Oxygen Uptake Dynamics Conform to Acute Changes in Muscle Excitation and Total Hemoglobin Concentration during Constant Work Rate Exercise

Gabriele Marinari; Robin Trama; Alessandro M. Zagatto; Danilo Iannetta; Juan M. Murias

doi:10.1249/MSS.0000000000003700

Oxygen Uptake Dynamics Conform to Acute Changes in Muscle Excitation and Total Hemoglobin Concentration during Constant Work Rate Exercise

Gabriele Marinari
, Robin Trama
, Alessandro M. Zagatto
, Danilo Iannetta
, Juan M. Murias^*

^*Corresponding author for this work

HBKU College of Health & Life Sciences

University of Calgary
Universidade Estadual Paulista Júlio de Mesquita Filho
University of Brescia

Research output: Contribution to journal › Article › peer-review

2 Citations (Scopus)

Abstract

Whether electromyography (EMG)-derived muscle excitation and near-infrared spectroscopy (NIRS)-derived total hemoglobin and myoglobin concentration (total[Hb + Mb]) are linked during cycling exercise is unknown. Purpose This study aimed to investigate whether muscle excitation during constant-work rate (WR) cycling is connected with total[Hb + Mb] and whether they interact with the oxygen uptake (VO₂) dynamics. Methods In experiment 1, 10 participants performed a 21-min constant-WR (CWR) within the heavy-intensity domain (i.e., 75% of the difference between the gas exchange threshold and the maximal metabolic steady state) and a ramp-to-constant-WR (rCWR) to the same WR. CWR and rCWR were repeated twice and allocated in random order. In experiment 2, nine participants performed a double-constant-WR (dCWR) consisting of a 21-min exercise bout, a short 20-s break, and a second bout of 21 min within the heavy domain. VO₂, EMG root-mean-square (EMG_RMS), total[Hb + Mb], and deoxygenated hemoglobin ([HHb]) were collected from the vastus lateralis. The EMG_RMS/total[Hb + Mb] and the EMG_RMS/[HHb] ratios were computed. Results The EMG_RMS was lower at minutes 1 and 7 and total[Hb + Mb] higher at minute 1 during the rCWR compared with the CWR condition (all P < 0.05). EMG_RMS displayed an overshoot at minute 1, which was different from minute 21 during the CWR condition (P < 0.05). EMG_RMS did not display an overshoot after the 20-s break during the dCWR condition. The EMG_RMS/total[Hb + Mb] inverted ratio was not different from VO₂ (%). The EMG magnitude of frequencies ranging from ∼30 to 90 Hz was initially higher and decreased over time (P < 0.05). Conclusions This study demonstrated that EMG_RMS-derived muscle excitation can be reduced by exercise protocols that promote higher total[Hb + Mb]. Furthermore, the interaction between muscle excitation and total[Hb + Mb] matched with systemic VO₂.

Original language	English
Pages (from-to)	1690-1701
Number of pages	12
Journal	Medicine and Science in Sports and Exercise
Volume	57
Issue number	8
DOIs	https://doi.org/10.1249/MSS.0000000000003700
Publication status	Published - 1 Aug 2025

Keywords

DEOXYGENATED HEMOGLOBIN
MUSCLE EXCITATION
OXIDATIVE PHOSPHORYLATION
OXYGEN UPTAKE KINETICS
TOTAL HEMOGLOBIN CONCENTRATION

