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 -