[Objectivity, validity and reliability of determination of recovery times following exhaustion trials in heavy dynamic muscle work from time series of heart rate].

Records of heart rate after 152 experiments with exhaustion of three male subjects were rated by three experts to determine the end of the recovery phase. Inter-rater-reliability of recovery times vary between 0.87-0.97 according to the method of calculation. An algorithm for the identification of the end of recovery is developed by approximation of the expert-ratings. The corresponding rater-reliability of the algorithm is 0.9. A stepwise multiple regression shows, that most of the variance of recovery times is explained by heart rate at the end of the working phase (63.8%) and by the conditions of the rest phase (18.9%), whereas the stress conditions in the working phase, as type (10.6%), level (20%) and duration (0%) of stressors are concerned, have less explanatory value. These results differ from the literature. The differences are discussed with respect to different criteria for "fatigue" and "recovery".