Effect of Low-Dose Caffeine on Performance in Elite Sitting Volleyball Players

Ulaç Can YILDIRIM

Status: Completed

Conditions: Paralympic Athletes; Muscle Strength; Caffeine; Physical Endurance

Treatments: Dietary Supplement: Placebo; Dietary Supplement: Caffeine

Study type: Interventional

Funder types: Other

Identifiers

NCT07056231

2025/91

Details and patient eligibility

About

Background: Sitting volleyball is a sport that relies primarily on upper body strength and anaerobic capacity. In critical in-game skills such as serve and spike, factors such as speed-endurance time and impact power play a decisive role in performance. There are limited studies in the literature examining the effects of low-dose caffeine consumption on these skills. The effects of ergogenic supplements in Paralympic sports have not been sufficiently investigated, and the potential benefits of caffeine on serve and spike performance in sitting volleyball players remain unclear. Purpose: The main purpose of this research was to determine the effects of low-dose caffeine (3 mg/kg) consumption on the serve speed, spike speed and Speed-Endurance performances of elite-level sitting volleyball players. Method: The study was designed using a randomized, double-blind, balanced, and crossover experimental design. 13 elite male athletes from the 2024 Paravolley European Champion Sitting Volleyball Men's National Team participated in the study. Participants were evaluated for serve speed, spike speed, and speed-endurance performances in both 3 mg/kg caffeine (CAF) and placebo (PLA) conditions.

Full description

This study aimed to investigate the effects of low-dose caffeine ingestion on key performance parameters in elite-level sitting volleyball athletes. Sitting volleyball is a Paralympic sport that relies heavily on upper body explosive strength and short-term anaerobic power. While caffeine is a well-known ergogenic aid in able-bodied sports, its role in Paralympic contexts remains underexplored. Using a randomized, double-blind, placebo-controlled crossover design, the effects of 3 mg/kg caffeine consumption were assessed in 13 elite male sitting volleyball players. Each participant completed performance assessments under both caffeine and placebo conditions. The primary goal was to examine whether caffeine intake would enhance serve speed, spike speed, and repeated sprint ability. The study provides new insights into the acute ergogenic effects of caffeine in Paralympic team sport athletes, highlighting its selective benefit on explosive upper-body tasks such as serving.

Enrollment: 13 patients

Sex: Male

Ages: 18 to 35 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Male sitting volleyball players aged between 18 and 40
• Member of the 2024 National Sitting Volleyball Team
• At least 3 years of competitive playing experience
• No caffeine consumption 48 hours prior to testing
• Provided informed consent to participate

Exclusion criteria

• Known cardiovascular, neurological, or metabolic disorders
• Current use of medications that may affect caffeine metabolism
• Allergy or sensitivity to caffeine
• Use of performance-enhancing substances within the last month

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: Quadruple Blind

---

13 participants in 2 patient groups

Low-Dose Caffeine Arm

Experimental group

Description:

Participants receive a single oral dose of caffeine (3 mg/kg) during the first session and a placebo in the second session. There is a washout period of at least 48 hours between sessions.

Treatment:

Dietary Supplement: Placebo

Dietary Supplement: Caffeine

Placebo Arm

Experimental group

Description:

Participants receive a placebo during the first session and a single oral dose of caffeine (3 mg/kg) in the second session. There is a washout period of at least 48 hours between sessions.

Treatment:

Dietary Supplement: Placebo

Dietary Supplement: Caffeine