Use of a backpack alters gait initiation of high school students

Vieira, Marcus Fraga; Lehnen, Georgia Cristina; Rodrigues, Fábio Barbosa; Avelar, Ivan Silveira de; Costa, Paula Hentschel Lobo da

doi:10.1016/j.jelekin.2016.03.008

Cited by 12 publications

(14 citation statements)

References 30 publications

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“…Conversely, it has been reported that a 20% BW asymmetric load with a single strap bag and a briefcase resulted in increased ML COP excursion and velocity as compared to a symmetric load with a backpack during quiet standing [2]. In addition, it has been reported that a 12% BW asymmetric backpack load resulted in increased ML COP excursion compared to a symmetric backpack load during gait initiation [3]. One potential reason for the difference in findings is that our symmetric loads were carried in the hands and thus were further from the center of mass than a symmetric backpack in the medial-lateral direction.…”

Section: Effect Of Unilateral Versus Bilateral Loadsmentioning

confidence: 99%

“…Asymmetric load carriage is expected to produce a lateral shift of the center of mass and may result in a challenge to postural control during walking [1]. Previous studies have reported that asymmetric load carriage increased medial-lateral (ML) center of pressure (COP) velocities during quiet standing [2] and increased ML COP displacement during gait initiation [3].…”

Section: Introductionmentioning

confidence: 99%

“…Previous studies have indicated that asymmetric load carriage [2,3], walking on uneven surfaces [5][6][7], and unloaded limb stance [1] present postural challenges and/or loading asymmetry in the ML direction. However, we are not aware of any studies that have evaluated postural stability of unilateral load carriage while walking on an uneven surface.…”

Section: Introductionmentioning

confidence: 99%

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Carrying asymmetric loads while walking on an uneven surface

Wang

Gillette

2018

Gait & Posture

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Background Individuals often carry asymmetric loads over challenging surfaces such as uneven or irregular terrain, which may require a higher demand for postural control than walking on an even surface. Research Question The purpose of this study was to assess postural stability in the medial-lateral (ML) direction while carrying unilateral versus bilateral loads when walking on even versus uneven surfaces. Methods Nineteen healthy young adults walked on even and uneven surface treadmills under three load conditions: no load, 20% body weight (BW) bilateral load, and 20% BW unilateral load. A Pedar in-shoe pressure system (Novel, Munich, Germany) was used to evaluate center of pressure (COP)-based parameters. Results Carrying 20% BW bilateral or unilateral loads significantly increased double support ratio. In addition, carrying a 20% BW unilateral load significantly increased coefficient of variation (CV) of double support ratio, CV of ML COP excursion, and CV of ML COP velocity. Walking on an uneven surface significantly increased double support ratio, ML COP excursion, ML COP velocity, and CV of double support ratio. When carrying a 20% BW unilateral load, unloaded limb stance had significantly increased double support ratio and ML COP velocity, although it appears that the loaded limb may be used to make step-by-step adjustments as evidenced by the higher CV of ML COP velocity. Significance Unilateral load carriage, walking on uneven surfaces, and unloaded leg stance are of particular concern when considering postural stability.

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Section: Effect Of Unilateral Versus Bilateral Loadsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Carrying asymmetric loads while walking on an uneven surface

Wang

Gillette

2018

Gait & Posture

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“…This agrees with our study since the altered behavior of the GI reflects the necessity to compensate for changes in the initial COM position. Vieira et al (2016) also found that having the weight at the shoulders on the stance foot side produces the same effect, although a greater trunk repositioning is necessary to maintain the COM at an initial stable position. This was also the case in the present study; when the weight was positioned at the shoulder on the stance foot side, we found a greater ML COP at the beginning of the APA phase to overcome the body inertia.…”

Section: Discussionmentioning

confidence: 75%

“…This suggests the necessity of a greater ML COP displacement to overcome the body's inertia, particularly in the ML direction, when the COM is in a higher position. In a study of high school students using a backpack (i.e., with an extra load positioned at the shoulders), Vieira et al (2016) found that the mediolateral COP displacement was larger during the first phase of the gait initiation using a bilateral backpack (i.e., with the weight uniformly ML distributed in the shoulders). This agrees with our study since the altered behavior of the GI reflects the necessity to compensate for changes in the initial COM position.…”

Section: Discussionmentioning

confidence: 99%

Effects of additional load at different heights on gait initiation: a statistical parametric mapping of center of pressure and center of mass behavior

Vieira

Rodrigues

Assis

et al. 2020

Preprint

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The purpose of this study was to investigate the effects of different vertical positions of an asymmetrical load on the anticipatory postural adjustments phase of gait initiation. Sixty-eight college students (32 males, 36 females; age: 23.65 ± 3.21 years old; weight: 69.98 ± 8.15 kg; height: 1.74 ± 0.08 m) were enrolled in the study. Ground reaction forces and moments were collected using two force platforms. The participants completed three trials under each of the following random conditions: no-load (NL), waist uniformly distributed load (WUD), shoulder uniformly distributed load (SUD), waist stance foot load (WST), shoulder stance foot load (SST), waist swing foot load (WSW), and shoulder swing foot load (SSW). The paired Hotelling’s T-square test was used to compare the experimental conditions. The center of pressure (COP) time series were significantly different for the SUD vs. NL, SST vs. NL, WST vs. NL, and WSW vs. NL comparisons. Significant differences in COP time series were observed for all comparisons between waist vs. shoulder conditions. Overall, these differences were greater when the load was positioned at the shoulders. For the center of mass (COM) time series, significant differences were found for the WUD vs. NL and WSW vs. NL conditions. However, no differences were observed with the load positioned at the shoulders. In conclusion, only asymmetrical loading at the waist produced significant differences, and the higher the extra load, the greater the effects on COP behavior. By contrast, only minor changes were observed in COM behavior, suggesting that the changes in COP (the controller) behavior are adjustments to maintain the COM (controlled object) unaltered.

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