Significant Differences In Muscle Activity Research Articles

Neural Respiratory Drive During Different Dyspnea Relief Positions and Breathing Exercises in Individuals With COPD.

When the work load of the respiratory muscles increases and/or their capacity decreases in individuals with COPD, respiratory muscle activation increases to maintain gas exchange and respiratory mechanics, and perception of dyspnea occurs. The present study aimed to compare diaphragm and accessory respiratory muscle activation during normal breathing, pursed-lip breathing, and breathing control in different dyspnea relief positions, supine and side lying. A cross-sectional study design was used. Sixteen individuals with COPD age between 40-75 y were included. Pulmonary function was evaluated by spirometry, muscle activation by surface electromyography, and dyspnea by the modified Borg scale. Muscle activation was measured in the diaphragm, scalene, sternocleidomastoid, and parasternal muscles. The evaluation was made in the dyspnea relief positions (sitting leaning forward, sitting leaning forward at a table, leaning forward with back against a wall, standing leaning forward, and high lying), seated erect, supine, and side lying. There were significant differences between the 8 positions (P < .001). There was no significant difference in muscle activation between sitting leaning forward and sitting leaning forward at a table position with analyzing post hoc test results (P > .99 for each muscle). However, muscle activation was lower in these 2 positions than in the other positions (P < .001 for each muscle). Muscle activation was greater in the supine position than in the other positions (P < .001 for each muscle). No difference was observed in muscle activation between the seated erect, leaning forward with back against a wall, standing leaning forward, high-lying, or side-lying positions (P > .05 for each muscle with a minimum P value of .09). The use of sitting leaning forward and sitting leaning forward at a table positions together with breathing control may help people with COPD to achieve more effective dyspnea relief and greater energy efficiency.

Influence of Amputation on Kinetic Chain Musculature Activity During Basic and Modified Core Exercises.

Core strength is vital for athletic performance, and many more exercises that involve the kinetic chain have been designed for able-bodied athletes. Disabilities that impair the kinetic chain can reduce the effectiveness of strength training. However, the impact of amputation on core strength training of people with disabilities and its underlying mechanism remains unclear. This study aimed to evaluate the muscle activation patterns and levels in athletes with amputation during 4 basic and modified weight-bearing core strength-training exercises. Fifteen elite athletes with unilateral amputation (170.6 [7.3]cm; 63.9 [11.9]kg; 25.9 [5.3]y) volunteered for this study. Surface electromyography was used to measure the muscle activity mainly in the lumbopelvic-hip complex-stabilizing muscles during 4 kinetic chain trunk exercises with and without modifications. The significance level was set at α = .05. The results showed a significant difference in muscle activation between different body sides (P < .05). Specifically, amputation on the support position resulted in a diagonal pattern of muscle activation, and amputation on the free distal segments resulted in a unilateral dominant pattern with higher activation in muscles on the nonamputated side (P < .05). Modifications led to significant decreases in muscle activation asymmetry index (P < .05). Amputation caused muscle activation asymmetry and 2 activation patterns. Modifications by enhancing proximal stability and adjusting distal loading effectively reduced the asymmetry of muscle activation. Coaches and clinicians can use these results to tailor exercises for athletes with disabilities in training and rehabilitation.

Identification of the Biomechanical Response of the Muscles That Contract the Most during Disfluencies in Stuttered Speech.

Stuttering, affecting approximately 1% of the global population, is a complex speech disorder significantly impacting individuals' quality of life. Prior studies using electromyography (EMG) to examine orofacial muscle activity in stuttering have presented mixed results, highlighting the variability in neuromuscular responses during stuttering episodes. Fifty-five participants with stuttering and 30 individuals without stuttering, aged between 18 and 40, participated in the study. EMG signals from five facial and cervical muscles were recorded during speech tasks and analyzed for mean amplitude and frequency activity in the 5-15 Hz range to identify significant differences. Upon analysis of the 5-15 Hz frequency range, a higher average amplitude was observed in the zygomaticus major muscle for participants while stuttering (p < 0.05). Additionally, when assessing the overall EMG signal amplitude, a higher average amplitude was observed in samples obtained from disfluencies in participants who did not stutter, particularly in the depressor anguli oris muscle (p < 0.05). Significant differences in muscle activity were observed between the two groups, particularly in the depressor anguli oris and zygomaticus major muscles. These results suggest that the underlying neuromuscular mechanisms of stuttering might involve subtle aspects of timing and coordination in muscle activation. Therefore, these findings may contribute to the field of biosensors by providing valuable perspectives on neuromuscular mechanisms and the relevance of electromyography in stuttering research. Further research in this area has the potential to advance the development of biosensor technology for language-related applications and therapeutic interventions in stuttering.

