Dept. of Kinesiology, Boise State University, Boise, ID, USA.
Dept. of Kinesiology, Boise State University, Boise, ID, USA.
Gait Posture. 2021 Feb;84:221-226. doi: 10.1016/j.gaitpost.2020.12.006. Epub 2020 Dec 14.
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.
To quantify the effects of body borne load and duration of walking on the jerkiness of sagittal and frontal plane knee motion.
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).
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.
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.
在训练中，军人通常会长时间背负重物行走。这些负荷改变了膝关节的生物力学特性，可能导致膝关节运动不平稳，据报道这会增加关节负荷并增加肌肉骨骼损伤的风险。然而，目前尚不清楚军人在背负身体负荷长时间行走时是否会出现膝关节运动不平稳的情况。
定量研究身体负荷和行走时间对矢状面和额状面膝关节运动不平稳的影响。
18 名参与者在背负 0、15 和 30 公斤三种身体负荷的情况下，以 1.3 米/秒的速度行走 60 分钟，测量其膝关节运动的角加速度。对矢状面和额状面膝关节运动的角加速度峰值和成本进行了量化，并提交给重复测量线性模型，以测试负荷（0、15 和 30 公斤）和时间（0、15、30、45 和 60 分钟）的主要效应和交互作用。
身体负荷使矢状面膝关节运动的角加速度峰值和成本分别增加了 35%和 110%，额状面膝关节运动的角加速度峰值和成本分别增加了 20%和 51%（均 p<0.001），而在行走 45 分钟后，额状面膝关节运动的角加速度成本增加了 31%（p=0.001）。
身体负荷使矢状面和额状面膝关节运动的角加速度均产生了较大（20%-110%）的增量，而行走时间的延长导致额状面膝关节运动的不平稳性增加了 31%。经常背负重物长时间行走的军人可能会因为膝关节运动不平稳的大幅增加而增加患肌肉骨骼损伤和疾病的风险。
