Correlations between Muscle Activities and Strap Length and Types of School Bag during Walking

The impact of varying trolley case usage modes and weights on body posture

OBJECTIVE

To study the body posture characteristics when walking with trolley case, and to explore the effects of different usage methods and weights of trolley case on body posture characteristics.

METHODS

Fifteen subjects pushed and pulled(Condition 1 and 2) the case with three load weights of 10 %, 20 % and 30 % of their own body weight with 0 % no load as baseline for both conditions. The basic gait parameters, kinematic and kinetic data were collected using the VICON infrared motion capture system and a 3D force platform. Two repeated measures factor (condition×weight) analysis of variance was used for statistical analysis of the gait temporal and spatial parameters, as well as trunk angle, kinetic ground reaction force, shoulder joint force, and trunk moment.

RESULTS

Significant condition*weight interactions were detected in DLST (Double Limb Stance Time) (F=5.341，P = 0.006), GRF (Ground Reaction Force) in frontal plane (F=10.507, p < 0.001) and vertical plane (F=3.751, p = 0.021), shoulder joint force in sagittal plane (F=21.129, p < 0.001), and flexion-extension angle of the trunk in the sagittal plane (F=4.888, p < 0.010). Significant main effects were detected in walking speed (F=35.842, p < 0.001), right support time (F=12.156, p < 0.001), left swing time (F=8.506, p < 0.001), left support time (F=1.122, p < 0.001), right step length (F=33.900, p < 0.001), and left step length (F=14.960, p < 0.001) under different weights. A significant main effect was detected in sagittal GRF (F=11.77, p < 0.001), trunk rotation angle (F=4.124, p = 0.016), amplitude of COM (F=2.993, p = 0.046), under different weights.

CONCLUSION

When the weight of the case exceeds 20 % of the body weight, from the perspective of energy efficiency, the push method is more advantageous than the pull method. When walking with luggage, people tend to maintain the stability of their trunk posture by adjusting the force on their arms more often.

Comparison of muscle activity in school students while carrying backpacks and trolley bags

BACKGROUND

Trolley bags have gained popularity among students, but there is limited research comparing them to backpack-style school bags.

OBJECTIVE

This study aimed to compare how carrying a backpack versus a trolley bag affects the activity of trunk and lower limb muscles in secondary school students.

METHODS

Electromyographic activity was measured in 25 students (13.4±1.1 years) as they walked on level ground and up/down stairs while carrying both types of bags. The activity of the gastrocnemius, tibialis anterior, semitendinosus, rectus femoris, lumbar erector spinae, and rectus abdominis muscles was assessed on both the dominant and non-dominant sides.

RESULTS

The study found significantly reduced muscle activation in most of the targeted muscles when walking on level ground with the trolley bag and when going up/down stairs with the backpack.

CONCLUSIONS

Lifting a trolley bag depends on the slope of the walking surface and is more efficient on level ground, while carrying a backpack is more efficient when going up and down stairs. Since it is not practical to switch bags when encountering stairs in schools, a bag with a mixed model design incorporating features of both trolley and backpack may be more beneficial and practical for students to use. Students, parents, and teachers should be aware of the injury risks associated with carrying different types of bags.

The association between backpack use and low back pain among pre-university students: A pilot study

Background

Individuals aged 30–60 years have a high possibility of experiencing low back pain. However, children and adolescents are not exempted from this problem. This study aimed to determine the relationship between backpack usage and the frequency of low back pain in pre-university students.

Methods

A total of 101 currently enrolled pre-university students were recruited for this cross-sectional study. They answered a questionnaire about their demographic details and their frequency of backpack usage. Their backpacks were weighed for four consecutive school days. The Roland–Morris Disability Questionnaire and Body Discomfort Chart were used to rate discomfort levels.

Results

The use and weight of a backpack were not significantly associated with low back pain, as indicated by the Roland–Morris Disability Questionnaire and Body Discomfort Chart (p > 0.05).

Conclusion

This study did not find an association between the use of a backpack and low back pain in Malaysian pre-university students.

Influence of load and carrying method on gait, specifically pelvic movement

[Purpose] The purpose of this study was to examine how carrying methods and load affects pelvic movement while walking. [Subjects and Methods] Sixteen healthy subjects (age 20.68 ± 1.95 years, height 167.56 ± 8.46 cm, weight 60.25 ± 9.37 kg) volunteered. The items carried included a hand bag, shoulder bag, cross bag, and a back pack. The load weights were 0%, 5%, 10% and 15% of body weight. G-Walk was used to record and analyze pelvic movement while the participants walked with different loads. [Results] In the case of hand bags and shoulder bags, pelvic tilt increased along with weight. In particular, when compared with the 0%, 5% and 10% load conditions, the 15% load of a hand bag induced a significant increase. Pelvic rotation showed a tendency to decrease as the weight increased. [Conclusion] Lateral pelvic tilt is thought to increase when the weight exceeds 15% of body weight, thereby resulting in decreased efficiency of gait. The pelvic rotation is thought to decrease as the weight increases, causing restricted upper limb movements.