تأثير مصرف هم‌زمان مكمل‌هاي كافئين و ال-كارنيتين بر عملكرد هوازي و سوبستراي انتخابي هنگام فعاليت ورزشي

Effect of Simultaneous Consumption of Caffeine and L-Carnitine on Aerobic Performance and Substrate Selection During Exercise

ﻫﺪف از اﻧﺠﺎم ﭘﮋوﻫﺶ ﺣﺎﺿﺮ، ﺗﻌﯿﯿﻦ ﺗﺄﺛﯿﺮ ﻣﺼﺮف ﻫﻢزﻣﺎن ﻣﮑﻤﻞﻫﺎي ﮐﺎﻓﺌﯿﻦ و ال-ﮐﺎرﻧﯿﺘﯿﻦ ﺑﺮ اﻧﺘﺨﺎب ﺳﻮﺑﺴﺘﺮاي ﻣﺼﺮﻓﯽ درﺣﯿﻦ ﺗﻤﺮﯾﻦ و اﺛﺮ اﺣﺘﻤﺎﻟﯽ آن ﺑﺮ ﻋﻤﻠﮑﺮد اﺳﺘﻘﺎﻣﺘﯽ در ﻣﺮدان ﮐﺎراﺗﻪﮐﺎر ﻧﺨﺒﻪ ﺑﻮد. ﺗﻌﺪاد 12 ﮐﺎراﺗﻪﮐﺎر در ﭼﻬﺎر ﮐﻮﺷﺶ ﻣﺠﺰا ﺑﺎ ﻓﺎﺻﻠﮥ زﻣﺎﻧﯽ ﯾﮏ ﻫﻔﺘﻪ ، ﻣﮑﻤﻞدﻫﯽ ﮐﺎﻓﺌﯿﻦ ) ﭘﻨﺞ ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﮐﯿﻠﻮﮔﺮم ﮐﺎرﻧﯿﺘﯿﻦ ) ﺳﻪ ﮔﺮم (، ﮐﺎﻓﺌﯿﻦ-ﮐﺎرﻧﯿﺘﯿﻦ ) ﭘﻨﺞ ﻣﯿﻠﯽ ﮔﺮم ﺑﺮ ﮔﯿﻠﻮﮔﺮم + ﺳﻪ ﮔﺮم ( و داروﻧﻤﺎ ) 250 ﻣﯿﻠﯽ ﮔﺮم ﻻﮐﺘﻮز ( را درﯾﺎﻓﺖ ﮐﺮدﻧﺪ و ﻧﯿﺰ آزﻣﻮن ﻓﺰاﯾﻨﺪة ارﮔﻮﻣﺘﺮي را اﻧﺠﺎم دادﻧﺪ. ﮔﺎزﻫﺎي ﺗﻨﻔﺴﯽ درﺧﻼل آزﻣﻮن و ﻧﻤﻮﻧﮥ ﺧﻮﻧﯽ ﻗﺒﻞ و ﺑﻌﺪ از آزﻣﻮن، ﺟﻤﻊآوري ﺷﺪﻧﺪ. ﻧﻘﺎط Fatmax ﺑﻪ ﻋﻨﻮان ﻧﻘﻄﻪاي ﮐﻪ ﭼﺮﺑﯽ ﺑﯿﺸﺘﺮﯾﻦ ﺳﻬﻢ را در اﻧﺮژي ﻣﺼﺮﻓﯽ ﺗﻤﺮﯾﻦ دارد و Cross over ﺑﻪﻋﻨﻮان ﻧﻘﻄﻪاي ﮐﻪ ﺳﻮﺧﺖ ﻏﺎﻟﺐ از ﭼﺮﺑﯽ ﺑﻪ ﮐﺮﺑﻮﻫﯿﺪرات ﺗﻐﯿﯿﺮ ﻣﯽﮐﻨﺪ، ﺗﻌﯿﯿﻦ و ﺑﺎر ﮐﺎري و اﮐﺴﯿﮋن ﻣﺼﺮﻓﯽ ﻣﻌﺎدل ﺑﺎ آنﻫﺎ اﺳﺘﺨﺮاج ﺷﺪ و ﺑﺎ ﺗﺤﻠﯿﻞ وارﯾﺎﻧﺲ ﺑﺎ اﻧﺪازهﮔﯿﺮي ﻣﮑﺮر ﺑﯿﻦ ﮐﻮﺷﺶﻫﺎ ﻣﻘﺎﯾﺴﻪ ﺷﺪﻧﺪ. ﭘﺲ از ﻣﺼﺮف ﮐﺎﻓﺌﯿﻦ و ﺗﺮﮐﯿﺐ ﮐﺎﻓﺌﯿﻦ و ال-ﮐﺎرﻧﯿﺘﯿﻦ، ﻣﯿﺰان ﺗﻐﯿﯿﺮات اﺳﯿﺪ ﭼﺮب ﭘﻼﺳﻤﺎ )FFA( درﺣﯿﻦ ﺗﻤﺮﯾﻦ، ﺑﺎر ﮐﺎري و اﮐﺴﯿﮋن ﻣﺼﺮﻓﯽ ﻣﻌﺎدل ﺑﺎ آﺳﺘﺎﻧﮥ ﺑﯽ ﻫﻮازي، ﻧﻘﺎط Cross overو Fatmaxﻧﺴﺒﺖ ﺑﻪ ﮐﻮﺷﺶ ﮐﻨﺘﺮل ﺑﯿﺸﺘﺮ ﺑﻮد )ﻫﻤﻪ 0.05

The purpose of the current study was to investigate the effect of coingestion of caffeine and L-carnitine supplements on substrate selection during exercise and its probable effect on endurance performances in elite male karate. Twelve elite athletes performed a progressive standard test following placebo (250 mg Lactose), caffeine (5 mg/kg), lcarnitine (3 g), and caffeine and l-carnitine (5 mg/kg, 3 g) consumption in four sessions separated by one-week interval. Respiratory gases and blood samples were collected before and after exercise. Cross over point (COP), as a point that metabolic substrate changes from fat to carbohydrates, and Fatmax, as a point at which fat has the highest contribution to energy supply, were determined, workload and oxygen consumption corresponding to them were extracted, and compared among trials by repeated measures analysis of variance. Following consumption of caffeine alone and in combined with Lcarnitine, the changes in plasma free fatty acid (FFA) during exercise, workload and oxygen consumption corresponding to COP and Fatmax points were significantly higher compared to the control trial (all P < 0.05). The values of these variables in combined trial were significantly higher than those found in the caffeine trial (all P < 0.05). L-carnitine consumption did not induce significant change in these variables compared to the control trial. In sum, Caffeine consumption improves endurance performance through changing substrate selection during exercise toward fat and this effect could be exacerbated by simultaneous consumption of L-carnitine.