Table 1.
Summary of studies included in the review.
| Study | Participants | Habitual Caffeine Intake | Caffeine Supplementation | Muscular Strength Test | Muscular Endurance Test |
|---|---|---|---|---|---|
| Arazi et al. (2016) | 10 teenage female karate athletes | <60 mg/day | 2 or 5 mg/kg ingested 60 min pre-exercise | 1RM leg press | 60% of 1RM to muscular failure in the bench press (1 set) |
| Fett et al. (2018) | 8 young resistance-trained women | Not reported | 6 mg/kg ingested 30 min pre-exercise | 1RM pull-down, hack squat, and bench press | Knee extension drop set using 100 kg, 80 kg, and 60 kg (1 set) |
| Filip-Stachnik et al. (2021) | 21 resistance-trained women | 5.8 ± 2.6 mg/kg/day | 3 or 6 mg/kg ingested 60 min pre–exercise | 1RM bench press | 50% of 1RM to muscular failure in the bench press (1 set) |
| Goldstein et al. (2010) | 15 young resistance-trained women | ≤250 mg/day n = 8 ≥250 mg/day n = 7 |
6 mg/kg ingested 60 min pre-exercise | 1RM bench press | 60% of 1RM to muscular failure in the bench press (1 set) |
| Norum et al. (2020) * | 15 young resistance-trained women | 341 ± 184 mg/day | 4 mg/kg ingested 60 min pre-exercise | 1RM squat and bench press | 60% of 1RM to muscular failure in the squat and bench press (1 set) |
| Pereira et al. (2021) | 29 young resistance-trained women | Not reported | 6 mg/kg ingested 60 min pre-exercise | n/a | Load of 10RM to muscular failure in the squat, leg press, bench press, shoulder press, and row (3 sets each exercise) |
| Sabblah et al. (2015) | 8 young resistance-trained women | Not reported | 5 mg/kg ingested 60 min pre-exercise | 1RM squat and bench press | 40% of 1RM to muscular failure in the bench press (1 set) |
| Waer et al. (2021) | 19 healthy middle-aged women | <200 mg/day | 100 or 400 mg ingested 60 min pre-exercise | n/a | As many repetitions as possible in 30 s in the squat (no external load) and biceps curl with 2.27 kg (1 set) |
RM: repetition maximum; * study controlled for menstrual cycle phase; according to the Filip et al. [27] habitual use of caffeine can be classified as follows: “naïve consumer”—<25 mg/day; “low consumer”—25 mg/day to 0.99 mg/kg/day; “mild consumer”—1.00–2.99 mg/kg/day; “moderate consumer”—3.00–5.99 mg/kg/day; “high consumer”—6.00–8.99 mg/kg/day; “very high consumer”—>9.00 mg/kg/day.