Shoulder girdle muscle activity and fatigue in traditional and improved design carpet weaving workstations

Objectives: Work-related musculoskeletal disorders in the neck and shoulder regions are common among carpet weavers. Working for prolonged hours in a static and awkward posture could result in an increased muscle activity and may lead to musculoskeletal disorders. Ergonomic workstation improvements can reduce muscle fatigue and the risk of musculoskeletal disorders. Material and Methods: The aim of this study is to assess and to compare upper trapezius and middle deltoid muscle activity in 2 traditional and improved design carpet weaving workstations. These 2 workstations were simulated in a laboratory and 12 women carpet weavers worked for 3 h. Electromyography (EMG) signals were recorded during work in bilateral upper trapezius and bilateral middle deltoid. The root mean square (RMS) and median frequency (MF) values were calculated and used to assess muscle load and fatigue. Repeated measure ANOVA was performed to assess the effect of independent variables on muscular activity and fatigue. The participants were asked to report shoulder region fatigue on the Borg�s Category-Ratio scale (Borg CR-10). Results: Root mean square values in workstation A are significantly higher than in workstation B. Furthermore, EMG amplitude was higher in bilateral trapezius than in bilateral deltoid. However, muscle fatigue was not observed in any of the workstations. Conclusions: The results of the study revealed that muscle load in a traditional workstation was high, but fatigue was not observed. Further studies investigating other muscles involved in carpet weaving tasks are recommended. © 2016, Nofer Institute of Occupational Medicine. All rights reserved

The effect of rocker shoe on the ground reaction force parameters in patients with rheumatoid arthritis

Objectives: Foot and ankle problems are common complications in rheumatoid arthritis disease. Gait pattern such as normal foot and ankle rocker is impaired in patients with rheumatoid arthritis. Rocker sole as an external shoe modification is commonly prescribed in this pathology. The aim of this study was to investigate the effect of rocker shoe on vertical ground reaction force parameters during walking in patients with rheumatoid arthritis. Methods: Sixteen female participants with rheumatoid arthritis were recruited in this study. All patients were prepared with a pair of high-top, heel-to-toe rocker shoe and were asked to wear the shoes for one month. Ground reaction force parameters including peak forces and peak force times were evaluated in the first session, and after seven days and thirty days follow up were carried on. Results: First maximal vertical force was significantly increased with rocker shoe compared to barefoot after 7 days follow up. Walking with rocker shoe reduced the minimal vertical force after 7 days. The second maximal vertical force showed to be statistically lower with rocker shoe than barefoot after 7 and 30 days. Furthermore, stance time decreased with rocker shoe after one month. Discussion: Results of this study revealed that vertical ground reaction force parameters changed in rheumatoid arthritis patients with heel-to-toe rocker shoe, both immediately and after one month follow up. This might suggest the effectiveness of rocker shoes in improving gait in rheumatoid arthritis patients

Assessment of correlation between electrogoniometer measurements and sports-specific movement in karate elites

Purpose: To examine the intra-rater reliability of knee movement data in sagital plane obtained from electrogoniometer (EGM) in a basic, sport-specific task of karate. Methods: A total of 23 elite karate athletes (13 females and 10 males; mean age of 16.10±1.26 yrs) participated in this study. The task was defined as performing three consecutive Zenkutsu-dachi in two sessions. The used EGM was a twin axis of Biometrics company. EGM curves were plotted in MATLAB software separately. The indices of three points in the plots corresponding to extremes of flexion and extension of knee in the first dachi were determined. There was also another (forth) point which was not in extremes of movement. As it was repeated in all curves, it was perceived as a biomechanical event and was assessed. The phases of movement between the points were scaled between 0 to 100 of activity. Results: Repeatability of the forth point index was assessed by intraclass correlation method. Intraclass correlation of the ratio in the first testing session was 0.666 and in second was 0.448. The interval between points were considered as phases of movement. After determining three phases of dachi, it was shown that these phases pertained a specific ratio of the total plot which were 48, 36 and 16 of total respectively. Conclusion: Dachi could be divided into three distinct phases; each of them should constitute a specific percent of the total in an elite athlete. © 2014 by Sports Medicine Research Center, Tehran University of Medical Sciences, All rights reserved

