The aim of the present study was to investigate the effect of protein and carbohydrate ingestion during early recovery from exhaustive exercise on performance after 18 h recovery. Eight elite cyclists (VO2max 74.0±1.6 ml∙kg-1∙min-1) completed two exercise and diet interventions in a double-blinded, randomized, crossover design. Participants cycled first at 73% of VO2max (W73%) followed by one-min intervals at 90% of VO2max until exhaustion. During the first two hours of recovery, participants ingested either 1.2 g carbohydrate∙kg-1∙h-1 (CHO) or 0.8 g carbohydrate + 0.4 g protein∙kg-1∙h-1 (CHO+PROT). The diet during the remaining recovery period was similar for both interventions and adjusted to body weight. After an 18 h recovery, cycling performance was assessed with a 10 s sprint test, 30 min of cycling at W73%, and a cycling time trial (TT). The TT was 8.5% faster (41:53±1:51 min vs 45:26±1:32 min; p<0.03) after CHO+PROT compared to CHO. Mean power output during the sprints was 3.7% higher in CHO-PROT compared to CHO (1063±54 W vs 1026±53 W; p<0.01). Nitrogen balance in the recovery period was negative in CHO and neutral in CHO+PROT (-82.4±11.5 vs 7.0±15.4 mg∙kg-1; p<0.01).
In conclusion: TT and sprint performances were improved 18 h after exhaustive cycling by CHO-PROT supplementation during the first two hours of recovery compared with isoenergetic CHO supplementation. Our results indicate that intake of carbohydrate plus protein after exhaustive endurance exercise more rapidly converts the body from a catabolic to an anabolic state than carbohydrate alone, thus speeding recovery and improving subsequent cycling performance.
Keywords: branched chain amino acids; cycling; glucose; glycogen; nitrogen balance.