Load distribution and postural changes in young adults when wearing a traditional backpack versus the BackTpack

Exploring musculoskeletal discomfort and school bag loads among Thai primary school students: a school-based cross-sectional survey

Musculoskeletal discomfort among children carrying school bags is an increasingly significant problem. This study sought to determine the prevalence and risk factors of musculoskeletal discomfort among Thai primary school students who carry excessively heavy school bags. We conducted cross-sectional descriptive research involving 489 primary school students (ages 7-12). We utilized the standardized Cornell Musculoskeletal Discomfort Questionnaire (CMDQ) to assess discomfort in various body regions. Measurements included student weight, school bag weight, and the angles of neck and trunk inclination. Logistic regression was used to analyze factors influencing musculoskeletal discomfort. The results showed that the majority of students had musculoskeletal discomfort (66.67%). The average relative weight of the school bags was 17.46 ± 6.02%. Significant risk factors for musculoskeletal discomfort included being female (AOR = 1.87, 95% CI = 1.12-3.10), being in grades 1-3 (AOR = 0.221, 95% CI = 0.05-0.91), carrying bags for more than 20 min per day (AOR = 28.87, 95% CI = 8.93-93.31), not storing books at school (AOR = 2.06, 95% CI = 1.07-3.95), and carrying a school bag weighing > 10% of the student's body weight (AOR = 65.46, 95% CI = 14.73-290.93). Additionally, neck and trunk inclinations > 20 degrees were associated with increased discomfort (AOR = 3.25, 95% CI = 1.89-5.57; AOR = 3.26, 95% CI = 1.58-6.70). The prevalence of musculoskeletal discomfort was higher in Thai primary school students. Female, Grades 1-3, carrying bags exceeding 20 min/day, carrying a school bag weighing > 10% of the student's body weight, and neck and trunk inclinations > 20 degrees were predictor variables for musculoskeletal discomfort. Thus, collaborative efforts from educational institutions, educators, parents, and students are essential in addressing this issue.

Changing the horizontal position of a fixed backpack load: The effect on postural stability in young adults

BACKGROUND

Modifying the horizontal position of the load in a backpack will change the size of the external torque it creates on the wearer but the effect on postural stability is unclear.

OBJECTIVE

To determine if changing the horizontal position of a fixed backpack load affects postural stability in young adults.

METHODS

A backpack was attached to a steel frame with a bar protruding posteriorly. A fixed load (5% body mass) was placed at three distances along the bar - 0 m, 0.20 m, and 0.40 m. Centre of pressure (CoP) derived measurements were recorded from a force platform sampling at 100 Hz. For each condition participants performed three 90s narrow stance trials with their eyes closed whilst standing on a firm surface. A comparison was made across unloaded (no backpack) and loaded conditions.

RESULTS

There was an immediate decrease in postural stability when a loaded backpack was worn. Only two of the CoP derived measures (Total Excursion - TEx, and Mean Velocity Total Excursion - MVel TEx) differed between the loaded at 0.20 m and loaded at 0 m conditions. All CoP derived measures differed between the loaded at 0.40 m and loaded at 0 m conditions. Furthermore, three of the CoP derived measures (Anterior/Posterior Root Mean Square - A/P RMSq, TEx, and MVel TEx) differed between the loaded at 0.40 m and loaded at 0.20 m conditions.

CONCLUSION

The distribution of a load within a backpack must be carefully considered. The findings for the 0.40 m condition are important for the use and design of large backpacks used by multi-day hikers, travellers, and the military.

Usability and effects on gait of an optimized schoolchildren backpack

BACKGROUND: Backpacks used by children is a global concern, because may cause musculoskeletal discomforts and pain. OBJECTIVE: The purpose of this study was to test the usability and effects on gait kinematics wearing the Trunkpack versus a traditional backpack and no backpack. METHODS: Twenty-four children (9 to 11 years old) from a public school participated in this study. The usability was evaluated after a five-week testing period using a questionnaire. Gait kinematics was evaluated (Vicon) when the children were wearing a standard backpack, an optimized backpack (Trunkpack), and no backpack. Both backpacks were loaded with 10% of body weight. RESULTS: Was observed more trunk, hip and knee flexion when the children carried a standard backpack in comparison using the Trunkpack and not carrying a backpack (p < 0.01). The Trunkpack and no backpack were similar. The Trunkpack was well accepted by the schoolchildren (81% positive responses); 79% liked the head opening, 88% liked the waist straps, and 83% liked the facility to put and take objects in and out of the Trunkpack. CONCLUSION: Trunkpack requires less postural adjustments during gait than a standard backpack. Gait kinematics with the Trunkpack was comparable to the gait without carrying a backpack.

