Platelet system changes associated with a training period of 18-20 months: a transverse and a longitudinal approach.

The effect of training for a 42-km run was investigated for the platelet count, the platelet distribution width (PDW), the mean platelet volume (MPV), and the plateletcrit (PCT). The measuring points were the start and 1 week before and 1 week after each contest (15, 25, and 42 km). For the starting position we reassessed the reference value for each platelet parameter. The results of all measuring points were compared transversely and longitudinally. As a result of the transverse approach, we found a significant decrease of the platelet count and of the MPV, which means a decrease of total thrombocytic clotting capacity with increasing training intensity. The longitudinal approach showed large intraindividual variations for all platelet parameters during the course of the study, expressed as high values for Nvar and CVp90.