Muscle Activity In Subjects Research Articles

Ultrasound Evaluation of Onset Core Muscle Activity in Subjects with Non-Specific Lower Back Pain and Without Lower Back Pain: An Observational Case-Control Study.

Lower back pain (LBP) has been the leading cause of disability since 1990. Objectives: The main objective of this observational case-control study was to evaluate, using ultrasound, whether there were differences in the onset and ratio of core muscle contraction between subjects with non-specific chronic lower back pain and healthy subjects. Methods: A total of 60 participants (52% women), split between those with non-specific chronic lower back pain (n = 26) and healthy (n = 34) subjects, were recruited. Initial muscle contraction of the lateral abdominal wall, pelvic floor, lumbar multifidus, and respiratory diaphragm was measured using ultrasound. The abdominal drawing-in maneuver, contralateral arm elevation, the Valsalva maneuver, and voluntary contraction of the pelvic floor in seated and standing positions were performed. The muscle thickness of the lateral abdominal wall and lumbar multifidus and excursion of the pelvic floor and diaphragm at rest and during testing were also analyzed. Results: No differences were found between the groups in the initial contraction. Statistically significant differences were found in the following variables: diaphragm excursion (p = 0.032, r = 0.277) and lumbar multifidus ratio (p = 0.010, r = 0.333) in the standing-abdominal retraction maneuver; pelvic floor excursion (p = 0.012, r = 0.325) in the standing-contralateral arm raise; and transverse abdominis ratio (p = 0.033, r = 0.275) in the sitting-contralateral arm raise. A statistically significant interaction between the groups and body mass index was observed in resting diaphragm excursion (p = 0.018, partial eta squared = 0.096) during sitting-voluntary pelvic floor contraction. Conclusions: It cannot be concluded that there is a specific pattern of core activation in any of the groups. However, statistically significant differences were found in the contraction indexes of the lumbopelvic musculature.

Physio-avatar EB: aftereffects in error learning with EMG manipulation of first-person avatar experience.

Many studies have investigated the manipulation of a virtual upper arm using electromyogram (EMG); however, these studies primarily used a machine learning model or trigger control for this purpose. Furthermore, most of them could only display the constant motion of the virtual arm because the motion to be displayed was selected by pattern recognition or trigger control. In addition, these studies did not examine changes in the electromyographic signals after experiencing the virtual arm. By contrast, we propose a real-time, continuous, learning-free avatar that manipulates the virtual arm with electromyogram signals or physio-avatar EMG biofeedback (EB). The goal of the physio-avatar EB system is to induce physiological changes through experiential interactions. We explored the possibility of changing motor control strategies by applying the system to healthy individuals as a case study. An intervention method that provided an experience of a body different from one's own was conducted on seven participants using a time-invariant calculation algorithm to determine the joint angles of the avatar. Control strategies for an indicator of the equilibrium point in the baseline and adaptation phases were determined to evaluate the physio-avatar EB intervention effect. The similarity of these BL and adaptation control strategies compared to those used during the washout period was assessed using the coefficient of determination. The accuracy and reliability of the virtual reality (VR) system were evaluated by comparison with existing studies and the required specs. Changes in motor control strategies due to the physio-avatar EB system were observed in four experiments, where the participants gradually returned to their pre-intervention control strategies. This result can be attributed to the aftereffects caused by error learning. This implies that the developed system influenced their motor control strategies. The number of EMG acquisition bits was 16 bits, and the sampling rate was 1,000 Hz. The refresh rate of the head-mounted display was 90 Hz, and its resolution was for a single eye. Additionally, the simulation frame rate was 30 FPS. These values were adequate compared to existing studies and required specs. The essential contribution of this study is the development of an avatar that is controlled by a different method than has been used in previous studies and the demonstration of changes in a subject's muscle activity after they experience an avatar. In the future, the clinical efficacy of the proposed system will be evaluated with actual patients.

Comparison of abductor hallucis muscle activity in subjects with mild hallux valgus during three different foot exercises.

