Premium
Influence of contractile work and muscle fiber recruitment on skeletal muscle blood flow in humans
Author(s) -
Richards Jennifer Clarke,
Crecelius Anne R.,
Kirby Brett S,
Dinenno Frank A.
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.24.1_supplement.lb645
Subject(s) - skeletal muscle , medicine , contraction (grammar) , blood flow , endocrinology , forearm , cardiology , chemistry , anatomy
Contractile work has been considered the primary determinant of skeletal muscle oxygen consumption (VO 2 ), which is tightly coupled with blood flow (BF). Recently it was observed that within matched work conditions, the BF response following a single contraction increased with a greater degree of muscle fiber recruitment (MFR). The purpose of this study was to determine whether the primary determinant of skeletal muscle BF was contractile work or MFR during exercise. Accordingly, we measured the forearm BF response (FBF; Doppler ultrasound) during 4 minutes of rhythmic handgrip exercise (RHE) in 9 young males. Each workload (low and high) consisted of two trials matched for total work by varying the load (% maximal voluntary contraction; %MVC) and the contraction: rest ratio (low: 20%1:7 vs 10%1:3, high: 20%1:3 vs 10%1:1). Greater MFR was attained by increasing %MVC. VO 2 was calculated from FBF and deep venous blood samples. Greater MFR significantly increased the FBF response at both low and high workloads (164±16 vs 139±16 p =.03 and 270±24 vs 240±20 p =.01 (ml min −1 )). Greater MFR did not significantly affect VO 2 (207±19 vs 177±23 p =0.3, and 327±44 vs 305±37 p =0.4(ml min −1 )) at any workload, however, the ratio of ΔFBF: ΔVO 2 was unchanged. Our preliminary data suggest contractile work is not the primary determinant of FBF and greater MFR may have an independent influence on FBF during RHE in humans. Supported by HL‐087952