Does dual‐tasking affect the ability to generate anticipatory postural adjustments in young adults?

AbstractThe aim of this study was to investigate how additional cognitive tasks (Stroop test and counting backwards task) influence young adults' ability to generate appropriate postural responses while standing on a continuously oscillating platform. Twenty young adults (25.95 ± 2.97 years) stood on a moving platform which was translated in the anterior–posterior direction at three different frequencies (0.10, 0.25 and 0.50 Hz) in three dual‐task conditions (counting backwards task, a Stroop task or no additional cognitive task). Postural muscle onset latencies and tonic activity levels of the leg muscles were measured through surface electromyography; the number of steps taken and cognitive errors made were recorded. Results showed no significant differences in muscle activity between dual and single‐tasking conditions nor between the two dual tasking conditions. Cognitive errors were made in the counting backwards task but not the Stroop task. A frequency effect was identified with participants showing greater tonic activity in rectus femoris (p = 0.012), gastrocnemius medialis (p = 0.016) and bicep femoris (p = 0.043) at 0.5 Hz, as well as earlier muscle activation in tibialis anterior, gastrocnemius medialis and bicep femoris (p &lt; 0.001) at 0.50 Hz. Transition and steady state muscle onset latencies were only significantly different for gastrocnemius medialis at 0.25 Hz (p = 0.001). Dual tasking did not seem to influence anticipatory postural adjustments in young adults; however, perturbation intensities did. The differences observed in the number of cognitive errors made could be indicative of the regional cortical activations and overlapping demand for resources interfering with balance control, though cortical activation was not recorded. Future research should include detailed cognitive behavior, including cortical activations and task reaction times to better understand the allocation of attentional resources during perturbed balance dual tasking.

Trunk muscle activation of core stabilization exercises in subjects with and without chronic low back pain.

Weakness and atrophy in trunk muscles have been associated with chronic low back pain (CLBP). This study aimed to identify isometric exercises resulting the highest trunk muscle activity for individuals with and without CLBP. Fourteen males with CLBP and 15 healthy age-matched healthy subjects were recruited for this study. Muscle activity during maximal voluntary isometric contraction (MVIC) was measured for a comparative reference with surface electromyography (sEMG) from six trunk muscles. Thereafter maximum EMG amplitude values were measured during eleven trunk stability exercises. The maximal EMG activity in each exercise relative to the MVICs was analyzed using generalizing estimating equations (GEE) models with the unstructured correlation structure. The GEE models showed statistically significant differences in muscle activity between exercises within both groups (p< 0.001), with no significant differences between groups (p> 0.05). The highest muscle activity was achieved with the hip flexion machine for multifidus, side pull with a resistance band for lumbar extensors, side and single-arm cable pull exercises for thoracic extensors, rotary plank and the hip flexion machine for abdominal. This study found five isometric trunk exercises that exhibited highest muscle activity depending on muscle tested, with no significant difference between individuals with and without CLBP.

Lower-Limb Myoelectric Calibration Postures for Transtibial Prostheses.

The use of an agonist-antagonist muscle pair for myoelectric control of a transtibial prosthesis requires normalizing the myoelectric signals and identifying their co-contraction signature. Extensive literature has explored the relationship between body posture and lower-limb muscle activation level using surface electromyography (EMG), but it is unknown how these relationships hold after amputation. Using a virtual tracking task, this study compares the effect of three different calibration postures (seated, standing, dynamic) on user tracking ability while in two tracking postures (seated, standing) for 18 able-bodied (AB) subjects and 9 subjects with transtibial (TT) amputation. As expected, AB subjects produced statistically significant differences in muscle activation for gastrocnemius (GAS) when seated vs. standing during calibration (p = 8.8e-4), but not for tibialis anterior (TA) (p = 0.76). TT subjects, however, showed no significant differences in GAS or TA between seated and standing (p = 0.90, 0.60 respectively). It was also determined that normalizing EMG by the global maximum signal observed (standard in biomechanic analysis) is undesirable for myoelectric control. For best general results with this framework, calibration in both seated and dynamic postures is recommended, taking the normalization information from the seated posture and the narrowest co-contraction slopes from the two.

