Event-Specific Adaptations to CrossFit and Running-Based HIIT in Elite Distance Runners at Moderate Altitude
试验速览
- 阶段
- 不适用
- 状态
- 已完成
- 入组人数
- 36
- 试验地点
- 1
- 主要终点
- Lactate Threshold (LT)
研究概览
简要总结
The goal of this clinical trial is to compare the effects of two high-intensity training programs on physical performance and physiological adaptations in elite male middle- and long-distance runners aged 25 to 35 years who live and train at moderate altitude (approximately 1,400 meters above sea level).
The main questions it aims to answer are:
Does running-based high-intensity interval training improve aerobic fitness and race performance in elite distance runners? Does CrossFit training improve muscle strength, power, and physiological markers in elite distance runners? Researchers will compare running-based high-intensity interval training (HIIT) with CrossFit training to determine how each program affects aerobic capacity, strength, running performance, and selected blood markers.
Participants will:
Be randomly assigned to either a running-based HIIT program or a CrossFit training program Train five days per week for six weeks under supervision Complete exercise testing before and after the training period, including treadmill fitness testing and timed running trials Provide blood samples before and after the intervention to measure selected physiological markers
详细描述
Background and Rationale:
Altitude training is widely employed by elite middle- and long-distance runners to stimulate key physiological adaptations, including erythropoietic upregulation, expansion of oxygen transport capacity, mitochondrial biogenesis, and skeletal muscle capillarization. These adaptations are considered central mechanisms through which hypoxic exposure enhances endurance performance. Despite the growing adoption of both running-based high-intensity interval training (HIIT) and multimodal CrossFit (CF) as primary high-intensity training modalities in elite endurance sport, no study has directly compared their respective physiological, neuromuscular, performance, and biomarker effects in runners residing and training at moderate altitude. Moreover, the extent to which event specialization (middle-distance: 800-3,000 m vs. long-distance: ≥5,000 m) moderates modality-specific training adaptations remains unexamined. This study is designed to address these gaps by providing the first direct empirical comparison of these two high-intensity training modalities in elite altitude-resident runners, stratified by competitive event specialization.
Study Design:
This is a six-week stratified quasi-experimental study employing a 2×2 factorial design with pre- and post-intervention assessments, conducted during the general preparatory phase of the competitive season at moderate altitude (approximately 1,400 m above sea level) in Zahedan, Iran. The two independent factors are training modality (HIIT vs. CF) and event specialization (middle-distance vs. long-distance). The study protocol has received ethical approval from the Ethics Committee of the University of Sistan and Baluchestan (Approval No. IR.USB.REC.1400.021) and will be conducted in full accordance with the Declaration of Helsinki and its subsequent amendments. Written informed consent will be obtained from all participants prior to any study-related procedures.
Randomization and Allocation Concealment:
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Factorial
- 主要目的
- Basic Science
- 盲法
- Single (Outcomes Assessor)
盲法说明
Although participants could not be blinded to their assigned training modality due to the inherently observable nature of the interventions, all data analysts and outcome assessors were masked to group assignment throughout the study to ensure objective evaluation of all physiological, performance, and biochemical outcomes.
入排标准
- 年龄范围
- 25 Years 至 35 Years（Adult）
- 性别
- Male
- 接受健康志愿者
- 是
入选标准
- •Nationally ranked elite male middle- or long-distance runner
- •Ranked within the national top 10 in their respective primary competitive event
- •Aged between 25 and 35 years
- •Minimum of six months of structured high-intensity training prior to enrollment, defined as more than five supervised sessions per week
- •Living and training year-round at moderate altitude (approximately 1,400 m) in Zahedan, Iran
- •Competing in one of the following event categories: middle-distance (800-3,000 m) or long-distance (≥5,000 m)
- •Willing and able to provide written informed consent prior to participation
- •Able to commit to five supervised training sessions per week for the full six-week intervention period
排除标准
- •Musculoskeletal injury within the three months preceding enrollment
- •Current or recent use of performance-enhancing substances
- •Use of new nutritional supplements during the study period
- •Any medical condition or physical limitation that could interfere with safe participation in high-intensity exercise training
- •Inability to complete the required number of training sessions due to scheduling conflicts or other commitments
- •Incomplete study application or failure to meet all inclusion criteria
结局指标
主要结局
Lactate Threshold (LT)
时间窗: Baseline and immediately after 6 weeks of intervention
Lactate threshold determined from a graded treadmill test using capillary blood lactate sampling and the modified Dmax method.
Maximal Oxygen Uptake (VO₂max)
时间窗: Baseline and immediately after 6 weeks of intervention
VO₂max assessed by automated breath-by-breath cardiopulmonary exercise testing during an incremental running protocol to volitional exhaustion.
1,500-Meter Time Trial Performance
时间窗: Baseline and immediately after 6 weeks of intervention
Time to complete a 1,500-meter maximal effort run on a standardized 400-meter synthetic track, recorded using an infrared timing system.
5,000-Meter Time Trial Performance
时间窗: Baseline and immediately after 6 weeks of intervention
Time to complete a 5,000-meter maximal effort run on a standardized 400-meter synthetic track, recorded using an infrared timing system.
次要结局
- Peak Power Output (PPO)(Baseline and immediately after 6 weeks of intervention)
- Deadlift One-Repetition Maximum (1RM)(Baseline and immediately after 6 weeks of intervention)
- Hemoglobin Concentration(Baseline and immediately after 6 weeks of intervention)
- Erythropoietin (EPO) Concentration(Baseline and immediately after 6 weeks of intervention)
- Creatine Kinase (CK) Activity(Baseline and immediately after 6 weeks of intervention)
- Interleukin-6 (IL-6) Concentration(Baseline and immediately after 6 weeks of intervention)
- Tumor Necrosis Factor-Alpha (TNF-α) Concentration(Baseline and immediately after 6 weeks of intervention)
研究者
Mohammadreza Rezaeipour, MD, PhD
MD, PhD, Associate Professor at the Sport Sciences Department
University of Sistan and Baluchestan