emg

People with both pronated feet and anterior cruciate ligament repair may benefit from walking on sand as a therapeutic option. The consequences of walking on sand on the muscular activity and gait biomechanics of these people are not well understood. This study aims to determine how sand training affects gait mechanics in individuals with both anterior cruciate ligament repair and pronated foot.

The intervention and control groups included 28 adult males with pronated feet, where anterior cruciate ligament repair was randomly performed. The walking task was done on an 18-meter walkway at a consistent velocity. Muscle activities and ground reaction forces (GRF) were recorded using an electromyography system and a Bertec force plate, respectively. 

Group-by-time interactions were significant for anterior and posterior reaction forces (P<0.019; d=0.49-0.66). Post hoc analysis demonstrated a significant increase for anterior and posterior reaction forces in control but not in the intervention groups. Also, group-by-time interactions were significant for vastus activities during heel contact (P=0.033; d=0.88). 

The results showed that vastus lateralis activity was higher in the intervention group during the heel contact than those of the control group.

Functional appliances such as twin blocks are widely used to treat skeletal Class II malocclusions. Myofunctional effects are one of the critical features of these appliances. The present study aimed to investigate the muscular effects of clear and traditional twin blocks.

In this randomized clinical trial, 60 skeletal Class II division 1 patient were randomly divided into two groups: clear twin block (CTB) and traditional twin block (TTB). Electromyographic (EMG) evaluation of masseter, anterior temporalis, orbicularis oris, and mentalis muscles was carried out during deglutition, rest, whistling, and forced occlusion before insertion (T1) and six months (T2) after insertion of the appliance. Data were analyzed using independent t-test, paired t-test, and Wilcoxon’s signed rank at the 0.05 significance level.

There were no significant differences in T2 values between the groups (P>0.05). The intragroup comparisons showed a significant change from T1 to T2 in the CTB group for the clenching of the masseter muscle and in the TTB group for swallowing and rest position of the anterior temporalis muscle and swallowing of the masseter muscle (P<0.05).

Both CTB and TTB changed the muscular activity of circumoral muscles. No significant difference was found when the post-treatment muscular activity of the two groups was compared.

The age of boots is a significant factor that can impact the risk of injury during daily activities. Conversely, military personnel rely on their footwear to meet the physical demands of their daily professional tasks.

This study aimed to evaluate how wearing thermoplastic polyurethane (TPU) and rubber military boots for six months affects lower limb muscle activity during running.

Thirty healthy male participants were provided with two new pairs of rubber and TPU military boots and instructed to wear them for six months. Electromyography signals were recorded during a pre-test and after six months while the participants ran at a speed of 3.2 m/s. Statistical analysis was conducted using a two-way ANOVA with repeated measures, with a significance level of 0.05.

The results did not show a significant overall effect of ”boots” or ”time” onmuscle activities during running. However, there were significant boot-by-time interactions formuscle activities during different phases of the running cycle. These interactions were observed for the tibialis anterior (P = 0.037, η 2 p = 0.146), gastrocnemius medialis (P = 0.023, η 2 p = 0.172), and gluteus medius (P = 0.038, η 2 p = 0.144) activities during the loading phase, tibialis anterior activity at the mid-stance phase (P = 0.003, η 2 p = 0.278), and gastrocnemius medialis activity during the push-off phase (P = 0.046, η 2 p = 0.135).

Wearing military boots appears to affect muscle activities, particularly the tibialis anterior, in healthy males. These findings underscore the importance of careful boot selection for running activities. Understanding the reasons behind differences in muscle activity between TPU and rubber military boots can inform further research and the development of specialized footwear tailored to specific operational needs.

The relationship between the use of braces and gait parameters in people with kyphosis has been not well understood. The aim of the present study was to evaluate the effect of two types of thoracolumbosacral braces on erector spinae, and gluteus medius muscles activities in individuals with kyphosis during walking.

Fifteen males with kyphosis volunteered to participate in the present study. All participants were right footed. Each participant performed three walking trials in each of the three brace conditions including without brace, with alarm brace, and with simple brace. Muscle activities were recorded during walking at constant walk speed. Statistical analysis was performed using repeated measures ANOVA test at the significant level of 0.05. All analyses were performed using the SPSS version 22.

