Effects of caffeine ingestion on upper and lower limb muscle power of handball players: a double-blind, placebo-controlled, crossover study

As jumping and throwing are fundamental technical skills in handball and caffeine has a potential to improve muscle power, this substance could optimize upper and lower limb muscle power of handball players. Thus, we aimed to investigate the effects of caffeine ingestion on upper and lower limb muscle power of handball players. Using a double-blind, counterbalanced, and repeated-measures design, 10 handball players (training: 4.0 ± 1.6 d/week) performed two horizontal jump and medicine ball throw tests, before and 50 min after ingesting 5 mg·kg⁻¹ of caffeine or cellulose (placebo). Blinding effectiveness was assessed by the Bang's Blinding Index. Blinding process was successful. Compared with placebo, caffeine ingestion did not affect performance in the horizontal jump test (Caffeine: + 4.1 ± 5.0%; Placebo: + 2.9 ± 3.5%, P = 0.33; d = 0.29). Likewise, there was no difference between caffeine and placebo conditions for medicine ball throw test (Caffeine:  – 0.9 ± 7.1%; Placebo: + 3.2 ± 7.9%, P = 0.20; d =  – 0.55). Our results suggest that pre-exercise caffeine ingestion is not effective to improve upper and lower limb muscle power of handball players.