Effects of β-Alanine Supplementation on Kickboxing-Specific Anaerobic Performance, Neuromuscular Power, and Strength Endurance: A Randomized, Double-Blind, Placebo-Controlled Trial
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 发起方
- 入组人数
- 28
- 试验地点
- 1
- 主要终点
- Total Time on Kickboxing Anaerobic Speed Test (KASTtotal)
研究概览
简要总结
This randomized, double-blind, placebo-controlled parallel-group trial will evaluate whether four weeks of β-alanine (BA) supplementation improves sport-specific anaerobic performance, neuromuscular power, and strength endurance in trained male kickboxers. β-Alanine is the rate-limiting precursor for skeletal muscle carnosine, an intramuscular buffer that can attenuate exercise-induced acidosis during repeated high-intensity efforts. Because kickboxing involves brief, repeated striking sequences with high glycolytic demand, BA may represent a practical, legal ergogenic aid for this population.
Twenty-eight adult male kickboxers will be randomized (stratified) to BA (6.4 g·day-¹) or placebo for 4 weeks while maintaining habitual training and diet. Assessments will occur at baseline and post-intervention under standardized laboratory conditions and time-of-day control. The primary outcome is the total time on the Kickboxing Anaerobic Speed Test (KASTtotal; five consecutive sets of a validated four-technique striking combination with 10-s passive recovery). Secondary outcomes include best single-set time (KASTbest), individual set times (KAST₁-₅), Performance Decrement Index (PDI), countermovement jump (CMJ) and squat jump (SJ) height, and upper-body strength endurance (maximal push-ups and pull-ups performed to strict standards). Timing is determined from 25-fps video with frame-level analysis; jump height is derived via a validated smartphone application.
Adverse events-particularly transient paresthesia-will be monitored throughout. The main analysis will use two-way repeated-measures ANOVA (group × time) with partial eta-squared to quantify effects; assumption checks and correction procedures will be applied as appropriate. BA will yield greater improvements than placebo in KASTtotal and upper-body strength endurance, with limited changes expected for jump performance.
详细描述
Rationale and Background: β-Alanine supplementation increases intramuscular carnosine, enhancing intracellular buffering capacity and potentially preserving excitation-contraction coupling during high-intensity, repeated efforts. Kickboxing competition is characterized by short striking bouts, rapid direction changes, and high glycolytic contribution-conditions under which increased buffering may translate to meaningful performance benefits. Prior work in combat sports has reported ergogenic effects of BA; however, evidence in kickboxing using a validated sport-specific test remains limited. This trial addresses that gap using the Kickboxing Anaerobic Speed Test (KAST), which offers strong ecological validity for combat athletes.
Design and Setting: Randomized, double-blind, placebo-controlled, parallel-group clinical trial with two assessment time points (pre, post). Participants continue usual training under coach supervision and are instructed to avoid other ergogenic aids and caffeine for 24 h before testing. All testing is performed under standardized environmental conditions (temperature and humidity controlled) and at the same time of day (±1 h) to minimize circadian and residual fatigue effects.
Participants: Twenty-eight healthy adult male kickboxers with ≥5 years of systematic training and active competition in the prior year. Key exclusions include musculoskeletal injury limiting high-intensity exercise, cardiometabolic or respiratory disease, β-alanine intolerance, and recent use of overlapping supplements. Written informed consent is obtained. The protocol complies with the Declaration of Helsinki and local ethics approval.
Interventions Experimental: β-alanine, 6.4 g·day-¹ for 4 weeks (e.g., divided doses). Comparator: Appearance-matched placebo (rice flour), same schedule. Products are dispensed in coded containers to preserve blinding of participants, investigators, and outcome assessors.
Outcome Measures Primary: KASTtotal (s), computed as the sum of five consecutive sets of a standardized four-technique combination performed at maximal effort with 10-s passive recovery. Timing starts at first bag contact and ends after the final kick; performance is video-recorded at 25 fps and analyzed frame-by-frame.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
盲法说明
Both participants and investigators are blinded to group allocation. Supplements are pre-packaged in identical, coded containers prepared by an independent staff member not involved in testing or data analysis. Coaches supervising the training sessions and all outcome assessors analyzing video and performance data are also blinded to the intervention codes until statistical analyses are complete.
入排标准
- 年龄范围
- 18 Years 至 35 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Healthy male kickboxers aged 18-35 years
- •Minimum 5 years of systematic kickboxing training experience
- •Actively engaged in competition or structured training within the last 12 months
- •Free from any musculoskeletal injuries, metabolic, cardiovascular, or respiratory disorders that could affect high-intensity exercise performance
- •Not currently taking any ergogenic aids, nutritional supplements, or medications known to influence performance or recovery
- •Willing to maintain habitual diet and training routines throughout the study period
- •Provided written informed consent before participation
排除标准
- •Current or recent (<6 months) musculoskeletal injury preventing maximal effort performance
- •Metabolic, cardiovascular, or respiratory conditions that may increase risk during high-intensity activity
- •Known allergy or intolerance to β-alanine
- •Use of performance-enhancing supplements (e.g., creatine, caffeine, sodium bicarbonate, beta-alanine) in the past 4 weeks
- •Any neurological, psychiatric, or endocrine disorder affecting physical performance or adherence
- •Inability or unwillingness to comply with supplementation protocol or testing procedures
研究组 & 干预措施
β-Alanine Supplementation
Participants receive 6.4 g of β-alanine per day for 4 weeks (e.g., 4 × 1.6 g divided doses). The supplement is provided as Hardline β-Alanine (Hardline Nutrition, Türkiye), standardized for active ingredient content.
干预措施: β-Alanine (Dietary Supplement)
Rice Flour
Participants receive a visually identical, flavor-matched placebo composed of rice flour, dosed equivalently to the experimental group (6.4 g·day-¹ for 4 weeks).
干预措施: Rice Flour (Placebo) (Dietary Supplement)
结局指标
主要结局
Total Time on Kickboxing Anaerobic Speed Test (KASTtotal)
时间窗: Baseline (Pre-supplementation) and after 4 weeks of supplementation (Post-intervention).
KASTtotal represents the cumulative time (in seconds) required to complete five consecutive sets of a standardized four-technique striking combination (jab-roundhouse-cross-roundhouse) performed at maximal intensity, with 10 seconds of passive recovery between sets. Timing begins at the first strike and ends at the completion of the final kick. This outcome reflects total anaerobic performance capacity under repeated high-intensity conditions specific to kickboxing.
次要结局
- Best Single-Set Time (KASTbest)(Baseline and Week 4)
- Push-up Repetitions(Baseline and Week 4)
- Countermovement Jump Height (CMJ)(Baseline and Week 4)
- Squat Jump Height (SJ)(Baseline and Week 4)
- Pull-up Repetitions(Baseline and Week 4)
研究者
Salih ÇABUK
Research Assistant
Erzurum Technical University