UNACCUSTOMED HIGH-MILEAGE VS INTENSITY TRAINING-RELATED CHANGES IN PERFORMANCE AND SERUM AMINO-ACID LEVELS

To test the overtraining-related ''imbalanced amino acid hypothesis'' (19), the influence of an unaccustomed average 103 %. 4 wk(-1) increas e in training mileage (ITV) on performance and on serum levels of indi vidual amino acids (AAs) was examined in distance runners and controll ed by an unaccustomed average 152 %. 4 wk(-1) increase in tempo-pace a nd interval runs (ITI). Two mmol . l(-1) lactate performance (2 LP) in creased, 4 LP stagnated and total running distance (TD) decreased in t he incremental test during ITV - which may indicate an ITV-dependent o vertraining - in contrast to an I'll-related increase in 2 LP, 4 LP an d TD. The summed serum AAs decreased in In, (2744 +/- 534 vs 2933 +/- 663 umol . l(-1); p <0.05) in contrast to an ITI-related increase (354 1 +/- 657 vs 3252 +/- 885 umol . l(-1); p < 0.05) with an average 29 % higher final summed AAs concentration during ITI (p <0.05). During IT V 12 individual AAs decreased by 6-17 %, 8 remained constant and 3 inc reased (Cys. Met, fTrp) by 6-19 %, as opposed to an ITI-related increa se in 16 AA by 6-55%. The observed ITV-related changes in serum AAs pr ofile were smaller than after completing contests as a marathon, a 100 km-run or an ultra-triathlon. It may be concluded that the observed s mall changes in AAs profile or AAA/BCAA and AA/LNAA ratios only repres ent an epiphenomenon without recognizable influence on incremental tes t performance, since increases in fTrp/LNAA ratios (+ 28 % in ITV vs 45 % in ITI) were found to be related both to performance impairment (ITV) and improvement (ITI).