Forskning

October 14, 2011

Impact of caffeine and protein on postexercise muscle glycogen synthesis

M Beelen et al, Impact of caffeine and protein on postexercise muscle glycogen synthesis, Medicine and Science in Sports and Exercise, 2011.

Both protein and caffeine co-ingestion with carbohydrate have been suggested to represent effective dietary strategies to further accelerate post-exercise muscle glycogen synthesis in athletes. The purpose of this study was to assess the impact of protein or caffeine co-ingestion on post-exercise muscle glycogen synthesis rates when optimal amounts of carbohydrate are ingested. Fourteen male cyclists were studied on 3 different test days. Each test day started with a glycogen depleting exercise session. This was followed by a 6 hour recovery period, during which subjects received 1.2 g.kg -1.h.-1 carbohydrate (CHO), or the same amount of carbohydrate with 0.3 g.kg-1h -1 of protein plus leucine mixture (CHO+PRO) or 1.7 mg.kg -1.h-1 caffeine (CHO+CAF). All drinks  were enriched with [U-13C6] labelled glucose to assess potential differences in the appearance rate of ingested glucose from the gut. Muscle biopsies were collected immediately after cessation of exercise and after 6h of post exercise recovery. These authors found that co-ingestion of protein or caffeine does not further accelerate post-exercise muscle glycogen synthesis when ample amounts of carbohydrate are ingested.