Associations Between an Individualized Heart Rate-Based Training Index and Mood States in Elite Female Kendo Athletes: An Exploratory Field Study

Athlete monitoring commonly includes subjective questionnaires such as the Profile of Mood States, which may be influenced by individual perceptions and situational factors. This one-week exploratory field study examined associations between Persist, an individualized wearable-derived behavioral–physiological measure, and mood states in seven elite female kendo athletes. Before the monitoring period, the heart rate corresponding to the point at which each athlete perceived exercise intensity as “somewhat hard” was individually determined using the rating of perceived exertion. Heart rate and training duration were recorded during kendo training sessions over one week using a wrist-worn wearable device. Mood states were assessed using the Profile of Mood States 2nd Edition (POMS 2). Persist showed a negative association with Fatigue–Inertia in the unadjusted analysis (rs = −0.847, p = 0.016), but this association did not remain statistically significant after Holm correction for multiple comparisons (adjusted p = 0.162). These preliminary findings indicate a possible association between Persist and fatigue-related mood states; however, larger repeated-measures studies are required to evaluate its validity and potential utility for athlete monitoring.