Carbohydrate-Protein Supplementation During Endurance Running

The purpose of this study is to determine whether the performance benefits from consuming a carbohydrate-protein (CHO-P) supplement, such as Accelerade, during endurance exercise, as opposed to the traditionally used carbohydrate (CHO) supplement, such as Gatorade, are attributed to the extra calories in the CHO-P supplement or the presence of protein alone in comparison to CHO supplements. Numerous studies comparing CHO and CHO-P supplements on endurance performance have found contradicting results in terms of CHO-P supplementation and performance benefits. While physiological mechanisms have been proposed as to why the CHO-P supplements elicit greater performance, research has yet to determine why some studies have found this, especially while other studies have found no performance benefits from CHO-P supplementation. This inconsistency in research may be due to the caloric difference between supplements tested; due to the addition of protein, the CHO-P supplement contains more calories per serving than the CHO supplement. As a result, this study will be comparing 4 different supplements during endurance exercise, a CHO-P supplement, CHO supplement, a double carbohydrate supplement (CHO-CHO), and a placebo (PLA). The CHO and CHO-P supplement will be matched for CHO content, whereas the CHO-P and CHO-CHO supplements will be matched for total caloric content. Participants will be asked to run four 12-mile runs on 4 separate occasions, approximately 7-10 days apart, and will be blinded to supplement content and order of supplement administration among trials. The 12-mile run will elicit an exercise bout greater than 60 minutes, which is relevant when supplementing exercise with CHO or CHO-P. Performance will be assessed via time it takes to complete both the 12-mile run and the 1.6 mile maximal effort at the end of the run.