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@article{73a2504b681948669b7222204403c75b,

title = "Oxygen Uptake Dynamics Conform to Acute Changes in Muscle Excitation and Total Hemoglobin Concentration during Constant Work Rate Exercise",

abstract = "Whether electromyography (EMG)-derived muscle excitation and near-infrared spectroscopy (NIRS)-derived total hemoglobin and myoglobin concentration (total[Hb + Mb]) are linked during cycling exercise is unknown. Purpose This study aimed to investigate whether muscle excitation during constant-work rate (WR) cycling is connected with total[Hb + Mb] and whether they interact with the oxygen uptake (VO2) dynamics. Methods In experiment 1, 10 participants performed a 21-min constant-WR (CWR) within the heavy-intensity domain (i.e., 75\% of the difference between the gas exchange threshold and the maximal metabolic steady state) and a ramp-to-constant-WR (rCWR) to the same WR. CWR and rCWR were repeated twice and allocated in random order. In experiment 2, nine participants performed a double-constant-WR (dCWR) consisting of a 21-min exercise bout, a short 20-s break, and a second bout of 21 min within the heavy domain. VO2, EMG root-mean-square (EMGRMS), total[Hb + Mb], and deoxygenated hemoglobin ([HHb]) were collected from the vastus lateralis. The EMGRMS/total[Hb + Mb] and the EMGRMS/[HHb] ratios were computed. Results The EMGRMS was lower at minutes 1 and 7 and total[Hb + Mb] higher at minute 1 during the rCWR compared with the CWR condition (all P < 0.05). EMGRMS displayed an overshoot at minute 1, which was different from minute 21 during the CWR condition (P < 0.05). EMGRMS did not display an overshoot after the 20-s break during the dCWR condition. The EMGRMS/total[Hb + Mb] inverted ratio was not different from VO2 (\%). The EMG magnitude of frequencies ranging from ∼30 to 90 Hz was initially higher and decreased over time (P < 0.05). Conclusions This study demonstrated that EMGRMS-derived muscle excitation can be reduced by exercise protocols that promote higher total[Hb + Mb]. Furthermore, the interaction between muscle excitation and total[Hb + Mb] matched with systemic VO2.",

keywords = "DEOXYGENATED HEMOGLOBIN, MUSCLE EXCITATION, OXIDATIVE PHOSPHORYLATION, OXYGEN UPTAKE KINETICS, TOTAL HEMOGLOBIN CONCENTRATION",

author = "Gabriele Marinari and Robin Trama and Zagatto, \{Alessandro M.\} and Danilo Iannetta and Murias, \{Juan M.\}",

note = "Publisher Copyright: {\textcopyright} Lippincott Williams \& Wilkins.",

year = "2025",

month = aug,

day = "1",

doi = "10.1249/MSS.0000000000003700",

language = "English",

volume = "57",

pages = "1690--1701",

journal = "Medicine and Science in Sports and Exercise",

issn = "0195-9131",

publisher = "Lippincott Williams and Wilkins",

number = "8",

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TY - JOUR

T1 - Oxygen Uptake Dynamics Conform to Acute Changes in Muscle Excitation and Total Hemoglobin Concentration during Constant Work Rate Exercise

AU - Marinari, Gabriele

AU - Trama, Robin

AU - Zagatto, Alessandro M.

AU - Iannetta, Danilo

AU - Murias, Juan M.

N1 - Publisher Copyright: © Lippincott Williams & Wilkins.

