Introduction

Military leaders must understand how modern military equipment loads affect trade-offs between movement speed and physiological strain to optimize pacing strategies.

Purpose

To evaluate the effects of load carried in a recently developed military backpack on the walking speed and cardiometabolic responses of dismounted warfighters.

Methods

Fifteen soldiers (1 woman, 14 men; age, 22 ± 2 years; height, 173 ± 7 cm; body mass (BM), 73 ± 10 kg) completed incremental walking tests with four external load conditions (0, 22, 44, or 66% BM) using the US Army's newest backpack: the Modular Lightweight Load-Carrying Equipment 4000 (MOLLE 4000). Oxygen uptake (V̇O₂) and heart rate (HR) were evaluated relative to maximal values (V̇O_2max and HR_max respectively). Testing ceased when participants completed the highest tested speed (1.97 m s⁻¹), exceeded a respiratory exchange ratio (RER) of 1.00, or reached volitional exhaustion.

Results

Peak speed significantly decreased (p < 0.03) with successively heavier loads (0% BM, 1.95 ± 0.06 m s⁻¹; 22% BM, 1.87 ± 0.10 m s⁻¹; 44% BM, 1.69 ± 0.13 m s⁻¹; 66% BM, 1.48 ± 0.13 m s⁻¹). Peak V̇O₂ was significantly lower (p < 0.01) with 0% BM (47 ± 5% V̇O_2max) than each load (22% BM, 58 ± 8% V̇O_2max; 44% BM, 63 ± 10% V̇O_2max; 66% BM, 61 ± 11% V̇O_2max). Peak HR was significantly lower (p < 0.01) with 0% BM (71 ± 5% HR_max) versus each load (22% BM, 83 ± 6% HR_max; 44% BM, 87 ± 6% HR_max; 66% BM, 88 ± 6% HR_max).

Conclusion

Overburdened warfighters suffer severe impairments in walking speed even when carrying recently developed military load carriage equipment. Our results suggest that the relative work intensity of heavy load carriage may be better described when expressed relative to HR_max versus V̇O_2max.

中文翻译：

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现代军用背包负荷对美军士兵步行速度和心脏代谢反应的影响

简介

军事领导人必须了解现代军事装备负载如何影响移动速度和生理应变之间的权衡，以优化步调策略。

目的

评估最近开发的军用背包中携带的负载对下马作战人员的步行速度和心脏代谢反应的影响。

方法

15 名士兵（1 名女性，14 名男性；年龄，22 ± 2 岁；身高，173 ± 7 厘米；体重 (BM)，73 ± 10 公斤）在四种外部负载条件下（0、22、44、或 66% BM）使用美国陆军最新的背包：模块化轻型承载设备 4000 (MOLLE 4000)。相对于最大值（分别为V̇O _2max和HR _max）评估摄氧量（V̇O ₂）和心率（HR ）。当参与者完成最高测试速度 (1.97 m s ^-1 )、超过 1.00 的呼吸交换比 (RER) 或达到意志力衰竭时，测试停止。

结果

峰值速度显着降低 (p < 0.03)，连续增加负载 (0% BM, 1.95 ± 0.06 m s ^-1 ; 22% BM, 1.87 ± 0.10 m s ^-1 ; 44% BM, 1.69 ± 0.13 m s ^-1 ; 66% BM , 1.48 ± 0.13 毫秒^-1 )。0% BM (47 ± 5% V̇O _2max ) 的峰值 V̇O ₂显着低于 (p < 0.01)比每个负载 (22% BM, 58 ± 8% V̇O _2max ; 44% BM, 63 ± 10% V̇O _2max ; 66 % BM, 61 ± 11% V̇O _2max )。与每种负荷（22% BM，83 ± 6% HR _max；44% BM，87 ± 6% HR _max；66% ）相比，0% BM (71 ± 5% HR _max ) 的峰值 HR 显着降低 (p < 0.01) BM，_最大心率 88 ± 6%）。

结论

即使在携带最近开发的军用载重车设备时，负担过重的作战人员也会严重影响步行速度。我们的结果表明，当相对于 HR _max与 V̇O _2max表示时，可以更好地描述重载车厢的相对工作强度。