title: Impaired endothelial function and blood flow in repetitive strain injury.
abstract: Repetitive Strain Injury (RSI) is a disabling upper extremity overuse injury that may be associated with pathophysiological changes in the vasculature. In this study we investigated whether RSI is associated with endothelial dysfunction and impaired exercise-induced blood flow in the affected forearm. 10 patients with RSI (age, 40.2 ± 10.3; BMI, 23.8 ± 3.3) and 10 gender- and age-matched control subjects (age, 38.0 ± 12.4; BMI, 22.7 ± 3.4) participated in this study. Brachial artery blood flow was measured at rest and during 3-min periods of isometric handgrip exercise at 15%, 30% and 45% of the individual maximal voluntary contraction. Brachial artery endothelial function was assessed as the flow mediated dilation (FMD), by measuring brachial artery diameter and velocity before and after 5-min ischemic occlusion. We found a lower exercise-induced brachial artery blood flow in patients with RSI than in controls (p=0.04). Brachial artery FMD was significantly lower in patients with RSI than in controls (p<0.01), whilst a lower FMD was also found in patient with unilateral RSI when comparing the affected arm with the non-affected arm (p=0.04). Our results suggest that patients with RSI have an attenuated exercise-induced blood flow and an impaired endothelial function in the affected arm. These findings importantly improve our understanding of the pathophysiological mechanism of RSI.
authors.affiliation: Department of Physiology, Radboud University Nijmegen Medical Centre, Nijmegen, The Netherlands.
authors.forename: J
authors.initials: J
authors.lastname: Brunnekreef
authors.forename: J J
authors.initials: JJ
authors.lastname: Brunnekreef
authors.forename: N
authors.initials: N
authors.lastname: Benda
authors.forename: N M M
authors.initials: NM
authors.lastname: Benda
authors.forename: T
authors.initials: T
authors.lastname: Schreuder
authors.forename: T H A
authors.initials: TH
authors.lastname: Schreuder
authors.forename: M
authors.initials: M
authors.lastname: Hopman
authors.forename: M T E
authors.initials: MT
authors.lastname: Hopman
authors.forename: D
authors.initials: D
authors.lastname: Thijssen
authors.forename: D H J
authors.initials: DH
authors.lastname: Thijssen
mesh_terms: D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology; D001916:Brachial Artery / Q000503:physiopathology; D012090:Cumulative Trauma Disorders / Q000503:physiopathology*; D004730:Endothelium, Vascular / Q000503:physiopathology; D005260:Female; D005542:Forearm / Q000098:blood supply*; D005543:Forearm Injuries / Q000503:physiopathology*; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D007511:Ischemia / Q000503:physiopathology; D007537:Isometric Contraction / Q000502:physiology; D008297:Male; D008875:Middle Aged; D014664:Vasodilation / Q000502:physiology