This study aimed to investigate the association between training load indices and Upper Respiratory Tract Infection (URTI) across different lag periods in elite soccer players. Internal training load was collected from 15 elite soccer players over one full season (40 weeks). Acute, chronic, Acute:Chronic Workload Ratio (ACWR), Exponentially Weighted Moving Averages (EWMA) ACWR, 2, 3 and 4-week cumulative load, training strain and training monotony were calculated on a rolling weekly basis. Players completed a daily illness log, documenting any signs and symptoms, to help determine an URTI. Multilevel logistic regression was used to analyze the associations between training load indices and URTIs across different lag periods (1 to 7-days). The results found a significant association between 2-week cumulative load and an increased likelihood of a player contracting an URTI 3 days later (Odds Ratio, 95% Confidence Interval: OR = 2.07, 95% CI = 0.026-1.431). Additionally, a significant association was found between 3-week cumulative load and a players’ increased risk of contracting an URTI 4 days later (OR = 1.66, 95% CI = 0.013–1.006). These results indicate that accumulated periods of high training load (2- and 3-week) associated with an increased risk of a player contracting an URTI, which may lead to performance decrements, missed training sessions or even competitions.

本研究旨在调查精英足球运动员不同滞后期的训练负荷指数与上呼吸道感染 (URTI) 之间的关联。内部训练负荷是在一个完整赛季（40 周）内从 15 名精英足球运动员那里收集的。急性、慢性、急性：慢性工作负荷比率 (ACWR)、指数加权移动平均线 (EWMA) ACWR、2、3 和 4 周累积负荷、训练压力和训练单调性是每周滚动计算的。玩家完成每日疾病日志，记录任何体征和症状，以帮助确定 URTI。多级逻辑回归用于分析不同滞后期（1 至 7 天）训练负荷指数和 URTI 之间的关联。结果发现 2 周累积负荷与球员 3 天后感染 URTI 的可能性增加之间存在显着关联（优势比，95% 置信区间：OR = 2.07，95% CI = 0.026-1.431）。此外，还发现 3 周累积负荷与球员 4 天后感染 URTI 的风险增加之间存在显着关联（OR = 1.66，95% CI = 0.013–1.006）。这些结果表明，高训练负荷（2 周和 3 周）的累积时期与球员感染 URTI 的风险增加有关，这可能导致表现下降、错过训练课程甚至比赛。发现 3 周累积负荷与球员 4 天后感染 URTI 的风险增加之间存在显着关联（OR = 1.66，95% CI = 0.013–1.006）。这些结果表明，高训练负荷（2 周和 3 周）的累积时期与球员感染 URTI 的风险增加有关，这可能导致表现下降、错过训练课程甚至比赛。发现 3 周累积负荷与球员 4 天后感染 URTI 的风险增加之间存在显着关联（OR = 1.66，95% CI = 0.013–1.006）。这些结果表明，高训练负荷（2 周和 3 周）的累积时期与球员感染 URTI 的风险增加有关，这可能导致表现下降、错过训练课程甚至比赛。