Marinari Gabriele, Trama Robin, Zagatto Alessandro M, Iannetta Danilo, Murias Juan M
Faculty of Kinesiology, University of Calgary, Calgary, CANADA.
Laboratory of Physiology and Sport Performance (LAFIDE), Department of Physical Education, School of Sciences, São Paulo State University-UNESP, Bauru, BRAZIL.
Med Sci Sports Exerc. 2025 Aug 1;57(8):1690-1701. doi: 10.1249/MSS.0000000000003700. Epub 2025 Mar 6.
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 (V̇O 2 ) dynamics.
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. V̇O 2 , 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.
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 V̇O 2 (%). The EMG magnitude of frequencies ranging from ~30 to 90 Hz was initially higher and decreased over time ( P < 0.05).
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 V̇O 2 .
本研究旨在探究在恒定功率（WR）骑行过程中肌肉兴奋是否与总血红蛋白和肌红蛋白浓度（[Hb + Mb]）相关，以及它们是否与摄氧量（V̇O₂）动力学相互作用。
在实验1中，10名参与者在高强度运动区间（即气体交换阈值与最大代谢稳定状态差值的75%）进行了21分钟的恒定功率骑行（CWR）以及达到相同功率的渐增-恒定功率骑行（rCWR）。CWR和rCWR重复进行两次，并随机分配顺序。在实验2中，9名参与者进行了双恒定功率骑行（dCWR），包括一段21分钟的运动时段、一个短暂的20秒休息以及在高强度区间的第二段21分钟运动。从股外侧肌采集V̇O₂、肌电图均方根（EMG RMS）、总血红蛋白和肌红蛋白浓度（[Hb + Mb]）以及脱氧血红蛋白（[HHb]）。计算EMG RMS/总血红蛋白和肌红蛋白浓度（[Hb + Mb]）以及EMG RMS/脱氧血红蛋白（[HHb]）的比值。
与CWR条件相比，rCWR过程中第1分钟和第7分钟的EMG RMS较低，第1分钟的总血红蛋白浓度（[Hb + Mb]）较高（所有P < 0.05）。EMG RMS在第1分钟出现过冲，这与CWR条件下第21分钟不同（P < 0.05）。在dCWR条件下，20秒休息后EMG RMS未出现过冲。EMG RMS/总血红蛋白和肌红蛋白浓度（[Hb + Mb]）的倒置比值与V̇O₂（%）无差异。频率范围约为30至90 Hz的EMG幅度最初较高，并随时间下降（P < 0.05）。
本研究表明，通过促进更高总血红蛋白和肌红蛋白浓度（[Hb + Mb]）的运动方案可以降低由EMG RMS得出的肌肉兴奋。此外，肌肉兴奋与总血红蛋白和肌红蛋白浓度（[Hb + Mb]）之间的相互作用与全身V̇O₂相匹配。
