Background

During training, service members routinely walk with heavy body borne loads for long periods of time. These loads alter knee biomechanics and may produce jerky knee motions that reportedly increase joint loading and risk of musculoskeletal injury. Yet, it is unknown if service members use jerky knee motions during prolong walking with body borne load.

Research question

To quantify the effects of body borne load and duration of walking on the jerkiness of sagittal and frontal plane knee motion.

Methods

Eighteen participants had angular jerk of knee motion quantified while they walked (1.3 m/s) for 60-min with three body borne loads (0, 15, and 30 kg). Peak and cost of angular jerk for sagittal and frontal plane knee motion was quantified and submitted to a repeated measures linear model to test the main effects and interaction of load (0, 15, and 30 kg) and time (0, 15, 30, 45, and 60 min).

Results

Body borne load increased peak and cost of angular jerk for sagittal plane knee motion up to 35 % and 110 %, respectively, and frontal plane knee motion up to 20 % and 51 %, respectively (all p<0.001), while jerk cost of frontal plane knee motion (p=0.001) increased 31 % after walking 45 min.

Significance

Body borne load produced large (between 20 % and 110 %), incremental increases in angular jerk for both sagittal and frontal plane knee motion; whereas, duration of walking led to a 31 % increase in jerkiness of frontal plane knee motion. Service members who often walking for long periods of time with heavy body borne loads may have greater risk of developing musculoskeletal injury and disease due to large increases in jerky knee motions.

中文翻译：

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长时间负重对膝关节前向和矢状运动角冲击的影响

背景

在训练期间，服役人员通常会长时间负重行走。这些负荷会改变膝关节的生物力学，并可能产生不平稳的膝关节运动，据报道会增加关节负荷和肌肉骨骼损伤的风险。然而，目前尚不清楚服务人员在长时间负重行走期间是否使用生涩的膝盖运动。

研究问题

量化身体负重和行走持续时间对矢状面和额面膝关节运动的急动性的影响。

方法

18 名参与者在以三种身体负重（0、15 和 30 公斤）行走 60 分钟（1.3 米/秒）时量化了膝关节的角跳动。对矢状面和额面膝关节运动的角冲击峰值和成本进行量化，并提交给重复测量线性模型，以测试负载（0、15 和 30 kg）和时间（0、15、30、 45 和 60 分钟）。

结果

身体承受的负荷增加了矢状面膝关节运动的峰值和角跳动成本分别高达 35% 和 110%，额平面膝关节运动分别高达 20% 和 51%（所有 p<0.001），而步行 45 分钟后，额平面膝关节运动 (p=0.001) 增加了 31%。

意义

身体承受的负荷产生很大（在 20 % 和 110 % 之间），在矢状面和额面膝关节运动的角度急动度增加；然而，步行的持续时间导致额平面膝关节运动的急动度增加了 31%。经常带着沉重的身体负重长时间行走的服务人员可能由于膝关节急促运动的大幅增加而更容易发生肌肉骨骼损伤和疾病。