There is no significant difference in electromyography activities of the lower limb muscles at the loading response and mid-stance phases (P>0.05). Also, results showed a significant difference during push-off phase for gastrocnemius medialis muscle (P<0.05).

The use of thoracolumbosacral braces reduced the electrical activity of the gastrocnemius medialis muscle during the push-off phase. These changes may lead to gait efficiency while using thoracolumbosacral braces.

Recent studies have examined the risk factors associated with lower limb injuries. This study aimed to explore the effect of 12 sessions of feedback corrective exercises on the kinematic indicators of the knee and the Electromyography Activity (EMG) of the muscles of the lower limbs of female wushu players. The present study has a quasi-experimental design with a pre-test/post-test design and a control group.

In this study, 16 female wushu players were selected by the available sampling method and placed in two groups of exercise and control. The exercise group performed feedback correction exercises for 12 sessions. Before and after the knee varus exercises, we measured, pelvic drop, and EMG of the lower limb muscles of both groups in the SLS movement. The independent two-sample t-test was used to examine intergroup differences and the two-group correlated t-test was used to compare intra group sizes. To analyze the statistical data, SPSS V. 23 was used (P≤0.05)

The results showed a significant difference in knee varus between the experiment group and the control group in the pre-test and there was a significant difference between the pelvic drop in the pre-test and post-test of the experiment group compared with the control. The angle of the knee varus in the exercise group showed a significant difference with the control group. The EMG results of the muscles in the pre-test and post-test were significantly different.

Based on the findings of the present study, the feedback correction exercise may improve motion control in wushu players. It also improved neuromuscular weakness in the subjects. According to the results and based on less muscle activity during movements, this exercise will reduce fatigue and the risk of injury.

The central nervous system (CNS) is optimizing arm movements to reduce some kind of cost function. Simulating parts of the nervous system is one way of obtaining accurate information about the neurological and treatment of neuromuscular diseases. The main purpose of this paper is to model and control the human arm in a reaching movement based on reinforcement learning theory (RL).

First, Zajac’s muscle model is improved by a fuzzy system. Second, the proposed muscle model applied to the six muscles which are responsible for a two-link arm that move in the horizontal plane. Third, the model parameters are approximated based on genetic algorithm (GA). Experimental data recorded from normal subjects for assessing the approach. At last, reinforcement learning algorithm is utilized to guide the arm for reaching task.

The results show that: 1) The proposed system is temporally similar to a real arm movement.  2) The reinforcement learning algorithm has the ability to generate the motor commands which are obtained from EMGs. 3) The similarity of obtained activation function from the system is compared with the real data activation function which may prove the possibility of reinforcement learning in the central nervous system (Basal Ganglia). Finally, in order to have a graphical and effective representation of the arm model, virtual reality environment of MATLAB has been used.

  Since reinforcement learning method is a representative of the brain's control function, it has some features, such as better settling time, not having any peek overshoot and robustness.

Electromyographic (EMG) signals obtained from a contracted muscle contain valuable information on its activity and health status. Much of this information lies in motor unit potentials (MUPs) of its motor units (MUs), collected during the muscle contraction. Hence, accurate estimation of a MUP template for each MU is crucial.

To investigate the possibility of improving MUP template estimation using the wavelet denoising technique.

In this analytical study, several MUP template estimators were developed by combining conventional estimation methods and wavelet denoising techniques. A MUP template was initially estimated using conventional methods such as mean, median, median-trimmed mean, or mode. Thereafter, it was post-processed using the wavelet denoising technique.

Evaluation results of the studied estimators using 40 simulated EMG signals with a true template for each constituent MUP train showed that augmented wavelet- based template estimation methods are more reliable than conventional methods. However, on average, wavelet denoising was not much effective. Around 40 MUPs of a MU is sufficient to estimate its MUP template.

Although wavelet techniques are effective in EMG signal analysis, here wavelet denoising did not practically improve MUP template estimation. Considering computational simplicity and estimation error, the two methods median and median-trimmed mean are practical estimators that can provide a good estimation of a MUP template for a MU when approximately 40 MUPs are available. Nevertheless, the baseline noise level in the MUP templates estimated using the median-trimmed mean method is slightly lower than that in the templates estimated using the median method.