Recovery from a cycling time trial is enhanced with carbohydrate-protein supplementation vs. isoenergetic carbohydrate supplementation

Background: In this study we assessed whether a liquid carbohydrate-protein (C+P) supplement (0.8 g/kg C; 0.4 g/kg P) ingested early during recovery from a cycling time trial could enhance a subsequent 60 min effort on the same day vs. an isoenergetic liquid carbohydrate (CHO) supplement (1.2 g/kg). Methods: Two hours after a standardized breakfast, 15 trained male cyclists completed a time trial in which they cycled as far as they could in 60 min (AM(ex)) using a Computrainer indoor trainer. Following AM(ex), subjects ingested either C+P, or CHO at 10, 60 and 120 min, followed by a standardized meal at 4 h post exercise. At 6 h post AM(ex) subjects repeated the time trial (PMex). Results: There was a significant reduction in performance for both groups in PMex versus AM(ex). However, performance and power decreases between PMex and AM(ex) were significantly greater (p <= 0.05) with CHO (-1.05 +/- 0.44 km and -16.50 +/- 6.74 W) vs C+P (-0.30 +/- 0.50 km and -3.86 +/- 6.47 W). Fat oxidation estimated from RER values was significantly greater (p <= 0.05) in the C+P vs CHO during the PMex, despite a higher average workload in the C+P group. Conclusion: Under these experimental conditions, liquid C+P ingestion immediately after exercise increases fat oxidation, increases recovery, and improves subsequent same day, 60 min efforts relative to isoenergetic CHO ingestion.