Evaluation of an ergonomically designed schoolbag: Heart rate variability and body discomfort rating

BACKGROUND: Unsuitable schoolbags may stress the spine and promote poor body posture, particularly for school students. Global recommendations have suggested that schoolbag weight must not exceed 10% of a healthy student’s body mass, which would need continuous monitoring and enforcement. OBJECTIVES: The present study presents a comparison between an ergonomically designed schoolbag, which helps reduce the potential effects of carrying a load, and a commercial one. METHODS: A total of 30 healthy male students were recruited for this experiment. Independent variables determined were schoolbag type (ergonomically designed and commercial schoolbags) and three load levels based on body mass percentage (i.e., 10%, 15%, and 20% of body mass). Heart rate variability (HRV) and body discomfort rating were then measured. RESULTS: Our results showed that the developed schoolbag promoted enhanced subjective measures and HRV response at 15% and 20% of body mass. Participants who wore the developed schoolbags experienced significantly lesser neck, shoulder, upper and lower trunk discomfort than those who wore the traditional ones. Changing the load percentage from 10% to 15% caused an increase in heart rate among participants carrying a commercial schoolbag but a decrease in heart rate among those carrying the developed schoolbag. CONCLUSIONS: The findings presented herein suggest introducing strategies for reducing the potential impact of load carrying through the combined effect of new educational inventions and policy changes.

Impact of Backpacks on Ergonomics: Biomechanical and Physiological Effects: A Narrative Review

(1) Background: the effects of load carriage packs on human gait biomechanics, physiology and metabolism depend on the weight carried, the design of the pack and its interaction with the user. (2) Methods: An extensive search in the PubMed database was performed to find all the relevant articles using the following keywords: backpack, rucksack, backpack ergonomy and sports backpack; 60 articles were included. (3) Results and significance: Double pack (DP) and T-pack (TP) designs are recommended solutions for school children, compared with backpacks (BP). For soldiers and hikers, a backpack remains the best compromise. A hip belt is recommended for BPs as well as for the back of DPs. Shorter and stiffer shoulder straps combined with a higher and tighter load placement on the back provide the best combination in terms of balance, muscle activation and energy expenditure. It is, therefore, possible to determine guidelines for designing the optimal load carriage system, depending on the application. (4) Conclusions: based on the available evidence, DP and TP are advantageous in terms of posture. DP is better than conventional BPs in terms of balance and muscle activation, but has the disadvantage of limited visibility, thermal sensation and obstructed ventilation. In general, it is desirable not to exceed 40% of body mass (BM).

The Impact of Load Style Variation on Gait Recognition Based on sEMG Images Using a Convolutional Neural Network

Surface electromyogram (sEMG) signals are widely employed as a neural control source for lower-limb exoskeletons, in which gait recognition based on sEMG is particularly important. Many scholars have taken measures to improve the accuracy of gait recognition, but several real-time limitations affect its applicability, of which variation in the load styles is obvious. The purposes of this study are to (1) investigate the impact of different load styles on gait recognition; (2) study whether good gait recognition performance can be obtained when a convolutional neural network (CNN) is used to deal with the sEMG image from sparse multichannel sEMG (SMC-sEMG); and (3) explore whether the control system of the lower-limb exoskeleton trained by sEMG from part of the load styles still works efficiently in a real-time environment where multiload styles are required. In addition, we discuss an effective method to improve gait recognition at the levels of the load styles. In our experiment, fifteen able-bodied male graduate students with load (20% of body weight) and using three load styles (SBP = backpack, SCS = cross shoulder, SSS = straight shoulder) were asked to walk uniformly on a treadmill. Each subject performed 50 continuous gait cycles under three speeds (V3 = 3 km/h, V5 = 5 km/h, and V7 = 7 km/h). A CNN was employed to deal with sEMG images from sEMG signals for gait recognition, and back propagation neural networks (BPNNs) and support vector machines (SVMs) were used for comparison by dealing with the same sEMG signal. The results indicated that (1) different load styles had remarkable impact on the gait recognition at three speeds under three load styles (p < 0.001); (2) the performance of gait recognition from the CNN was better than that from the SVM and BPNN at each speed (84.83%, 81.63%, and 83.76% at V3; 93.40%, 88.48%, and 92.36% at V5; and 90.1%, 86.32%, and 85.42% at V7, respectively); and (3) when all the data from three load styles were pooled as testing sets at each speed, more load styles were included in the training set, better performance was obtained, and the statistical analysis suggested that the kinds of load styles included in training set had a significant effect on gait recognition (p = 0.002), from which it can be concluded that the control system of a lower-limb exoskeleton trained by sEMG using only some load styles is not sufficient in a real-time environment.