Normal alignment of the foot is important because the feet support the body's weight. The intrinsic muscles of the foot mainly maintain the alignment and movement of the foot, whereas the abductor hallucis (AbdH) aligns the first metatarsophalangeal joint and maintains the medial longitudinal arch. This study was conducted to investigate the muscle activity of the AbdH and hallux valgus (HV) angle during three different foot exercises. Participants included 15 subjects aged 20-24 years with mild HV. All subjects performed three different foot exercises in random order: short foot exercise (SF), toe spread out exercise (TSO), and TSO with a pressure bio-feedback unit (TSOP). The muscle activity of the AbdH and the HV angle were measured during each foot exercise using surface electromyography and X-ray and then compared using one-way repeated-measures analysis of variance, followed by Bonferroni adjustment. AbdH muscle activity differed significantly among SF, TSO, and TSOP. AbdH muscle activity was greater in TSOP (89.60%) than in SF (19.99%) and TSO (60.96%) (p= 0.006). The HV angle was significantly smaller in TSOP (15.72∘) than in SF (18.85∘) and TSO (16.81∘) (p= 0.001). TSOP can be recommended as an effective AbdH strengthening exercise in subjects with mild HV.

Low-Frequency Repetitive Transcranial Magnetic Stimulation for Chronic Tension-Type Headache: A Randomized Controlled Study.

Nearly 1-3% of the population is affected by chronic tension-type headaches (CTTH). However, it is still difficult to treat owing to the lack of knowledge of the disease's pathophysiology. Available literature suggests a role for pericranial muscle activity and abnormal modulation of central pain. Repetitive transcranial magnetic stimulation (rTMS) therapy done at the dorsolateral prefrontal cortex (DLPFC) can help modulate pericranial muscle overactivity and central pain modulation in subjects with CTTH. This randomized controlled study aimed to assess the effect of rTMS used in the low-frequency dorsolateral prefrontal cortex on pain and muscle activity in subjects with a chronic tension-type headache. The present randomized controlled clinical study was commenced in a health care center on 20 subjects with chronic tension-type headaches who were given either sham or low-frequency repetitive transcranial magnetic stimulation at the right dorsolateral prefrontal cortex. The therapy effect was evaluated statistically using Welch's corrected t-test. The study results depicted that daily use of rTMS therapy for two weeks led to a considerable reduction in the intensity of the pain, the activity of pericranial muscles, and headache impact, along with an increase in the nociceptive excitability thresholds in subjects with CTTH, with p=0.001 compared to the sham group. Considering its limitations, the present study depicts that rTMS is an efficacious management tool for reducing pain associated with CTTHand can serve as the cornerstone for additional investigations.

The development of split-treadmill with a fall prevention training function.

The weakening of the ability of the elderly to perform gait is becoming a major cause of the increase in the frequency of falls. In this study, we designed and manufactured a treadmill capable of restraining walking by providing a sudden repulsive force on the left and right legs of a pedestrian when walking for the fall prevention training of the elderly. Through this, it is possible for the elderly person to strengthen the lower extremity muscles to prevent and prepare for falling through the fall prevention training similar to the fall environment that may occur in daily life. The development system includes a motor for generating a driving force in the form of a left and a right driving system and a belt separated from each other, an electromagnetic clutch for rapidly stopping the running belt of the motor transmitted to the running belt to stop the running belt, and a controller for controlling the driver. In order to evaluate the development system, the motor driving ability test and the power transmission, connection and shut-off performance of the electromagnetic clutch were carried out. The subject's muscle activity of the lower extremity muscles was evaluated when the running belt stopped at the beginning of the right folding. It is expected that the developed dual function system would be helpful for the fall prevention exercise as well as the rehabilitation exercise for patients who have recovered from surgery or hemiplegic patients.

