title: Relative safety of 4 weeks of blood flow-restricted resistance exercise in young, healthy adults.
abstract: This study evaluated the effect of 4 weeks of low-load resistance exercise with blood flow restriction (BFRE) on increasing strength in comparison with high-load resistance exercise (HLE), and assessed changes in blood, vascular and neural function. Healthy adults performed leg extension BFRE or HLE 3 days/week at 30% and 80% of strength, respectively. During BFRE, a cuff on the upper leg was inflated to 30% above systolic blood pressure. Strength, pulse-wave velocity (PWV), ankle-brachial index (ABI), prothrombin time (PT) and nerve conduction (NC) were measured before and after training. Markers of coagulation (fibrinogen and D-dimer), fibrinolysis [tissue plasminogen activator (tPA)] and inflammation [high sensitivity C-reactive protein (hsCRP)] were measured in response to the first and last exercise bouts. Strength increased 8% with BFRE and 13% with HLE (P<0.01). No changes in PWV, ABI, PT or NC were observed following training for either group (P>0.05). tPA antigen increased 30-40% immediately following acute bouts of BFRE and HLE (P=0.01). No changes were observed in fibrinogen, D-dimer or hsCRP (P>0.05). These findings indicate that both protocols increase the strength without altering nerve or vascular function, and that a single bout of both protocols increases fibrinolytic activity without altering selected markers of coagulation or inflammation in healthy individuals.
authors.affiliation: Department of Biomedical Sciences, Institute for Neuromusculoskeletal Research, Ohio University, Athens, Ohio 45701, USA. clarkb2@ohio.edu
authors.forename: B C
authors.initials: BC
authors.lastname: Clark
authors.forename: T M
authors.initials: TM
authors.lastname: Manini
authors.forename: R L
authors.initials: RL
authors.lastname: Hoffman
authors.forename: P S
authors.initials: PS
authors.lastname: Williams
authors.forename: M K
authors.initials: MK
authors.lastname: Guiler
authors.forename: M J
authors.initials: MJ
authors.lastname: Knutson
authors.forename: M L
authors.initials: ML
authors.lastname: McGlynn
authors.forename: M R
authors.initials: MR
authors.lastname: Kushnick
mesh_terms: D000222:Adaptation, Physiological; D000293:Adolescent; D000328:Adult; D055109:Ankle Brachial Index; D001783:Blood Flow Velocity; D002097:C-Reactive Protein / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D005338:Fibrin Fibrinogen Degradation Products / Q000378:metabolism; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D007866:Leg / Q000098:blood supply / Q000502:physiology*; D008297:Male; D053580:Muscle Strength; D018482:Muscle, Skeletal / Q000098:blood supply / Q000502:physiology*; D009431:Neural Conduction; D011517:Prothrombin Time; D012039:Regional Blood Flow / Q000502:physiology; D055070:Resistance Training; D010959:Tissue Plasminogen Activator / Q000097:blood; D055815:Young Adult
chemical_list: D005338:Fibrin Fibrinogen Degradation Products; C036309:fibrin fragment D; D005340:Fibrinogen; D002097:C-Reactive Protein; D010959:Tissue Plasminogen Activator