Effects of carrying backpacks on the foot

NewsBot · Oct 12, 2020

Backpacks Effect on Foot Posture in Schoolchildren with a Neutral Foot Posture: A Three-Year Prospective Study
Pilar Alfageme-García et al
Int J Environ Res Public Health. 2020 Oct 7;17(19):E7313

Background: There is a paucity of data on the relationship between backpack use and foot posture in children. The aim of this study was to assess the effects of a backpack on foot posture in children with neutral foot posture during three years of follow-up.

Methods: A prospective longitudinal observational study was conducted in a sample of 627 children with neutral foot. For each participant included in the study, age, sex, weight, height, body mass index, type of schoolbag (backpack or non-backpack), foot shape, metatarsal formula and type of shoes were recorded. Foot posture was described by the mean of the foot posture index (FPI) and reassessed after three years in a follow-up study.

Results: The average age of the children was 8.32 ± 1.32 years. A total of 458 used a backpack when going to school. Over the three-year follow-up period, 50 children who had neutral foot developed supinated foot (n = 18) or pronated foot (n = 32). Univariate and multivariate analysis showed that the children using a backpack were at a higher risk of developing pronated foot (adjusted Odds Ratio (aOR) = 2.05, 95% IC: 1.08-3.89, p = 0.028). Backpack use was not associated with the change from neutral foot to supinated foot.

Conclusions: We found a positive association between using a backpack and the risk of developing pronated but not supinated foot. Clinical trials should be conducted to analyze the effect of backpack use on the foot among schoolchildren.
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NewsBot · Oct 16, 2021

Association between the Use of Backpack and Static Foot Posture in Schoolchildren with Static Pronated Foot Posture: A 36-Month Cohort Study
Pilar Alfageme-García et al
Children (Basel). 2021 Sep 11;8(9):800

Background: Schoolchildren often spend a lot of time carrying a backpack with school equipment, which can be very heavy. The impact a backpack may have on the pronated feet of schoolchildren is unknown. Aims: The objective of this study was to evaluate the association of the backpack use on static foot posture in schoolchildren with a pronated foot posture over 36 months of follow-up. Methods: This observational longitudinal prospective study was based on a cohort of consecutive healthy schoolchildren with pronated feet from fifteen different schools in Plasencia (Spain). The following parameters were collected and measured in all children included in the study: sex, age, height, weight, body mass index, metatarsal formula, foot shape, type of shoes, and type of schoolbag (non-backpack and backpack). Static foot posture was determined by the mean of the foot posture index (FPI). The FPI was assessed again after 36 months. Results: A total of 112 participants used a backpack when going to school. Over the 36-month follow-up period, 76 schoolchildren who had a static pronated foot posture evolve a neutral foot posture. Univariate analysis showed that the schoolchildren using backpacks were at a greater risk of not developing neutral foot (odds ratio [OR]: 2.09; 95% CI: 1.08-4.09). The multivariate analysis provided similar results, where the schoolchildren using a backpack (adjusted OR [aOR]: 1.94; 95% CI: 1.02-3.82) had a significantly greater risk of not developing a neutral foot posture. Conclusions: A weak relationship was found between backpack use and schoolchildren aged from five to eleven years with static pronated feet not developing a neutral foot posture over a follow-up period of 36 months.
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NewsBot · Oct 19, 2021

Effects of backpack-induced fatigue on gait ground reaction force characteristics in primary school children with flat-foot deformity
SoodebehmaramAliJalalvandMohammadReza Jahani
Journal of Biomechanics 16 October 2021, 110817

This study aimed to assess the effects of backpack carriage in different weights and muscle fatigue on the GRF components in primary school children with flat-foot deformity. The GRF components from 42 primary school children (21 with low arch, and 21 with normal) were collected before and after backpack-induced fatigue protocol during shod walking with backpacks in weight 7.5, 10, 12.5 and 15% of the child's bodyweight. The amplitudes of Fx2 of 10%BW and Fz3 of 7.5%BW in the flatfeet group were less than in the healthy group without fatigued condition. (P<0.05). After fatiguing, the amplitudes of Fx2 of 7.5%BW, Fz3 of 12.5 and 15%BW were significantly decreased in the low arch group than those in the healthy subjects (P<0.05). Within-group comparisons of measured Fx2 of 10%BW, Fy1 (7.5,10 and 15 %BW), Fy2 of 7.5%BW, FZ1 (7.5,10 and 15 %BW), FZ2 (7.5,10 and 15 %BW), and TTP of TFz1 of 7.5%BW, TFz3 (7.5,10 and 12.5%BW), Loading rate (7.5,10 and 15%BW) were significantly different from pre- to post-fatigue in the flatfeet group(P<0.05). Within-group comparisons of measured Fy1 of 10%BW, Fy2 (7.5% and 10 %BW), FZ1 (7.5% and 10 %BW), FZ2 (7.5% and 10%BW), and TTP of TFz3 of 7.5%BW, Loading rate (7.5% and 10%BW) were significantly different from pre- to post-fatigue in the healthy group(P<0.05). It seems that TTP of GRF variables does have clinical importance for rehabilitation of flatfeet deformity. Carrying heavy backpacks and backpack-induced fatigue had different effects on GRF characteristics among children with low and normal foot arch.
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NewsBot · Nov 26, 2021

