title: Concentrically trained cyclists are not more susceptible to eccentric exercise-induced muscle damage than are stretch-shortening exercise-trained runners.
abstract: Here, we test the hypothesis that continuous concentric exercise training renders skeletal muscles more susceptible to damage in response to eccentric exercise. Elite road cyclists (CYC; n = 10, training experience 8.1 ± 2.0 years, age 22.9 ± 3.7 years), long-distance runners (LDR; n = 10, 9.9 ± 2.3 years, 24.4 ± 2.5 years), and healthy untrained (UT) men (n = 10; 22.4 ± 1.7 years) performed 100 submaximal eccentric contractions at constant angular velocity of 60° s(-1). Concentric isokinetic peak torque, isometric maximal voluntary contraction (MVC), and electrically induced knee extension torque were measured at baseline and immediately and 48 h after an eccentric exercise bout. Muscle soreness was assessed and plasma creatine kinase (CK) activity was measured at baseline and 48 h after exercise. Voluntary and electrically stimulated knee extension torque reduction were significantly greater (p < 0.05) in UT than in LDR and CYC. Immediately and 48 h after exercise, MVC decreased by 32 % and 20 % in UT, 20 % and 5 % in LDR, and 25 % and 6 % in CYC. Electrically induced 20 Hz torque decreased at the same times by 61 and 29 % in UT, 40 and 17 % in LDR, and 26 and 14 % in CYC. Muscle soreness and plasma CK activity 48 h after exercise did not differ significantly between athletes and UT subjects. In conclusion, even though elite endurance athletes are more resistant to eccentric exercise-induced muscle damage than are UT people, stretch-shortening exercise-trained LDR have no advantage over concentrically trained CYC.
authors.affiliation: Research Center for Fundamental and Clinical Movement Science, Lithuanian Academy of Physical Education, Sporto 6, 44221 Kaunas, Lithuania. a.snieckus@gmail.com
authors.forename: Audrius
authors.initials: A
authors.lastname: Snieckus
authors.forename: Sigitas
authors.initials: S
authors.lastname: Kamandulis
authors.forename: Tomas
authors.initials: T
authors.lastname: Venckūnas
authors.forename: Marius
authors.initials: M
authors.lastname: Brazaitis
authors.forename: Gintautas
authors.initials: G
authors.lastname: Volungevičius
authors.forename: Albertas
authors.initials: A
authors.lastname: Skurvydas
mesh_terms: D000328:Adult; D001642:Bicycling / Q000293:injuries*; D004558:Electric Stimulation; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D018763:Muscle Fatigue / Q000502:physiology; D018482:Muscle, Skeletal / Q000293:injuries*; D009135:Muscular Diseases / Q000209:etiology*; D059385:Plyometric Exercise; D016059:Range of Motion, Articular / Q000502:physiology*; D012420:Running / Q000293:injuries*; D019415:Torque; D055815:Young Adult