Introduction: Adaptations with endurance training induce improvements in muscle oxidative energy capacity and mitochondrial biogenesis. The regulation of protein synthesis involves several signalling pathways which are influenced by amino acids, insulin and mechanical stimulation. PGC-1á plays a vital role in regulating mitochondrial biogenesis by co-activating a number of transcription factors involved in the adaptation process. Limited research exists on the benefits of protein supplementation for endurance athletes, in particular the effects of co-ingestion of whey protein isolates and carbohydrate on endurance training adaptations. The aim of the present study is to therefore, investigate the effects of 2 weeks of co-ingestion of whey protein isolate and carbohydrate supplementation on endurance recovery processes. Method: Six endurance trained male cyclists and triathletes (age 29 ± 4 years, weight 74 ± 2 kg, VO2 max 63 ± 3ml oxygen/kg/min, height 183 ± 5 cm; mean ± SEM) were randomly assigned to one of two dietary interventions in a single blind cross over design; carbohydrate (CHO) or carbohydrate and whey protein isolates (CHO+WPI). Each dietary intervention was followed for 16 days which included 2 days having increased CHO content, re-presenting a loading phase. The dietary interventions were iso-caloric and carbohydrate content matched. Participants then performed a controlled exercise bout, followed by time trial to exhaustion. Blood samples and muscle biopsies were taken at various time points. Results: Plasma insulin was significantly increased in the recovery period at 180 mins (P<0.05) and PGC-1á mRNA expression was significantly up regulated in the CHO+WPI group at the end of 6 hours of recovery (P<0.05), compared to CHO group. Muscle glycogen concentration were comparable at rest, decreased (P<0.05) following exercise and increased at the end of 6 h recovery. Conclusion: The results suggest co-ingestion of CHO+WPI supplementation benefits recovery and adaptations to endurance exercise. Protein supplementation with adequate carbohydrate availability during training did not influence pre and post muscle glycogen levels. However, increases in plasma insulin content and muscle PGC-1á mRNA expression, indicates a response in metabolism for improved adaptations to training.
© Copyright 2012 17th Annual Congress of the European College of Sport Science (ECSS), Bruges, 4. -7. July 2012. Published by Vrije Universiteit Brussel. All rights reserved.