The Effects of Scapular Stabilization Exercises Accompanied by Spine Stabilization Exercises Using An Unstable Surface on Muscle Activities for Subjects with Scapular Winging

This study was intended to inspect the influence of scapular stabilization exercises accompanied by spine stabilization exercises using an unstable surface on muscle activity in subjects with scapular winging. Thirty subjects with scapular winging participated in the experiment. The subjects were randomly divided into two groups. One group performed scapular stabilization exercises accompanied by spine stabilization exercises on an unstable surface, whereas the other group performed only scapular stabilization exercises. In order to study the influence of the intervention, the muscle activity around the shoulder was measured. According to the experimental results, the activation of the lower trapezius muscle and serratus anterior muscle increased significantly in both groups after intervention. The muscle activities of the lower trapezius and serratus anterior in the control group were not as high as those in the experimental group. Moreover, the muscle activities of upper trapezius and pectoralis major decreased significantly in both groups after the exercise interventions, but no significant difference was observed between the two groups. As a result, the scapular stabilization exercises that are widely used in clinical practice were shown to increase lower trapezius and serratus anterior activities. Moreover, a combination of such exercises with spine stabilization exercises on an unstable surface was shown to confer greater benefits than scapular stabilization exercises alone and is thus recommended.

Effect of side-sling plank exercise on trunk and hip muscle activation in subjects with gluteus medius weakness.

The effectiveness of side-sling plank (SSP) exercises on trunk and hip muscle activation in subjects with gluteus medius (Gmed) weakness is unclear. To quantify muscle activation of the rectus abdominis (RA), external oblique (EO), erector spinae (ES), lumbar multifidus (LM), Gmed, gluteus maximus (Gmax), and tensor fasciae latae (TFL) during SSP with three different hip rotations compared to side-lying hip abduction (SHA) exercise in subjects with Gmed weakness. Twenty-two subjects with Gmed weakness were recruited. SHA and three types of SSP exercises were performed: SSP with neutral hip (SSP-N), hip lateral rotation (SSP-L), and hip medial rotation (SSP-M). Surface electromyography was used to measure the activation of the trunk and hip muscles. The trunk and hip muscles activations were generally significantly higher level during three SSP than SHA. SSP-M showed significantly lower EO activation while significantly higher ES and LM activation than SSP-L. Gmed activation was significantly higher during SSP-M than during SSP-L. TFL activation was significantly lower during SSP-M than during SSP-N and SSP-L. SSP could be prescribed for patients who have reduced Gmed strength after injuries. Especially, SSP-M could be applied for patients who have Gmed weakness with dominant TFL.

Analysis of phase detects altered timing of muscle activation in subjects with chronic shoulder pain

Optimal exercise therapy for shoulder pain is unknown due to limited information regarding specific changes in muscle function associated with pain. Timing of muscle activity with respect to movement (phase) can provide information about muscle activation patterns without requiring electromyography data normalization which is problematic in the presence of pain. The aim of this study was to determine if a phase measure is able to detect differences in the timing of shoulder muscle activation in subjects with chronic shoulder pain. Fourteen subjects with pain and 14 without pain were recruited. Electromyography from eight shoulder muscles was recorded. Approximately 20 cycles of small amplitude (∼30°) rapid shoulder flexion/extension was performed. A cross-correlation and spectrographic analysis provided a measure of phase. Welch’s t-tests were used to compare mean phase angles between groups. Subjects with chronic shoulder pain had greater variability in the relative timing of muscle activation with significant differences found in the phase angles for pectoralis major, infraspinatus, supraspinatus, upper and lower trapezius and serratus anterior. This preliminary study indicates that the examination of the timing of muscle activation using a phase measure can identify significant differences in muscle function between normal subjects and those with chronic shoulder pain.

Immediate Effects of Flexi-bar Exercise With Knee Push-up Plus on Shoulder Joint Position Sense and Muscle Activity in Subjects With Scapular Winging

Immediate Effects of Flexi-bar Exercise With Knee Push-up Plus on Shoulder Joint Position Sense and Muscle Activity in Subjects With Scapular Winging

The Correlation Between Gastrocnemius Muscle Thickness And Activity Limitations In Patients With Severe OA

