TY - JOUR
T1 - Influence of muscular contraction on vascular conductance during exercise above versus below critical power
AU - Hammer, Shane M.
AU - Hammond, Stephen T.
AU - Parr, Shannon K.
AU - Alexander, Andrew M.
AU - Turpin, Vanessa Rose G.
AU - White, Zachary J.
AU - Didier, Kaylin D.
AU - Smith, Joshua R.
AU - Barstow, Thomas J.
AU - Ade, Carl J.
N1 - Publisher Copyright:
© 2021 Elsevier B.V.
PY - 2021/11
Y1 - 2021/11
N2 - We tested the hypothesis that limb vascular conductance (LVC) would increase during the immediate recovery phase of dynamic exercise above, but not below, critical power (CP) indicating a threshold for muscular contraction-induced impedance of limb blood flow (LBF). CP (115 ± 26 W) was determined in 7 men and 7 women who subsequently performed ∼5 min of near-supine cycling exercise both below and above CP. LVC demonstrated a greater increase during immediate recovery and remained significantly higher following exercise above, compared to below, CP (all p < 0.001). Power output was associated with the immediate increases in LVC following exercise above, but not below, CP (p < 0.001; r = 0.85). Additionally, variance in percent LBF impedance was significantly lower above (CV: 10.7 %), compared to below (CV: 53.2 %), CP (p < 0.01). CP appears to represent a threshold above which the characteristics of LBF impedance by muscular contraction become intensity-dependent. These data suggest a critical level of LBF impedance relative to contraction intensity exists and, once attained, may promote the progressive metabolic and neuromuscular responses known to occur above CP.
AB - We tested the hypothesis that limb vascular conductance (LVC) would increase during the immediate recovery phase of dynamic exercise above, but not below, critical power (CP) indicating a threshold for muscular contraction-induced impedance of limb blood flow (LBF). CP (115 ± 26 W) was determined in 7 men and 7 women who subsequently performed ∼5 min of near-supine cycling exercise both below and above CP. LVC demonstrated a greater increase during immediate recovery and remained significantly higher following exercise above, compared to below, CP (all p < 0.001). Power output was associated with the immediate increases in LVC following exercise above, but not below, CP (p < 0.001; r = 0.85). Additionally, variance in percent LBF impedance was significantly lower above (CV: 10.7 %), compared to below (CV: 53.2 %), CP (p < 0.01). CP appears to represent a threshold above which the characteristics of LBF impedance by muscular contraction become intensity-dependent. These data suggest a critical level of LBF impedance relative to contraction intensity exists and, once attained, may promote the progressive metabolic and neuromuscular responses known to occur above CP.
KW - Contraction impedance
KW - Critical power
KW - Limb blood flow
KW - Vascular conductance
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U2 - 10.1016/j.resp.2021.103718
DO - 10.1016/j.resp.2021.103718
M3 - Article
C2 - 34126260
AN - SCOPUS:85107957347
SN - 1569-9048
VL - 293
JO - Respiratory Physiology and Neurobiology
JF - Respiratory Physiology and Neurobiology
M1 - 103718
ER -