PY - 2025/8/1

Y1 - 2025/8/1

N2 - Whether electromyography (EMG)-derived muscle excitation and near-infrared spectroscopy (NIRS)-derived total hemoglobin and myoglobin concentration (total[Hb + Mb]) are linked during cycling exercise is unknown. Purpose This study aimed to investigate whether muscle excitation during constant-work rate (WR) cycling is connected with total[Hb + Mb] and whether they interact with the oxygen uptake (VO2) dynamics. Methods In experiment 1, 10 participants performed a 21-min constant-WR (CWR) within the heavy-intensity domain (i.e., 75% of the difference between the gas exchange threshold and the maximal metabolic steady state) and a ramp-to-constant-WR (rCWR) to the same WR. CWR and rCWR were repeated twice and allocated in random order. In experiment 2, nine participants performed a double-constant-WR (dCWR) consisting of a 21-min exercise bout, a short 20-s break, and a second bout of 21 min within the heavy domain. VO2, EMG root-mean-square (EMGRMS), total[Hb + Mb], and deoxygenated hemoglobin ([HHb]) were collected from the vastus lateralis. The EMGRMS/total[Hb + Mb] and the EMGRMS/[HHb] ratios were computed. Results The EMGRMS was lower at minutes 1 and 7 and total[Hb + Mb] higher at minute 1 during the rCWR compared with the CWR condition (all P < 0.05). EMGRMS displayed an overshoot at minute 1, which was different from minute 21 during the CWR condition (P < 0.05). EMGRMS did not display an overshoot after the 20-s break during the dCWR condition. The EMGRMS/total[Hb + Mb] inverted ratio was not different from VO2 (%). The EMG magnitude of frequencies ranging from ∼30 to 90 Hz was initially higher and decreased over time (P < 0.05). Conclusions This study demonstrated that EMGRMS-derived muscle excitation can be reduced by exercise protocols that promote higher total[Hb + Mb]. Furthermore, the interaction between muscle excitation and total[Hb + Mb] matched with systemic VO2.

AB - Whether electromyography (EMG)-derived muscle excitation and near-infrared spectroscopy (NIRS)-derived total hemoglobin and myoglobin concentration (total[Hb + Mb]) are linked during cycling exercise is unknown. Purpose This study aimed to investigate whether muscle excitation during constant-work rate (WR) cycling is connected with total[Hb + Mb] and whether they interact with the oxygen uptake (VO2) dynamics. Methods In experiment 1, 10 participants performed a 21-min constant-WR (CWR) within the heavy-intensity domain (i.e., 75% of the difference between the gas exchange threshold and the maximal metabolic steady state) and a ramp-to-constant-WR (rCWR) to the same WR. CWR and rCWR were repeated twice and allocated in random order. In experiment 2, nine participants performed a double-constant-WR (dCWR) consisting of a 21-min exercise bout, a short 20-s break, and a second bout of 21 min within the heavy domain. VO2, EMG root-mean-square (EMGRMS), total[Hb + Mb], and deoxygenated hemoglobin ([HHb]) were collected from the vastus lateralis. The EMGRMS/total[Hb + Mb] and the EMGRMS/[HHb] ratios were computed. Results The EMGRMS was lower at minutes 1 and 7 and total[Hb + Mb] higher at minute 1 during the rCWR compared with the CWR condition (all P < 0.05). EMGRMS displayed an overshoot at minute 1, which was different from minute 21 during the CWR condition (P < 0.05). EMGRMS did not display an overshoot after the 20-s break during the dCWR condition. The EMGRMS/total[Hb + Mb] inverted ratio was not different from VO2 (%). The EMG magnitude of frequencies ranging from ∼30 to 90 Hz was initially higher and decreased over time (P < 0.05). Conclusions This study demonstrated that EMGRMS-derived muscle excitation can be reduced by exercise protocols that promote higher total[Hb + Mb]. Furthermore, the interaction between muscle excitation and total[Hb + Mb] matched with systemic VO2.

KW - DEOXYGENATED HEMOGLOBIN

KW - MUSCLE EXCITATION

KW - OXIDATIVE PHOSPHORYLATION

KW - OXYGEN UPTAKE KINETICS

KW - TOTAL HEMOGLOBIN CONCENTRATION

UR - https://www.scopus.com/pages/publications/105000287515

U2 - 10.1249/MSS.0000000000003700

DO - 10.1249/MSS.0000000000003700

M3 - Article

AN - SCOPUS:105000287515

SN - 0195-9131

VL - 57

SP - 1690

EP - 1701

JO - Medicine and Science in Sports and Exercise

JF - Medicine and Science in Sports and Exercise

IS - 8

ER -

Oxygen Uptake Dynamics Conform to Acute Changes in Muscle Excitation and Total Hemoglobin Concentration during Constant Work Rate Exercise

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Keywords

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