菸鹼酸鉻增補對自由車選手耐力運動後期衝刺表現之影響

Abstract

目的：探討菸鹼酸鉻增補對自由車選手90分鐘耐力運動後衝刺表現的影響。方法：受試者為10名男性受過訓練的自由車選手，每位受試者皆會在Cyclus2固定式腳踏車測功儀上先進行一次最大攝氧量測量，再以雙盲、平衡次序方式進行三次運動測驗。運動測驗係以70%最大攝氧量騎乘90分鐘，隨即進行30秒溫蓋特無氧動力測驗，每次運動測驗都至少間隔一週，運動測驗過程中隨機給予受試者每公斤體重0.2克碳水化合物 (CHO) 或碳水化合物添加200微克的菸鹼酸鉻 (CHOCr) 或安慰劑添加於飲用水中，增補時間分別為運動測驗開始及運動測驗第20、40、60、80分鐘。另外，在安靜時、運動測驗第15、75分鐘及運動測驗後3分鐘分別由指尖採血測量血乳酸及血糖。實驗參數包含平均動力輸出、最大動力輸出、到達最大動力輸出時間、疲勞遞減率、自覺努力程度 (RPE)、血糖及血乳酸等。結果：在最大動力輸出部份，三組之間皆達顯著差異，依序為CHOCr組 (746.04±90.32 W) > CHO組 (721.63±75.35 W) > 安慰劑組 (674.13±94.79W) (p<.05)，但在平均動力輸出部份，僅CHOCr組 (631.39±41.73 W) 顯著高於安慰劑組(583.02±53.51 W) (p <.05)；另外，CHOCr組與CHO組在運動測驗中之RPE皆顯著低於安慰劑組 (p <.05)；同時，CHO組之血糖亦顯著高於安慰劑組 (p <.05)，而CHOCr組與安慰劑組則無顯著差異。結論：在自由車耐力運動過程中，增補碳水化合物加NBC，可以降低疲勞感，同時會有較佳的血糖利用，有助於運動最後階段的衝刺表現。

Purpose: The purpose of this study was to investigate the effect of niacin-bound chromium (NBC) supplement on sprint performance following 90 min of endurance exercise in cyclists. Methods: Ten trained cyclist participated in three exercise trials on Cyclus2 stationary ergometer. Each exercise trial was performed at least one week apart. Following a double-blind, crossover design, the subjects cycled at 70% O2max for 90 minutes and then immediately performed 30s Wingate Anaerobic Power Test (WAPT) to measure mean power, peak power, time to peak power, fatigue index, RPE. Subjects received supplement 0.2g/kg carbohydrate beverage (CHO trial), a CE beverage containing 200µg NBC (CHOCr trial), or placebo (PLAC trial) at 0, 20, 40, 60 and 80 min during each exercise trial. Blood glucose and lactate concentrations were determined from finger blood at resting, 15, 75 min during exercise, and at 3 min post-WAPT. Result: Peak power was significantly different between trials, CHOCr trial (746.04 ± 90.32 W) > CHO trial (721.63 ± 75.35 W) > placebo trial (674.13±94.79 W) (p<.05), but only CHOCr trial (631.39±41.73 W) significantly higher than placebo trial (583.02 ± 53.51 W) in mean power (p <.05). RPE was significantly lower in CHOCr trial and CHO trial than placebo trial (p <.05). Blood glucose was significantly higher in CHO trial than placebo trial (p <.05). Conclusion: NBC combined with carbohydrate supplement may attenuate mental fatigue, and even improve blood glucose utilization and sprint performance following endurance exercise in cyclists.