Serum hormone and myocellular protein recovery after intermittent runs at the velocity associated with VO2max

The responses of serum myocellular proteins and hormones to exercise were s tudied in ten well-trained middle-distance runners [maximal oxygen consumpt ion ((V) over dot O-2max) = 69.4 (5.1) ml . kg(-1) . min(-1)] during 3 reco very days and compared to various measures of physical performance. The pur pose was to establish the duration of recovery from typical intermittent mi ddle-distance running exercises. The subjects performed, in random? order t wo 28-min treadmill running exercises at a velocity associated with (V) ove r dot O-2max: 14 bouts of 60-s runs with 60 s of rest between each run (IR6 0) and 7 bouts of 120-s runs with 120 s of rest between each run (IR120). B efore the exercises (preexercise), 2 h after, and 1, 2 and 3 days after the exercises? the same series of measurements were performed, including those for serum levels of the myocellular proteins creatine kinase, myoglobin an d carbonic anhydrase III (S-CK, S-Mb and S-CA III, respectively), serum hor mones testosterone, Luteinizing hormone, follicle-stimulating hormone and c ortisol (S-testosterone, S-LH, S-FSH and S-cortisol, respectively) and vari ous performance parameters: maximal vertical jump height (CMJ) and stride l ength, heart rate and ratings of perceived exertion during an 8-min run at 15 km . h(-1) (SL15 km (.) (h-1), HR15 km (.) (h-1) and RPE15 km . h-1, res pectively). Two hours after the end of both exercise bouts the concentratio n of each measured serum protein had increased significantly (P < 0.001) co mpared to the pre-exercise level, but there were no changes in SL15 km . h- 1 or CMJ. During the recovery days only S-CK was significantly raised (P < 0.01), concomitant with a decrease in CMJ (P < 0.01) and an increase in RPE 15km . h-1 (P < 0.01). Hormone levels remained unchanged compared to the pr e-exercise levels during the recovery days and there were no significant di fferences between the two exercise bouts in any of the observed post-exerci se day-to-day responses. With the exception of S-CK, after IR120 the post-e xercise responses returned to their pre-exercise levels within the 3 days o f recovery. The present findings suggest that a single 28-min intermittent middle-distance running exercise does not induce changes in serum hormones of well-trained runners during recovery over 3 days, while changes in S-CK, CMJ and RPE15 km . h-1 indicate that 2-3 days of light training may be nee ded before the recovery at muscle level is complete.