity/reliability of apps and on commercial apps could not be robustly determined due to the limited number of studies identified in the literature and the low-to-moderate quality of commercial apps. Conclusions The results from this scientific review showed that few apps have been empirically tested, and among those that have, not all were valid or reliable. In addition, commercial apps were of low-to-moderate quality, suggesting that their potential for assessing CRF has yet to be realized. Lastly, this manuscript has identified evidence-based practical recommendations that apps might potentially offer to objectively and remotely assess CRF as a complementary tool to traditional methods in the clinical and sports settings

Implementation of interval walking training in patients with type 2 diabetes in Denmark: rationale, design, and baseline characteristics

Mathias Ried-Larsen,1–3 Reimar W Thomsen,2,4 Klara Berencsi,4 Cecilie F Brinkløv,1,5 Charlotte Brøns,1,5 Laura S Valentiner,1,6 Kristian Karstoft,1,3 Henning Langberg,1,6 Allan A Vaag,1,2,5 Bente K Pedersen,1,3 Jens S Nielsen7 1Department of Infectious Diseases, Centre for Physical Activity Research, Rigshospitalet, University of Copenhagen, Copenhagen, 2The Danish Diabetes Academy, Odense University Hospital, Odense, 3Department of Infectious Diseases, Centre of Inflammation and Metabolism, Rigshospitalet, University of Copenhagen, Copenhagen, 4Department of Clinical Epidemiology, Aarhus University Hospital, Aarhus Nord, 5Department of Endocrinology (Diabetes and Metabolism), Rigshospitalet, University of Copenhagen, 6CopenRehab, Department of Public Health, Section of Social Medicine, University of Copenhagen, Copenhagen, 7Department of Endocrinology, Odense University Hospital, Odense, Denmark Abstract: Promoting physical activity is a first-line choice of treatment for patients with type 2 diabetes (T2D). However, there is a need for more effective tools and technologies to facilitate structured lifestyle interventions and to ensure a better compliance, sustainability, and health benefits of exercise training in patients with T2D. The InterWalk initiative and its innovative application (app) for smartphones described in this study were developed by the Danish Centre for Strategic Research in T2D aiming at implementing, testing, and validating interval walking in patients with T2D in Denmark. The interval walking training approach consists of repetitive 3-minute cycles of slow and fast walking with simultaneous intensity guiding, based on the exercise capacity of the user. The individual intensity during slow and fast walking is determined by a short initial self-conducted and audio-guided fitness test, which combined with automated audio instructions strives to motivate the individual to adjust the intensity to the predetermined individualized walking intensities. The InterWalk app data are collected prospectively from all users and will be linked to the unique Danish nationwide databases and administrative registries, allowing extensive epidemiological studies of exercise in patients with T2D, such as the level of adherence to InterWalk training and long-term effectiveness surveys of important health outcomes, including cardiovascular morbidity and mortality. Currently, the InterWalk app has been downloaded by >30,000 persons, and the achieved epidemiological data quality is encouraging. Of the 9,466 persons providing personal information, 80% of the men and 62% women were overweight or obese (body mass index ≥25). The InterWalk project represents a contemporary technology-driven public health approach to monitor real-life exercise adherence and to propagate improved health through exercise intervention in T2D and in the general population. Keywords: exercise, telemedicine, cell phone