Table 1_Oxygen consumption efficiency in firefighters: roles of fatigue and rescue task.docx

ObjectiveThis study compared standardized oxygen consumption responses during rescue tasks with varying loads and methods across different fatigue states in firefighters to identify optimal rescue strategies and enhance operational efficiency.
MethodsSixty-three professional healthy male firefighters were recruited. Oxygen consumption was measured using a wearable metabolic system as they performed 5 × 20-m shuttle sprints with different task loads (10 kg, 20 kg, 30 kg) and rescue methods (shoulder-, cradle-, hand-carrying) under five fatigue states (non-fatigue, whole-body, and mild/moderate/severe knee fatigue).
ResultsA mixed-model ANOVA revealed a significant main effect of task load on standardized oxygen consumption (F = 620.61, P < 0.001, ƞp2 = 0.798). Post-hoc tests showed that standardized oxygen consumption was significantly lower during medium-load (2.464 ± 0.616 mL/min/kg2) and large-load tasks (1.615 ± 0.317 mL/min/kg2) compared to small-load tasks (4.718 ± 1.043 mL/min/kg2) (all P < 0.05). Consumption during large-load tasks was also significantly lower than during medium-load tasks (P < 0.05). The main effects of fatigue states and rescue methods were not significant.
ConclusionTask load is the primary factor influencing oxygen efficiency during high-intensity shuttle sprints. Large-load tasks resulted in significantly lower standardized oxygen consumption across all fatigue states and rescue methods, indicating a “small load-low efficiency” phenomenon. Prioritizing large-load (30 kg) tasks in time-critical emergencies may improve rescue efficiency.

研究目的 本研究旨在对比消防员在不同疲劳状态下，采用不同负重与救援方式执行救援任务时的标准化耗氧量响应，以明确最优救援策略并提升作业效能。
研究方法 招募63名身体健康的职业男性消防员。在五种疲劳状态（无疲劳、全身疲劳以及轻度/中度/重度膝部疲劳）下，让受试者完成5组×20米折返冲刺任务，分别搭配三种任务负重（10 kg、20 kg、30 kg）与三种救援方式（肩扛式、怀抱式、手提式），并通过可穿戴代谢系统测量其耗氧量。
研究结果 混合模型方差分析（mixed-model ANOVA）结果显示，任务负重对标准化耗氧量存在显著主效应（F = 620.61, P < 0.001, ƞp² = 0.798）。事后检验表明，中负重（2.464 ± 0.616 mL/min/kg²）与大负重任务下的标准化耗氧量，均显著低于小负重任务（4.718 ± 1.043 mL/min/kg²）（所有P < 0.05）；大负重任务的耗氧量亦显著低于中负重任务（P < 0.05）。而疲劳状态与救援方式的主效应均未达到显著水平。
研究结论 任务负重是影响高强度折返冲刺作业氧利用效率的核心因素。在所有疲劳状态与救援方式下，大负重任务的标准化耗氧量均显著更低，印证了“小负荷-低效率”现象。在时间紧迫的应急场景中优先采用大负重（30 kg）作业方式，可有效提升救援效率。