Association between the Use of Backpack and Static Foot Posture in Schoolchildren with Static Pronated Foot Posture: A 36-Month Cohort Study

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.

Correlation between craniovertebral angle in the sagittal plane and angles and indices measured in the frontal plane at the moment of inducing forward head posture

BACKGROUND

Forward head posture (FHP) is the most common malposition in the head and neck area. With the growing use of digital devices, the prevalence of FHP may be expected to increase dramatically. Thus far, FHP has been evaluated only in the sagittal plane.

OBJECTIVE

The objective of this study was to measure angles and indices from anatomical landmarks in the frontal plane and determine the possible correlations between these variables and craniovertebral angle (CVA) as an index of FHP in the sagittal plane.

METHODS

Fifty eight healthy individuals (29 men, 29 women) between 18 and 40 years old participated in this cross-sectional study. Participants were evaluated with an 8-camera motion analysis system. After markers were placed on predetermined landmarks, the participants were asked to maintain their head and neck in the neutral position for 5 seconds. Then participants induced FHP by flexing and lowering their head. The correlation between CVA and a set of angles and indices was calculated at the moment of FHP induction.

RESULTS

A moderate correlation was observed between 3-D CVA and the angle formed between the sternum and both tragi for the whole sample and separately in both sexes. A moderate negative correlation was observed between 3-D CVA and height, weight, and BMI in women. A moderate negative correlation was observed between 3-D CVA and height, weight, BMI, and hours on digital devices in men.

CONCLUSIONS

Changes in CVA in the sagittal plane can be predicted from changes in the angle formed between the midpoint of the sternum and the left and right tragi in the frontal plane.

Finite element analysis of lumbar spine with different backpack positions in parachuting landing

The purpose of this study was to investigate the lumbar spine stress with different backpack positions in parachuting landing using a finite element model of lumbar vertebra 1-5. The backpack gravity center was set at three positions (posterior-high (case PH), posterior-low (case PL), and anterior-low (case AL)) respectively. In results, the peak Von-Mises stresses of the matrix, nucleus, fibers, endplate and ligament in case AL were 2.765 MPa, 0.534 MPa, 6.561 MPa, 4.045 MPa and 1.790 MPa respectively, lower than those in case PL (6.913 MPa, 1.316 MPa, 20.716 MPa, 10.917 MPa and 5.147 MPa respectively) and case PH (7.328 MPa, 1.394 MPa, 22.147 MPa, 11.617 MPa and 5.464 MPa respectively). In conclusion, setting the gravity center of backpack at anterior-low position would reduce lumbar spine stress and reduce lumbar spine injuries.

Added body mass alters plantar shear stresses, postural control, and gait kinetics: Implications for obesity

Context

Obesity is a growing global health concern. The increased body mass and altered mass distribution associated with obesity may be related to increases in plantar shear that putatively leads to physical functional deficits. Therefore, measurement of plantar shear may provide unique insights on the effects of body mass and body distribution on physical function or performance.

Purpose

1) To investigate the effects of body mass and distribution on plantar shear. 2) To examine how altered plantar shear influences postural control and gait kinetics.

Hypothesis

1) a weighted vest forward distributed (FV) would shift the center of pressure (CoP) location forward during standing compared with a weighted vest evenly distributed (EV), 2) FV would increase plantar shear spreading forces more than EV during standing, 3) FV would increase postural sway during standing while EV would not, and 4) FV would elicit greater compensatory changes during walking than EV.

