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Andrew Foskett, Ajmol Ali and Nicholas Gant

There is little evidence regarding the benefits of caffeine ingestion on cognitive function and skillful actions during sporting performance, especially in sports that are multifaceted in their physiological, skill, and cognitive demands.

Purpose:

To examine the influence of caffeine on performance during simulated soccer activity.

Methods:

Twelve male soccer players completed two 90-min soccer-specific intermittent running trials interspersed with tests of soccer skill (LSPT). The trials were separated by 7 days and adhered to a randomized crossover design. On each occasion participants ingested 6 mg/kg body mass (BM) of caffeine (CAF) or a placebo (PLA) in a double-blind fashion 60 min before exercise. Movement time, penalties accrued, and total time were recorded for the LSPT. Physiological and performance markers were measured throughout the protocol. Water (3 ml/kg BM) was ingested every 15 min.

Results:

Participants accrued significantly less penalty time in the CAF trial (9.7 ± 6.6 s vs. PLA 11.6 ± 7.4 s; p = .02), leading to a significantly lower total time in this trial (CAF 51.6 ± 7.7 s vs. PLA 53.9 ± 8.5 s; p = .02). This decrease in penalty time was probably attributable to an increased passing accuracy in the CAF trial (p = .06). Jump height was 2.7% (± 1.1%) higher in the CAF trial (57.1 ± 5.1 cm vs. PLA 55.6 ± 5.1 cm; p = .01).

Conclusions:

Caffeine ingestion before simulated soccer activity improved players’ passing accuracy and jump performance without any detrimental effects on other performance parameters.

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Nicholas Gant, Ajmol Ali and Andrew Foskett

Carbohydrate and caffeine are known to independently improve certain aspects of athletic performance. However, less is understood about physiological and performance outcomes when these compounds are coingested in a rehydration and carbohydrate-replacement strategy. The aim of this study was to examine the influence of adding a moderate dose of caffeine to a carbohydrate solution during prolonged soccer activity. Fifteen male soccer players performed two 90-min intermittent shuttle-running trials. They ingested a carbohydrate-electrolyte solution (CON) providing a total of 1.8 g/kg body mass (BM) of carbohydrate or a similar solution with added caffeine (CAF; 3.7 mg/kg BM). Solutions were ingested 1 hr before exercise and every 15 min during the protocol. Soccer passing skill and countermovement-jump height (CMJ) were quantified before exercise and regularly during exercise. Sprinting performance, heart rate, blood lactate concentration (La) and the subjective experiences of participants were measured routinely. Mean 15-m sprint time was faster during CAF (p = .04); over the final 15 min of exercise mean sprint times were CAF 2.48 ± 0.15 s vs. CON 2.59 ± 0.2 s. Explosive leg power (CMJ) was improved during CAF (52.9 ± 5.8 vs. CON 51.7 ± 5.7 cm, p = .03). Heart rate was elevated throughout CAF, and ratings of pleasure were significantly enhanced. There were no significant differences in passing skill, rating of perceived exertion, La, or body-mass losses between trials. The addition of caffeine to the carbohydrate-electrolyte solution improved sprinting performance, countermovement jumping, and the subjective experiences of players. Caffeine appeared to offset the fatigue-induced decline in self-selected components of performance.

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Nicolette C. Bishop, Michael Gleeson, Ceri W. Nicholas and Ajmol Ali