Effects of backpack-induced fatigue on gait ground reaction force characteristics in primary school children with flat-foot deformity
Soode Behmaram et al
J Biomech. 2021 Oct 16;129:110817

This study aimed to assess the effects of backpack carriage in different weights and muscle fatigue on the GRF components in primary school children with flat-foot deformity. The GRF components from 42 primary school children (21 with low arch, and 21 with normal) were collected before and after backpack-induced fatigue protocol during shod walking with backpacks in weight 7.5, 10, 12.5 and 15% of the child's bodyweight. The amplitudes of Fx2 of 10%BW and Fz3 of 7.5%BW in the flatfeet group were less than in the healthy group without fatigued condition. (P < 0.05). After fatiguing, the amplitudes of Fx2 of 7.5%BW, Fz3 of 12.5 and 15%BW were significantly decreased in the low arch group than those in the healthy subjects (P < 0.05). Within-group comparisons of measured Fx2 of 10%BW, Fy1 (7.5,10 and 15%BW), Fy2 of 7.5%BW, FZ1 (7.5,10 and 15%BW), FZ2 (7.5,10 and 15%BW), and TTP of TFz1 of 7.5%BW, TFz3 (7.5,10 and 12.5%BW), Loading rate (7.5,10 and 15%BW) were significantly different from pre- to post-fatigue in the flatfeet group(P < 0.05). Within-group comparisons of measured Fy1 of 10%BW, Fy2 (7.5% and 10%BW), FZ1 (7.5% and 10%BW), FZ2 (7.5% and 10%BW), and TTP of TFz3 of 7.5%BW, Loading rate (7.5% and 10%BW) were significantly different from pre- to post-fatigue in the healthy group (P < 0.05). It seems that TTP of GRF variables does have clinical importance for rehabilitation of flatfeet deformity. Carrying heavy backpacks and backpack-induced fatigue had different effects on GRF characteristics among children with low and normal foot arch.
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NewsBot · Jan 21, 2022

Can increased load carriage affect lower limbs kinematics during military gait?
Manoela Vieira Sousa et al
Ergonomics. 2022 Jan 11

The aim of this study was to investigate if increased load carriage, in male military personnel, can affect the lower limbs kinematics. Twelve male military volunteers from the Portuguese Army were recruited and evaluated in an unloaded and loaded gait condition. Linear kinematics and lower limbs joint angle at heel strike, midstance and toe off were calculated. The stance, swing and double support times were found to be different between load conditions (p < 0.05). There was an interaction between load and limb (p < 0.05) for joint angles, during midstance, with limbs performing different movements in the frontal plane during loaded gait. Load increase had a different effect on the right knee, with a reduction in the abduction (valgus). This study may be beneficial in offering suggestion to improve the performance of gait with load and in an attempt to help prevent possible injuries. Practitioner summary: Increased load can affect lower limbs of male soldiers at the pelvic, hip and knee angles on the frontal plane, which can alter the joint force distribution. While these alterations may indicate protective mechanics, load management procedures should be implemented along with gait monitoring to avoid negative effects in performance.
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NewsBot · Jan 26, 2022

Impact of Overloaded School Backpacks: An Emerging Problem
João Barbosa et al.
Source

The possible adverse effects of overloading students' backpacks are a public concern and should be considered by the scientific and educational community. This topic has gained particular importance due to the childhood development process, which can increase the promotion of future disorders (e.g., back pain, low back pain, spinal column deviations). In this brief review, we critically analyze the impact of excess load in students' backpacks and attempt to identify solutions that can be useful to minimize the effects of this problem. It is necessary to find a viable alternative to classic backpacks that can contribute to minimizing the effects of backpack loads on children.
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NewsBot · Jan 31, 2022

Factors Associated with Musculoskeletal Injuries While Hiking with a Backpack at Philmont Scout Ranch
Ky B Stoltzfus et al
Wilderness Environ Med. 2022 Jan 20

Introduction: Participants at Philmont Scout Ranch embark on 12-d treks with pre-trek physical conditioning and medical clearance by their primary care physician. In this study, we investigated potential contributing factors to self-reported musculoskeletal injuries during a backpack trek.

Methods: This study was a prospective cohort study that used a 3-part survey administered to participants before, during, and after their trek from June through August 2019. Health history and demographic information were retrieved from each hiker's medical record. A logistic regression model was used to assess factors associated with injuries, and odds ratios and 95% confidence intervals were reported.

Results: There were 1206 individuals enrolled in this study, and none withdrew from participation. The median age of the participants was 17 y (interquartile range 15-47); 1130 were male, 75 were female, and 1 was of unknown sex. Injuries were reported by 7% (n=88) of participants while in the backcountry, with injuries occurring in various anatomic locations (knee, ankle, leg, foot, hand, arm). Participants without missing data (74%; n=897) were included in the logistical regression analysis to describe factors significantly associated with injury. Factors significantly associated with injury included greater backpack weight to body weight ratio, body mass index greater than 30 kg·m-2, and past injuries that required a doctor visit.