Methods

Twenty healthy young males participated in four different tests: 1) static test (for measuring plantar shear and CoP location without acceleration, 2) bilateral-foot standing postural control test, 3) single-foot standing postural test, and 4) walking test. All tests were executed in three different weight conditions: 1) unweighted (NV), 2) EV with 20% added body mass, and 3) FV, also with 20% added body mass. Plantar shear stresses were measured using a pressure/shear device, and several shear and postural control metrics were extracted. Repeated measures ANOVAs with Holms post hoc test were used to compare each metric among the three conditions (α = 0.05).

Results

FV and EV increased both AP and ML plantar shear forces compared to NV. FV shifted CoP forward in single-foot trials. FV and EV showed decreased CoP range and velocity and increased Time-to-Boundary (TTB) during postural control compared to NV. EV and FV showed increased breaking impulse and propulsive impulse compared to NV. In addition, EV showed even greater impulses than FV. While EV increased ML plantar shear spreading force, FV increased AP plantar shear spreading force during walking.

Conclusion

Added body mass increases plantar shear spreading forces. Body mass distribution had greater effects during dynamic tasks. In addition, healthy young individuals seem to quickly adapt to external stimuli to control postural stability. However, as this is a first step study, follow-up studies are necessary to further support the clinical role of plantar shear in other populations such as elderly and individuals with obesity or diabetes.

Backpacks Effect on Foot Posture in Schoolchildren with a Neutral Foot Posture: A Three-Year Prospective Study

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.

The effect of backpack load position on photographic measures of craniovertebral posture in 150 asymptomatic young adults

BACKGROUND

Altering the horizontal position of the weight in a backpack will influence the magnitude of the external torque it creates but the effect on posture is unclear.

OBJECTIVE

To use photogrammetry to determine if changes in the horizontal position of a fixed backpack weight affect external measures of craniovertebral posture in 150 asymptomatic young adults.

METHODS

A backpack was attached to a steel frame with a bar protruding posteriorly. A fixed load (5% body mass) was placed at three distances along the bar -0 m, 0.20 m, and 0.40 m. Sagittal and frontal plane photogrammetry was used to measure the craniovertebral angle (CVA), upper cervical gaze angle (UCGA) and lateral head tilt angle (LHTA). A comparison was made across unloaded (no backpack) and loaded conditions.

RESULTS

There was a significant decrease in the CVA between unloaded and loaded conditions. Changes in the UCGA were small and, while significant, may not have practical importance. There were no differences in the LHTA between the conditions.

CONCLUSIONS

Changes in the horizontal position of a fixed load affect external measures of craniovertebral posture so consideration needs to be given to not only the weight of a backpack but how the weight is positioned within the backpack.

Comparison between the Physiological Responses and Subjective Ratings of a Group of Male Students to Three Backpack Designs

It is important for schoolchildren and their parents (or guardians) to know which backpacks exert the least strain on the cardiorespiratory system. In this study, we investigated the physiological responses of participants while they were walking on a treadmill and wearing one of three different backpacks (A, B, and C) under two different load-carrying conditions (equivalent to 10% and 15% of their body mass, respectively). The first condition was used as a control and involved walking without a backpack, while the second involved wearing a backpack and carrying a certain weight. Thirty-one male students from King Saud University walked on a treadmill at 0.861 m/s and at a 0% inclination angle, while having their heart rates (beatsmin⁻¹), oxygen uptakes (VO2, mLmin⁻¹), respiratory rates (breaths, VO2min⁻¹), perceived exertion rates (PER, Borg scale), and backpack preference rates (BPR) measured and recorded. The results of our within-subject experimental design revealed that the physiological results varied significantly depending on the type of backpack. Backpacks B and C were superior to Backpack A, resulting in lower physiological responses and higher subjective preferences. Students carrying more weight experienced higher physiological stress; moreover, the use of Backpack C led to the lowest physiological strains and higher subjective preferences.

