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The release of muscle proteins after downhill running, which mainly includes eccentric muscle action, was compared i,I females (F: n=9) and males (M; n=9). The3 performed 20 mtn of downhill treadmill running with 16% decline with a target heart rate of 70% of the individual VO[sub2peak], which was determined two weeks before. Blood samples were drawn before, 6 and 24 h after exercise to measure plasma levels of skeletal troponin I (sTnl), myosin heavy chain fragments (MHC), creatine kinase (CK), and myoglobin (Mb). Baseline levels before exercise were significantly higher in males compared to females for the cytoplasmic proteins CK and Mb, but the difference for MHC and sTnl was not significant. Both groups displayed marked and significant early (6 h) increases (P<0.05) for sTnl (median: F: 8.2 μg/L: M: 22.0 μg/L), Mb (median: F: 86.8 μg/L; M: 407 μg/L), and CK (median: F: 162 U/ L: M: 339 U/L). A significant (P<.0.05) but delayed (24 h) increase was found for MHC (median: F: 482 μU/L; M: 651 &mug;U/L). The absolute values for all four parameters were significantly (P.-<0.05) higher in males compared to females; however, no difference was found for the relative increases and the time course of all parameters between females and males. We conclude 1) that there were no significant differences in the basal concentrations of predominantly bound proteins, and 2) that there were no differences in the relative muscle protein release between females and males before and after one round of high-intensive eccentric exercise. The higher plasma concentrations of all measured muscle proteins in males are probably caused by the higher muscle mass compared to females. [ABSTRACT FROM AUTHOR]

BACKGROUND: Objective of this study was to get more insight in hematology, biochemistry, and endocrinology of ultra-endurance exercise, to improve knowledge in this field, supplementation, and medical care of affected athletes. METHODS: A large body of individual hematological, biochemical, and endocrinological parameters was analyzed in the blood taken from ultra-athletes before and after completing the 1993 Colmar ultra triathlon covering 7.5 km swimming, 360 km cycling, and approximately 85 km running. PARTICIPANTS: Nine experienced ultra-athletes participated in the study. A follow-up was not possible since the athletes left Colmar within 24 hrs after the contest. RESULTS: The athletes finished the ultra-contest at rankings 4, 5, 7, 8, 9, 11, 18, 22, 23 in a total time between 23:38:53 and 27:54:30 hr:min:sec. Their final body mass (68.6 +/- 1 kg) was significantly lower than at baseline (71.9 +/- 4.2 kg). Non of the athletes made use of medical care. Data after this contest reflect mild hyponatremia, intravascular hemolysis, increased triglyceride turnover, acute-phase reaction, hyperaldosteronemia 2061 +/- 1013 pmol.L-1), hypercortisolemia 971 +/- 486 nmol.L-1), hyper-growth-hormonemia (median 6.8 ng.ml-1), hypoinsulinemia, hypo-free-testosteronemia (42 +/- 17 pmol.L-1), protein catabolism, depressed testicular function, oliguria, and muscle cell leakage. CONCLUSIONS: In our opinion, data presented do not reflect any acute health risks in healthy athletes who are well prepared and carefully supplied during such a contest. [ABSTRACT FROM AUTHOR]

Focuses on the clinical practice of exercise physiology. Determination of acute exercise responses in spinal cord injury (SCI); Loss of central-nervous-system-mediated organ function in SCI; Prevention of osteoporosis in women treated for cancer.