Carbohydrate-Protein Coingestion Enhances Cycling Performance with Minimal Recovery Time between Bouts of Exhaustive Intermittent Exercise

Abstract

Introduction: The addition of protein to a carbohydrate solution has been shown to effectively stimulate glycogen synthesis in an acute setting and enhance exercise performance in a subsequent bout of exhaustive exercise. This study examined the effects of carbohydrate-protein (CHO-P), carbohydrate (CHO), and placebo (PLA) within a 2-hour recovery period on subsequent high-intensity exercise performance. Methods: This was a randomized, single-blind between-subject design. Participants (n = 25) were assigned to consume one of three beverages during a 2-hour recovery period: PLA, CHO (1.2 g/kg bm), or CHO-P (0.8 g/kg bm CHO + 0.4 g/kg bm PRO). During Visit#1, participants completed graded exercise testing (VO2peak; cycle ergometer). Familiarization (Visit#2) consisted of 5 x 4 min intervals at 70-80% of peak power output [PPO, watts] with two minutes of active recovery at 50W, followed by time to exhaustion [TTE] at 90% PPO. The same high-intensity interval protocol with TTE was conducted pre-and post-beverage consumption on Visit #3. Results: The ANCOVA indicated a significant difference among the group means for the posttest TTE (F2,21=8.248, p=.002, ƞ2=.440) and RER (F2,21=6.811, p=.005, ƞ2=.393) values after adjusting for the pretest differences. Conclusions: Carbohydrate-protein co-ingestion was effective in promoting an increase in TTE performance with limited time to recover.