Variation of spatiotemporal parameters in school children carrying different backpack loads: a cross sectional study

The purpose of this study was to analyze spatiotemporal parameters of gait in children using varyingly loaded Backpacks(BP). This cross-sectional study examined 231 schoolchildren (118 boys, 113 girls) aged six to 12 years, carrying a traditional BP to manipulate loading (Crossing Backpack Children Arpenaz 7 Litres, Junior Red Quechua). Load was added to the BPs in increments of 5%, 10%, 15% and 20% of the child's body weight. Spatio-temporal parameters were measured with the OptoGait system. Significant differences were observed in single support (p < 0.001), and double support (p < 0.001). No statistically significant differences were observed in step length (p = 0.959) between the five loading conditions. Similarly, no statistically significant differences were found in the contact phase (p = 0.208), although significant changes were seen between baseline, 15% of body weight (p < 0.005), and 20% of body weight (p < 0.005). The effect sizes from the ANOVA in the single support was low (0.015), and double support was moderate (0.02). Increased weight in BPs reduced both children's balance and single support, increased double support, but did not change step length. The children increase double support with heavier loads to help their balance. The spatio-temporal changes were most evident with BP loads between 15-20% of body weight. Affective responses, including the perception of heaviness or difficulty in carrying the schoolbags need to be included in further and prospective investigations.

Importance of Sock Type in the Development of Foot Lesions on Low-Difficulty, Short Hikes

Background and objectives: Foot lesions can be developed during hiking because of external factors. This makes it important to study the effect of hiking equipment on lesion development. Materials and Methods: Technical and non-technical socks were given to 109 hikers to wear during a short hike. Participants were examined at three stages of the hike to determine the development of dermal, muscle and nail lesions, temperature and perimeter in various areas of each foot. Results: The percentage of hikers without injuries was significantly higher among those wearing technical socks (p-value < 0.001). Differences were also observed in mean foot temperature, which was higher in participants wearing technical socks (p-value < 0.001). Conclusion: The results indicate that even on a low-difficulty, short-term sport activity, it is advisable to wear technical socks to prevent lesion development and keep the foot temperature more stable. Sock type was identified as an external conditioning factor in lesion development.

Schoolbag weight carriage in Portuguese children and adolescents: a cross-sectional study comparing possible influencing factors

BACKGROUND

Schoolbags and the consequences of carrying them, particularly those associated with overload, are often studied as a health concern. Modifications in gait and posture were reported when children carried loads that corresponded to more than 10% of their body weight (BW). The aims of this study were to verify the load that is carried by Portuguese students and how it is influenced by factors such as school grade, school schedule, lunch site, physical education, sex and body mass index (BMI). Acquiring a more specific knowledge of the Portuguese context and understanding the influence of these factors may allow us to generate proposals to control them in ways that benefit students.

METHODS

The load carried by students in the 5th grade (10.6 ± 0.4 years) and 9th grade (14.7 ± 0.6 years) were weighed with a luggage scale on all days of the week, resulting in 680 evaluations. Data related to the school day were also collected, such as the student's lunch site, how he or she got to school and his or her school schedule for that day. Individual height and weight were also assessed.

RESULTS

The 5th grade students carried greater loads than the 9th grade students, resulting in a substantial difference relative to their BW. The school loads of the 5th grade students were mostly greater than 10% of their BWs. Girls tended to carry heavier loads than boys, and overweight students also tended to carry heavier loads. Students who could eat lunch at home carried less weight, and on physical education days, the total load carried increased, but the backpacks of the 5th grade students were lighter.

CONCLUSIONS

The results of the current study describe excessive schoolbag weight among Portuguese students and expound on some of the factors that influence it, which can help researchers and professionals design a solution to decrease children's schoolbag loads.

Impact of Load Variation on the Accuracy of Gait Recognition from Surface EMG Signals

As lower-limb exoskeleton and prostheses are developed to become smarter and to deploy man–machine collaboration, accurate gait recognition is crucial, as it contributes to the realization of real-time control. Many researchers choose surface electromyogram (sEMG) signals to recognize the gait and control the lower-limb exoskeleton (or prostheses). However, several factors still affect its applicability, of which variation in the loads is an essential one. This study aims to (1) investigate the effect of load variation on gait recognition; and to (2) discuss whether a lower-limb exoskeleton control system trained by sEMG from different loads works well in multi-load applications. In our experiment, 10 male college students were selected to walk on a treadmill at three different speeds (V3 = 3 km/h, V5 = 5 km/h, and V7 = 7 km/h) with four different loads (L0 = 0, L20 = 20%, L30 = 30%, L40 = 40% of body weight, respectively), and 50 gait cycles were performed. Back propagation neural networks (BPNNs) were used for gait recognition, and a support vector machine (SVM) and k-nearest neighbor (k-NN) were used for comparison. The result showed that (1) load variation has significant effects on the accuracy of gait recognition (p < 0.05) under the three speeds when the loads range in L0, L20, L30, or L40, but no significant impact is found when the loads range in L0, L20, or L30. The least significant difference (LSD) post hoc, which can explore all possible pair-wise comparisons of means that comprise a factor using the equivalent of multiple t-tests, reveals that there is a significant difference between the L40 load and the other three loads (L0, L20, L30), but no significant difference was found among the L0, L20, and L30 loads. The total mean accuracy of gait recognition of the intra-loads and inter-loads was 91.81%, and 69.42%, respectively. (2) When the training data was taken from more types of loads, a higher accuracy in gait recognition was obtained at each speed, and the statistical analysis shows that there was a substantial influence for the kinds of loads in the training set on the gait recognition accuracy (p < 0.001). It can be concluded that an exoskeleton (or prosthesis) control system that is trained in a single load or the parts of loads is insufficient in the face of multi-load applications.

