BEHAVIOR OF CORTISOL, CK AND LACTATE IN A SESSION OF VARIABLE RESISTANCE

ABSTRACT Introduction: Complex Training (CT) has been used to achieve Post-activation Potentiation (PAP) of physical capabilities and, in doing so, improve the sports performance of athletes. However, few studies have considered alterations in serum Cortisol, Metabolic Creatine Kinase (MB-CK), Total Creatine Kinase (Total-CK), and Lactate concentrations ([La]) resulting from this training method. Objective: This study determined the behavior of the following blood serum substances in a CT session: Cortisol, MB-CK, Total CK and [La]. Method: Ten military athlete volunteers aged 28.5 ± 4.8 years; 66.2 ± 2.8 kg, 171.4 ± 3.7 cm, 22.6 ± 1.2 kg/m2; 11.3 ± 2.9% of fat tissue took part in the study. The study had a quasi-experimental, intrasubject design. The variable measurements were: Cortisol, MB-CK, Total-CK, and [La], measured before physical exercise and 24 hours post-stress. The CT session consisted of: four series of five repetitions at 30% of 1RM, plus four repetitions at 60% of 1RM, plus three throws of a 575 g projectile, 15 seconds apart. The statistical analysis was carried out through repeated measure ANOVA for Lactate and a Wilcoxon Matched Pairs t-Test for Cortisol, MB-CK and Total-CK. Results: There was no evidence of alterations in the indicators for fatigue ([La] p = 0.36), and muscular injury (Cortisol p = 0.16; MB-CK p = 0.23; Total-CK p = 0.64) after the training sessions. Conclusion: Variables for muscular injury showed no evidence of alterations 24 hours after the CT sessions, hence confirming that the workload did not generate significant post-stress muscular injury. Level of Evidence I; Therapeutic Study: Investigating Treatment Results.

摘要
引言：复合训练（Complex Training, CT）此前被用于实现运动能力的激活后增强效应（Post-activation Potentiation, PAP），借此提升运动员的运动表现。然而，鲜有研究关注该训练方式所引发的血清皮质醇、肌酸激酶同工酶MB（Metabolic Creatine Kinase, MB-CK）、总肌酸激酶（Total Creatine Kinase, Total-CK）以及乳酸浓度（[La]）的变化。
研究目的：本研究旨在明确复合训练课中，血清皮质醇、MB-CK、Total-CK及[La]的变化规律。
研究方法：本研究招募10名军事运动员志愿者，其年龄为28.5±4.8岁，体重66.2±2.8kg，身高171.4±3.7cm，体质量指数22.6±1.2kg/m²，体脂占比11.3±2.9%。本研究采用准实验性受试者内设计。于运动前及应激后24小时，分别测定受试者的皮质醇、MB-CK、Total-CK及[La]水平。本次复合训练课内容为：以单次最大负重（1RM）的30%完成4组、每组5次重复动作，再以1RM的60%完成4次重复动作，随后间隔15秒投掷575g的投掷物3次。统计分析方面，针对乳酸浓度采用重复测量方差分析，针对皮质醇、MB-CK及Total-CK则采用威尔科克森配对样本t检验。
研究结果：训练课后，疲劳相关指标[La]（p=0.36）以及肌肉损伤相关指标（皮质醇p=0.16；MB-CK p=0.23；Total-CK p=0.64）均未出现显著变化。
研究结论：复合训练课后24小时，肌肉损伤相关指标未出现显著变化，由此证实本次训练负荷未引发应激后显著肌肉损伤。
证据等级I；治疗性研究：探讨治疗效果。