title: Acceleration tolerance after ingestion of a commercial energy drink.
abstract: BACKGROUND
  Caffeine ingestion has been demonstrated to increase physical performance in some situations. This study examined the ability of a commercial energy drink containing caffeine to enhance acceleration tolerance and strength under G load.
  
  
  METHODS
  Eight experienced centrifuge subjects completed three separate experimental acceleration exposures following ingestion of 11.5 ml x kg(-1) bodyweight of (1) a commercial energy drink, providing 5.0 mg caffeine/kg bodyweight; (2) a commercial energy drink without caffeine; or 3) a placebo. The acceleration exposures consisted of a relaxed gradual onset run to peripheral light loss, a rapid onset run to 6 G for 15 s, and a simulated air combat maneuver (SACM) run of repeated alternations between 4.5 G for 15 s and 7 G for 15 s until volitional exhaustion.
  
  
  RESULTS
  Relaxed G tolerance was 13% higher under the caffeinated energy drink session, whereas SACM duration did not differ among the drink conditions. Hip adductor muscle strength was 37% lower during the placebo session than during the other two sessions.
  
  
  CONCLUSIONS
  Consumption of a caffeine-based energy drink may enhance relaxed G tolerance and may increase strength, but does not impact acceleration tolerance duration.
authors.affiliation: 711th Human Performance Wing, Brooks City-Base, TX, USA. thomas.walker@brooks.af.mil
authors.forename: Thomas B
authors.initials: TB
authors.lastname: Walker
authors.forename: Ulf
authors.initials: U
authors.lastname: Balldin
authors.forename: Joseph
authors.initials: J
authors.lastname: Fischer
authors.forename: William
authors.initials: W
authors.lastname: Storm
authors.forename: Gordon L
authors.initials: GL
authors.lastname: Warren
mesh_terms: D000054:Acceleration; D000328:Adult; D000337:Aerospace Medicine; D000339:Affect; D001628:Beverages; D001794:Blood Pressure / Q000187:drug effects; D002110:Caffeine / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D000697:Central Nervous System Stimulants / Q000008:administration & dosage / Q000097:blood / Q000494:pharmacology*; D005260:Female; D006112:Gravitation; D006801:Humans; D008297:Male; D014474:Unconsciousness; D055815:Young Adult
chemical_list: D000697:Central Nervous System Stimulants; D002110:Caffeine