Corrigendum to: �Experimental study of prosthesis modifications based on passive dynamic walking model: A limit cycle stability analysis�. J. Biomech. 104 (2020) 109743 (Journal of Biomechanics (2020) 104, (S0021929020301597), (10.1016/j.jbiomech.2020.109743))

The authors regret an error and wish to make the following correction to their recently published paper Moradi et al. (2020): In the results section, an error occurred in part B of Table 2; where the descriptive results of step length were reported incorrectly the same as part A. The corrected table is presented below. © 2020 Elsevier Lt

The Immediate Effect of Lateral Wedge Insoles, With and Without a Subtalar Strap, on the Lateral Trunk Lean Motion in Patients With Knee Osteoarthritis

Background: Orthotic interventions for knee osteoarthritis (OA) aim to reduce mechanical loading on the medial compartment of the knee and may lessen the lateral trunk lean as the most important compensatory gait strategy. The lateral wedge insole is a known orthotic intervention for knee OA. However, the question whether the addition of a subtalar strap to the wedge improves its effect has not been addressed in the literature. Objective: To compare the effects of lateral wedge insoles, with and without a subtalar strap, on the lateral trunk lean in patients with knee OA. Methods: Twenty-three patients aged over 40 years, with grade I or II OA of the medial compartment of one knee, based on the American College of Rheumatology criteria, were included in this study. The patients were diagnosed with OA based on a clinical examination, and the diagnosis was confirmed with radiographs. A 3-dimensional motion measurement system was used to collect the gait data for 3 different conditions: (1) with no insole, (2) with a lateral wedge insole, and (3) with a lateral wedge insole and a subtalar strap. The immediate effect of the 3 test conditions on the lateral trunk lean was compared during a gait cycle a stance phase and at the point of midstance. Results: Based on the laboratory coordinate system, the 3 conditions had no significant effect on the lateral trunk lean during a gait cycle and a stance phase and at the point of midstance in patients with knee OA. Conclusion: The results of this study demonstrated that the lateral wedge insoles, with and without a subtalar strap, had no immediate effect on the lateral trunk lean in patients with knee OA. However, the long-term effect of lateral wedge insoles on the lateral trunk lean in these patients requires further investigation. © The Author(s) 2013

The effect of increasing volume of exercise on activation pattern of vastus medialis and lateralis and its correlation with anterior knee pain in karate elites

Background: The effects of exercise volume on the pattern of muscle activity is one of the most important factors in training management and injury risk reduction. In the lower limb, the quadriceps muscle which plays a determining role in performing the stance and other karate techniques could be injured in intensive exercise and may induce anterior knee pain in athletes. Objectives: The aim of this study was to determine the relationship between training volume and muscle activity of vastus medialis and vastus lateralis and its association with anterior knee pain in karate elites. Patients and Methods: Male and female athletes from national junior and cadet karate team (14 to 18 years) were invited to participate in the study at the beginning and the end of the training camps. Studies involved measurement of electromyographic muscle activity of vastus medialis and vastus lateralis in both lower extremities with surface electromyography device and assessment of movement by electrogoniometery. Muscle activity was recorded in three tests of dachi, walking up and walking down stairs. Simultaneously, anterior knee pain was evaluated using visual analogue scale and anterior knee pain scale questionnaire. Results: Eight athletes of a total number of 23 reported increased ratings of pain in their right knees. No differences in muscle activity were observed in tests of Dachi and stairs between the groups with and without pain. Comparing Dachi task pattern at the beginning and end of training camps, there was no significant difference in pattern of biomechanical movement; however, reducing the amount of muscle activity in early and late phases of tasks was observed in electromyographic assessment. Conclusions: The results showed that performing the same task after a six-week training period, less muscle activity was required in all phases in two groups of tasks, including karate-specific movement (dachi) and activities of daily living (up or down stairs). © 2016, Sports Medicine Research Center

