Effects of High and Low Concentration Carbohydrate Solution on Endurance Performance Consumed Prior to and During Intense, Intermittent Exercise

The aim of the study was to compare the effects of high and low concentration carbohydrate (CHO) solutions on the endurance performance of recreational, male soccer players consumed prior to and during intense, intermittent exercise. Methods: Seven participants consumed four different fluids using a randomised double blind procedure, an 8% carbohydrate electrolyte solution (2.5% galactose and 5.5% glucose polymer) (8% CES), a 2.5% carbohydrate (2.5% galactose) electrolyte solution (2.5% CES), an electrolyte solution (E) and water (W). A further three participants acted as controls by consuming E only on four occasions. We used the Loughborough Intermittent Shuttle Test (LIST) to simulate the intense, intermittent nature of a soccer match. The LIST protocol consists of two parts: Part A required walking, jogging and sprinting, utilising a 20 m shuttle procedure, for 75 min, recovering for 3 min every 15 min. Part B required participants to perform intermittent running to exhaustion, alternating between 55% and 95% of their predicted maximal oxygen uptake. Each beverage was administered immediately prior to exercise (5 ml · kg-1) and every 15 min thereafter (2 ml · kg-1) until the conclusion of Part A. Results: The performance run times for Part B (mean ± SD) were 16.3 ± 1.5 min (8% CES), 11.1 ± 1.2 min (2.5% CES), 10.0 ± 1.0 min (E) and 9.3 ± 0.9 min (W). The 8% CES beverage produced a significantly greater time to exhaustion (Part B) than the other drinks (5.0 ± 1.5 min, P<0.05). Conclusions: A high CHO concentration formulation (8% CES) is associated with a significant increase in endurance performance during intense, intermittent exercise in recreational, male soccer players.