Conclusions: Self-reported injuries while hiking at Philmont Scout Ranch are infrequent and do not often require evacuation or advanced medical care. Camp policies to maintain appropriate backpack weight and counseling of obese and previously injured individuals may mitigate injury occurrence.
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NewsBot · Apr 4, 2022

The impact of a school backpack's weight, which is carried on the back of a 7-year-old students of both sexes, on the features of body posture in the frontal plane
Mirosław Mrozkowiak & Marta Stępień-Słodkowska
BMC Sports Science, Medicine and Rehabilitation volume 14, Article number: 57 (2022)

Background
The lifestyle of children has a significant impact on the future health of the whole society. Therefore, health education, prevention and monitoring of health determinants is important at every stage of ontogenesis. This requires a thorough knowledge of the schoolchild's environment, perceived as a wide set of stressors, including not only genetic but also epigenetic factors. One of them is the issue of the correct and abnormal body posture at school and on the way there. The goal of the study was to show the influence of the weight of the back carried container with school supplies on body posture.

Method
The research was carried out as part of a project that examined the impact of carrying weights, which are school supplies, by children on their posture. The research material consisted of data obtained from a group of 65 students (35 girls, 30 boys) aged 7 years. Body posture tests were carried out, using the projection moiré method in 4 positions: 1-habitual posture, 2-posture after 10-min of asymmetric axial load, 3-a posture after 1 min of the load removal, 4-a posture after two minutes of the load removal. Physical fitness was measured with the Sekita test. The obtained data were statistically analyzed.

Results
The significance of differences between the 1st and 2nd measurements was analyzed to determine the impact of the backpack load and the correlation with physical fitness, and to study its influence on the value of the differences in posture features. Considering the differences in the volume of posture features among boys between the 1st and 2nd measurement, the Wilcoxon’s rank test showed a statistically significant difference in the range of all analyzed variables, except for the torso bend angle to the right (KNT+), where no statistically significant change was noted. A statistically significant difference in the volume of all analyzed variables was observed among the girls.

Conclusions
Carrying school supplies on the back induces significant changes in the value of the features describing the body posture in the frontal plane. The greater weight of the container and carrying time, and intensity of physical effort is the greater the changes will be. Physical fitness has a various and sex-dependent influence on the value of changes in body posture features because of carrying school supplies. Among boys it significantly affects the asymmetry of the torso bend, shoulder height, the waist triangles height and width, whereas among girls it affects the asymmetry of the shoulders and the distance of the angles of the lower shoulder blades from the line of the spinous processes of the spine. Among boys the changes in the value of posture features are mostly influenced by endurance and speed, but strength, power and agility are of lower influence, whereas among girls only agility matters.
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NewsBot · Jun 21, 2022

The effect of backpack carriage in different weights on ground reaction force components, loading rate and free moment of Schoolchildren's gait
Soodebehmaram et al
International Journal of Industrial Ergonomics; Volume 90, July 2022, 103324

Highlights
•Backpack carriage was associated with altered GRFs characteristics.
•Schoolchildren's gait performance was affected by carrying loads in the backpacks.
•Carrying heavy backpacks should also be considered as a risk factor.
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Background
The objective of this study was to investigate the effect of backpack carriage in different weights on ground reaction force components, loading rate and free moment of schoolchildren's gait.

Methods
Twenty-one healthy primary school children (8–11 years old) of second, third, fourth and fifth grade participated in this study where quasi-experimental design was administered. The weight of the backpacks used was 7.5, 10, 12.5 and 15 percent of the participant's body weight. Gait was evaluated using a Kistler force plate at a frequency of 1000 Hz. The GRF along anterior-posterior(y), and medial-lateral (x) and vertical (z) axes, time to peak (TTP), the rate of loading, free moment were calculated. A repeated-measures ANOVA was used to compare the data between subjects.

Results
The amplitudes of Fy2 and Fx2 were affected by the carrying load with 15 percent body weight. The amplitudes of Fy1, Fz1 and Fz3 were also affected by the carrying load with 12 and 15 percent body weight.

Conclusions
The carrying load with %12 and 15% of the body weight altered schoolchildren's gait performance. These altered variables should be considered as a risk factor for carrying a backpack.
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NewsBot · Jul 30, 2022

Effects of anterior load carriage on dynamic gait stability during level overground walking
JiyunAhnCarolineSimpkinsFengYang
Human Movement Science Volume 85, October 2022, 102981

Anterior load carriage, identified as a fall risk factor, is commonly required in daily living activities and occupations. Dynamic gait stability quantifies the kinematic relationship between the human body's center of mass and base of support and has been widely used to assess fall risk. The current study was conducted as a portion of a larger project exploring the effects of anterior load carriage on the control of body stability during various walking conditions. Particularly, this study examined the effect of anterior load carriage on dynamic gait stability during level overground walking among young adults. It was hypothesized that anterior load carriage would compromise dynamic gait stability during walking. Thirty young adults were evenly randomized into three groups: no load (Group 1), 10% body mass (bm) (Group 2), and 20% bm (Group 3). Each group walked overground at a self-selected speed carrying the assigned load. Kinematics were collected for the body and load through motion capture. Dynamic gait stability, gait speed, step length, and trunk angle were determined based on the kinematics and compared between groups. The results did not detect significant load-related effects on dynamic gait stability, step length, or gait speed. A significant load-related difference was found in trunk angle: the heavier the load, the more backward leaned trunk. Further analyses revealed a more posteriorly-leaned trunk in Groups 2 and 3 than Group 1 and in Group 3 than Group 2. The results indicated that young adults could maintain dynamic gait stability when carrying a front load by leaning the trunk backward but keeping other gait parameters unchanged.
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NewsBot · Oct 14, 2022

Influence of school backpack load on plantar foot pressure during walking in 9-11 years old girls
Štefan Balkó et al
Cent Eur J Public Health. 2022 Sep;30(3):185-189

Objective: This study aimed to assess the relative load of the midfoot and the metatarsals of both feet when schoolchildren walked with backpacks of different loads.

