title: Mechanisms underpinning protection against eccentric exercise-induced muscle damage by ischemic preconditioning.
abstract: Eccentric exercise training is effective for increasing muscle mass and strength, and improving insulin sensitivity and blood lipid profiles. However, potential muscle damage symptoms such as prolonged loss of muscle function and delayed onset of muscle soreness may restrict the use of eccentric exercise, especially in clinical populations. Therefore, strategies to reduce eccentric exercise-induced muscle damage (EIMD) are necessary, and an extensive number of scientific studies have tried to identify potential intervention modalities to perform eccentric exercises without adverse effects. The present paper is based on a narrative review of current literature, and provides a novel hypothesis by which an ischemic preconditioning (IPC) of the extremities may reduce EIMD. IPC consists of an intermittent application of short-time non-lethal ischemia to an extremity (e.g. using a tourniquet) followed by reperfusion and was discovered in clinical settings in an attempt to minimize inflammatory responses induced by ischemia and ischemia-reperfusion-injury (I/R-Injury) during surgery. The present hypothesis is based on morphological and biochemical similarities in the pathophysiology of skeletal muscle damage during clinical surgery and EIMD. Even though the primary origin of stress differs between I/R-Injury and EIMD, subsequent cellular alterations characterized by an intracellular accumulation of Ca2+, an increased production of reactive oxygen species or increased apoptotic signaling are essential elements for both. Moreover, the incipient immune response appears to be similar in I/R-Injury and EIMD, which is indicated by an infiltration of leukocytes into the damaged soft-tissue. Thus far, IPC is considered as a potential intervention strategy in the area of cardiovascular or orthopedic surgery and provides significant impact on soft-tissue protection and downregulation of undesired excessive inflammation induced by I/R-Injury. Based on the known major impact of IPC on skeletal muscle physiology and immunology, the present paper aims to illustrate the potential protective effects of IPC on EIMD by discussing possible underlying mechanisms.
authors.affiliation: Institute of Anatomy I, Heinrich Heine University Medical School Duesseldorf, Germany. Electronic address: alexander.franz@hhu.de.
authors.forename: Alexander
authors.initials: A
authors.lastname: Franz
authors.affiliation: Institute of Training Science and Sports Informatics, German Sport University Cologne, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Behringer
authors.affiliation: School of Medical and Health Sciences, Edith Cowan University Joondalup, WA, Australia.
authors.forename: Kazunori
authors.initials: K
authors.lastname: Nosaka
authors.affiliation: Institute of Training Science and Sports Informatics, German Sport University Cologne, Germany.
authors.forename: Bettina Alexandra
authors.initials: BA
authors.lastname: Buhren
authors.affiliation: Department of Orthopedics, University Hospital Duesseldorf, Germany.
authors.forename: Holger
authors.initials: H
authors.lastname: Schrumpf
authors.affiliation: Department of Orthopedics, University Hospital Duesseldorf, Germany.
authors.forename: Constantin
authors.initials: C
authors.lastname: Mayer
authors.affiliation: Department of Orthopedics, University Hospital Duesseldorf, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Zilkens
authors.affiliation: Exercise, Health and Technology Center, Shanghai Jiao Tong University Shanghai, China; Department of Molecular and Cellular Sports Medicine, German Sport University Cologne, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Schumann
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D017209:Apoptosis; D002118:Calcium / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D006706:Homeostasis; D006801:Humans; D007249:Inflammation; D019194:Ischemic Preconditioning / Q000379:methods*; D007962:Leukocytes / Q000166:cytology; D008055:Lipids / Q000737:chemistry; D018482:Muscle, Skeletal / Q000503:physiopathology*; D009135:Muscular Diseases / Q000503:physiopathology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015427:Reperfusion Injury / Q000517:prevention & control; D015398:Signal Transduction
chemical_list: D000975:Antioxidants; D008055:Lipids; D017382:Reactive Oxygen Species; D002118:Calcium
keywords: Blood flow restriction; EIMD; Immunology; Ischemic preconditioning; Skeletal muscle