急性阻力運動對心肌灌流與左心室耗能指標變化之影響──規律阻力與混合訓練族群比較

Effects of acute resistance exercise on myocardial perfusion and left ventricular energy waste: Comparisons between habitually resistance-trained only and combined exercise-trained populations

緒論：比較規律單純阻力與結合有氧與阻力訓練習慣的男性，在不同動脈脈波傳導速度指標是否有差異，同時比較在進行急性不同強度阻力運動後，心肌灌流與左心室耗能指標之變化情況。方法：本研究採重複量數實驗設計，共招募22位規律阻力訓練男性，進一步依照調查有氧運動時間（> 150分鐘/週），分為從事有氧與阻力訓練的混合組（年齡= 23±1歲，n = 11）與單純阻力訓練組（年齡= 25±1歲，n = 11）。受試者在進行完不同動脈脈波傳導速度檢測（頸動脈、頸-股、肱-踝）與肱二頭肌最大肌力測試後，隨機分派進行40%或80% 1RM的單次肱二頭肌阻力運動（10反覆/組，共5組）；不同測試至少間隔24小時。本研究於運動前後使用血管壓力計，量測橈動脈波形並轉換為頸動脈波形，計算中心動脈壓、心肌膜下活力率與左心室耗能指標，同時輔以血管檢測儀測得心臟收縮間隔指標，評估心臟交感神經活動程度。結果：儘管規律高強度阻力訓練組，在不同脈波傳導速度指標皆高於規律混合訓練組，但兩組並未達顯著差異。單次不同強度肱二頭肌運動，對兩組均未造成顯著中心動脈壓力上升。阻力訓練組在進行80% 1RM時，頸動脈脈壓呈現上升趨勢（p = .07），心肌膜下活力率則顯著低於運動前（p = .02），且左心室耗能指標亦呈現上升趨勢（p = .08），同時顯著高於混合訓練組（p = .02）；各項量測指標在40%1RM並未產生顯著變化。另一方面，規律混合訓練組，在進行不同強度運動後，於心肌灌流與左心室耗能指標，並未造成顯著的改變。心臟交感神經活動於不同組別與強度下，並無顯著變化。結論：與單純阻力訓練的年輕族群相較，結合規律有氧（> 150分鐘/週）與阻力運動的混合訓練者，能減緩高強度阻力運動對心臟功能產生的生理壓力，顯示有氧運動編排於規律阻力訓練的重要性。

Introduction: We aimed to compare differences in pulse wave velocity (PWV) parameters between resistance-trained individuals and those without habitual aerobic training and to investigate whether the changes in myocardial perfusion and left ventricular energy waste in response to different intensities of acute resistance exercise differed between the groups. Methods: This study used a repeated measures design. Twenty-two habitually resistance-trained men were recruited and divided into a combined exercise-trained group (aerobic and resistance exercise training [RT+ET]; mean age = 23±1 years; n = 11) and a resistance-trained only group (RT; mean age = 25±1 years; n = 11) based on self-reported weekly aerobic exercise time (>150 minutes/week as recommended). Subjects were randomly assigned to perform a single bicep-curl at 40% or 80% 1RM (10 repetitions/set, 5 sets), respectively, after performing different PWV tests (ultrafast local carotid PWV and carotid–femoral and brachial–ankle PWV) and one-repetition maximum of bicep curls (1RM). The exercise sessions were performed at least 24 hours apart. Radial arterial waveforms were acquired before and after exercise using a vascular tonometer to obtain carotid blood pressure, subendocardial viability ratio (SEVR), and left ventricular energy waste. Systolic time intervals (STI) were also used to assess cardiac sympathetic activity. Results: The RT group had a higher PWV than the RT+ET group in all arterial stiffness measures, although these differences were not significant. A single bicep curl exercise at different intensities did not cause a significant increase in carotid arterial pressure in either group. Following exercise, RT showed an increase in carotid pulse pressure at 80% 1RM (p = .07), a significant decrease in SEVR (p = .02), and an increase in left ventricular energy waste (p = .08), which was significantly higher than that in the RT+ET group (p = .02). However, no significant changes in myocardial perfusion and left ventricular energy waste were observed in the RT+ET group after exercise. No significant changes of STI index were observed in either group. Conclusions: The attenuation of cardiac stress induced by an acute bout of high-intensity resistance exercise appears to be better in habitually combined exercise-trained young adults than in their resistance-trained only counterparts, indicating the importance of combining aerobic exercise with a regular training program in this population.