This study will examine the effects of beta-alanine supplementation on physical performance in female rugby players, who will ingest 4.8 grams/day over a four-week period. The research will evaluate both cardiovascular and neuromuscular outcomes, with cardiovascular performance assessed using the Bronco Test (a field-based measure of endurance and repeated high-intensity running ability) and neuromuscular performance (e.g.vertical jump capacity).
This study will examine the effects of beta-alanine supplementation on physical performance in female rugby players, who will ingest 4.8 grams/day over a four-week period. Beta-alanine is a dietary supplement known to increase muscle carnosine levels, which may enhance buffering capacity and delay fatigue during high-intensity exercise. The research will evaluate both cardiovascular and neuromuscular outcomes, providing a comprehensive assessment of performance adaptations relevant to rugby. Cardiovascular performance will be assessed using the Bronco Test, a validated field-based measure of endurance and the ability to perform repeated high-intensity running efforts. Neuromuscular performance will be evaluated through measures of upper and lower-body strength /power output. Additionally, the study aims to explore whether beta-alanine supplementation can improve the ability to sustain high-intensity actions and overall physical readiness in female team-sport athletes.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
TRIPLE
Enrollment
30
Placebo group will receive 4.8 grams per day of placebo, containing fructose (3000 mg) and excipients (1800 mg) such as cellulose, calcium phosphate, silicon dioxide, and magnesium stearate. Both supplements will be matched in appearance and dosing schedule to ensure proper blinding. Compliance with the supplementation protocol will be monitored throughout the intervention period.
Participants assigned to the experimental group will receive beta-alanine supplementation (CROWN Sport Nutrition, La Rioja, España) at a dose of 4.8 grams per day for a period of four weeks . The supplement will be administered in divided doses throughout the day to enhance absorption and minimize potential side effects such as paresthesia
Álvaro López Samanes
Madrid, Madrid, Spain
Bronco Test (Cardiovascular Test)
The Bronco Test will be used to assess cardiovascular fitness and the ability to perform repeated high-intensity running efforts. This field-based test consists of continuous shuttle running over increasing distances (typically 20, 40, and 60 meters) repeated multiple times without rest, totaling 1,200 meters. Participants are required to complete the test as quickly as possible, with total time recorded as the main performance outcome. The Bronco Test is widely used in team sports such as rugby due to its strong ecological validity, as it reflects the intermittent and high-intensity nature of match play. Improvements in completion time are indicative of enhanced aerobic capacity, speed endurance, and overall cardiovascular performance.
Time frame: Before and after the intervention period, which lasted four weeks.
Repeated sprint ability capacity
Repeated-sprint ability will be assesed using a 6 × 30 m repeated-sprint test, from which two indices were derived: total sprint time and percent sprint decrement. Total sprint time was calculated as the sum of the six individual sprint times, expressed in seconds, and represents overall sprint performance across repeated efforts. The percent sprint decrement was used as an indicator of fatigue, reflecting the decline in performance across successive sprints.
Time frame: Before and after the intervention period, which lasted four weeks.
Isometric handgrip strength
Isometric handgrip strength will be assessed using a calibrated handgrip dynamometer. Participants will perform the test in a standardized position (standing), with the arm fully extended elbow and without contact with the body. After a brief familiarization, participants will be instructed to squeeze the dynamometer with maximal effort for 3-5 seconds. Two trials will be performed for each hand, with adequate rest between attempts to avoid fatigue. The highest value recorded (Newtons) will be used for analysis.
Time frame: Before and after the intervention period, which lasted four weeks.
This platform is for informational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional.
Vertical jump capacity (countermovement jump)
Vertical jump performance will be assessed using the countermovement jump (CMJ) test, a widely used measure of lower-body neuromuscular performance. Participants will begin in an upright standing position, then perform a rapid downward movement (eccentric phase) followed immediately by a maximal upward jump (concentric phase), with hands placed on the hips to eliminate arm swing. Jump height will be recorded using a validated measurement system (contact mat). Participants will perform two maximal attempts and the best performance will be used for analysis.
Time frame: Before and after the intervention period, which lasted four weeks.
Modified agility T-test
Agility will be assessed using the Modified Agility T-test measure by photocells, a reliable and sport-specific measure of change-of-direction speed. Participants will start behind the starting line, sprint forward to a central cone, shuffle laterally to one side, then move across to the opposite side, and finally return to the center before backpedaling to the starting position. The modified version typically involves shorter distances and emphasizes lateral movements relevant to team sports such as rugby. Performance time will be recorded using electronic timing gates. or a stopwatch, with faster times indicating better agility performance. Participants will perform two trials with adequate rest between attempts, and the best time will be used for analysis. This test evaluates multidirectional speed, coordination, and the ability to rapidly change direction, all of which are essential components of rugby performance.
Time frame: Before and after the intervention period, which lasted four weeks.
Rate of perceived exertion (RPE)
Rate of perceived exertion will be assessed using the Borg 6-20 scale to quantify participants' subjective perception of effort during exercise. Participants will be asked to rate their level of exertion immediately after training session by selecting a number that best reflects how hard the effort felt, ranging from 6 (no exertion at all) to 20 (maximal exertion). The Borg 6-20 scale is a valid and reliable tool that correlates well with physiological markers such as heart rate, and it is widely used to monitor internal load and exercise intensity in both research and applied sport settings.
Time frame: Before and after the intervention period, which lasted four weeks.