Physiological and biomechanical effects on the human musculoskeletal system while carrying a suspended-load backpack

Huang, Ledeng; Yang, Zhenhua; Wang, Ruishi; Xie, Longhan

doi:10.1016/j.jbiomech.2020.109894

Cited by 21 publications

(12 citation statements)

References 43 publications

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“…A backpack load, for example, increases the dynamic forces on the human body. Huang et al [16] and Yang et al [17] designed suspended-load backpacks as an assistive device to reduce the dynamic forces.…”

Section: Introductionmentioning

confidence: 99%

“…Slope walking has been reported to lead to greater leg extensor muscle activities and joint moments. However, most of the studies investigated muscle activities [18][19][20] or joint moments [21][22][23][24] during slope walking without load carriages or only investigated the joint moment changes [9,10,12] and muscle activities [15,16,25] with load carriages during level walking. Whether the muscle activations such as the signal amplitude are influenced by the mixed factor of load mass and grade and whether the influence of the degrees of load mass and grade on different muscles are equal have not yet been investigated.…”

Section: Introductionmentioning

confidence: 99%

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Effects of Backpack Loads on Leg Muscle Activation during Slope Walking

Liu

Qiang²,

Song

et al. 2020

Applied Sciences

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Hikers and soldiers usually walk up and down slopes with a load carriage, causing injuries of the musculoskeletal system, especially during a prolonged load journey. The slope walking has been reported to lead to higher leg extensor muscle activities and joint moments. However, most of the studies investigated muscle activities or joint moments during slope walking without load carriage or only investigated the joint moment changes and muscle activities with load carriages during level walking. Whether the muscle activation such as the signal amplitude is influenced by the mixed factor of loads and grades and whether the influence of the degrees of loads and grades on different muscles are equal have not yet been investigated. To explore the effects of backpack loads on leg muscle activation during slope walking, ten young male participants walked at 1.11 m/s on a treadmill with different backpack loads (load masses: 0, 10, 20, and 30 kg) during slope walking (grade: 0, 3, 5, and 10°). Leg muscles, including the gluteus maximus (GM), rectus femoris (RF), hamstrings (HA), anterior tibialis (AT), and medial gastrocnemius (GA), were recorded during walking. The hip, knee, and ankle extensor muscle activations increased during the slope walking, and the hip muscles increased most among hip, knee, and ankle muscles (GM and HA increased by 46% to 207% and 110% to 226%, respectively, during walking steeper than 10° across all load masses (GM: p = 1.32 × 10−8 and HA: p = 2.33 × 10−16)). Muscle activation increased pronouncedly with loads, and the knee extensor muscles increased greater than the hip and ankle muscles (RF increased by 104% to 172% with a load mass greater than 30 kg across all grades (RF: p = 8.86 × 10−7)). The results in our study imply that the hip and knee muscles play an important role during slope walking with loads. The hip and knee extension movements during slope walking should be considerably assisted to lower the muscle activations, which will be useful for designing assistant devices, such as exoskeleton robots, to enhance hikers’ and soldiers’ walking abilities.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effects of Backpack Loads on Leg Muscle Activation during Slope Walking

Liu

Qiang²,

Song

et al. 2020

Applied Sciences

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“…Moreover, most of the elastically suspended backpacks adopt the linear guide rail and slider structure to restrict the load movement to keep in the vertical direction [8], [12], which means an additional mass in the structure of the device. On the contrary, the spherical pendulum structure only adopts cables and a rigid pole which is as light as the typical backpack.…”

Section: E Advantages Over Elastically Suspended Backpacksmentioning

confidence: 99%

Allowing the Load to Swing Reduces the Mechanical Energy of the Stance Leg and Improves the Lateral Stability of Human Walking

Yang

Zhang

et al. 2021

IEEE Trans. Neural Syst. Rehabil. Eng.

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Loaded walking with typical rigid backpack results in a significant increase in the mechanical energy of the stance leg and a decrease in lateral stability. Allowing the load to swing, which has been applied in shoulder pole, a tool widely used in Asia for load carriage assistance, may attenuate these effects. This paper theoretically analyzes and experimentally validates the biomechanical and energetic effects of the swinging loads. When walking with a 30 kg load, allowing the load to swing reduces the fore-aft leg impulses by over 19% and further reduces the mechanical energy of the stance leg by 12.9% compared to the typical rigid backpack. The whole-body metabolic cost has no significant change, which may be attributed to the increase in the muscle work of the upper body and the leg swing. Moreover, the load movement out of phase to the human in the lateral direction reduces the lateral excursion of extrapolated center-of-mass by 27.2%, indicating an increase in the lateral margin of stability and implying an improvement in lateral stability. The results demonstrate that allowing the load to swing reduces the horizontal leg impulses and the mechanical energy of the stance leg, and improves the lateral stability of human walking.

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“…Soldiers and hikers need to carry heavy loads in a backpack to perform military, occupational, and recreational tasks. These added masses on human body increase metabolic costs during walking, accelerate muscle fatigue, and increase the risk of injury [1]. Exoskeletons have been developed for human strength augmentation to enhance human strength and endurance during locomotion [2].…”

Section: Introductionmentioning

confidence: 99%

Mechanical design of a passive lower-limb exoskeleton for load-carrying assistance

Liu

Ning

et al. 2022

J. Phys.: Conf. Ser.

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This paper presents a passive exoskeleton with 17 degrees-of-freedom (DOF) for load-carrying, which includes two 3DOFs ankle joint, two 2DOFs hip joint, two 1DOF knee joint, one 1DOF backpack, and two redundant DOFs at the thigh and shank, respectively, to improve the compatibility of human-machine locomotion. The modular backpack was designed to facilitate carrying of different loads. A horn-shaped spatial mechanism was designed to connect the hip joint and the backpack, and transfer the payload to the ground. A tension spring was adopted to absorb the gravitational potential energy of the load when walking, and fix the horn-shaped spatial mechanism at both sides. The segmented brace at the thigh and the shank were designed to adjust different legs. In order to improve the force transmission performance, we cancelled the extension DOF of the hip joint, and moved the rotation axis of the knee joint backward. The knee joint assistance mechanism was designed to allow the knee joint move freely when the flexion angle did not exceed 60°. However, when the knee bends over 60°, the knee joint presses the torsion spring to store energy. After then, it releases energy to assist knee extending. The Cooper-Harper scale tests demonstrated that the exoskeleton had excellent static support effect and movement flexibility, which verified the rationality of the exoskeleton design.

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Physiological and biomechanical effects on the human musculoskeletal system while carrying a suspended-load backpack

Cited by 21 publications

References 43 publications

Effects of Backpack Loads on Leg Muscle Activation during Slope Walking

Effects of Backpack Loads on Leg Muscle Activation during Slope Walking

Allowing the Load to Swing Reduces the Mechanical Energy of the Stance Leg and Improves the Lateral Stability of Human Walking

Mechanical design of a passive lower-limb exoskeleton for load-carrying assistance

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