攝取甜菜根汁對於蹲舉表現之急性影響

Abstract

目的：探討攝取甜菜根汁對於蹲舉表現之影響。方法：本研究招募共12名健康男性，且蹲舉1RM (one-repetition maximum) 需大於或等於1.5倍自身體重。先實施控制處理 (CON)，隨後再依隨機交叉方式，於測驗前2.5小時攝取含400毫克硝酸鹽之甜菜根汁 (Beetroot Juice, BJ) 或安慰劑 (無硝酸鹽成分之安慰劑，PL)。在每次的實驗處理後，進行標準化熱身，再進行5組75%1RM之蹲舉 (膝關節至90度)，組間休息3分鐘，每組需至衰竭。另外，在測驗前後測量血乳酸值，和詢問運動自覺強度。3次實驗處理皆全程配戴近紅外線光譜儀，觀察血流量及肌肉氧飽和指標之變化。並且使用彈震式測量系統，蒐集相關之動力學與運動學指標。結果：第1組反覆次數，BJ顯著高於其餘兩個處理 (CON vs. BJ vs. PL, 15.3 ± 3.5 vs. 19.8 ± 5.0 vs. 17.4 ± 4.4 次，p< .05)。整體反覆次數，BJ亦顯著高於CON (CON vs. BJ vs. PL, 58.4 ± 13.9 vs. 76.4 ± 21.0 vs. 73.4 ± 20.9 次，p < .05)。於第4組 (CON vs. BJ vs. PL, 0.78 ± 0.23 vs. 0.89 ± 0.21 vs. 0.92 ± 0.25 公尺/秒2，p < .05) 和第5組 (CON vs. BJ vs. PL, 0.76 ± 0.28 vs. 0.93 ± 0.25 vs. 0.90 ± 0.25 公尺/秒2，p < .05) 之平均加速度，BJ與PL顯著高於CON。休息期間，BJ之總血紅素變化量顯著低於CON與PL。運動後之運動自覺強度在3個處理間無顯著差異。結論：運動前增補甜菜根汁，顯著提升蹲舉運動反覆次數與整體平均加速度，這可能和改善組間休息時的恢復有關。

Purpose: To investigate the effect of beetroot juice on squat performance. Methods: Twelve healthy males were recruited in this study, and their squat 1RM (one-repetition maximum) was required to be at least 1.5 times their own body mass. Following a control treatment (CON), the participants ingested either beetroot juice (BJ), which contained 400 mg of nitrate, or a placebo (PL), administered 2.5 hours prior to the exercise test, in a randomized crossover design. Then they conducted a standardized warm-up, and 5 sets of squats with 75% 1RM until exhaustion with a 3-minute rest between sets. In addition, blood lactate and rating of perceived exertion (RPE) were measured during the test. Near-infrared spectroscopy was used to monitor blood flow and muscle oxygen saturation index, while dynamic and kinematic variables were collected by a ballistic measurement system. Results: The number of repetitions in the first set, BJ was significantly higher than others (CON vs. BJ vs. PL, 15.3 ± 3.5 vs. 19.8 ± 5.0 vs. 17.4 ± 4.4 repetitions, p< .05). In total repetitions, BJ was significantly higher than CON (CON vs. BJ vs. PL, 58.4 ± 13.9 vs. 76.4 ± 21.0 vs. 73.4 ± 20.9 repetitions, p < .05). The average acceleration of BJ and PL were significantly higher than CON in the fourth (CON vs. BJ vs. PL, 0.78 ± 0.23 vs. 0.89 ± 0.21 vs. 0.92 ± 0.25 m/s2, p < .05) and the fifth (CON vs. BJ vs. PL, 0.76 ± 0.28 vs. 0.93 ± 0.25 vs. 0.90 ± 0.25 m/s2, p < .05) set. During the rest intervals, the changes in total hemoglobin in BJ was significantlylower than CON and PL. No significant difference was found in RPE after exercise among treatments. Conclusion: Supplementation with BJ might enhance the number of repetitions and the average acceleration achieved during squats by facilitating improved recovery during rest intervals.