Georgiadis et al. ALL DATA

Background: We examined changes in hematological, biochemical, and hormonal biomarkers, along with endurance and explosive performance indices in amateur soccer players over a 4-week preseason period. Methods: Thirteen players (age: 19.7 ± 2.0 years; body mass: 73.0 ± 6.8 kg; height: 180 ± 0.1 cm; body fat: 8.6 ± 3.5%) were monitored during a 4-week preseason program, which included 21 training days, three friendly matches and four days of rest. Before and after this period, endurance capacity was evaluated using the Yo-Yo IR1 test, and leg power was assessed using the CMJ. Blood samples were collected for three consecutive days in week 1 and after week 4, to assess hematological and biochemical parameters. I nternal load during all weeks was assessed with session RPE (sRPE). Results: There was a 25.5% increase in Yo-Yo IR1 distance (2123 ± 413 vs. 1560 ± 356 m, p = 0.002), with VO₂max and the speed associated with VO₂max (vVO₂max) improving by 8.7% (49.5 ± 3.0 to 54.2 ± 3.5 ml/kg/min, p=0.002) and 5.3% (16.0±0.7 to 16.9±0.6 km/h, p=0.002), respectively. In contrast, CMJ performance in weeks 2-4 declined by 13.4–21% relative to baseline, while sRPE peaked during week 3 (4011 ± 440 AU). Hematological variables were mostly stable except for small increases in MCV and MCH (1.5–1.8%, p < 0.001), while there were significant reductions in urea (12%), uric acid (6.2%), and erythropoietin (33%). Conclusions: A 4-week preseason program substantially improved aerobic capacity, yet compromised leg power. Changes in biomarker profiles suggest that the training load maintained an appropriate balance between overload and recovery. These insights provide valuable guidance for coaches aiming to optimize training protocols while minimizing overtraining risks and preventing injury during the competitive season.

研究背景：本研究针对业余足球运动员，于为期4周的季前备战阶段，对其血液学、生化及激素生物标志物，以及耐力与爆发力性能指标的变化展开观测分析。
研究方法：本研究对13名运动员（年龄：19.7±2.0岁；体质量：73.0±6.8 kg；身高：180±0.1 cm；体脂率：8.6±3.5%）在为期4周的季前备战计划期间进行监测，该计划包含21次训练、3场友谊赛及4天休整期。在该阶段前后，分别采用Yo-Yo间歇耐力测试1型（Yo-Yo IR1）评估耐力能力，采用反向跳跃测试（Countermovement Jump, CMJ）评估下肢爆发力。于第1周及第4周结束后连续3天采集血液样本，以检测血液学与生化参数。采用训练课自觉疲劳评分（session Rating of Perceived Exertion, sRPE）评估各周的内部训练负荷。
研究结果：Yo-Yo IR1测试的完成距离较基线提升25.5%（2123±413 vs. 1560±356 m，p=0.002）；最大摄氧量（VO₂max）及其对应运动速度（vVO₂max）分别提升8.7%（49.5±3.0 升至54.2±3.5 ml/kg/min，p=0.002）与5.3%（16.0±0.7 升至16.9±0.6 km/h，p=0.002）。与之相对，第2至4周的CMJ表现较基线下降13.4%~21%，而sRPE评分在第3周达到峰值（4011±440 任意单位）。血液学指标整体较为稳定，仅平均红细胞体积（Mean Corpuscular Volume, MCV）与平均红细胞血红蛋白量（Mean Corpuscular Hemoglobin, MCH）小幅升高1.5%~1.8%（p<0.001）；尿素、尿酸及促红细胞生成素（erythropoietin）则分别显著降低12%、6.2%与33%。
研究结论：为期4周的季前备战计划可显著提升有氧耐力，但会对下肢爆发力造成一定损害。生物标志物谱的变化提示，本次训练负荷在超负荷与恢复之间维持了恰当的平衡。本研究结果可为教练员优化训练方案、降低过度训练风险并预防赛事季运动损伤提供有价值的参考依据。