摘要：Serum activities of creatine kin ase (CK) and lactate dehydrogenase (LDH) en zymes are used as markers of skeletal muscle cell dam age.There are fe w da ta about those effe cts at the aerobic (AT) an d the anaerobic (ANT) thresholds which areused to predict endu rance.Th ust it tυa s aim ed in this study to inve stig ate the effe cts of ste ad y-sta te treadmill running tes ts at the AT an d the ANT,perform ed by 13 well-trained male amateur soccer players (20.6 ± 1.7 yrs),on ser um CK a nd LDH activities.Ath letes ran fo r 45 m inflr st a t ATf then for 33∙8 (± 4.0) mins at 97.2% of the ANTf 48 h later.Fasting blood sam ples were withdrawn,10 min prior to the AT run (ATl)f fiv e minutes,an hour and 48 hfo llowing the test (AT2t AT3 an d A T4t respectively):an d similarly fo r the AN T test,10 min prior to,5 mint an hour an d 48 h follow ing it (ANTI,ANT2f ANT3 an d AN T4t respectively).Be sid es the CK an d LDH activities,serum total protein ∣TP)f albumin (Alb)t glucose (Glu)f creatinine (Cm) a nd urea nitrogen (BUN) concentrations were determined.Plasma volume changes we re calculated by using hemoglobin and hematocrit values at each sam pling to perform the neces sar y corrections.AT I and ANTI were sele cted as reference points.CK activity increased significantly (p<0∙01) at A T2t AT3f ANT2 and ANT3.While it decreased (p<0∙01) at AN Tlt it continued to increase (p<0.01) atANT4,LDH activity increased by the sam e amount of 6∙2 o∕o (p>0.05) at AT2 and ANT2f and further increased at AT3 (o∕o l4 ∙9 ) and ANT3 (%10∙4)∙ Peak serum CK and LDH activities which were reached after the ANTT test remained below those reached after the ATT.Other serum parameters behaved differently,though they were significantly increased ANT3.To conclude,total CK activities may be considered as a better criteria than LDH activities in assessin g exercise loads and durations in w ell trained soccer players.The fa ct that all parameters except C K and BUN returned to baseline levels 48h after both tests and remained in their normal ranges throughout the study may further indicate the aerobic nature o f both tests.
关键词：Aerobic threshold;anaerobic threshold;serum CK and LDH activities;blood chemistry
