The Effect of Ergonomic Principles Education on Musculoskeletal Disorders among Computer Users

Objective: The aim of this study was to evaluate the education ergonomic principles on musculoskeletal disorders among computer users at Rasht welfare organization in 2011. Materials & Methods: This semi-experimental study, 283 female computer users whom had musculoskeletal disorders randomly assigned into two groups. The case group were educated practically and theoretically about ergonomic issues for three months and ergonomic interventions were carried out for this group. Body map questionnaire was used for estimation of musculoskeletal disorders level and statistical analysis was performed using kolmogorov-smirnov and covariate test. Results: The results of the present study showed that the highest prevalence rate of musculoskeletal disorders were reported in right knee (27.91%), neck region (27.20%) , lumbar and right shoulder (24.14%), left knee (25.79%), back (23.67%). The results of this research showed that there was homogeneity of variance and the meaning of the F covariance at the level of P&le0.05 revealed that the education of ergonomic principles leads to a reduction of Musculoskeletal Disorders among computer users. Conclusion: Education of ergonomic principles for the computer users and ergonomic interventions like correction of postures, reducing of work duration , armrest, foot rest, and cushion strengthening exercise and regulating of work station application have a significant effect on the decreasing musculoskeletal disorders prevalence among computer users

Analysis of the Ankle Moment-Angle Curve in Different Gait Speeds and Phases for Designing Ankle-Foot Prosthesis

Objective: Aim of this study was to analysis the ankle moment-angle relation and its characteristics at different gait speeds and phases for using in prosthetic ankle-foot design. Materials & Methods: This was a cross-sectional analytic study in which 20 participants were chosen with assessable sampling method. Gait analysis at different speeds was performed with two force-plates and five high speed cameras. Ankle characteristics including quasi-stiffness and work were estimated at three periods of stance phase based on moment-angle loop. Mean differences were analyzed with repeated measure ANOVA and regression analysis was performed to fit the linear model to the data. Results: Moment-angle curve was clockwise at slower speeds and turned counter-clockwise while speed increased. The best fitted line to the work-walking speed curve had R2=0.81. There were significant differences in quasi-stiffness between fast and normal speed and slower speeds (P<0.001). Conclusion: Moment-angle curve displayed ankle passive function in slower speeds and active function in faster speeds. Results showed ankle characteristics varied at different gait phases and speeds. Thus, at slower speeds a spring-damper model with regulable damping would simulate the ankle function. However, at higher speeds the active elements also should be considered

Effects of Lateral Heel Wedges and Lateral Forefoot Wedge on the Knee Adduction Moment in Healthy Male Students

Objective: Lateral wedged insoles have been designed to decrease the force applied on the medial knee compartment. The aim of this study was to assess the effects of laterally wedged insoles regarding to the placement of the wedge under the sole (under the heel or under the forefoot) on the knee adduction moment and the ground reaction forces. Material & Methods: In this pretest-posttest study, three-dimensional gait analysis was performed on 20 healthy men between 18-30 years old. Knee adduction moment and ground reaction forces were compared among following three types of insoles: a flat insole, a 6˚ laterally inclined heel wedged insole and a 6˚ laterally- inclined forefoot wedged insole. Results: there was no difference between three conditions (flat insole (9.72±1.501), lateral heel wedge (9.866±2.141) and lateral forefoot wedge (9.952±1.986) in peak knee adduction moment (P>0.05). Ground reaction forces and spatiotemporal parameters of gait were not affected by any types of these insoles (P>0.05). Conclusion: Based on the current finding, placement of the lateral wedge under the sole, that is, under the heel or under the forefoot has no effect on the efficacy of these insoles on the adduction moment of the knee and ground reaction forces

Designing and Manufacturing an Electrical Control System for Myoelectric Transradial Prothesis

Objective: The goal of this study was to record the Electromyogram (EMG) signal from the biceps and triceps muscles utilizing two individual channels to control an EMG driven myoelectric prosthesis. Materials & Methods: To achieve the study goal a system for recording and processing the signal was designed and fabricated. Based on recorded signals from biceps and triceps muscles, a successful system was developed to control a powered prosthesis. Results: According to the results of this study it was revealed that utilizing the average amount signal is a very successful way to obtain the control signal. Conclusion: Since the amplitude and frequency of the EMG signal has not yet been defined and sometime there are some unwanted electrical activities on the skin, prosthetic control is rather difficult for the users. Additionally, in IAV domain, no distinct border between strong and week contractions was obtained after conducted tests