Ingesting carbohydrate (CHO) beverages during prolonged, continuous heavy exercise results in smaller changes in the plasma concentrations of several cytokines and attenuates a decline in neutrophil function. In contrast, ingesting CHO during prolonged intermittent exercise appears to have negligible influence on these responses, probably due to the overall moderate intensity of these intermittent exercise protocols. Therefore, we examined the effect of CHO ingestion on plasma interIeukin-6 (IL-6), tumor necrosis factor-α (TNF-α) and lipopolysaccharide (LPS)-stimuIated neutrophil degranulation responses to high-intensity intermittent running. Six trained male soccer players performed 2 exercise trials, 7 days apart, in a randomized, counterbalanced design. On each occasion, they completed six 15-min periods of intermittent running consisting of maximal sprinting interspersed with less intense periods of running and walking. Subjects consumed either CHO or artificially sweetened placebo(PLA) beverages immediately before and at 15-min intervals during the exercise. At 30 min post-exercise, CHO versus PLA was associated with a higher plasma glucose concentration (p< .01), a lower plasma cortisol and IL-6 concentration (p < .02), and fewer numbers of circulating neutrophils (p < .05). Following the exercise, LPS-stimulated elastase release per neutrophil fell 31 % below baseline values on the PLA trial (p = .06) compared with 11% on the CHO trial (p = .30). Plasma TNF-α concentration increased following the exercise (main effect of time, p < .001) but was not affected by CHO. These data indicate that CHO ingestion attenuates changes in plasma IL-6 concentration, neutrophil trafficking, and LPS-stimulated neutrophil degranulation in response to intermittent exercise that involves bouts of very high intensity exercise.

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Christine Crooks, Martin L. Cross, Clare Wall and Ajmol Ali

Purpose:

This study investigated the effect of bovine colostrum (BC) on mucosal defense in the respiratory tracts of athletes and a nonexercising control group.

Methods:

An athlete cohort (ATH) of 25 (12 male, 13 female) elite swimmers (age 14–23 yr) and a control cohort (CON) of 28 (9M, 19F) students (age 18–27 yr) were randomly allocated in a double-blind manner to receive either 25 g BC (low-protein colostrum powder) or isocaloric placebo (PL) per day for 10 wk. Postprandial saliva samples were analyzed for immunoglobulins (A, G, and M) and osmolality at baseline, after 4 and 10 wk, and 2 wk postsupplementation. Blood samples were analyzed for immunoglobulins and C-reactive protein at baseline, after 5 and 10 wk, and 2 wk postsupplementation. Dietary intake was assessed by self-recorded dietary records. Upper respiratory tract symptoms (URS) and exercise were also self-recorded daily.

Results:

There was no significant time-related effect of the BC supplement on either saliva or plasma immunoglobulin levels for either cohort. After 4 wk supplementation fewer ATH/BC (25%) than ATH/PL participants (61%) reported URS incidents (p = .062). No significant difference occurred in URS reports in the control group.

Conclusion:

There was no measurable effect on immunoglobulin levels of consuming BC, which is in contrast to effects that have been reported previously in marathon runners, indicating that the effect of BC supplementation is not universal in all groups of athletes. Fewer athletes reported URS (although cause unknown) when consuming BC, which may be advantageous for training.

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Farid Farhani, Hamid Rajabi, Raoof Negaresh, Ajmol Ali, Sadegh Amani Shalamzari and Julien S. Baker

Purpose: To examine the validity and reliability of a novel futsal special performance test (FSPT) as a measure of futsal performance and skills. Methods: Thirty-six futsal players with different levels of experience were recruited and divided into 2 groups (elite and nonelite). Players participated in 4 sessions (at least 7 d apart): (1) familiarization session, (2) anaerobic power (Wingate test), (3) FSPT trial 1, and (4) FSPT trial 2. The FSPT was carried out on a futsal court (wooden sprung floor) and skills such as dribbling, rotation, long and short passing, and shooting were examined. Content validity was assessed by 6 experienced futsal coaches and instructors. Results: There was a significant correlation between FSPT and various aspects of anaerobic power (r = .5–.91; P ≤ .001). Moreover, significant large correlations were observed between test and retest of FSPT (r = .77; 95% confidence interval [CI], .56–.98; P ≤ .001). All instructors and coaches confirmed the content validity. There was high interrater reliability of the FSPT (r = .89; 95% CI, .85–.93; P < .001). FSPT total time (P = .001), penalty time (P = .022), and performance time (P = .001) were superior in elite relative to nonelite players. Anaerobic power was greater in elite players (P < .001). Conclusion: The results support the use of the FSPT to assess futsal players’ performance in conjunction with skill and anaerobic fitness.