Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway.
Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Verona, Italy.
Scand J Med Sci Sports. 2024 Jul;34(7):e14688. doi: 10.1111/sms.14688.
To assess the impact of endurance training on skeletal muscle release of H and K.
Nine participants performed one-legged knee extension endurance training at moderate and high intensities (70%-85% of W), three to four sessions·week for 6 weeks. Post-training, the trained and untrained (control) leg performed two-legged knee extension at low, moderate, and high intensities (40%, 62%, and 83% of W) in normoxia and hypoxia (~4000 m). The legs were exercised simultaneously to ensure identical arterial inflow concentrations of ions and metabolites, and identical power output was controlled by visual feedback. Leg blood flow was measured (ultrasound Doppler), and acid-base variables, lactate- and K concentrations were assessed in arterial and femoral venous blood to study K and H release. Ion transporter abundances were assessed in muscle biopsies.
Lactate-dependent H release was similar in hypoxia to normoxia (p = 0.168) and was lower in the trained than the control leg at low-moderate intensities (p = 0.060-0.006) but similar during high-intensity exercise. Lactate-independent and total H releases were higher in hypoxia (p < 0.05) and increased more with power output in the trained leg (leg-by-power output interactions: p = 0.02). K release was similar at low intensity but lower in the trained leg during high-intensity exercise in normoxia (p = 0.024) and hypoxia (p = 0.007). The trained leg had higher abundances of Na/H exchanger 1 (p = 0.047) and Na/K pump subunit α (p = 0.036).
Moderate- to high-intensity endurance training increases lactate-independent H release and reduces K release during high-intensity exercise, coinciding with increased Na/H exchanger 1 and Na/K pump subunit α muscle abundances.
评估耐力训练对骨骼肌释放 H 和 K 的影响。
9 名参与者进行单腿膝关节伸展耐力训练，强度适中且较高（70%-85%的 W），每周 3-4 次，持续 6 周。训练后，训练腿和未训练腿（对照组）在常氧和低氧（~4000m）下进行双腿膝关节伸展运动，强度分别为低、中、高强度（40%、62%和 83%的 W）。双腿同时进行运动，以确保动脉内离子和代谢物的浓度相同，通过视觉反馈控制相同的功率输出。测量腿部血流量（超声多普勒），并评估动脉和股静脉血液中的酸碱变量、乳酸和 K 浓度，以研究 K 和 H 的释放。评估肌肉活检中的离子转运体丰度。
低氧条件下，依赖于乳酸的 H 释放与常氧相似（p=0.168），且在低-中强度运动时，训练腿低于对照组（p=0.060-0.006），但在高强度运动时相似。非依赖于乳酸的和总 H 释放量在低氧条件下较高（p<0.05），且在训练腿中随着功率输出的增加而增加更多（腿与功率输出的相互作用：p=0.02）。在低强度时，K 释放量相似，但在常氧和低氧条件下，训练腿在高强度运动时较低（p=0.024 和 p=0.007）。训练腿的 Na/H 交换器 1（p=0.047）和 Na/K 泵亚基 α（p=0.036）丰度较高。
中等到高强度的耐力训练增加了高强度运动时非依赖于乳酸的 H 释放，并减少了 K 的释放，同时 Na/H 交换器 1 和 Na/K 泵亚基 α 的肌肉丰度增加。
