Caffeine and sports performance

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Caffeine and sports performance
SCAN Symposium'07 Sports Nutrition Training
Camp April 13-15, Austin Texas

• Professor Louise Burke,
• Department of Sports Nutrition,
• Australian Institute of Sport

Professor Louise Burke Department of Sports
Nutrition Australian Institute of Sport
CSEP Annual Scientific Conference November 14-17
2007, London, Ontario
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Elite sports performance versus studies of
exercise capacity

• Only the most exceptional college students win
  medals
• There are no medals for riding or running to
  fatigue
• Statisticians do not award the outcome of events
• Athletes generally dont choose baseline
  metabolic condition as ideal event preparation
• Sporting competitions run under an anti-doping
  code of conduct (e.g. WADA)

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Ideal examination ofcaffeine and sports
performance

• Highly trained subjects
• Diet and training preparation reflecting real
  life practices
• Relevant measurements of performance event
  simulation, close-looped outcomes
• Magnitude of performance differences compared
  with what is worthwhile in sport
• Protocols meet sports code of conduct

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Overview of issues

• What range of events might benefit from caffeine
  supplementation?
• What are some possible protocols of use?
• What are some issues that athletes need to
  consider in real life competition?
• Interaction with competition diet and nutrition
  strategies
• Issues of repeating supplementation for multiple
  events
• The politics of caffeine in sport

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Caffeine and endurance sports (60 min )
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Caffeine and endurance sports (60 min )
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Caffeine and endurance sports (60 min )
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Caffeine and cycling performance
Why do cyclists drink a sports drink for the
first two thirds of a road race, then switch to
defizzed Coke?

• Well-trained male cyclists
• Cycling protocol 2 h _at_ 70 VO2max 25 min TT
• Standardised training
• 24 h carbohydrate-rich diet pre-trial breakfast
• No caffeine intake over previous 48 hours
• 1 g/kg carbohydrate intake during exercise

Cox et al. J Appl Physiol 200293990-999
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Overview of protocol 1
Breakfast 2 g/kg carbohydrate 120 min pre-trial
Time Trial 7 kJ /kg BM
120 min CYCLING _at_ 70 VO2max
-60 0 20 40 60
80 100 120








TESTING SPORTS DRINK (5 ml/kg)







CAPSULES
PRE (1 X 6 mg) DURING (6 x 1 mg) PLACEBO COKE
Coca Cola
Coca Cola
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Caffeine and cycling performance 1
Time trial performance (7 kJ/kg
Enhancement compared with placebo
3.4 0.2 to 6.5
2818 040
6 mg/kg pre 6 x 1 mg during Coke (1.5
mg/kg) Placebo
3.4 -0.1 to 6.5
2824 057
3.1 -0.2 to 6.2
2824 030
2918 044
Cox et al. J Appl Physiol 200293990-999
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Effect of caffeine intake onurinary caffeine
Urinary caffeine (ug/ml)
12- 10- 8- 6- 4- 2-
IOC limit
Pre, during gt Coke, placebo
Pre During Coke Placebo
Cox et al. J Appl Physiol 200293990-999
12
Overview of protocol 2
Breakfast 2 g/kg carbohydrate 120 min pre-trial
Time Trial 7 kJ /kg BM
120 min CYCLING _at_ 70 VO2max
-60 0 20 40 60
80 100 120








TESTING SPORTS DRINK (5 ml/kg)




6 CHO, 0 caffeine 11 CHO, 0 caffeine 6 CHO,
13 mg/100 ml caffeine 11 CHO, 13 mg/100 ml
caffeine (Coca cola)
Cola drink
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Caffeine and cycling performance 2
Time trial performance (7 kJ/kg
Enhancement compared with placebo
3.2 0.8 to 5.9
Coke 6CHO 1.5 mg/kg caf 11
CHO 6CHO (Placebo)
2615 043
Effect of caffeine 2.2 0.5 to 3.8
1.9 -0.6 to 4.4
2636 042
0.6 -1.8 to 3.1
Effect of additional CHO 1 -0.7 to 2.7
2655 053
2705 042
Cox et al. J Appl Physiol 200293990-999
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Caffeine and sustained high-intensity sports
(1-30 min)
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Caffeine and 1 km cycle TT
5 mg/kg caffeine 75 min pre-event
Change in time (s)
Mens Kilo (1 km TT) 17 competitors 1st
2nd 0.185 s
(0.31) 2.39 s 1st
10th
Improvement 3.1 0.7-5.6
Wiles et al J Sports Sci 2006 24 1165-1171
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Caffeine and 1 km cycle TT
Change in time (s)
Individual subject outcomes
Wiles et al J Sports Sci 2006 24 1165-1171
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PERFORMANCE ENHANCEMENT WHAT IS SIGNIFICANT TO
AN ATHLETE?

• CV of performance of elite
• athletes is 1-4
• Worthwhile change in
• performance is 0.5 CV
• To detect small changes in performance
• - large sample size
• - reliable and valid protocols

Hopkins et al. Med Sci Sports Exerc 1999 31
472-485
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Caffeine and team/intermittent sports
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Caffeine and rugby performance

• 11 well-trained rugby union players
• Familiarised with lab protocol simulating a rugby
  game
• 14 circuits of a 11 station battery of tests
• 7 circuits (40 min) 10 min 7 circuits (40
  min)
• 6 mg/kg caffeine, 75 min pre-game
• Water consumed during the game

Stuart et al. Med Sci Sports Exerc 2006 37
1988-2005
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Caffeine and reduction in fatigue
Substantial change gt0.8 for sprints, gt4.7 for
Drive and gt 4.1 passing www.sportsci.org
Stuart et al. Med Sci Sports Exerc 2006 38
1985-2005
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Caffeine and jumps, lifts, throws and short
sprints
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Summary Caffeine and sport

• Caffeine may enhance performance of a variety of
  sports
• Endurance
• Sustained high intensity (1-30 min)
• Team/intermittent including skill
• Benefits seen at low-moderate caffeine doses
• Dose response? No gt 3 mg/kg, possible lt 3 mg/kg
  
• A variety of protocols of use can work
• before, during exercise, before onset of fatigue
• Responses are variable and may include
  side-effects
• Athletes should experiment to find if a protocol
  is beneficial for their event
• The politics of caffeine in sport are complicated