Ingesting a 6% carbohydrate-electrolyte solution improves endurance capacity, but not sprint performance, during intermittent, high-intensity shuttle running in adolescent team games players aged 12–14 years

Abstract

The main aim of this study was to investigate the influence of consuming a 6% carbohydrate-electrolyte (CHO-E) solution on the intermittent, high-intensity endurance performance and capacity of adolescent team games players. Fifteen participants (mean age 12.7 +/- 0.8 years) performed two trials separated by 3-7 days. In each trial, they completed 60 min of exercise composed of four 15-min periods of part A of the Loughborough Intermittent Shuttle Test, followed by an intermittent run to exhaustion (part B). In a double-blind, randomised, counterbalanced fashion participants consumed either the 6% CHO-E solution or a non-carbohydrate (CHO) placebo (5 ml kg(-1) BM) during the 5 min pre-trial and after each 15-min period of part A (2 ml kg(-1) BM). Time to fatigue was increased by 24.4% during part B when CHO was ingested (5.1 +/- 1.8 vs. 4.1 +/- 1.6 min, P < 0.05), with distance covered in part B also significantly greater in the CHO trial (851 +/- 365 vs. 694 +/- 278 m, P < 0.05). No significant between-trials differences were observed for mean 15-m sprint time (P = 0.35), peak sprint time (P = 0.77), or heart rate (P = 0.08) during part A. These results demonstrate, for the first time, that ingestion of a CHO-E solution significantly improves the intermittent, high-intensity endurance running capacity of adolescent team games players during an exercise protocol designed to simulate the physiological demands of team games.

Beverage carbohydrate concentration influences the intermittent endurance capacity of adolescent team games players during prolonged intermittent running

“…The findings of Phillips et al (2010) were generated despite one fewer drink period compared with adult work, as adolescents commonly play team games for a shorter duration than adults (60 vs. 90 min; Ekblom 1986). As a result, mean CHO intake was 0.56 g min -1 compared with *0.79-1.3 g min -1 in adult work (Nicholas et al 1995;Welsh et al 2002).…”

“…Furthermore, the [CHO] of the MCHO solution was the same as that used in previous research from this laboratory (Phillips et al 2010) and was similar to solutions used in the majority of adult work (Davis et al 1999;Nicholas et al 1995;Welsh et al 2002). The HCHO solution was employed, as solutions with a [CHO][10% are rarely used in contemporary research due to current adult guidelines regarding fluid and CHO intake during prolonged, steadystate exercise (Jeukendrup 2004).…”

“…Instead, biological maturity offset was assessed using the established, non-invasive equations of Mirwald et al (2002), as previously described (Phillips et al 2010). For the participants in this study, mean biological maturity offset was ?1.25 years (range ?0.62 to ?2.68 years).…”

“…We recently reported a significant 24% improvement in intermittent endurance running capacity (hereafter referred to as intermittent endurance capacity) when 12 to 14-yearold team games athletes ingested a 6% carbohydrateelectrolyte (CHO-E) solution before and during a modified Loughborough Intermittent Shuttle Test (LIST; Phillips et al 2010). This was achieved using the same body mass (BM)-standardised ingestion volumes and timings as the original adult work of Nicholas et al (1995).…”

The Young Athlete

“…However, ingestion of a similar drink had no effect on rating of perceived exertion when boys cycled 1 hour at 70% VO 2 peak . In a doubleblinded and randomized counterbalanced study, Phillips et al (2010) examined the effect of ingestion of a 6% carbohydrate-electrolyte drink on performance tests that consisted of 60-minute runs (4-to 15-minute intervals) followed by an intermittent 15-minute run to exhaustion with competitive young (12-14 years) players of football, rugby, and fi eld hockey. Time to exhaustion increased by 24% in the 15-minute runs when carbohydrate was ingested prior to and during the test, but no difference was found in the 15-minute sprint time or peak sprint time.…”