Slow expiration reduces sternocleidomastoid activity and increases transversus abdominis and internal oblique muscle activity during abdominal curl-up

Effects of trunk muscle strength training on lung function in healthy runners

BACKGROUND

Abdominal pressure is important for athlete performance and conditioning, and lung function is implicated in running performance and economy. We aimed to determine the synergistic effects of trunk muscle strength training on abdominal pressure and lung function in university student runners.

METHODS

A total of 18 healthy male runners participated in the study. Abdominal pressure was measured against air pressure applied by a cuff belt wrapped around the trunk. Forced expiratory volume in 1 second (FEV1) and FEV in 6 seconds (FEV6) were measured. Trunk muscle strength training was performed for 8 weeks, and abdominal pressure and lung function were compared preintervention as well as at 8 weeks and 6 months postintervention. Correlations between the preintervention abdominal pressure and FEV1 and FEV6, as well as the rate of change (Δ) of each item at each time point, were examined.

RESULTS

Preintervention correlations between abdominal pressure and lung function were significant for abdominal pressure and FEV1 (r=0.475, P=0.047) and abdominal pressure and FEV6 (r=0.473, P=0.047). Significant correlations were found between Δabdominal pressure and ΔFEV1 (r=0.489, P=0.040) and Δabdominal pressure and ΔFEV6 (r=0.478, P=0.045) between preintervention and 8 weeks postintervention. Significant correlations were found between Δabdominal pressure and ΔFEV6 (r=0.557, P=0.016) between 8 weeks and 6 months postintervention.

CONCLUSIONS

The trunk muscle strength training intervention improved abdominal pressure and lung function, and the rate of change was also positively correlated, suggesting a synergistic effect between the two.

Effects of laptop screen height on neck and shoulder muscle fatigue and spine loading for office workers

BACKGROUND

Due to the unfavourable neck-shoulder muscle loads caused by poor posture, the people who use the laptop for a long time may face the risk of neck and shoulder injuries.

OBJECTIVE

The purpose of this study investigates the impact of the screen height on the muscle activation of head flexion, neck and shoulder, and the cervical spine torque to provide the favorite screen height for laptop user.

METHODS

Twelve healthy young participants completed a15-minute task of the reading at the four different screen heights. sEMG signals of the splenius capitis (SC) and upper trapezius (UT) were measured and calculated the root mean square (RMS) and mean power frequency (MPF) to determine muscle fatigue. The different height of laptop users was simulated and the forces on the spine of users at different screen heights were analyzed by Jack.

RESULTS

Adjusting the height of the laptop screen can effectively reduce head flexion and muscle activity of SC and UT, and has a positive effect on reducing fatigue of SC, but has no significant effect on UT.

CONCLUSIONS

Adjusting the height of the laptop screen can delay the occurrence of SC muscle fatigue to a certain extent. The joint analysis of sEMG spectrum and amplitude reports that the screen heights of D15 and D45 have the highest and the lowest frequency of fatigue, respectively. At the same time, the moment of spineT1/T2 and spineL4/L5 decrease with the increase of screen height.

Effects of hypopressive exercises on pelvic floor and abdominal muscles in adult women: A systematic review of randomized clinical trials

INTRODUCTION

Hypopressive exercises (HE) are postural and breathing exercises that activate deep muscles in the abdomen and pelvic floor. Despite this, there is still no consensus in the literature on its real effectiveness. The objective was to analyze the effects of HE on the abdominal and pelvic floor muscles in women with or without dysfunctions in these regions.

METHODS

This is a systematic review of randomized clinical trials found in the PEDro, PubMed, Cochrane, LILACS, and Embase databases. We include studies that evaluate the effects of HE (with or without other techniques) on the pelvic floor and abdominal region for 8 weeks or more, in women over 18 years old, with or without dysfunction in these regions, with the presence of a control group (active or passive).

RESULTS

HE were effective in improving strength, tone, and reducing symptoms of pelvic floor dysfunctions, in magnitude less than (in two studies) or equal (in one study) to the pelvic floor muscle training (PFMT). When HE were performed with PFMT in the same group, no additional benefits were found. Only one study evaluated abdominal muscles activation, where HE were effective in improving postural control and activation of the transversus abdominis muscle.

CONCLUSIONS

The HE presented positive results to the evaluated parameters. However, the information is still preliminary and scarce. There are methodological divergences regarding the execution, follow-up and standardization of the method, which could affect the results. According to the existing information, HE cannot yet be reliably indicated for the treatment of the pelvic floor, despite pointing out relevant results in some studies. More randomized clinical trials and long-term studies are needed to analyze the effects of HE not only for pelvic floor, but also for other regions, such as abdominal muscles and related dysfunctions.

Emotional state as a modulator of autonomic and somatic nervous system activity in postural control: a review

Advances in our understanding of postural control have highlighted the need to examine the influence of higher brain centers in the modulation of this complex function. There is strong evidence of a link between emotional state, autonomic nervous system (ANS) activity and somatic nervous system (somatic NS) activity in postural control. For example, relationships have been demonstrated between postural threat, anxiety, fear of falling, balance confidence, and physiological arousal. Behaviorally, increased arousal has been associated with changes in velocity and amplitude of postural sway during quiet standing. The potential links between ANS and somatic NS, observed in control of posture, are associated with shared neuroanatomical connections within the central nervous system (CNS). The influence of emotional state on postural control likely reflects the important influence the limbic system has on these ANS/somatic NS control networks. This narrative review will highlight several examples of behaviors which routinely require coordination between the ANS and somatic NS, highlighting the importance of the neurofunctional link between these systems. Furthermore, we will extend beyond the more historical focus on threat models and examine how disordered/altered emotional state and ANS processing may influence postural control and assessment. Finally, this paper will discuss studies that have been important in uncovering the modulatory effect of emotional state on postural control including links that may inform our understanding of disordered control, such as that observed in individuals living with Parkinson's disease and discuss methodological tools that have the potential to advance understanding of this complex relationship.