Methods: A group of 12 healthy girls (9.9 ± 0.8 years; 33.8 ± 6.7 kg, 1.40 ± 0.10 m) walked barefoot to assess plantar pressures during gait without load (L0%) and with a loaded backpack equal to 10% (L10%) and 20% (L20%) of their body weight. A Footscan® system (RSscan International, Belgium) was used to determine the contact area and relative pressure impulse in the midfoot and metatarsals on the dominant (DL) and non-dominant legs (NL).

Results: The effect of load was significant for the contact area of the midfoot for both NL (p = 0.013) and DL (p = 0.001). In the metatarsals, there was significantly greater relative impulse during L10% compared to L0% in the first (p = 0.041) and second (p = 0.050) metatarsals of the DL. Comparing the NL and DL showed significantly greater relative impulse on the DL in the fourth metatarsal during L10% (p = 0.023), greater contact area in the fifth metatarsal during L0% (p = 0.050), and greater impulse in the midfoot during L20% (p = 0.028) on the NL.

Conclusions: The school backpack load influences relative plantar pressure distribution, especially in the midfoot. Further, our findings suggest greater propulsion of the DL and supporting function of the NL.
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NewsBot · Oct 16, 2022

The effect of backpack load on intersegmental motions of the foot and plantar pressure in individuals with mild flatfoot
Min Gyu Kyung, Ppu Ri Bak, Jong Wook Lim, Dong-Oh Lee, Gil Young Park & Dong Yeon Lee
Journal of Foot and Ankle Research volume 15, Article number: 76 (2022)

Background
The feet play an essential role in shock absorption, and foot posture is closely related to gait. The compensatory mechanism under heavy-load conditions in individuals with mild flatfoot is poorly understood. In the authors’ country, individuals with mild flatfoot are drafted as active-duty soldiers and participate in military rucking wearing heavy backpacks. This study investigated the effect of backpack load on gait and foot plantar pressure and possible differences in participants with mild flatfoot. The average weight of the backpack during military rucking (approximately 20 kg), was simulated in this study.

Methods
This study prospectively enrolled 30 healthy young males, divided into a control group (CON, n = 15) and a mild low-arched group (MLA, n = 15), based on the presence of flatfoot. Segmental foot kinematics were evaluated using a three-dimensional multi-segment foot model, and gait data of the temporal and spatial parameters were obtained. The dynamic plantar pressure was simultaneously measured using a pedobarography platform with gait trials. The protocol was repeated with all participants wearing 20 kg backpacks. Comparisons between the baseline and loaded states, as well as comparison between groups, were conducted.

Results
Although the cadence, gait speed, and stride length decreased in the loaded condition, step time and proportion of the stance phase increased in both groups. Although the MLA group showed more supinated and abducted positions of the forefoot and more pronated positions of the hindfoot than the CON group, the change in intersegmental foot and ankle motion in each group after backpack loading was minimal. However, the former showed a larger step width and a greater increase in contact area in the midfoot region, while the latter demonstrated a greater increase in peak pressure.

Conclusions
Individuals with mild flatfoot demonstrated significantly different gait curve patterns (waveforms) compared to the controls. In the loaded condition, the CON and MLA groups may have adopted different strategies to maintain balance during gait. We suggest that although individuals with asymptomatic mild flatfoot are drafted as active-duty soldiers, they should be thoroughly investigated under loaded conditions, and orthoses may be helpful.
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NewsBot · Jan 19, 2023

Effects of Load Carriage on Postural Sway and Relative Ground Reaction Forces in Special Police Officers: A Cross-Sectional Study
Mario Kasović et al
Int J Environ Res Public Health. 2022 Dec 13;19(24):16710

Although excessive load carriage results in biomechanical gait changes, little evidence has been provided regarding its impact on postural sway. Therefore, the main purpose of this study was to determine whether heavier loads have effects on changing foot stability and postural sway in special police officers. Thirty male special police officers (age = 40 ± 6 years, height = 180 ± 5 cm, weight = 89 ± 8 kg) were assessed in four conditions: (1) carrying no load, (2) carrying a 5 kg load, (3) carrying a 25 kg load, and (4) carrying a 45 kg load. Foot characteristics during standing were assessed with Zebris pedobarographic pressure platform. Heavier loads increased the center of pressure (COP) path length and average velocity, length of minor and major axis, and 95% confidence ellipse area, while a decrease in angle between Y and major axis was observed. Relative forces beneath the left forefoot and right backfoot regions decreased and an increase in relative forces beneath the left backfoot and right forefoot was observed. When carrying heavy loads, static foot parameters rapidly changed, especially in COP path length and average velocity.
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NewsBot · Mar 16, 2023

The Soft Prefabricated Orthopedic Insole Decreases Plantar Pressure during Uphill Walking with Heavy Load Carriage
Hsien-Te Peng et al
Bioengineering 2023, 10(3), 353

