Many Alerts, Few Injuries: Alert Burden and Yield of Common Training-Load and Wellness Rules in Elite Women's Football

Athlete monitoring systems often turn training-load and wellness data into simple alerts, but little is known about how many alerts these rules produce or how often an alert is followed by injury.This study applied four common rules to two seasons of self-reported data from two elite Norwegian women's football teams (SoccerMon dataset; 50 players, 2020-2021): an acute:chronic workload ratio (ACWR) above 1.5, a week-to-week load increase above 15%, a wellness z-score of -1.5 or lower, and training monotony above 2.0.Alert burden was expressed as new alerts per week for a 25-player squad, and alert yield as the percentage of new alerts followed by a self-reported injury within 7 days (29 monitored injury onsets in 11 players).The weekly-load rule fired on 35% of eligible days and produced a median of 16.4 new alerts per squad-week; the other rules produced about 3.5 each.Only 0.2-1.2% of new alerts were followed by an injury report, close to the 0.9% baseline on any monitored day, and confidence intervals were wide.Simple rules therefore created a substantial workload for staff, while no rule's yield was clearly above the baseline in this sample.