Author(s): SCHLIE, J., HEIBER, M., SCHITTENHELM, A., BECKERT, M., GRAF, P., SCHMIDT, A., Institution: UNIVERSITY OF THE BUNDESWEHR MUNICH, Country: GERMANY, Abstract-ID: 388

INTRODUCTION:
The lactate threshold (LT) is a critical performance measure traditionally obtained using costly laboratory-based tests. Wearables offer a practical and noninvasive alternative for LT assessment in recreational and professional athletes. However, the comparability of these estimates with the regular field tests requires further evaluation.
METHODS:
In our sample of 26 participants (nf=7 and nm=19), we compared the estimated running pace and heart rate (HR) at LT with two subsequent tests. First, participants performed the Fenix 7® threshold running test after a calibration phase. Subsequently, they were tested in a standardized, graded blood lactate field test. Age was 25.97 (± 6.26) years, body mass index (BMI) was 24.58 (± 2.8) kg/m2. After the calibration phase, pace and HR at LT were obtained using the Fenix 7® threshold running test. Subsequently, participants underwent a graded blood lactate field test.
RESULTS:
Pace at LT calculated by Fenix 7® (M=11.87 km/h ± 1.26 km/h) was 11,8 % lower compared to the field test (M=13.28 km/h ± 1.72 km/h), which was significant (p <.001, d=-1.19). HR estimated by the Fenix 7® at LT was 1,72 % lower (p >.05). LT data obtained in the field test showed greater overall variance.
CONCLUSION:
Our results suggest sufficient accuracy of Fenix 7® LT estimates for recreational athletes. It can be assumed that for professional athletes, it would fail to provide the nuanced data needed for high-quality training management.