Individually guided training prescription by heart rate variability and self-reported measure of stress tolerance in recreational runners: Effects on endurance performance.

The aim of this study was to determine the effect of endurance training individually guided by objective (Heart Rate Variability-HRV) or self-report measure of stress (DALDA-questionnaire) in comparison to predefined endurance training prescription for improving endurance performance in recreational runners. After a 2-week preliminary baseline period to establish resting HRV and self-reported measure of stress, thirty-six male recreational runners were randomly assigned to HRV-guided (G HRV; n  = 12), DALDA-guided (G D ; n  = 12) or predefined training (G T ; n  = 12) prescription groups. Before and after 5-weeks of endurance training, participants performed a track field peak velocity (V peak_TF ), time limit (T lim ) at 100% of V peak_TF and 5 km time-trial (5 km TT) tests. G D lead to higher improvements in V peak_TF (8.4 ± 1.8%; ES = 1.41) and 5 km TT (-12.8 ± 4.2%; ES = -1.97), than G HRV (6.6 ± 1.5% and -8.3 ± 2.8%; ES = -1.20; 1.24) and G T (4.9 ± 1.5% and -6.0 ± 3.3%; ES = -0.82; 0.68), respectively, with no differences for T lim . Self-report measures of stress may be used to individualize endurance training prescription on a daily basis leading to better performance enhancement, which may be used with HRV for a holistic understanding of daily training-induce adaptations.