Table 2.
Effects of caffeine ingestion on performance in the muscular endurance test, countermovement jump, and Wingate: results from a series of one-way repeated measures analyses of variance.
| Variable | Placebo | Caffeine | Hedges’ g and 95% CI | p-Value |
|---|---|---|---|---|
| Muscular endurance test | ||||
| Maximum repetitions at 85% 1RM | 6.9 ± 2.2 | 8.2 ± 2.1 | 0.58 (0.29, 0.91) | <0.001 |
| Mean power matched for repetitions (W) | 418 ± 116 | 492 ± 138 | 0.56 (0.32, 0.83) | <0.001 |
| Mean velocity matched for repetitions (m/s) | 0.27 ± 0.05 | 0.32 ± 0.05 | 0.96 (0.58, 1.41) | <0.001 |
| Peak power matched for repetitions (W) | 669 ± 250 | 740 ± 258 | 0.27 (0.14, 0.42) | <0.001 |
| Peak velocity matched for repetitions (m/s) | 0.41 ± 0.08 | 0.46 ± 0.07 | 0.64 (0.38, 0.94) | <0.001 |
| CMJ | ||||
| Vertical jump height (cm) | 35.0 ± 6.1 | 35.8 ± 5.9 | 0.13 (0.02, 0.25) | 0.034 |
| Wingate test | ||||
| Peak power in the Wingate test (W) | 859 ± 237 | 948 ± 229 | 0.37 (0.21, 0.55) | <0.001 |
| Mean power in the Wingate test (W) | 598 ± 101 | 634 ± 100 | 0.34 (0.17, 0.54) | <0.001 |
| Minimum power in the Wingate test (W) | 349 ± 103 | 392 ± 96 | 0.41 (0.07, 0.78) | 0.020 |
1RM: one repetition maximum: CMJ: countermovement jump; CI: confidence interval.