ORIGINAL ARTICLES   

The Journal of Sports Medicine and Physical Fitness 1998 September;38(3):188-93

Copyright © 1999 EDIZIONI MINERVA MEDICA

language: English

Monitoring intensive endurance training at moderate energetic demands using resting laboratory markers failed to recognize an early overtraining stage

Gastmann U. ¹, Petersen K. G. ², Bocker J. ³, Lehmann M. ¹

¹ Department of Sports Medicine, University Medical Clinic, Ulm; ² Department of Endocrinology, University Clinic Freiburg, Freiburg, Germany; ³ Department of Clinical Biochemistry, University Clinic Freiburg, Freiburg, Germany

Back­ground. Aim was to ­answer the ques­tion ­whether ­resting labor­a­tory param­e­ters are suit­able for mon­i­toring inten­sive endu­rance ­training at mod­erate ener­getic ­demands. ­This was ­designed ­since ­markers of over­training at ­high ener­getic ­demands, ­e.g. mild ­anemia, leu­ko­penia, ­iron defi­ciency, ­reduced ­serum ­albumin, glu­cose, tri­gly­ce­ride, tri­gly­ce­ride-­rich cho­les­terol (LDL, ­VLDL), ­free ­fatty ­acid, ­increased ­plasma nor­a­dren­a­line ­levels, and ­decreased ­basal cat­e­chol­a­mine excre­tions ­were rec­om­mended.
­Methods. A pros­pec­tive 6-wk, 6-dys/wk inten­sive ­steady ­state and ­interval ­cycle ergom­eter ­training of 40-60 min/dy was per­formed. ­Total ­load was ­about 6-­time pre­training activ­ities fol­lowed by a 2-wk, 2-hour/wk regen­er­a­tive ­training ­period. Six rec­re­a­tional ath­letes (VO2max 51.5±4.5 ml·kg-1·min-1) par­tic­i­pated and fin­ished the ­study. A ­large pat­tern of ­resting hemat­o­log­ical, ­blood-chem­ical, and hor­monal param­e­ters was ­tested ­regarding suit­ability for mon­i­toring ­over­training.
­Results. ­After 3 wks, sub­max­imum and max­imum per­for­mance ­were sig­nif­i­cantly ­increased, ­stopped ­improving ­between wk 3 and 6, or dete­ri­orated. No super­com­pen­sa­tion ­occurred ­after regen­er­a­tion, but a ­decrease in ­work ­output. ­Lack of pro­gres­sion and super­com­pen­sa­tion, and ­decreased max­imum ­work ­output indi­cate a crit­ical ­stage in the ­training pro­cess.
Con­clu­sions. All exam­ined ­resting labor­a­tory param­e­ters ­failed to ­reflect ­this crit­ical ­stage ­except for a sig­nif­i­cant ­decrease in ­serum glu­cose, fer­ritin, and ­free ­fatty ­acid con­cen­tra­tions.