Upper Extremity Electromyography During Bouldering: Research Report

Background: Despite the growing popularity of bouldering, little is known about the degree and variabilityof muscle activation that occurs while solving bouldering problems. The purpose of this study was to explorethe electromyography of eight upper extremity and trunk muscles during a session of indoor bouldering whilecompleting four different problems.Methods: Eleven climbers with self-reported ability to climb a V-scale V4 problem grade or higher and regularlyboulder at least two days/week for at least six months participated in this study. Electromyography was used torecord muscle activity of the flexor digitorum superficialis, extensor carpi radialis longus, biceps brachii, tricepsbrachii, anterior deltoid, middle deltoid, posterior deltoid, and latissimus dorsi.Conclusion: The highest average EMG across all four climbs occurred in the flexor digitorum superficialis,latissimus dorsi, and extensor carpi radialis brevis. Significant differences in muscle activity were noted betweenthe anterior deltoid and latissimus dorsi, flexor digitorum superficialis and biceps brachii, triceps brachii andflexor digitorum superficialis, posterior deltoid and latissimus dorsi, and triceps brachii and latissimus dorsi.This information may be useful in developing a strength and conditioning program for

The effect of EMG biofeedback training on muscle activation in an impingement population

Subacromial impingement syndrome (SAIS) is one of the most diagnosed causes of pain in the upper extremity. The purpose of this study was to investigate muscle activity between asymptomatic and SAIS shoulders on the same subject while understanding the effectiveness of EMG biofeedback training (EBFB) on bilateral overhead movements. Ten participants (7 male), that tested positive for 2/3 SAIS clinical tests, volunteered for the study. Bilateral muscle activity was measured via electrodes on the upper trapezius (UT), lower trapezius (LT), serratus anterior (SA), and lumbar paraspinals (LP). Participants performed bilateral scapular plane overhead movements before and after EBFB. EBFB consisted of 10 bilateral repetitions of I, W, T, and Y exercises focused on reducing UT and increasing LT and SA activity. Prior to EBFB, no significant difference in muscle activity was present between sides. A significant main effect of time indicated that after EBFB both sides exhibited reduced UT activity at 60° (p=0.003) and 90° (p=0.036), LT activity was increased at all measured humeral angles (p<0.0005), and SA muscle activity was increased at 110° (p=0.001). EBFB in conjunction with scapular based exercise effectively alters muscle activity of asymptomatic and symptomatic scapular musculature.

탄력밴드를 이용한 고유수용성신경근촉진법의 안정화 운동이 몸통 및 엉덩부위 근 활성도에 미치는 영향

This study attempted to investigate body and hip muscle activities, using resistance band against 12 adult men. For this, one leg-supported pose in bridge position, skater-patterned bridge pose, bird-dog exercise in quadruped position and skater-patterned exercise pose trainings were performed. Specifically, the maximum voluntary isometric contraction (MVIC) of internal abdominal oblique, external abdominal oblique, multifidus, gluteus maximus and gluteus medius muscle was measured, using surface electromyography (sEMG) after conducting bridge pose and quadrupled exercise, and the results found the followings: In the bridge exercise and quadrupled exercise intervention-based proprioceptive neuromuscular facilitation (PNF), internal abdominal oblique and external abdominal oblique revealed a significant difference in muscle activity (p<0.05). In multifidus, gluteus maximus and gluteus medius muscle, on the contrary, no significant difference was observed in bridge exercise (p>0.05). In the quadrupled exercise intervention-based PNF, however, a significant difference of muscle activity was found (p<0.05). The above results confirm that a skater pattern which combined the single pattern of the PNF could reduce pain and enhance body stabilization through body balancing if selectively applied to those who are suffering from lumbar pain and difficulty in supporting their body weight due to weak abdominal and hip muscles and anterior pelvic tilt.