This study aimed to investigate the effect of varying the hardness of prefabricated orthopedic insoles on plantar pressure and muscle fatigue during uphill walking with a heavy backpack. Fifteen healthy male recreational athletes (age: 20.4 ± 1.0 years, height: 176.9 ± 5.7 cm, weight: 76.5 ± 9.0 kg) wore prefabricated orthopedic insoles with foot arch support; a heel cup with medium (MI), hard (HI), and soft (SI) relative hardnesses; and flat insoles (FI). They performed treadmill walking on uphill gradients with 25 kg backpacks. The plantar pressure and surface electromyographic activity were recorded separately, in 30 s and 6 min uphill treadmill walking trials, respectively. The HI, MI, and SI significantly decreased peak plantar pressure in the lateral heel compared to FI. The MI and SI significantly decreased the peak plantar pressure in the fifth metatarsal compared to FI. The MI significantly reduced the pressure–time integral in the lateral heel compared to FI. The HI significantly increased the peak plantar pressure and pressure–time integral in the toes compared to other insoles, and decreased the contact area in the metatarsal compared to SI. In conclusion, a prefabricated orthopedic insole made of soft material at the fore- and rearfoot, with midfoot arch support and a heel cup, may augment the advantages of plantar pressure distribution during uphill weighted walking.
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NewsBot · Mar 30, 2023

The Soft Prefabricated Orthopedic Insole Decreases Plantar Pressure during Uphill Walking with Heavy Load Carriage
Hsien-Te Peng et al
Bioengineering (Basel). 2023 Mar 13;10(3):353

This study aimed to investigate the effect of varying the hardness of prefabricated orthopedic insoles on plantar pressure and muscle fatigue during uphill walking with a heavy backpack. Fifteen healthy male recreational athletes (age: 20.4 ± 1.0 years, height: 176.9 ± 5.7 cm, weight: 76.5 ± 9.0 kg) wore prefabricated orthopedic insoles with foot arch support; a heel cup with medium (MI), hard (HI), and soft (SI) relative hardnesses; and flat insoles (FI). They performed treadmill walking on uphill gradients with 25 kg backpacks. The plantar pressure and surface electromyographic activity were recorded separately, in 30 s and 6 min uphill treadmill walking trials, respectively. The HI, MI, and SI significantly decreased peak plantar pressure in the lateral heel compared to FI. The MI and SI significantly decreased the peak plantar pressure in the fifth metatarsal compared to FI. The MI significantly reduced the pressure-time integral in the lateral heel compared to FI. The HI significantly increased the peak plantar pressure and pressure-time integral in the toes compared to other insoles, and decreased the contact area in the metatarsal compared to SI. In conclusion, a prefabricated orthopedic insole made of soft material at the fore- and rearfoot, with midfoot arch support and a heel cup, may augment the advantages of plantar pressure distribution during uphill weighted walking.
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NewsBot · Jul 20, 2023

Relationships between tibial accelerations and ground reaction forces during walking with load carriage
Caleb D. Johnson et al
Journal of Biomechanics
Volume 156, July 2023, 111693

Peak tibial accelerations (TAs) during running are strongly related to early stance vertical ground reaction forces (GRFs), which are associated with musculoskeletal injury. However, few studies have examined these correlations during walking, and none have evaluated them during walking with loads, a relevant activity for military personnel. Our purpose was to determine the relationships between GRFs and TAs in US Army trainees (n = 649) walking with loads. An inertial measurement unit was attached over their distal antero-medial tibia. Participants walked on an instrumented treadmill at 1.21–1.34 m/s, with a pack loaded with 18.1 kg, for a 3-min warm-up followed by a minimum of 14 strides of data collection. Simple linear regression models were calculated for peak vertical and resultant TAs with vertical and posterior GRF loading rates and peak forces. The strongest relationships were between vertical loading rates and peak vertical TA (R = 0.43–0.50), however the relationships were weaker than has been reported for unloaded walking and running (R > 0.7). All other relationships were trivial to small (R = 0.06–0.27). The weaker relationships for vertical GRFs and TAs may be due to methodological differences between studies, or differences in gait mechanics, such as a longer double-limb support phase in loaded vs. unloaded walking.
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NewsBot · Sep 29, 2023

The Acute Effects of Schoolbag Loading on Posture and Gait Mechanics in 10- to 13-Year-Old Children: A Cohort from the North West Province
Bridget Grobler, Mark Kramer
Children (Basel). 2023 Sep 1;10(9):1497.

