Acute effect of caffeine supplementation on neuromuscular performance and repeated-sprint ability in wheelchair rugby players: a case study

Introduction: Wheelchair sports, such as wheelchair rugby (WR), are intermittent in nature, combining high- and low-intensity actions. Although some data exists on the effects of caffeine intake in WR players, further research using specific physical tests related to the demands of WR gameplay is necessary. Aims: The aim of this study was to analyze the acute effect of caffeine supplementation on neuromuscular performance and repeated-sprint ability (RSA) in WR players. Methodology: A total of four WR players participated in this study. Participants ingested 4 mg/kg of anhydrous caffeine dissolved with saccharin in 200 mL of water (CAF) and 200 mL of plain water with saccharin (PLA) 45 minutes before warming up. The following tests were performed: rotator cuff maximum voluntary isometric contraction (MVIC) test, initial maximum push-rim propulsion (IMPRP) test, 10-m sprint test and RSA test (12 x 5 m). Results: CAF resulted in increased strength and power values in the MVIC and IMPRP tests (≈14.0–18.0%). Also, the CAF group reported a shorter sprint time at 3 (≈5.0%), 5 (≈3.0%), and 10 meters (≈2.0%). Discussion: Improvements in distance in the IMPRP as well as in a 20m sprint test have previously been reported in WR players after ingesting 4 mg/kg caffeine. Conclusions: The intake of 4 mg/kg of caffeine 45 minutes before warming up could be slightly enhance performance, especially in neuromuscular actions, in WR players.