The activation pattern of trunk and lower limb muscles in an electromyographic assessment; comparison between ground and treadmillwalking

Background: Due to biomechanical differences, various patterns of muscle contraction are expected to occur while walking over ground versus when walking on a treadmill. Objectives: This study aimed to compare amplitude and duration of activation of selected trunk and lower extremity muscles during over-ground and treadmill walking. Materials and Methods: Through a simple sampling method, 19 sedentary healthy men within the age range of 20-40 were selected. Surface electromyography of rectus abdominis, external oblique, longissimus and multifidus muscles as the selected trunk muscles and vastus medialis, vastus lateralis and hamstrings as the selected lower limb muscles were recorded. Results: In each gait cycle, there were no statistically significant differences in duration of selected trunk as well as lower limb muscles activitybetweentreadmillandover-ground walking. Howeverthemeanamplitude of rectus abdominis (P=0.005), longissimus (P = 0.018) and multifidus (P = 0.044) as the selected trunk muscles as well as the mean amplitude of vastus lateralis (P = 0.005) and vastus medialis (P < 0.001) as the lower limb muscles was greater on treadmill compared with over ground. Conclusions: Due to the stabilizing role of trunk and lower limb muscles during walking, these muscles seem to be active throughout the entire gait cycle. The increased muscle amplitude on treadmill can demonstrate that more motor units may be recruited during the contraction,which can be helpful in prescribing the appropriate type of exercise especially for patients with core muscle weakness. © 2016, Sports Medicine Research Center

Reliability of center of pressure measures of postural stability in patients with unilateral anterior cruciate ligament injury

The aim of this study was to estimate the test-retest reliability of some commonly used center of pressure measures in postural control investigations of sport injuries under the diverse stressful postural conditions. Twelve patients with anterior cruciate ligament injury were evaluated on two separate sessions. The center of pressure was recorded from force platform and the following measures were calculated (1) standard deviation of amplitude (2) mean velocity (3) standard deviation of velocity (4) phase plane parameters and (5) area (95 confidence ellipse). Relative and absolute reliability was assessed using intra-class correlation coefficient and coefficient of variation, respectively. Mean velocity and total phase plane parameters were the most reliable measures having high to very high correlation across all postural conditions. The mean and range of intra-class correlation coefficient for mean velocity and total phase plane parameters were 0.88 (range: 0.80 to 0.96) and 0.81 (range: 0.71 to 0.88), respectively. Interestingly, pattern of the coefficient of variation values was, to a great extent, consistent with the intra-class correlation coefficients. Therefore, mean velocity and total phase plane parameters may be sensitive center of pressure measures to differentiate balance between Anterior Cruciate Ligament (ACL) injured patients and to evaluate the effect of a rehabilitation program in this population. © 2008 Asian Network for Scientific Information

Search for Exotic Mesons in pi- P Interactions at 18 GeV/c

The recent search for non $q \bar{q}$ mesons in $\pi^{-}p$ interactions at Brookhaven National Laboratory is summarized. Many final states such as $\eta \pi$, $\eta' \pi^{-}$, $a_{0} \pi$, $f_{1} \pi$, $a_{2} \pi$, $b_{1} \pi$, which are favored decay modes of exotics, are under investigation.Comment: 9 pages, PostScript, Presented at the International School of Nuclear Physics, Erice, Sicily, Italy, September 199

Observation of Pseudoscalar and Axial Vector Resonances in pi- p -> K+ K- pi0 n at 18 GeV

A new measurement of the reaction pi- p -> K+ K- pi0 n has been made at a beam energy of 18 GeV. A partial wave analysis of the K+ K- pi0 system shows evidence for three pseudoscalar resonances, eta(1295), eta(1416), and eta(1485), as well as two axial vectors, f1(1285), and f1(1420). Their observed masses, widths and decay properties are reported. No signal was observed for C(1480), an IG J{PC} = 1+ 1{--} state previously reported in phi pi0 decay.Comment: 7 pages, 6 figs, to be submitted to Phys. Let