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.

Making the case for resistance training in improving vascular function and skeletal muscle capillarization

“…FMD is considered a primary marker of vascular health and impairment, reduced function, or dysfunction of the endothelium, as measured by FMD, is associated with increased risk of cardiovascular disease and future cardiovascular events (Elliott et al, 1987). Currently, data are mixed, as research groups report brachial FMD (bFMD) is augmented (Gonzales et al, 2011;Franklin et al, 2014;Buchanan et al, 2017;de Oliveira et al, 2020), impaired (Franklin et al, 2014;Choi et al, 2016;Morishima et al, 2018;de Oliveira et al, 2020;Morishima et al, 2020), or unaffected (Jurva et al, 2006;Casey et al, 2007a;Phillips et al, 2011;Buchanan et al, 2017). Discordant reports can be attributed to participant differences in baseline diameter and training status (trained participants being less likely to exhibit a transient reduction sometimes referred to 'athlete's artery' (Green et al, 2012;Zhong et al, 2018).…”