Physiological and Performance Effects of Caffeine Gum Consumed During a Simulated Half-Time by Professional Academy Rugby Union Players

Russell, Mark; Reynolds, Nicholas A; Crewther, Blair T; Cook, Christian J; Kilduff, Liam P

doi:10.1519/JSC.0000000000002185

Author(s)

Russell, Mark

Reynolds, Nicholas A

Crewther, Blair T

Cook, Christian J

Kilduff, Liam P

Publication Date

2020-01

Abstract

Despite the prevalence of caffeine (CAF) as an ergogenic aid, few studies have examined the use of caffeinated gums, especially during half-time in team sports. The physiological (blood lactate and salivary hormone concentrations) and performance (repeated sprints and cognitive function) effects of consuming CAF gum during a simulated half-time were examined. Professional academy rugby union players (n = 14) completed this double-blind, randomized, counterbalanced study. After pre-exercise measurements, players chewed a placebo (PLC) gum for 5 minutes before a standardized warm-up and completing repeated sprint testing (RSSA1). Thereafter, during a 15-minute simulated half-time period, players chewed either CAF (400 mg; 4.1 +/- 0.5 mg[middle dot]kg<sup>-1</sup>) or PLC gum for 5 minutes before completing a second repeated sprint test (RSSA2). Blood lactate, salivary testosterone and cortisol concentrations, and indices of cognitive function (i.e., reaction time and Stroop test) were measured at baseline, pre-RSSA1, post-RSSA1, pre-RSSA2, and post-RSSA2. Sprint performance was not affected by CAF (p = 0.995) despite slower sprint times after the first sprint of both RSSA tests (all p < 0.002). After half-time, salivary testosterone increased by 70% (+97 +/- 58 pg[middle dot]ml<sup>-1</sup>) in CAF vs. PLC (p < 0.001), whereas salivary cortisol remained unchanged (p = 0.307). Cognitive performance was unaffected by time and trial (all p > 0.05). Although performance effects were absent, chewing CAF gum increased the salivary testosterone concentrations of professional rugby union players over a simulated half-time. Practitioners may, therefore, choose to recommend CAF gum between successive exercise bouts because of the increases in salivary testosterone observed; a variable associated with increased motivation and high-intensity exercise performance.

Citation

Journal of Strength and Conditioning Research, 34(1), p. 145-151

ISSN

1533-4287

1064-8011

Pubmed ID

29210957

Link

https://hdl.handle.net/1959.11/29155

Language

en

Publisher

Lippincott Williams & Wilkins

Title

Physiological and Performance Effects of Caffeine Gum Consumed During a Simulated Half-Time by Professional Academy Rugby Union Players

Type of document

Journal Article

Entity Type

Publication

Author(s)	Russell, Mark Reynolds, Nicholas A Crewther, Blair T Cook, Christian J Kilduff, Liam P
Publication Date	2020-01
Abstract	Despite the prevalence of caffeine (CAF) as an ergogenic aid, few studies have examined the use of caffeinated gums, especially during half-time in team sports. The physiological (blood lactate and salivary hormone concentrations) and performance (repeated sprints and cognitive function) effects of consuming CAF gum during a simulated half-time were examined. Professional academy rugby union players (n = 14) completed this double-blind, randomized, counterbalanced study. After pre-exercise measurements, players chewed a placebo (PLC) gum for 5 minutes before a standardized warm-up and completing repeated sprint testing (RSSA1). Thereafter, during a 15-minute simulated half-time period, players chewed either CAF (400 mg; 4.1 +/- 0.5 mg[middle dot]kg<sup>-1</sup>) or PLC gum for 5 minutes before completing a second repeated sprint test (RSSA2). Blood lactate, salivary testosterone and cortisol concentrations, and indices of cognitive function (i.e., reaction time and Stroop test) were measured at baseline, pre-RSSA1, post-RSSA1, pre-RSSA2, and post-RSSA2. Sprint performance was not affected by CAF (p = 0.995) despite slower sprint times after the first sprint of both RSSA tests (all p < 0.002). After half-time, salivary testosterone increased by 70% (+97 +/- 58 pg[middle dot]ml<sup>-1</sup>) in CAF vs. PLC (p < 0.001), whereas salivary cortisol remained unchanged (p = 0.307). Cognitive performance was unaffected by time and trial (all p > 0.05). Although performance effects were absent, chewing CAF gum increased the salivary testosterone concentrations of professional rugby union players over a simulated half-time. Practitioners may, therefore, choose to recommend CAF gum between successive exercise bouts because of the increases in salivary testosterone observed; a variable associated with increased motivation and high-intensity exercise performance.
Citation	Journal of Strength and Conditioning Research, 34(1), p. 145-151
ISSN	1533-4287 1064-8011
Pubmed ID	29210957
Link	https://hdl.handle.net/1959.11/29155
Language	en
Publisher	Lippincott Williams & Wilkins
Title	Physiological and Performance Effects of Caffeine Gum Consumed During a Simulated Half-Time by Professional Academy Rugby Union Players
Type of document	Journal Article
Entity Type	Publication

Physiological and Performance Effects of Caffeine Gum Consumed During a Simulated Half-Time by Professional Academy Rugby Union Players

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