title: Muscle strength and pressor response.
abstract: The purpose of this study was to determine if muscle strength influences the hyperemic response to dynamic exercise. Men with low (n=8) and high (n=9) maximal forearm strength performed dynamic handgrip exercise as the same absolute workload increased in a ramp function (0.5 kg x min (-1)). Forearm blood flow (FBF) was measured instantaneously by ultrasound Doppler and blood pressure was measured by auscultation. The pressor response to exercise was greater (P<0.05) for low strength men at workloads >1.5 kg allowing volumetric FBF (ml x min (-1)) and vascular conductance to increase in proportion to absolute workload similar to high strength men. When FBF was expressed relative to forearm volume (ml x min (-1).100 ml (-1)) the hyperemic response to exercise (slope of relative FBF vs. workload) was greater in low strength men (3.2+/-1.5 vs. 1.7+/-0.4 ml x min (-1).100 ml (-1) x kg (-1), P<0.05) as was relative FBF at workloads >1.5 kg. However, when relative FBF was compared across relative work intensity, no difference was found between low and high strength groups. Together, these findings suggest men with low strength require a greater pressor response to match blood flow to exercise intensity as compared to high strength men.
authors.affiliation: Department of Kinesiology, Pennsylvania State University, University Park 16802, United States. jug18@psu.edu
authors.forename: J U
authors.initials: JU
authors.lastname: Gonzales
authors.forename: B C
authors.initials: BC
authors.lastname: Thompson
authors.forename: J R
authors.initials: JR
authors.lastname: Thistlethwaite
authors.forename: A J
authors.initials: AJ
authors.lastname: Harper
authors.forename: B W
authors.initials: BW
authors.lastname: Scheuermann
mesh_terms: D000328:Adult; D001314:Auscultation; D001794:Blood Pressure; D005080:Exercise Test; D005542:Forearm / Q000098:blood supply / Q000502:physiology; D006801:Humans; D006940:Hyperemia / Q000378:metabolism; D008297:Male; D009119:Muscle Contraction / Q000502:physiology*; D053580:Muscle Strength / Q000502:physiology*; D018608:Ultrasonography, Doppler; D055815:Young Adult