Table 1.  Effect of caffeine or placebo on the total amount of work done, mean power and energy expenditure during 15 min of steady state cycling (Phase A). Values are means (±SD, n = 10).
 

Time

Placebo

Caffeine

Mean change (%) ± 90% confidence limits

P

Work done
(J·kg-1)

5 min

281 (86)

271 (66)

-.11 (.19)

  

10 min

279 (74)

273 (64)

-.07 (.11)

  

15 min

277 (73)

280 (81)

.03 (.09)

  

Total

837 (232)

825 (210)

.05 (.08)

.39

Mean power (Watts)

5 min

55 (15)

54 (15)

-.06 (.20)

  

10 min

56 (15)

56 (14)

-.03 (.09)

  

15 min

56 (16)

56 (15)

-.01 (.10)

  

Overall

57 (16)

55 (14)

-.12 (.14)

.80

Energy
(kJ·min-1)

5 min

20 (5)

21 (4)

.20 (.20)

  

10 min

21 (5)

21 (4)

.08 (.19)

  

15 min

20 (5)

22 (5)

.48 (.25)

  

Energy (kJ)

Total

304 (296)

322 (315) *

.25 (.14)

.07
P indicates interaction effect of time and trial. * indicates a significant difference (p = 0.01) in total energy (kJ) values between trials based on results from a one-way ANOVA analysis.