Validity of the garmin Forerunner 265 to predict VO2max and race performance times

Advances in fitness tracker technology have led to increased measurements and predictions of physiological variables, such as VO2max and race prediction times. These data can help develop personalized exercise programs. The validity of wrist-based fitness trackers to estimate VO2max is mixed, and studies have not yet investigated race performance prediction. It was hypothesized that Garmin-estimated VO2max and race prediction times would fall within the INTERLIVE Network's consumer-level acceptability threshold (MAPE <10%), with accuracy improving after 12 weeks of use. Twenty subjects participated in 12 weeks of half-marathon training, wore a Garmin Forerunner 265 for the training program, and ran a half-marathon race. Garmin watch estimates of VO2max and race performance predictions were compared to criterion measures using paired samples t-test. Significance was set at p < 0.05. The initial mean VO2max estimate from Garmin (43.95 ± 7.99 ml/kg/min) was significantly higher than the criterion max test (41.10 ± 8.02 ml/kg/min), p = 0.009. After 12-weeks of training, estimated VO2max from Garmin (45.00 ± 7.21 ml/kg/min) was significantly higher than criterion (42.43 ± 8.54 ml/kg/min), p=.007. Garmin's race predictions for the half-marathon (129.97 ± 18.29 min) were significantly faster than the official race times (137.55 ± 21.03 min), p=.003. Despite this, mean absolute percent error of VO2max and race prediction were below 10%, indicating the Garmin Forerunner 265 may be suitable for tracking general fitness trends.