Exercises With Optimal Scapulothoracic Muscle Activation for Individuals With Paraplegia.

Individuals with paraplegia and coexisting trunk and postural control deficits rely on their upper extremities for function, which increases the risk of shoulder pain. A multifactorial etiology of shoulder pain includes "impingement" of the supraspinatus, infraspinatus, long head of the biceps tendons, and/or subacromial bursa resulting from anatomic abnormalities, intratendinous degeneration, and altered scapulothoracic kinematics and muscle activation. Targeting serratus anterior (SA) and lower trapezius (LT) activation during exercise, as part of a comprehensive plan, minimizes impingement risk by maintaining optimal shoulder alignment and kinematics during functional activities. To prevent excessive scapular upward translation, minimizing upper trapezius (UT) to SA and LT activation is also important. To determine which exercises (1) maximally activate SA and minimize UT:SA ratio and (2) maximally activate LT and minimize UT:LT ratio. Kinematic and muscle activation data were captured from 10 individuals with paraplegia during four exercises: "T," scaption (sitting), dynamic hug, and SA punch (supine). Means and ratios were normalized by percent maximum voluntary isometric contraction (MVIC) for each muscle. One-way repeated measures analysis of variance determined significant differences in muscle activation between exercises. Exercises were rank ordered: (1) maximum SA activation: SA punch, scaption, dynamic hug, "T"; (2) maximum LT activation: "T," scaption, dynamic hug, SA punch; 3) minimum UT:SA ratio: SA punch, dynamic hug, scaption, "T"; and (4) minimum UT:LT ratio: SA punch, dynamic hug, "T," scaption. Exercise elicited statistically significant changes in percent MVIC and ratios. Post hoc analyses revealed multiple significant differences between exercises (p < .05). SA punch produced the greatest SA activation and lowest ratios. Dynamic hug also produced optimal ratios, suggesting supine exercises minimize UT activation more effectively. To isolate SA activation, individuals with impaired trunk control may want to initiate strengthening exercises in supine. Participants maximally activated the LT, but they were not able to minimize UT while upright.

People With Low Back Pain Exhibit Higher Trunk Muscle Activity and Impaired Postural Control During Static and Dynamic Functional Tasks: A Cross-Sectional Study.

The study compared superficial trunk muscle activity and postural control among an active extension subgroup of people with nonspecific chronic low back pain (AE-NSCLBP) with painfree controls during functional tasks. Thirty-two people (17 people with low back pain [LBP] and 15 painfree controls) participated in this study. Muscle activity of 5 trunk muscles and postural control were investigated during both standing tasks (eyes open/closed; single/double-leg balance) and dynamic functional tasks (spinal forward flexion and return, and a sit to stand transfer). Results showed that during single-leg standing, people with AE-NSCLBP exhibit higher muscle activity than painfree controls for 3 trunk muscles, especially with their eyes closed. There were no significant differences in muscle activity between eye conditions during double-leg standing and sit to stand transfer, forward flexion, and return from flexion. The AE-NSCLBP subgroup also demonstrated significantly impaired postural control (lower time to boundary) in 4 of 8 conditions, especially during single-leg standing and with their eyes closed. These findings show people with LBP typically demonstrated greater trunk muscle activity and poorer postural control while maintaining standing posture. This pattern was most evident when the postural challenge was higher, such as single-leg standing or with eyes closed. While this study design cannot infer causality, these findings have implications for LBP rehabilitation, particularly regarding approaches which seek to alter muscle activation among people with LBP.

