Beta-Alanine Effects on Neuromuscular and Cardiovascular Performance in Female Rugby Players

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.

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.

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.

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.

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.

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.