摘要:International Journal of Exercise Science 12(4): 69-76, 2019. The Polar T31 uncoded heart rate monitor (T31) is currently accepted as a precision measurement device that can be used in lieu of electrocardiography. However, minimal literature exists to verify reliability when used for this purpose. The purpose of this study is to evaluate the reliability of heart rate (HR) measurements obtained from the T31. Forty volunteers participated in a three-day test-retest protocol. Participants gave anthropometric data on the first day. On the second day, they performed two 5-minute self-paced free motion walks (FMW) and two 5-minute self-paced free motion jogs (FMJ). Finally, on the third day, they performed two 5-minute treadmill walks (TW) and two 5-minute treadmill jogs (TJ). Treadmill speeds for each TW and TJ were determined by the distances traveled during the FMWs and FMJs on day 2. HR values at rest (HRR) and while in motion (minutes 1-5) were evaluated (HRM). Values calculated used Cronbach’s α (≥0.70) for reliability with significance accepted at p<0.05. FMW HRR (all, α=0.96; male, α=0.97; female, α=0.94), FMJ HRR (all, α=0.98; male, α=0.98; female, α=0.99), TW HRR (all, α=0.96; male; α=0.92; female, α=0.98), TJ HRR (all, α=0.97; male, α=0.98; female, α=0.96), FMW HRM (all, α=0.93; male, α=0.93; female, α=0.91), FMJ HRM (all, α=0.93; male, α=0.94; female, α=0.90), TW HRM (all, α=0.95; male, α=0.92; female, α=0.95), TJ HRM (all, α=0.94; male, α=0.95; female, α=0.92). All p-values < 0.001. The T31 provided reliable measures at rest and for walking and jogging in both a free motion and treadmill setting.