Effects of an active halftime rewarm-up, with carbohydrate supplementation, on player's blood glucose and second half performance during a collegiate soccer match

BACKGROUND: The half-time (HT) period of a soccer match is viewed as a period for recovery. Completely inactive and passive HT has implications on metabolic responses and subsequent performance during the initial phases of the second half. PURPOSE: Determine the effects of an active rewarm-up, compared to a passive period, at halftime on various measures of performance during the first 15-minutes of the second half using global positioning system (GPS) units. Identify the effects of the active versus passive HT period, with CHO beverage supplementation, on blood parameters. METHODS: Crossover design study, twenty collegiate male soccer players participated in two 90-minute soccer matches with passive rest (CON) or a moderate-intensity rewarm-up (RWU) during HT with CHO supplementation. Subjects received five fingerstick blood samples throughout the match (BG) and four subjects had serum insulin/BG taken three times during the match. RESULTS: RWU had significantly (p<0.05) higher measures for total distance, average speed, speed exertion, accelerations, HMP distance, decelerations, and EE during TI-4 half when compared to CON. No subjects experienced hypoglycemia. However, CON did have a significant drop in BG after HT and the lowest mean BG taken at 60-minutes. Tendency for CON and RWU to have HT insulin levels that were elevated and reduced, respectively. CONCLUSION: A passive HT period is not optimal, given its causal role in temporary physical performance deficits in the second half of soccer matches. The results provide a strong rationale for collegiate soccer players and teams to incorporate the 8-minute RWU into the HT regime to optimize second half performance. General Audience Abstract The half-time (HT) period of a soccer match is commonly viewed as a period of rest and recovery. A completely inactive HT period has metabolic and performance implications during the initial phases of the second half. A transient reduction in blood glucose (BG) concentrations could contribute to the second half performance decrement. The purpose of this study was to determine the effects of an active rewarm-up, compared to a passive period, at halftime on various measures of performance using global positioning system (GPS) units. Additionally, identify the effects of the active versus passive half-time period, with carbohydrate (CHO) beverage supplementation, on blood parameters. In a crossover design study, twenty collegiate male soccer players participated in two 90-minute soccer matches that included a passive rest (CON) or a moderate-intensity rewarm-up (RWU) during the 15-minute HT period with the consumption of a CHO beverage. Each subject received five finger stick blood samples throughout the match to monitor plasma blood glucose and a subset of four subjects had serum insulin taken three times during the match. The study found that an active HT, compared to passive, mixed with CHO supplementation significantly improved physical performance at the start of the second half. A passive HT period is not advised or optimal, given its causal role in temporary physical performance deficits in the second half of soccer matches. The results from this study provide a strong rationale for collegiate soccer players and teams to incorporate the 8minute moderate-intensity into the HT regime in order to optimize second half performance.