Journal of Human Sport and Exercise (May 2010)
INFLUENCE OF INGESTING CASEIN PROTEIN AND WHEY PROTEIN CARBOHYDRATE BEVERAGES ON RECOVERY AND PERFORMANCE OF AN ENDURANCE CYCLING TEST
Abstract
The main aim of this study was to determine if short-term post exercise recovery, cycling performance and blood analysis were altered when consuming three different beverages with the same amounts of calories, a carbohydrate-only beverage (CHO, 9% carbohydrate) a carbohydrate and casein protein beverage (CHO+Pc, 7% carbohydrate and 2% protein) and a carbohydrate and whey hydrolyzed drink (CHO+Pw, 7% + 2 %). Fifteen male cyclists (VO2peak= 63.4±9.6 ml•kg-1•min-1) performed three trials using a randomly counterbalanced, double-blind design. In each trial one litre of one of the test drinks was consumed in fasting conditions after 1 hour ride at 75% VO2peak. After a two hours recovery period the cyclists rode 20 km at the rider’s maximum speed for this distance. The results showed no significant differences in the 20-km ride when consuming the CHO (1770±210 s), the CHO+Pc drink (1819±185 s) or the CHO+Pw (1803±201). Post-exercise creatine kinase (CK) was not significantly different between treatments. However, serum insulin concentrations were higher during recovery when CHO+Pc and CHO+Pw beverages were consumed (P<0.05). Glucagon and lactic acid levels increased more on the CHO than on the CHO+Pc and CHO+Pw treatments (P<0.05) at the end of the 20 km test. Within the context of this experimental design, the CHO+Pc and CHO+Pw beverages showed different physiological effects than the CHO drink. One purported mechanism indicates muscle glycogen re-synthesis is enhanced when protein is added to a CHO recovery formula. The CHO+Pw and CHO+Pc drinks could be recommended for improving recuperation from intensive exercise. Although this was not reflected in post-recovery exercise performance in this 20 km test, a harder or longer test may be more affected by the physiological parameters especially in the last kilometres of the test.