Muscle thickness offers an excellent indicator of maximal force generating capacity, and, accordingly, a reduction in muscle thickness may contribute to muscle weakness; this in turn may be related to functional limitations in patients undergoing total knee replacement. The purpose of this study was to correlate the morphologic changes in the gastrocnemius muscle in relation to muscle activity in subjects with severe knee osteoarthritis (OA), in order to establish an objective means of measuring muscle function and muscle recovery. Two subject groups participated in this study, one group of 10 non-pathological subjects (NP) and a separate group of 10 subjects with severe OA. The muscle thickness (MT) and EMG muscle activity (MA) of the medial gastrocnemius (MG) and lateral gastrocnemius (LG) were assessed using ultrasonography (US) and electromyography (EMG), respectively. The correlation between MA and MT was thus investigated, and linear regression analysis performed to determine prediction equations for muscle activity. The results showed that MA is highly related to MT for both MG and LG in NP subjects. The MA prediction equation based on linear regression analysis resulted in R2 values of 0.90 and 0.95 (p<0.05) for LG and MG, respectively, while in OA subjects, a good correlation was shown between MA and MT within the MG, with R2 = 0.80, though a more moderate correlation was found for LG, with R2 = 0.52. The thickness of the MG was not significantly increased during maximum voluntary contraction (MVC) as compared with the resting state, while the thicknesses of LG significantly increased, from 15 to 22 mm, on moving from resting to MVC. This study thus demonstrated that MG is more useful parameter than LG for the prediction of muscle force generating intensity in patients with severe OA.

The Effects of Scapular Alignment Exercise and Nerve Mobilization on Pain and Muscle Activity in Subjects with Scapular Depression Alignment

The Effects of Scapular Alignment Exercise and Nerve Mobilization on Pain and Muscle Activity in Subjects with Scapular Depression Alignment

Osteoarthrosis: Analyze of the Molar Bite Force, Thickness and Masticatory Efficiency.

Osteoarthrosis is a disorder of synovial joints, resulting from destruction of the cartilage and subchondral bone. The present study is aimed to investigate the molar bite force, thickness and efficiency of the masseter and temporalis muscles of subjects with osteoarthrosis. A total of forty-eight subjects participated in the study. They were distributed into two groups: with osteoarthrosis (n=24) and asymptomatic controls (n=24). Subjects were analyzed on the basis of maximal molar bite force (right and left side), thickness (mandibular rest and dental clenching in maximal voluntary contraction) and electromyographic activity of masticatory cycles through the linear envelope integral in habitual (raisins and peanuts) and non-habitual (Parafilm M) chewing of the masseter and temporalis muscles. All the data were analyzed statistically using t-test with a significance level of p≤0.05. There was no difference between groups in maximal molar bite force, muscle thickness and non-habitual chewing. Differences were found on the raisins (p=0.02) and peanuts (p=0.05) chewing for right temporal muscle, with reduced masticatory muscle efficiency in osteoarthrosis subjects. This study showed that osteoarthrosis induces negative changes in habitual chewing, highlighting the efficiency of the right temporalis muscles. The greater temporal muscle activity in subjects with osteoarthrosis may compromise chewing and consequently the nutritional status of adult subjects.

Immediate Effects of the Downhill Treadmill Walking Exercise on Thoracic Angle and Thoracic Extensor Muscle Activity in Subjects With Thoracic Kyphosis

Immediate Effects of the Downhill Treadmill Walking Exercise on Thoracic Angle and Thoracic Extensor Muscle Activity in Subjects With Thoracic Kyphosis

A convergence study of the effects of asymmetric standing posture on knee joint position and lower extremity muscle activity in subjects with hyper-extended knee

A convergence study of the effects of asymmetric standing posture on knee joint position and lower extremity muscle activity in subjects with hyper-extended knee

Effects of suboccipital release with craniocervical flexion exercise on craniocervical alignment and extrinsic cervical muscle activity in subjects with forward head posture

