Sedigheh Karimi Avargani, Ali Maleki, Shahin Besharati, Reza Ebrahimi,
Volume 8, Issue 3 (10-2020)
Abstract
Background and Aim: Carriage of backpack sprayers is an inevitable part of agricultural operations that increases the risk of injury along with undesirable changes in walking mechanics. The purpose of this study is to formulate the muscle moment changes in the hip, knee and ankle for the backpack sprayer operator body.
Methods: In this study, a seven-link sprayer operator model is designed and the moment changes in the hip, knee and ankle joints are evaluated. Data are obtained using Plot-digitizer software. Excel software is used to fit the third degree curve on the data.
Results: In the hip joint, the moment is reduced by changing the angle from zero to 15°. At the end of the swing phase, the moment applied to the hip joint increases with increasing the angle up to 30°. In the beginning of the swing phase, the knee joint starts to open at -55°. At the end of the swing phase, the knee joint releases up to -5 ° and the moment applied to the knee joint increases slowly. The moment applied to the ankle joint increases by changing the ankle angle from -7.5° to 7.5°.
Conclusion: According to the results of this study, amount of moment changes of hip, knee and ankle joint affect the force applied to the backpack sprayer operator body. With the knowledge of the moment changes of joints, practical solutions can be provided to reduce amount of damage to these joints.
Faridah Aghahasni Mahabadi, Abbas Farjad Pezeshk, Mohammad Yousefi,
Volume 12, Issue 2 (7-2024)
Abstract
Objectives: Using a backpack with a hip belt limits hip movements and prevents disruption in hip and trunk coordination. Therefore, this study aimed to compare the effect of common mechanisms in the design of hip belts in mountaineering backpacks on the coordination between trunk and pelvis organs during walking.
Methods: This semi-experimental research was conducted on 16 men. Three types of backpacks with different hip belts were used. Participants carried backpacks with a load of 13 kg. The continuous relative phase and its variability were used to analyze the coordination. Descriptive statistics of mean and standard deviation and analysis of variance with repeated measures were used to compare variables in four conditions.
Results: According to the results, there was a difference between the level of coordination in two conditions of without a backpack and a normal backpack, with the normal backpack showing a significant decrease in coordination (P<0.05). The results also indicated that the variability in coordination increased after using backpacks with movable hip belts and cross frames compared to walking without a backpack (P<0.05).
Conclusion: Based on the existing findings, backpacks with a cross-movable frame maintain the antiphase coordination between the trunk and pelvis by allowing freedom of movement in these two organs. It also creates more flexibility by increasing variability in coordination.
Saeed Ilbeigi, Zahra Karimi, Abbass Farjad Pezeshk,
Volume 13, Issue 2 (9-2025)
Abstract
Background and Purpose: Backpacks with pelvic belts are commonly used for carrying loads during long treks and mountaineering, as they help distribute the load between the upper and lower body and reduce muscular effort. However, they may also restrict movement. This study aimed to compare three common pelvic belt mechanisms in backpacks regarding their effects on postural control and center of pressure (COP) parameters during standing and walking.
Methods: This semi-experimental study was conducted on 20 male physical education students aged 19 to 25. Participants used three types of backpacks (1–with a movable pelvic belt, 2–with a crossed-frame back support, and 3–a regular backpack) while carrying a standard 13 kg load on a flat surface. A walking test without a backpack was also conducted as a control. COP indicators—including area, displacement, velocity, and sway—were measured. Data normality was assessed using the Shapiro-Wilk test, and statistical comparisons were made using repeated measures ANOVA and Bonferroni post hoc tests.
Findings: No significant differences were observed among the backpacks in terms of COP area during standing and walking. However, during eyes-closed standing, significant differences were found in COP displacement and velocity in the anterior-posterior direction (p=0.009), particularly between the regular backpack and the one with a movable pelvic belt. For COP sway (p=0.030), significant differences were found among the three backpacks in the medial-lateral direction, though pairwise comparisons showed no statistical significance.
Conclusion: The backpack with a movable pelvic belt showed superior performance in minimizing COP sway, displacement, and velocity. Differences in pelvic belt designs become more evident under higher complexity postural tasks.
