Abstract des Autors

An endurance athlete's formula for success, hard training, may also, unfortunately, be the formula for demise. The apparent limitation to endurance exercise performance is the ability of the athlete to endure strenuous training in order to elicit positive adaptations without breakdown or maladaptation in any physiological system. Unfortunately, no model exists that can be used so that the overload training stimulus results in optimal improved performance while minimizing the potential to develop overreaching or the overtraining syndromes. These maladaptations are essentially an imbalance between stimulus and recovery. The universal finding, in overreached or overtrained athletes is a decrease in performance abillty. Accompanying signs and symptoms may be diffuse in nature resulting in generalized fatigue with or without a variety of specific physiological symptoms. Alternatively, a specific physiological system may break down, e.g., the breakdown of some aspect of the musculoskeletal system may result in an overuse syndrome such as a stress fracture. The boundary between hard training and overtraining is not clear. Individual variability in response to training is such that an appropriate training load for one athlete may cause the overtraining syndrome in another. Additionally, not all aspects of performance are affected simultaneously nor to the same degree. Identification of physiological markers prodromal to the overtraining syndrome in endurance athletes is likewise difficult. Some markers are seemingly contradictory, e.g., both increased and decreased resting heart rates have been reported in overtrained runners. Other overtrained athletes may lack specific symptoms, yet experience performance decrements and an inability to train at customary levels. Verf.-Referat