Concurrent Validity and Reliability of Average Heart Rate and Energy Expenditure of Identical Garmin Instinct Watches During Low Intensity Resistance Training

ABSTRACT Wearable technology and resistance training are two of the top five worldwide fitness trends for 2022 as determined by ACSM. Many devices, such as Garmin’s Instinct, have functions to track various physiological aspects during resistance training. However, to our knowledge, independent verification of the validity and reliability of these devices for estimating average heart rate (HR) and energy expenditure (EE) during resistance training are nonexistent. PURPOSE: To determine the concurrent validity and reliability of identical Garmin Instinct watches during resistance training. METHODS: Twenty subjects (n=10 female and male; age: 23.2±7.7 years; height: 169.7±11.1; weight: 76.3±15.7 kg) completed this study. Two Garmin Instinct watches were evaluated, along with the Polar H10 chest strap and Cosmed K5 portable metabolic unit as the criterion devices for average HR and EE, respectively. Subjects completed 4 circuits of 4 exercises (front squat, reverse lunge, push-ups, and shoulder press) using dumbbells at a light intensity with 1 set of 10 repetitions per exercise, 30 seconds rest between exercises, and 1-1.5 min. rest between circuits. Data were analyzed for validity (Mean Absolute Percent Error [MAPE] and Lin’s Concordance Coefficient [CCC]) and reliability (Coefficient of Variation [CV]), with predetermined thresholds of MAPE0.70, and CVRESULTS: Garmin Instinct 1 and Instinct 2 were significantly (