Research NoteReliability of Zephyr BioHarness Respiratory Rate at Rest, During the Modified Canadian Aerobic Fitness Test and RecoveryNazari, Goris1,2; MacDermid, Joy C.1,2Author Information 1Physical Therapy, Western University, London, Ontario, Canada; and 2Roth McFarlane Hand and Upper Limb Center, St. Joseph's Hospital, London, Ontario, Canada Address correspondence to Goris Nazari, firstname.lastname@example.org. Supplemental digital content is available for this article. Direct URL citations appear in the printed text and are provided in the HTML and PDF versions of this article on the journal's Web site (http://journals.lww.com/nsca-jscr). Journal of Strength and Conditioning Research: January 2020 - Volume 34 - Issue 1 - p 264–269 doi: 10.1519/JSC.0000000000003046 Buy SDC Metrics Abstract Nazari, G and MacDermid, JC. Reliability of Zephyr BioHarness respiratory rate at rest, during the modified Canadian Aerobic Fitness Test and recovery. J Strength Cond Res 34(1): 264–269, 2020—Technological innovations have led to the development of wearable physiological monitoring devices, such as the Zephyr BioHarness (ZB). It is necessary to establish the measurement properties of a device and to determine its reliability parameters, before its utilization. The purpose of current study was to determine the test-retest reliability of ZB respiratory rate variable at rest, during the modified Canadian Aerobic Fitness Test (mCAFT) (a submaximal test) and throughout recovery. Stratified convenience and snowballing were used to recruit 60 participants (30 females). Respiratory rate reliability was assessed at rest, with total of 20 measurements, during the mCAFT with total of 24 measures and throughout the recovery with total of 20 measures between the first and second sessions. At rest, test-retest respiratory rate intraclass correlation coefficients (ICCs) and SEM for ZB ranged from 0.76 to 0.84 (0.62–0.83). During the mCAFT, the ZB ICCs and (SEM) ranged from 0.76 to 0.89 (1.53–4.00). Throughout the recovery, the ICCs and SEM ranged from 0.79 to 0.90 (0.90–1.28). To conclude, ZB respiratory rate variable demonstrated excellent reliability measures in a large sample of healthy male and female individuals across different age groups at rest, during a submaximal activity and throughout recovery. Our study findings add to the existing pool of literature regarding the reliability parameters of ZB wearable device and propose that stable and consistent measures of respiratory rate can be obtained using ZB device among healthy male and female participants at rest, during submaximal activity (mCAFT) and throughout recovery. Copyright © 2020 by the National Strength & Conditioning Association.