Effects of a 5-Day Weight Loss Period and Glycemic Index on Elite Judoists` Performance and Blood Factors

Journal of Exercise Nutrition & Biochemistry 2010;14(4):183-189.

Abstract

The purpose of this study was to determine whether a short-term period of weight loss affect Judoists` performance in addition to determining whether their dietary ingestion during the time between weight measurement and their competition on the same day. For this purpose, 37 Judoists from Y University were performed VO2max test and blood collection before and after the short period of weight loss, and their food ingestion was recorded and determined glycemic index based on which all participants were grouped in to low (n=11), middle (n=8) and high (n=18). The results showed that the 5-day period of weight loss induced a significant decrease (-6%) in their performance determined by VO2max values (p<0.001), but no group difference was detected. No significant difference among the groups was detected on blood TG, TC, ammonia and FFA. However, significant difference was observed on blood lactate between pre- and post-periods of weight loss (p<0.05). In conclusion, our study showed that the short-period of weight loss significantly reduces Judoists` performance on their games, and although the middle GI group shows less negative effects of the short-period weight loss on exercise performance their food consumption based on GI does not significantly prevent negative changes. Therefore, it is necessary to find out a way for Judoists to prevent their performance decline caused during a couple of days before their games; thus, they play the games in their best condition.

Key Words: Training down, diet supplements, blood Lactate, maximal oxygen consumption