A Study of Different Frequencies of Repetitive Transcranial Magnetic Stimulation on Upper Extremity Muscle Activity and Hand Function in Chronic Stroke Patients

The purpose of this study was to compare the use of different frequencies of repetitive transcranial magnetic stimulation (rTMS) on the upper extremity muscle activity and hand function of chronic stroke patients. The study subjects comprised 18 chronic stroke patients: the 5 Hz rTMS group (HFG), which included nine patients who received rTMS to the affected cerebral hemisphere, and the 1 Hz low-frequency group (LFG), which had nine patients who received rTMS to the nonaffected cerebral hemisphere. The intervention was conducted three times a week for four weeks. Electromyography was used to check muscle activity, and the stroke upper extremity function test (MFT) and grip strength test were performed to check hand function. Pre- and post-evaluations were performed for both groups. A comparison between the two groups showed a significant difference in the activity of the trapezius anterior and triceps brachii muscle for the muscle activities in the HFG group (p 0.05) as well as a significant difference in the MFT results for hand function (p 0.05). In the LFG group, a significant difference was noted in the triceps brachii muscle for muscle activity (p 0.05), but no significant difference was evident in hand function (p 0.05). The comparison of the two groups showed a significant difference in muscle activity in the triceps brachii muscle (p 0.05) but no significant difference in hand function (p 0.05). This study confirmed that high-frequency rTMS has a positive effect on upper extremity muscle activity and hand function in chronic stroke patients.

Influence of Loads and Loading Position on the Muscle Activity of the Trunk and Lower Extremity during Squat Exercise.

This study aimed to investigate the effect of the load and bar position on trunk and lower extremity muscle activity during squat exercise. High bar back squats (HBBS) and low bar back squats (LBBS) were performed in random order at 50%, 60%, and 70% loads of one repetition maximum by 28 experienced healthy adult men who had been performing squats for at least one year. Before the experiment, the maximal voluntary contraction of the vastus medialis, vastus lateralis, rectus femoris, biceps femoris, rectus abdominis, transverse abdominis, external oblique, and erector spinae muscles was measured by means of surface electromyography. In addition, eccentric and concentric exercises were performed for 3 s each to measure the muscle activity. There was a significant difference in muscle activity according to the load for all muscles in the eccentric and concentric phases (p < 0.05), indicating that muscle activity increased as the load increased. In addition, in the comparison between HBBS and LBBS, significant differences were shown in all lower extremity muscles and all trunk muscles except for the external oblique in the concentric phase according to the bar position (p < 0.05). HBBS showed a higher muscle activity of the lower extremity in the eccentric and concentric phases than in LBBS, while LBBS showed a higher muscle activity of the trunk muscle in the eccentric and concentric phases than in HBBS (p < 0.05). HBBS requires more force in the lower extremity than LBBS and is particularly advantageous in strengthening the muscular strength of the quadriceps. In contrast, LBBS requires more muscle activity in the trunk than HBBS and is more effective in carrying heavier loads because of the advantage of body stability. This study suggests that rehabilitation experts apply the bar position and load as important variables affecting the intensity and method of training for target muscle strengthening of the lower extremities and trunk.

힙 힌지 동작에 따른 둥근 어깨와 정상인의 근활성도 비교

This study applied Hip hinge movement, a pelvic activation exercise, to round shoulder subjects and normal people based on the theory of the Anatomy train that our bodies are connected by kinesthetic chains and was executed to explore and compare muscle activity changes of the selected two groups during hip hinge movements. It was classified as round shoulder(n=9) and normal(n=9) for healthy young men in their 20s. The standard for selecting round shoulders at this point was to measure the height of the back of the shoulder bone peak from the side of the table and if the height is a ＜2.5㎝ or more, it is selected as round shoulders. The movement is to hold a rod fastening it at the back of the head, thoracic vertebrae and coccyx, then push the hips back by retracting the hip joint and get up. It is performed 15 times in a set alternating between the two sides.<BR> The results of this work show that when performing hip hinge movement, the Pectoralis major from the round shoulder group differ significantly in the left Pectoralis major(p＜.05) when the left arm is raised and showed no significant difference in muscle activity of the Deltoid posterior, Gluteus medius and Semitendinous also showed significant difference in muscle activity(p＜.05) and overall it was seen high in the round shoulder group. This produced a meaningful result in hip hinge exercises in some parts of round shoulder posture and this study is significant in suggesting different directions for future methods of exercise involving round shoulders.

