Key result
Elimination of any delay in O2 delivery during the rest-to-contraction transition did not significantly affect muscle VO2 on-kinetics in isolated canine muscle (21.8 vs 23.8 seconds).
Why the study?
Does faster adjustment of O2 delivery improve VO2 on-kinetics in isolated in situ canine muscle?
Population
Isolated canine gastrocnemius muscles (n=7) from adult mongrel dogs of either sex.
Comparison
Pump-perfused blood flow adjusted ~15 s before… vs Spontaneous adjustment of blood flow and…
Design
Preclinical, The order of treatments was randomized, except that C Spont was…
Follow-up
3 minutes of electrically stimulated isometric tetanic…
Authors
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O2 delivery does not limit VO2 on-kinetics in isolated muscle; leaves open metabolic inertia as primary driver in humans.
Does faster adjustment of O2 delivery improve VO2 on-kinetics in isolated in situ canine muscle?
Absolute Event Rate: 21.8% vs 23.8%
p-value: p=not significant
Elimination of any delay in O2 delivery during the rest-to-contraction transition did not affect muscle VO2 kinetics, suggesting that these kinetics are mainly set by an intrinsic inertia of oxidative metabolism.
Grassi et al. (1998) studied Healthy (canine model) (n=7). Faster adjustment of O2 delivery (pump-perfused constant blood flow) vs. Spontaneous adjustment of blood flow was evaluated on Time to reach 63% of the difference between baseline and steady-state VO2 during contractions (t63% in seconds) (p=not significant). Elimination of any delay in O2 delivery during the rest-to-contraction transition did not significantly affect muscle VO2 on-kinetics in isolated canine muscle (21.8 vs 23.8 seconds).
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