Most schoolchildren carry schoolbags, of which a substantial proportion carry loads that exceed 15% of their body mass. Although the effects of loading have been investigated to varying degrees, the status of schoolbag loading and the acute affects thereof on gait and posture have not been thoroughly investigated within the South African context. A total of 60 participants in the 10-13-year age range volunteered for the present study. Significant differences were evident for relative load carriage (χ2(3) = 14.54, p < 0.001), forefoot and heel forces (Mdiff = 17.05-34.86 N, p < 0.001), force ratios (Mdiff = 0.02, p = 0.029), and gait speed (Mdiff = -0.18 km/hr, p = 0.016), but not for any postural angles (Mdiff = -3.37-6.08 deg, all p > 0.052). Those who exceeded 15% BM were ~9 times more likely to report pain than those below 15% BM. The children in the current study carried significantly heavier relative loads (p < 0.001) compared to similarly aged children from other countries. Loading leads to acute changes in posture and gait that are likely not meaningful. However, excessive loading (>15% BM) leads to significantly higher perceptions and reporting of pain in 10-13-year-old children.
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NewsBot · Nov 13, 2023

Effects of different cushioned insoles on ankle and knee joints biomechanics during load carriage running
Tao Yang, Liangliang Xiang, Shanshan Ying, Jianshe Li, Justin Fernandez and Yaodong Gu
International Journal of Biomedical Engineering and TechnologyVol. 43, No. 3

Load carriage training resulted in substantial injuries among military recruits, particularly in their lower limbs and feet. This study analysed the phase-specific effects of load carriage with three different material insoles on GRF, angle, and moment of ankle and knee joints during running with military boots. Eighteen male participants were recruited for this study from a local veteran club. A two-way repeated-measures analysis of variance (ANOVA) was conducted to determine statistical effects. The vertical active peak in the ortholite insole group was significantly lower than the control (p = 0.002) and cork insoles (p = 0.002) with the unloading condition. The control group's ankle dorsiflexion moment was greater than that of the ortholite and cork insoles at zero (p = 0.001) and 15 kg load carriage (p = 0.001) (46-83% stance). The findings show that the ortholite insole and cork insole improve cushioning performance in the lower limbs and stability of military boots compared with the control insole.
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NewsBot · Apr 19, 2024

Profiling injuries sustained following implementation of a progressive load carriage program in United States marine corps recruit training
Karen Kelly et al
Work. 2024;77(4):1391-1399

Background: Load carriage tasks during United States Marine Corps (USMC) recruit training can cause injury. Load carriage conditioning, if optimized, can reduce injury risk.

Objective: To compare injuries sustained by USMC recruits following participation in either the Original Load Carriage (OLC) program or a Modified Load Carriage (MLC) program.

Methods: Retrospective musculoskeletal injury data were drawn from the USMC San Diego Sports Medicine injury database for recruits completing the OLC (n = 2,363) and MLC (n = 681) programs. Data were expressed as descriptive statistics and a population estimate of the OLC:MLC relative risk ratio (RR) was calculated.

Results: The proportion of injuries sustained in the MLC cohort (n = 268; 39% : OLC cohort, n = 1,372 : 58%) was lower, as was the RR (0.68, 95% CI 0.61- 0.75). The leading nature of injury for both cohorts was sprains and strains (OLC n = 396, 29%; MLC n = 66; 25%). Stress reactions were proportionally higher in MLC (n = 17, 6%; OLC n = 4, 0.3%), while stress fractures were proportionately lower (MLC n = 9, 3%; OLC n = 114, 8%). Overuse injuries were lower in MLC (- 7%). The knee, lower leg, ankle, and foot were the top four bodily sites of injuries and the Small Unit Leadership Evaluation (SULE), Crucible, overuse-nonspecific, running, and conditioning hikes were within the top five most common events causing injury. The prevalence rates of moderate severity injury were similar (MLC = 23%; OLC = 24%), although MLC presented both a higher proportion and prevalence of severe injuries (MLC = 6%; OLC = 3%, respectively).

Conclusion: A periodized load carriage program concurrently increased exposure to load carriage hikes while reducing injuries both during the load carriage hikes and overall.
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NewsBot · Jun 30, 2024

Backpack loading position and self-selected foot position as measured by foot tracings
Lee Daffin et al
Work. 2024 Jun 27

Background: It is known that even under static conditions a backpack wearer will need to make some adjustments to maintain postural stability. There is a paucity of research exploring the impact of altering the position of the feet with imposed loads of variable distance from the posterior midline.

Objective: Therefore, the aim of this study was to determine if changes in the horizontal position of a fixed load when wearing a backpack affect specific variables derived from foot tracings of males and females standing with their self-selected natural feet position.

Methods: 150 healthy volunteer participants were instructed to adopt a natural stance across four conditions: Backpack with no weight, backpack with a weight (5% of body mass) placed at 0 cm, 20 cm, and 40 cm distance from the posterior body. Foot tracings were made for each condition. Base of Support (BoS), Feet Width (FW), and Feet Opening Angle (FOA) were calculated.

Results: The BoS significantly decreased in loaded conditions (0 cm, 20 cm and 40 cm) compared to unloaded. This was supported by FW and FOA significant findings that once the load was imposed the response was to approximate the feet and reduce 'toeout'.

Conclusion: This reaction of people to reduce their BoS in response to added backpack load appears counter intuitive and raises the question of whether this is maladaptive. Clarification by further investigation will inform backpack wearers to counter this instinctive response to load and increase postural stability.
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NewsBot · Jul 25, 2024

Does a Standardized Load Carriage Increase Spatiotemporal Gait Asymmetries in Police Recruits? A Population-based Study
Andro Štefan et al
Mil Med. 2024 Jul 19

Introduction: Although the effects of carrying loads on gait biomechanics have been well-documented, to date, little evidence has been provided whether such loads may impact spatial and temporal gait asymmetries under the different foot regions. Therefore, the main purpose of the study was to examine the effects of carrying a standardized police equipment on spatiotemporal gait parameters.