Postural balance and neck angle changes in school children while carrying a traditional backpack versus a double-sided bag

Study aim: This study compared the body balance and neck angle differences in children when carrying a traditional backpack versus a double-sided bag. Material and methods: By using the Biodex balance system and a three dimensional motion analysis system, the postural bal­ance and neck angles were assessed in 33 school children while carrying a traditional backpack or a double-sided bag, weigh­ing 15% of body weight. Results: The overall and anteroposterior stability indices were significantly higher when carrying a traditional backpack com­pared to no load and a double-sided bag (p < 0.05). The mediolateral stability index was significantly higher when carrying the traditional backpack and the double-sided bag compared to no load (p < 0.05). The craniohorizontal angle was significantly greater, and the craniovertebral angle and sagittal shoulder posture were significantly lesser when carrying the traditional back­pack compared to no load and the double-sided bag conditions (p < 0.05). Conclusion: Carrying the double-sided bag restores the body balance and head posture to a condition that is similar to the no load condition.

Effects of backpack load and position on body strains in male schoolchildren while walking

Data regarding the effects of backpack carriage on children’s body strains while walking are limited. This study measured the body posture, muscle activation, and subjective discomfort scores of 12 male schoolchildren (age: 12.3 (range 12.1–13.0) y, height: 151.3 (range 144.2–154.6) cm, weight: 46.6 (range 43.6–49.7) kg) carrying backpacks weighing 5%, 10%, and 15% of their respective body weights (BWs) and walking for 10 min on a treadmill. For each load, three positions along the spinal column (T7, T12, and L3) were examined. Participants carrying a backpack weighing 15% of BW exhibited higher head flexion, trunk flexion, and corresponding muscle activation, and a lower lumbosacral angle compared with those carrying loads of 5% and 10% of BW. The waist received the highest discomfort scores when the backpacks were carried at the L3 position. Conversely, the discomfort rating for the neck and shoulders where the highest when the backpack was at the T7 position; this high backpack position also caused more head flexion than the other two positions. For the musculoskeletal health of children, the findings suggest that carrying a school backpack weighing 15% of BW should be avoided, and carrying at the T12 position may be recommended for schoolboys.

Effects of a wearable type lumbosacral support for low back pain among hospital workers: A randomized controlled trial

Objective:

To examine the effects of a new wearable type of lumbosacral support on low back pain.

Methods:

A total of 121 healthcare workers participated in this study. They were randomly allocated into the experimental and control groups and the former wore the support with signals of compression on the back by poor posture for the first 3 months. The control group remained on a waiting list for the first 3 months. Medical history, musculoskeletal symptoms, feeling in good posture, sleep habits, psychological distress, Roland-Morris Disability Questionnaire, and Somatosensory Amplification Scale (SSAS) were evaluated. The range of motion (ROM) in the shoulder and hip joints as well as spinal alignment were evaluated. Our primary concern was the difference in the change of low back pain measured by visual analog scale (VAS) between the two groups.

Results:

A total of 54 participants in the experimental and 53 participants in the control groups were analyzed. VAS and SSAS scores as well as lumbar spinal ROM in the experimental group significantly decreased. Low back pain (OR=0.401, 95% CI=0.168-0.954) and neck pain in the experimental group (OR=0.198, 95% CI=0.052-0.748) significantly decreased.

Conclusions:

The new lumbar support reduced VAS and SSAS scores, lumbar spinal ROM, low back pain, and neck pain. This new type of lumbar support reduced low back pain among healthcare workers.