BackgroundForward head posture is a head-on-trunk malalignment, which results in musculoskeletal dysfunction and neck pain. To improve forward head posture, both the craniocervical flexion exercise and the suboccipital release technique have been used. Objectives: The purpose of this study was to compare the immediate effects of craniocervical flexion exercise and suboccipital release combined with craniocervical flexion exercise on craniovertebral angle, cervical flexion and extension range of motion, and the muscle activities of the sternocleidomastoid, anterior scalene, and splenius capitis during craniocervical flexion exercise in subjects with forward head posture. MethodsIn total, 19 subjects (7 males, 12 females) with forward head posture were recruited using G-power software. Each subject performed craniocervical flexion exercise and suboccipital release combined with craniocervical flexion exercise in random order. After one intervention was performed, the subject took a 20min wash out period to minimize any carry-over effect between interventions. Craniovertebral angle, cervical flexion and extension range of motion, and the muscle activities of the sternocleidomastoid, anterior scalene, and splenius capitis were measured. A one-way, repeated-measures ANOVA was used to assess differences between the effects of the craniocervical flexion exercise and suboccipital release combined with craniocervical flexion exercise interventions in the same group. ResultsCraniovertebral angle (p<0.05), cervical flexion range of motion (p<0.05), and cervical extension range of motion (p<0.001) were significantly greater after suboccipital release combined with craniocervical flexion exercise compared to craniocervical flexion exercise alone. The muscle activities of the sternocleidomastoid, anterior scalene, and splenius capitis were significantly lower during suboccipital release combined with craniocervical flexion exercise than during craniocervical flexion exercise alone across all craniocervical flexion exercise phases except the first (all p<0.05). ConclusionThe addition of suboccipital release to craniocervical flexion exercise provided superior benefits relative to craniocervical flexion exercise alone as an intervention for subjects with forward head posture.

Comparison of the Activity and Proprioception of Trunk Muscles According to Different Types of Bridge Exercises in Subjects with and without Chronic Low Back Pain

Purpose: The purpose of the present study was to examine joint position senses and muscle activity in subjects with and without chronic low back pain and to determine the effects of different types of bridge exercises on their trunk muscle activity. Methods: Thrity -eight subjects with chronic low back pain and thrity healthy controls participated in the experiment. Joint position senses and trunk muscle activity levels were measured during the different bridge exercise methods. Results: The joint position senses of the healthy group and chronic low back pain group showed significant differences during lumbar flexion, lumbar extension, lumbar lateral flexion, and lumbar rotation. The muscle activity levels of the transversus abdominis (TrA), internal oblique (IO), and external oblique (EO) were highest in the prone bridge exercise (PBE) group, followed by the supine bridge swiss ball exercise (SBSE) group and supine bridge exercise (SBE) group in order of precedence. The muscle activity level of the erector spinae (ES) was highest in the SBSE group, followed by the SBE and PBE groups in order of precedence. Conclusion: Overall, the results suggest that chronic low back pain is associated with declines in joint position senses and that PBEs increase trunk muscle activity more than conventional bridge exercises.

Relative index of ankle muscle activations on agonistic phase between subjects with and without flat foot

Background: Although co-activation of ankle muscles has been reported, relative ankle muscle activation in subjects with flat foot has not been carefully investigated. The aim of this study was to compare the relative activation index (RAI) on the tibialis anterior (TA) and medial gastrocnemius (GTN) muscles during active ankle range of motion (ROM) between subjects with and without flat foot. Methods: There were 17 subjects with flat foot and 17 age- and gender-matched control subjects who participated in this study. The RAI based on electromyography (EMG) was measured during the agonist phase at a controlled velocity of ankle motion (10°/second). The subject was seated upright with the tested foot held firmly onto a footplate that was attached to a torque sensor. The ankle being measured was strapped to the leg support of the Intel stretch device at 60° of knee flexion. The RAI was analyzed by the summation of EMG activity from the agonistic time window divided by the total EMG activity during full active ankle ROM. Results: The RAI was significantly different on the TA muscle (t = 3.08, P = 0.004), but no difference was found on the GTN muscle (t = -1.24, P = 0.23) in subjects with flat foot. There was an interaction between group and RAI (F =7.89, P = 0.007); however, the RAI demonstrated no interaction with age (F = 2.59, P = 0.14), height (F = 3.73, P = 0.06), or weight (F = 2.96, P = 0.09). Conclusions: The RAI indicated a lack of TA muscle activation in the flat foot group. Such dissociated activation in the flat foot group might be relevant to the inefficiency of synergistic motions. The relative activation of the agonistic phase needs to be further investigated to compare co-activation of synergistic muscle activation with various functional tasks.