Materials and methods: In this population-based study, participants were 845 first-year police recruits (age: 21.2 ± 2.3 years; height: 178.1 ± 10.2 cm; weight: 78.4 ± 11.3 kg; body mass index: 24.7 ± 3.2 kg/m2; 609 men and 236 women; 72.1% men and 27.9% women) measured in 2 conditions: (i) "no load" and (ii) "a 3.5 kg load." Spatiotemporal gait parameters were derived from the FDM Zebris pressure platform. Asymmetry was calculated as (xright-xleft)/0.5*(xright + xleft)*100%, where "x" represented a given parameter being calculated and a value closer to 0 denoted greater symmetry.

Results: When compared to "no load" condition, a standardized 3.5 kg/7.7 lb load significantly increased asymmetries in spatial gait parameters as follows: gait phases of stance (mean diff. = 1.05), load response (mean diff. = 0.31), single limb support (mean diff. = 0.56), pre-swing (mean diff. = 0.22), and swing (mean diff. = 0.90) phase, while no significant asymmetries in foot rotation, step, and stride length were observed. For temporal gait parameters, we observed significant asymmetries in step time (mean diff. = -0.01), while no differences in cadence and gait speed were shown.

Conclusions: The findings indicate that the additional load of 3.5 kg/7.7 lb is more likely to increase asymmetries in spatial gait cycle components, opposed to temporal parameters. Thus, external police load may have hazardous effects in increasing overall body asymmetry, which may lead to a higher injury risk and a decreased performance for completing specific everyday tasks
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NewsBot · Jun 18, 2025

Exploring the impact of Backpack carrying on plantar pressure and gait patterns in children: A systematic review
Puspangi Agarwal et al
J Bodyw Mov Ther. 2025 Jun:42:875-884.

Background: Since ages backpacking has been accepted as an essential and convenient form of daily practice for carrying supplies to school. However, this daily act adds 8-12% of additional weight to the body's stipulated weight, which imposes negative impact on one's locomotor system.

Methods: Databases of PubMed, Google Scholar, PEDro, MEDLINE and Cochrane were searched in a thorough manner. Methodological quality was assessed independently by two authors, using JBI Critical Appraisal Checklist for Analytical Cross Sectional Studies.

Results: In total 18 studies with 2131 patients included in the review. The mean age of patients included is 15.2 ± 2.4 years. Backpack carriage significantly affects plantar pressure distribution and gait parameters in children. Increased pressure on the forefoot and heel regions was consistently reported, along with alterations in stride length, step width, and walking speed. Factors such as backpack design, load distribution, and individual characteristics further influenced these effects.

Conclusion: Findings reveal regular use of school backpack by children pose deteriorating impact on their plantar pressure, thereby affecting the spatiotemporal parameters of gait.
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NewsBot · Jul 13, 2025

The Influence of School Backpack Load on Dynamic Gait Parameters in 7-Year-Old Boys and Girls
Paulina Tomal et al
Sensors (Basel). 2025 Jul 6;25(13):4219.

School-aged children are routinely exposed to additional physical stress due to carrying school backpacks. These backpacks often exceed recommended limits and can contain not only books and notebooks but also laptops, water bottles, and other personal items. The present study aimed to evaluate the impact of different backpack loads (10%, 15%, and 20% of body weight) on dynamic gait parameters in 7-year-old girls and boys. Twenty-six children (13 girls, 13 boys) participated in the study. Gait analysis was performed using the Footscan® system (RSscan International, Olen, Belgium; 2 m × 0.4 m × 0.02 m, 16,384 sensors) equipped with Footscan software version 7 (Gait 2nd generation), examining peak force (FMAX), peak pressure (PMAX), contact area (CA), and time to peak force (Time to FMAX) across five anatomical foot zones. The study revealed significant changes in all parameters, particularly at loads of 15% and 20% of body weight. Increases in plantar pressure, contact area, and asymmetry were observed, along with delays in time to peak force. These findings support the recommendation that children's backpack loads should not exceed 10% of their body weight to prevent potential adverse effects on postural and musculoskeletal development.
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NewsBot · Jul 13, 2025

Biomechanical effects of asymmetric backpack shoulder straps on the unilateral flatfoot: a finite element analysis
Chen Hu et al
Comput Methods Biomech Biomed Engin. 2025 Jul 12:1-11.

This study investigated the biomechanical effects of asymmetric backpack shoulder strap configurations on individuals with unilateral flatfoot (UF) using finite element analysis (FEA). A male subject with UF was recruited, and different shoulder strap settings were simulated to assess their impact on plantar fascia and Achilles tendon stress and strain, as well as on changes in foot arch morphology. The results showed that using equal-length straps on both shoulders resulted in lower stress and strain levels in the plantar fascia and Achilles tendon during walking. However, when the strap length on the flatfoot side was increased, the longitudinal and transverse arch deformation of the affected foot also increased, while deformation in the normal foot's longitudinal arch was reduced. These findings suggest that lengthening the strap on the flatfoot side may help improve arch morphology on that side, but at the cost of increased soft tissue loading and potential restriction of normal foot development.
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NewsBot · Sep 8, 2025

This was just registered:

The Relation Between Plantar Pressure Distriution on the Foot and The Way of Carrying Backpack in Students Between 12 to 18 Years

What is this study about? This is an observational study that investigates how different ways of carrying a school backpack affect the pressure distribution on the soles of the feet (plantar pressure) in adolescents.

