Effect of variable backpack load and strap option on the pulmonary function of children: A simulation using treadmill walking

Musculoskeletal problems and backpack carriage among students in Nigeria

BACKGROUND

The health implication of backpack carriage among school-aged children is a topic of growing research and public health interest. Low weighing backpacks may decrease the risk of musculoskeletal discomforts (MSDs).

OBJECTIVE

To investigate MSDs and their association with backpack carriage practices among secondary school students in eastern Nigeria.

METHOD

Across-sectional study of 404 (243 females and 161 males) secondary school students aged thirteen to seventeen who were residents of Enugu State, Nigeria was conducted. The Modified Standard Nordic Musculoskeletal Questionnaire was adapted and used to collect information onstudents' demographics, musculoskeletal painand backpack carriage. Descriptive statistics (frequencies and percentages) were utilized to summarize results. Chi-square test was used to explore the association between MSD prevalence and backpack carriage practices. Data were analysed using SPSS version 20.0. Alpha level was kept at 0.05.

RESULTS

The average backpack weight carried by the students in this study was 2.49 kg. Shoulder (185, 45.8%), neck (121, 30.0%), upper back (91, 22.6%) and lower back (22, 5.5%) in that order were the body regions most affected by MSDs within the last 12 months. More females than males reported MSDs (60.5% vs 45.2%; x2 = 8.09, p = 0.04). Other students'characteristics and backpack carriage related factors were not associated with MSDs.

CONCLUSION

There is a high prevalence of MSDs among secondary school students in this study but it is not related to backpack carriage. Further research is required to identify the factors responsible for the MSDs, as well as suitable interventions to reduce its impact in this population.

Effect of Backpack Strap Patterns on Gait Parameters in Young Adults at Self-Selected Normal and Fast Walking Speeds

BACKGROUND

The effects of backpack load on young adults' gait parameters have received little attention. We previously reported that with a backpack load within 15% body weight (BW), young adults maintain their gait parameters at the expense of increased exertion during a 6-minute walk at self-selected normal walking speed. However, the effect of backpack strap pattern on gait parameters during faster walking or longer stride length has not been evaluated.

OBJECTIVE

To determine the effect of different backpack strap patterns on gait parameters during a 12-minute walk test in young adults at self-selected normal and fast walking speeds.

DESIGN

A crossover, self-controlled experimental study with repeated measures.

SETTING

Department of Medical Rehabilitation, University of Nigeria.

PARTICIPANTS

A convenience sample of 24 healthy young adults (21.29 ± 1.20 years) who voluntarily signed an informed consent form, were able to wear a backpack on 1 and on both shoulders, were able to walk independently, and passed the physical activity readiness screening participated in this study.

METHODS

Using a validated method of an observational gait analysis, each participant carried out a 12-minute walk test at self-determined normal and fast walking speeds, respectively. The effect of the following test conditions on the selected gait parameters was evaluated: normal and fast walking without load, and normal and fast walking with 10% and 20% BW backpack carried each on 1 and both shoulders.

MAIN OUTCOME MEASUREMENT

Stride length, stride time, velocity, cadence, and base of support were assessed by the equation definitions method of the velocity field diagram.

RESULTS

At self-selected fast walking speed with 10% BW backpack load, stride time (P = .004) and cadence (P = .006) were significantly decreased when participants wore a double-strap backpack. At self-selected normal walking speed with 20% BW backpack load, cadence was significantly decreased with double-strap backpack carriage (P = .008). Cadence (P < .001), velocity (P < .001), and stride time (P < .001)were also significantly decreased at both conditions of single and double-strap backpack carriage of 20% BW respectively at fast walking speed.

CONCLUSION

Backpack strap patterns do not affect the gait parameters of young adults in a 12-minute bout of normal walking speed, provided that the load is less than 20% BW. However, a load up to 10% BW carried on a double strap causes a decrease in stride time and cadence when these individuals walk fast.

LEVEL OF EVIDENCE

Not applicable.