Effects of Treadmill Incline and Speed on Ankle Muscle Activity in Subjects After a Stroke

ObjectivesTo examine the effects of walking on a treadmill at varying gradients and speeds on ankle muscle activation in stroke survivors, and to compare the effect of increasing speed on plantarflexor muscle activity in participants grouped according to spasticity severity. DesignWithin-subject and cross-sectional design. Participants walked on a standard treadmill at 3 different inclines (0°, 3°, 6°) and speeds (self-selected, self-selected+20%, self selected+40%). SettingUniversity laboratory. ParticipantsA convenience sample of stroke survivors (N=19; 13 men, 6 women) available in university clinics. InterventionsNot applicable. Main Outcome MeasuresElectromyographic activity of medial gastrocnemius (MG) and tibialis anterior (TA) muscles at push-off phase of the gait. ResultsParetic MG muscle activity increased (but TA did not change) at faster speeds irrespective of the incline (P<.05). In contrast, MG muscle activity increased at a higher incline in the nonparetic side (P<.05), but not in the paretic side (P>.05). In the high-spasticity subgroup (Tardieu Scale ≥2), paretic MG activity increased as walking speed increased (P=.004). ConclusionsStroke survivors appear to use distinct muscle activation strategies on the paretic and nonparetic sides in response to different walking speeds and inclines. Our data indicates that individuals with stroke can be safely trained on a treadmill to walk 20% to 40% above the self-selected pace to improve MG output without adversely affecting TA output. The speed-dependent characteristic of spasticity may help generate greater MG activity during push-off.

Effects of fatigue on lower limb, pelvis and trunk kinematics and lower limb muscle activity during single-leg landing after anterior cruciate ligament reconstruction.

Because there are no studies that have evaluated the effects of fatigue on the kinematics of the trunk and pelvis or on muscle activation in subjects with ACL reconstruction, the aim of this study was to evaluate the effects of fatigue on the lower limb, pelvis and trunk kinematics and lower limb muscle activation in subjects with ACL reconstruction during a single-leg landing compared to a healthy control group. The participants included 20 subjects with ACL reconstruction (ACL reconstruction group-ACLRG) and 20 healthy subjects (control group-CG) who were aged between 18 and 35years. Kinematic and electromyographic analyses were performed during a single-leg landing before and after fatigue. The fatigue protocol included a series of 10 squats, two vertical jumps, and 20 steps. The effects of fatigue were increased peak trunk flexion and increased activation of the vastus lateralis, biceps femoris (BF) and gluteus maximus (GMax) during the landing phase. After the fatigue protocol, an increase in peak trunk flexion and activation of the GMax and BF were observed, most likely as a strategy to reduce the load on the ACL. ACL injury prevention programs should include strength and endurance exercises for the hip and trunk extensor muscles so that they can efficiently control trunk flexion during landing. Prospective comparative study, Level II.

Infield masticatory muscle activity in subjects with pain-related temporomandibular disorders diagnoses.

Pain-related temporomandibular disorders (TMDs) are the most prevalent conditions among TMDs. There is contrasting evidence available for association of pain-related TMD and masticatory muscle activity (MMA). The present investigation assesses the associations between MMA levels of masseter and temporalis muscles during awake and sleep among pain-related TMD diagnostic groups. The department of Oral Diagnostic Sciences, University at Buffalo. Twenty females and six males participated in this study. Using the diagnostic criteria for temporomandibular disorders (DC-TMDs), participants were diagnostically categorized. Subjects used a custom monitoring system, which recorded infield muscle activities. A factorial model tested for association between independent variable (muscle, time period, MMA level, and diagnostic group) effects and the logarithm of MMA. Greenhouse-Geisser test was used to determine any statistically significant associations (p≤0.003). No statistically significant association was found between four-way, three-way, and two-way analyses. However, among the main effects, range of magnitudes was the only variable to be statistically significant. Although the data suggest a trend of increased masseter MMA in the pain-related TMD diagnoses group both during awake and sleep time periods, such observation is not maintained for the temporalis muscle. In addition, temporalis MMA was found to be higher in the pain-related TMD diagnoses group only at extreme activity levels (<25 and ≥80% ranges). This data support the association between masticatory muscle hyperactivity and painful TMD conditions.