The main questions it aims to answer are:

Does carrying a backpack on one shoulder (unilaterally) change the pressure on the bottom of the foot compared to carrying it on both shoulders (bilaterally)?

Does carrying a backpack change the amount of the foot that touches the ground (contact area)?

Are there differences in foot pressure between the right and left foot based on how the backpack is carried?

Researchers compared four different carrying conditions to see their effects:

Carrying no backpack.

Carrying a backpack on both shoulders.

Carrying a backpack on the right shoulder only.

Carrying a backpack on the left shoulder only.

Who participated? The study included 92 healthy adolescent students (32 boys and 60 girls) from Mansoura City, Egypt. Their ages ranged from 12 to 18 years old, they had a normal Body Mass Index (BMI), and had no existing postural or musculoskeletal problems.

What did participants do?

Participants in the study were asked to:
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Have their height, weight, and posture checked to ensure they were eligible.

Stand and walk barefoot on a special computerized pressure-sensitive mat (a Foot Scan Plate System).

Perform these standing and walking tasks under the four different backpack conditions listed above. The backpack was always loaded to weigh 15% of the student's body weight.

What did the study find?

The key findings were:

How you carry the backpack affects how much of your foot touches the ground. Carrying a backpack on one shoulder (especially the right) increased the contact area of both feet on the ground, both while standing and walking.

The average and maximum pressures on the soles of the feet did not change significantly. Regardless of how the backpack was carried, the intensity of the pressure under the feet remained relatively the same in these healthy adolescents.

Overall balance was maintained. Even though the carrying method changed how the feet contacted the ground, the body compensated well, and no significant imbalance in pressure between the right and left foot was found during walking.

What does this mean for patients, families, and healthcare providers?

For Teens and Families: This study highlights that how you carry your backpack matters for your foot mechanics. While a brief change may not cause immediate pain, consistently carrying a backpack on one shoulder can alter your posture and gait. It is best to use both shoulder straps to distribute weight evenly and promote healthy body alignment.

For Healthcare Providers: This research provides evidence that backpack carriage method is a modifiable factor influencing plantar loading patterns in adolescents. Assessing a patient's backpack habits could be a useful part of evaluating complaints of foot, knee, or back pain. Educating patients and families on symmetrical load carriage and proper backpack weight (≤15% of body weight) is a valuable preventive strategy.

The bottom line: While the body can adapt to short-term uneven loading, making a habit of carrying a backpack on both shoulders is the best practice for supporting healthy foot pressure distribution and overall posture in growing adolescents.

NewsBot · Oct 6, 2025

Average vertical loading rate and tibial accelerometry are not valid assessments of internal tibial loads when walking or running with or without load carriage: A cross-sectional laboratory study
Richard W. Willy et al
Source

Valid surrogates are needed to monitor tibial forces during tactical load carriage training. We assessed (a) effects of load carriage on internal tibial forces, average vertical loading rate (AVLR), and peak tibial accelerations; and (b) the relationships among these variables. Walking (1.35 m/s: 0-kg, 20.4-kg, and 34.0-kg) and running (2.7 m/s: 0-kg and 20.4-kg) biomechanics were sampled (n = 34). Peak tibial force increased with load carriage during walking and running (all p < 0.001; F:25.79–371.54). AVLR increased during walking with load carriage (p < 0.001; F = 131.83), with no difference (p = 0.61; F = 0.27) when running with load carriage. Peak tibial accelerations during walking increased with 20.4-kg of load carriage (p < 0.001–0.02). When load carriage was increased to 34.0-kg, small increases were observed for peak positive acceleration (+0.1 g, p = 0.02) only, with no change in peak resultant acceleration (p = 0.99). During running, peak tibial accelerometry surprisingly decreased (p = 0.01–0.04; F = 4.69–7.35) with load carriage. Peak tibial resultant accelerometry was only weakly to moderately associated with peak tibial force during running (r = 0.38–0.52; p = 0.002–0.04); with no other associations between peak tibial force, AVLR, and peak positive tibial acceleration (r = −0.23 – 0.13; p = 0.20–0.92). Thus, AVLR and tibial acceleration are questionable surrogates for internal tibial forces during walking or running, with or without load carriage.
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Effects of carrying backpacks on the foot

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Effects of Limb Length Discrepancy on Spinal Motion During Gait

Structural Effects in Foot Soft Tissues Depending on the Mechanical Contact Between Joints

Effects of Biomimetic Shoes on Healthy Young Children's Gait

Effects of Diuretics on Foot Edema in Patients with Cancer

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Effects of the Short Foot Exercise

Effects of Limitation of Movement of the First Metatarsophalangeal Joint

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Effects of carrying backpacks on the foot

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Effects of Limb Length Discrepancy on Spinal Motion During Gait

Structural Effects in Foot Soft Tissues Depending on the Mechanical Contact Between Joints

Effects of Biomimetic Shoes on Healthy Young Children's Gait

Effects of Diuretics on Foot Edema in Patients with Cancer

Side effects of gel nail polish

Effects of the Short Foot Exercise

Effects of Limitation of Movement of the First Metatarsophalangeal Joint

Share This Page

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