Validation of the Polar Fitness Test for Estimation of Maximal Oxygen Consumption at Rest in Medically Supervised Exercise Training: Comparison with CPET and the 6-Minute Walk Test. - Neudorfer M; Ötzlinger L; Kumar D; Niebauer J; Smeddinck JD; Sareban M; Treff G (Sensors (Basel, Switzerland), 2025)