Electromyographic responses to Nordic curl and prone leg curl exercises in football players

Background and Study Aim. The aim of this study is to examine the electromyographic responses to Nordic curl and prone leg curl exercises, having two different mechanics.&#x0D; Material and Methods. The athletes performed the prone leg curl and Nordic curl exercises in random order, 6 repetitions each. Electromyographic data of semimemranosus, semitendinosus, biceps femoris and rectus femoris muscles were recorded by 8-channel electromyography in order to examine the muscle responses to exercises. Total duration of exercise, cumulative integrated electromyographic values and muscle activation rates in 5 different intensity zones determined according to MVC% values have been compared.&#x0D; Results. Prone leg curl exercise occurred in less time than Nordic curl exercise. According to the cumulative integrated electromyography data results, all muscles showed similar muscle activation in both exercises. Comparing the muscle activation rates in the five intensity zones, more muscle activity was observed for Nordic curl exercise in the first intensity zone, while prone leg curl exercise was more active in the third and fourth zones. During the prone leg curl exercise, the muscle activation rate of the dominant leg is higher in the first intensity zone, whereas the non-dominant leg in the fourth intensity zone has a higher muscle activation. During the Nordic curl exercise, the muscle activation rates of the dominant leg in the first and fifth intensity zones are higher, whereas the nondominant leg in the fourth intensity zone is higher.&#x0D; Conclusions. Prone leg curl exercises can be preferred in order to stimulate high muscle activation in a short time. Comparing the two exercises there was no significant difference in muscle activity in dominant and nondominant legs.

The effects of an upper body conditioning stimulus on lower body post-activation performance enhancement (PAPE): a pilot study

Complex training where a high-load conditioning stimulus (CS) is performed prior to a biomechanically similar plyometric movement has been demonstrated to acutely enhance the performance of the plyometric movement in a phenomenon called post-activation performance enhancement (PAPE). Despite the positive influence PAPE can have on power production, the abundance of research has only investigated PAPE locally while comparing biomechanically similar movements. The purpose of this study was to determine if a heavy barbell bench press could elicit PAPE in a lower body plyometric movement. Eight (n = 8) resistance-trained males performed one set of countermovement jumps (CMJs) before (pre-CS) and three sets of CMJs after (post-CS) a heavy bench press set. Changes in muscle activation, jump height, work, power output, and rate of force development (RFD) during the early (E-RFD) and late (L-RFD) stages were compared between pre-CS and post-CS. The level of significance was set at p &lt; .05. There were no significant differences in muscle activation, jump height, work, power output, or E-RFD (p &gt; .05). There was a significant increase in L-RFD between pre-CS and the final set of jumps post-CS (p = .01). These results suggest that an upper body CS may not influence PAPE in the lower body. However, pairing a high-load upper body exercise with a lower body plyometric does not seem disadvantageous, and could be implemented as a strategy to maximize workout time efficiency with proper fatigue management incorporation.

청소년의 스마트폰 사용 중 간헐적 경부 스트레칭 운동이 근골격계 건강위험요인에 미치는 영향

The purpose of this study was to analyze how intermittent stretching exercise affects musculoskeletal health risk factors(neck range of motion, muscle activity, pressure pain) when using the smartphone in adolescents. The results of this study are as follows. First, there was no significant difference in musculoskeletal health risk factors pre and post smartphone use in the experimental group. Second, there were significant differences in musculoskeletal health risk factors pre and post smartphone use of the control group. Third, there was no significant difference in musculoskeletal health risk factors before the use of smartphone in the experimental group and the control group. Fourth, the musculoskeletal health risk factors before the use of smartphone in the experimental group and the control group showed a significant difference in muscle activity of the levator scapula, and no significant difference in other factors. From the above results, it was found that when adolescents use their smartphones for 60 minutes without stretching exercises in a chair sitting position, it was found that the musculoskeletal system (neck range of motion, muscle activity, pressure pain) was negatively affected, but 15 minutes It was found that the negative effects on the musculoskeletal system were significantly reduced when simple neck stretching exercises were performed in units.

