Effects of Different Doses of Caffeine Supplementation on Collegiate Male Volleyball Players’ Specific Performance and Skills: A Randomized, Double-Blind, Placebo-Controlled, Crossover Study

Abstract

Background: The improvement of performance and skill indices of volleyball players can affect their success rate. Therefore, the present study aimed to evaluate the effects of acute caffeine supplementation of varied doses on collegiate volleyball players’ specific performance and skills. Method: This research was a randomized, double-blind, crossover design study in which 15 male volleyball players aged 18 to 25 years participated voluntarily. Participants were randomly placed in three different conditions, including 3 mg of caffeine per kilogram of body weight (C3), 6 mg of caffeine per kilogram of body weight (C6), and a placebo (PLA) with a one-week wash-out period between exercise trials. The supplement was taken 60 min before each exercise session. Ball throwing, hand movement speed, agility, Sargent’s jump and handgrip, and attacking and serving skill tests were measured and analyzed to check the performance and skill of the volleyball players. Results: This study showed a significant increase in agility test in C6 compared with the PLA condition (p = 0.02). Additionally, there was a significant improvement in Sargent’s jump in C6 compared with PLA (p = 0.00) and C6 compared with the C3 condition (p = 0.00). Also, attacking skill significantly increased in C3 compared with PLA (p = 0.00) and C6 compared with the PLA condition (p = 0.00). In addition, there was a significant increase in serving skill for C6 compared with PLA (p = 0.00) and C3 (p = 0.00). However, there were no significant differences in hand movement speed (p = 0.06), left handgrip (p = 0.85), right handgrip (p = 0.47), or medicine ball throwing (p = 0.22) between the three conditions. Conclusions: In conclusion, the findings of the current study suggested that a higher dose of caffeine compared with a lower dose may be more effective in movements requiring lower-body explosive power and the ability to change direction. Also, according to the findings, it seems that caffeine can lead to the improvement of complex skills, such as serving and attacking in volleyball.

Effects of Acute Ingestion of Caffeine Capsules on Muscle Strength and Muscle Endurance: A Systematic Review and Meta-Analysis

“…A randomized, double-blind crossover study of upper body muscle strength in female habitual caffeine users showed that an acute ingestion of 6 mg/kg BW of caffeine resulted in a significant boost in barbell speed during the bench press, as compared to the ingestion of 3 mg/kg BW [ 59 ]. In addition, Nemati et al [ 60 ] showed that 6 mg/kg BW of caffeine was more effective in enhancing lower body muscle strength in collegiate male volleyball players compared to 3 mg/kg BW. This may be due to the fact that caffeine at ≥6 mg/kg BW better promotes Ca 2+ release and enhances the contractility of skeletal muscle, making the potentiating effect significant.…”

Effect of Off-Season Iron Supplementation on Aerobic Capacity of Female Handball Player: A Randomized, Double-Blinded, Placebo-Controlled Study

“…Using block randomization, eligible participants were randomly assigned in a 1:1 ratio to either the supplement or placebo group [ 27 ]. Participants were instructed to avoid consuming caffeinated sources and perform vigorous exercise ≥24 h before the experiment to control for any acute and side effects on the measured variables [ 28 ]. The randomization allocation table was created by a study team member blinded to assessments; allocation numbers were then placed in sealed envelopes ( Figure 1 ).…”

Examining the impact of differing caffeine dosages in conjunction with plyometric training on physiological adaptations in basketball players

“…Of the used supplements by athletes, caffeine stands as an effective supplement for neuromuscular, metabolic, and cardiovascular functions, leading to enhanced technical and physical performance. Caffeine is particularly renowned for its acute and chronic impact on athletic performance 20 . Caffeine is a potent supplement that can boost energy expenditure after physical activity 20 .…”

“…Caffeine is particularly renowned for its acute and chronic impact on athletic performance 20 . Caffeine is a potent supplement that can boost energy expenditure after physical activity 20 . It is a widely consumed bioactive substance in our diet and is known to stimulate the central nervous system 21 , 22 .…”

“…In addition, supplementations with caffeine could increase the muscle fibers' contractile properties, enhancing maximal intensity exercise performance 23 . These caffeine-induced effects result in enhanced jumping ability 20 , sprint performance 24 , 25 , reactive agility and decision time 26 , anaerobic power 21 , strength and muscular power 23 , sprint performance 24 , 25 , and endurance time to exhaustion 27 .…”