title: Dynamics of indirect symptoms of skeletal muscle damage after stretch-shortening exercise.
abstract: Healthy untrained men (age 20.4+/-1.7 years, n=20) volunteered to participate in an experiment in order to establish dynamics of indirect symptoms of skeletal muscle damage (ISMD) (decrease in maximal isometric voluntary contraction torque (MVCT) and torque evoked by electrostimulation at different frequencies and at different quadriceps muscle length, height (H) of drop jump (DJ), muscle soreness and creatine kinase (CK) activity in the blood) after 100 DJs from 0.75 m height performed with maximal intensity with an interval of 20s between the jumps (stretch-shortening exercise, SSE). All ISMDs remained even 72 h after SSE (P<0.01-0.001). The muscle experienced greater decrease (P<0.01) in torque evoked by electrostimulation (at low stimulation frequencies and at short muscle length in particular) after SSE than neuromuscular performance (MVCT and H of DJ) which demonstrated secondary decrease (P<0.01) in neuromuscular performance during the first 48 h after SSE. Within 24-72 h after the SSE the subjects felt an acute muscle pain (5-7 points approximately) and the CK activity in the blood was significantly increased up to 1200 IU/L (P<0.001). A significant correlation between decrease in MVCT and H of DJ 24-48 h after SSE on the one hand and muscle soreness registered within 24-48 h after SSE on the other was observed, whereas correlation between the other indirect symptoms of skeletal muscle damage was not significant.
authors.affiliation: Laboratory of Human Motorics, Lithuanian Academy of Physical Education, Sporto 6, LT 44221 Kaunas, Lithuania. a.skurvydas@lkka.lt
authors.forename: Albertas
authors.initials: A
authors.lastname: Skurvydas
authors.forename: Saule
authors.initials: S
authors.lastname: Sipaviciene
authors.forename: Grazina
authors.initials: G
authors.lastname: Krutulyte
authors.forename: Alina
authors.initials: A
authors.lastname: Gailiuniene
authors.forename: Arvydas
authors.initials: A
authors.lastname: Stasiulis
authors.forename: Gediminas
authors.initials: G
authors.lastname: Mamkus
authors.forename: Aleksas
authors.initials: A
authors.lastname: Stanislovaitis
mesh_terms: D000208:Acute Disease; D000328:Adult; D000704:Analysis of Variance; D015415:Biomarkers / Q000097:blood; D003402:Creatine Kinase / Q000097:blood; D004558:Electric Stimulation; D006339:Heart Rate; D006801:Humans; D007537:Isometric Contraction; D008297:Male; D018763:Muscle Fatigue; D052580:Muscle Stretching Exercises / Q000009:adverse effects*; D009135:Muscular Diseases / Q000097:blood / Q000503:physiopathology*; D010146:Pain / Q000097:blood / Q000503:physiopathology; D010807:Physical Endurance; D052097:Quadriceps Muscle / Q000378:metabolism / Q000503:physiopathology; D012026:Reflex, Stretch; D019415:Torque
chemical_list: D015415:Biomarkers; D003402:Creatine Kinase