EFFECTS OF CORE STABILIZATION EXERCISE ON MUSCLE ACTIVITY DURING HORIZONTAL SHOULDER ADDUCTION WITH LOADS IN HEALTHY ADULTS: A RANDOMIZED CONTROLLED STUDY

The importance of core stabilization exercises for extremities associated with dynamic spinal stabilization prior to movement has been demonstrated. However, no previous studies have investigated the muscle-coordinated effects on the upper trapezius (UT), anterior deltoid (AD), pectoralis major (PM), bilateral transverse abdominis (TrA), bilateral internal oblique (IO), and bilateral external oblique (EO) in healthy adults. The purpose of this study was to compare the effects of the dynamic neuromuscular stabilization (DNS) breathing technique and the abdominal bracing (AB) technique on UT, AD, PM, bilateral IO/TrA, and bilateral EO motor control in healthy participants during horizontal shoulder adduction. Thirty-six participants, eight of whom were female, were randomized into an AB and a DNS group and performed horizontal shoulder adduction with loads (8 and 17 lb). The clinical outcomes were UT, AD, and PM muscle activation and TrA/IO and EO muscle activation. Paired t-tests were used to analyze electromyography (EMG) data to determine statistically significant differences in muscle activity between the two techniques. For the EMG analysis, the maximal voluntary isometric contraction was measured for normalization and then divided by the EMG amplitude value. The results showed that UT, AD, and PM muscle amplitudes were lower and TrA/IO and EO muscle amplitudes were higher with DNS than with AB ([Formula: see text]). Our findings provide clinical evidence that core exercise with DNS is more effective in lessening UT, AD, and PM muscle activation and improving bilateral TrA/IO motor control than with AB.

Influence of Feet Position and Execution Velocity on Muscle Activation and Kinematic Parameters During the Inclined Leg Press Exercise.

The leg press is one of the most typical exercises for strengthening the lower limbs. The objectives of this study were to compare 5 inclined leg press exercise conditions, varying the feet width stance (100% or 150% hip width), the feet rotation (0° or 45° external rotation) on the footplate and using 2 different movement velocities (MVs; maximum intended, and 2:2 seconds steady-paced velocities) to determine their effect on muscle activation as well as on the kinematic parameters between trained men and trained women. There will be no significant differences in muscle activation with regard to the feet position. The higher the MV, the greater the muscle activation. A cross-sectional cohort study. Level 3. A repeated-measures between-group design was performed to examine muscle activation and kinematic parameters for the different conditions between gender groups. The level of significance was set at alpha = 0.05 for all statistical analyses. Muscle activation presented no differences between conditions regarding feet width stance or feet rotation. Furthermore, muscle activation was greater during positive phases than negative phases of the exercise for all conditions and was also greater under maximum intended velocity conditions compared with steady-paced conditions. Otherwise, the muscle activation pattern presented slight differences by gender. In men, the greatest muscle activation was for the vastus medialis, followed by the vastus lateralis (VL), rectus femoris (RF), and gluteus medialis (GMED), while in women, the greatest muscle activation was for the vastus medialis, followed by the RF, VL, and GMED. Finally, greater mean propulsive velocity, maximum velocity, maximum power, and footplate displacement values were reported for men than for women under all the conditions. The inclined leg press exercise produces the highest muscle activation in the vastus medialis, regardless of the velocity, feet stance, or gender. Given that there are no differences in muscle activation regarding the feet stance, a participant's preferred feet stance should be encouraged during the inclined leg press exercise. Furthermore, the MV would preferably depend on the session objective (a training or a rehabilitation program), being aware that there is greater muscle activation at higher speeds. The inclined leg press exercise could be performed as a closed kinetic chain exercise when the main objective is to activate the vastus medialis.

The Effect of Icing on Hamstring Muscle with Nordic Hamstring Exercise

The purpose of this study was the effect of icing on the muscle activity of Hamstring muscles during Nordic Hamstring Exercise after applying the icing. Twenty-eight healthy men participated in this study. Subjects were assigned to experiment and control groups. Nordic Hamstring Exercise was practiced to the experiment and the control groups without applying the icing. The control group rested for 20 minutes with no intervention, while the experiment group was applied 20 minutes of icing. Then Nordic Hamstring Exercise was performed again to compare the differences in muscle activity between the two groups. No significant differences in muscle activity were observed in the control group. However, In the experimental group, significant differences in muscle activity were found pre and post icing. There were also significant differences between the two groups. In conclusion, icing is considered to have a positive effect on promoting hamstring muscle activity.