ORIGINAL ARTICLES   

The Journal of Sports Medicine and Physical Fitness 1998 March;38(1):10-7

Copyright © 1998 EDIZIONI MINERVA MEDICA

language: English

Effects of prolonged strenuous endurance exercise on plasma myosin heavy chain fragments and other muscular proteins. Cycling vs running

Koller A. ¹, Mair J. ², Schobersberger W. ³, Wohlfarter Th. ⁴, Haids Ch. ⁵, Mayr M. ², Villiger B. ⁶, Frey W. ⁶, Puschendorf B. ²

¹ Department of Sports Medicine, University of Innsbruck, Austria; ² Department of Medical Chemistry and Biochemistry, University of Innsbruck, Austria; ³ Clinic for Anaesthesia and General Intensive Care Medicine, University of Innsbruck, Austria; ⁴ Department of Internal Medicine, University of Innsbruck, Austria; ⁵ Department of Orthopaedic Surgery, University of Innsbruck, Austria; ⁶ Thurgauisch-Schaffhausische, Höhenklinik Davos, Switzerland

Background. This ­study eval­u­ates crea­tine ­kinase, myo­sin ­heavy ­chain, and car­diac tro­po­nin ­blood lev­els fol­low­ing ­three ­types of exer­cise: 1) ­short-dis­tance ­uphill or down­hill run­ning; 2) ­alpine ultra­mar­a­thon; and 3) ­alpine ­long-dis­tance ­cycling.
Methods. Experimental ­design: Comparative ­field ­study; fol­low-up up to 10 ­days. Setting: Department of Sports Medicine. All bio­chem­i­cal mark­ers ­were ana­lysed at the Department of Medical Chemistry and Biochemistry. Patients or par­tic­i­pants: Subjects includ­ed ­healthy, ­trained ­males (N=53). All sub­jects ­were non­smok­ers and ­free ­from med­i­ca­tion ­prior to and dur­ing the ­study. Each vol­un­teer was an expe­ri­enced run­ner or ­cyclist, who had at ­least ­once suc­cess­ful­ly fin­ished the Swiss Alpine Marathon of Davos or the Ötztal-Radmarathon ­before. Interventions: Running or ­cycling. Measures: Plasma con­cen­tra­tions of crea­tine ­kinase, myo­sin ­heavy ­chain frag­ments and car­diac tro­po­nins ­were meas­ured to diag­nose skel­e­tal and car­diac mus­cle dam­age, respec­tive­ly.
Results. Skeletal mus­cle pro­tein ­release is mark­ed­ly dif­fer­ent ­between ­uphill and down­hill run­ning, ­with ­very lit­tle evi­dence for mus­cle dam­age in the ­uphill run­ners. There is con­sid­er­able mus­cle pro­tein leak­age in the ultra­mar­a­thon­ers (67 km dis­tance; 30 km down­hill run­ning). In con­trast, ­only mod­est ­amounts of skel­e­tal muscle dam­age are ­found ­after ­alpine ­long- di­stance ­cycling (230 km dis­tance).
Conclusions. This ­study ­proves ­that ­there is ­slow-­twitch skel­e­tal mus­cle ­fiber dam­age ­after pro­longed stren­u­ous endu­rance exer­cise and ­short-dis­tance down­hill run­ning. Exhaustive endu­rance exer­cise involv­ing down­hill run­ning and ­short-dis­tance down­hill run­ning ­lead to ­more pro­nounced inju­ry ­than stren­u­ous endu­rance exer­cise involv­ing con­cen­tric ­actions. From our ­results ­there is no rea­son for sug­gest­ing ­that pro­longed ­intense exer­cise may ­induce myo­car­dial inju­ry in symp­tom­less ath­letes with­out car­diac deseas­es.