Abdominal Expansion versus Abdominal Drawing-In Strategy on Thickness and Electromyography of Lumbar Stabilizers in People with Nonspecific Low Back Pain: A Cross-Sectional Study

The abdominal expansion (AE) strategy, involving eccentric contraction of the abdominal muscles, has been increasingly used in clinical practices; however, its effects have not been rigorously investigated. This study aimed to investigate the immediate effects of the AE versus abdominal drawing-in (AD) strategy on lumbar stabilization muscles in people with nonspecific low back pain (LBP). Thirty adults with nonspecific LBP performed the AE, AD, and natural breathing (NB) strategies in three different body positions. Ultrasonography and surface electromyography (EMG) were, respectively, used to measure the thickness and activity of the lumbar multifidus and lateral abdominal wall muscles. The AE and AD strategies showed similar effects, producing higher EMG activity in the lumbar multifidus and lateral abdominal wall muscles when compared with the NB strategy. All muscles showed higher EMG activity in the quiet and single leg standing positions than in the lying position. Although the AE and AD strategies had similar effects on the thickness change of the lumbar multifidus muscle, the results of thickness changes of the lateral abdominal muscles were relatively inconsistent. The AE strategy may be used as an alternative method to facilitate co-contraction of lumbar stabilization muscles and improve spinal stability in people with nonspecific LBP.

Breathing Exercise Called the Maximal Abdominal Contraction Maneuver

Background and objectives: The maximal abdominal contraction maneuver (MACM) was designed as an effective and efficient breathing exercise to increase the stability of the spinal joint. However, it has not been determined whether MACM is more effective and efficient than the maximal expiration method. Thus, the present study was undertaken to investigate whole abdominal muscle thickness changes after MACM. Materials and Methods: Thirty healthy subjects (17 males and 13 females) participated in this study. An experimental comparison between MACM and the maximal expiration task was conducted by measuring the change of abdominal muscle thickness such as the transverse abdominis (TrA), internal oblique (IO), external oblique (EO) and rectus abdominis (RA) using ultrasound images. Results: The results indicated that MACM resulted in significantly greater muscle thickness increases of the TrA and RA than the maximal expiration exercise (p < 0.05). Conclusion: MACM provided better exercise than the maximal expiration exercise in terms of increasing spine stability, at least from a co-contraction perspective.

The effects of the neck stabilization exercise on the muscle activity of trunk respiratory muscles and maximum voluntary ventilation of chronic stroke patients

BACKGROUND

Unstable neck posture, muscle imbalance, and segmental instability can cause neck pain and decrease the respiratory function.

OBJECTIVE

To examine effects of a neck stabilization exercise on respiratory muscle activity and maximal voluntary ventilation (MVV) in patients with a chronic stroke.

METHODS

A total of 40 patients with a chronic stroke participated in this study. They were randomly divided into two groups (20 in each group). However, ten patients dropped out of the experiment (5 in each group). The experimental group (n= 15) performed a 15-minute neck stabilization exercise and a 15-minute breathing retraining exercise in addition to a rehabilitation exercise treatment. The control group (n= 15) completed a 30-minute breathing retraining exercise in addition to a rehabilitation exercise treatment. Exercises were conducted for 30 minutes a day, five times a week, for a total of six weeks. Activities of major respiratory muscles and MVV were measured before and after the experiment.

RESULTS

Both the experimental group and the control group showed significant difference in activities of major respiratory muscles and MVV before and after the experiment (p< 0.05). The experimental group showed a significantly higher increase compared to the control group (p< 0.05).

CONCLUSIONS

The application of a combination of a neck stabilization exercise and a breathing retraining exercise to patients with a chronic stroke can increase activity of respiratory muscles and MVV.

Surface electromyography in inspiratory muscles in adults and elderly individuals: A systematic review

INTRODUCTION

Electromyography (EMG) helps to evaluate disorders and pulmonary behavior, as impairments in respiratory muscle function are associated with the development of diseases. There is a wide range of methods and protocols used to record and analyze EMG obtained from respiratory muscles, demonstrating a lack of standardization.

OBJECTIVE

To identify the most common procedures used to record surface EMG (sEMG) of inspiratory muscles in adults and elderly individuals through a systematic review (primary), and to evaluate the quality of the report presented by the studies (secondary).

METHOD

Studies published from January 1995 until June 2018 were searched for in the Web of Science, PubMed, LILACS, EBSCO and Embase databases. Only studies evaluating sEMG of inspiratory muscles were included.

RESULTS

The electronic search retrieved a total of 6697 titles and 92 of them were included. A great variability on the methods applied to both recording and processing/analyzing data was found. Therefore, the synthesis of practical/clinical evidence to support immediate recommendations was impaired. In general, the descriptions presented by the studies are poor.

CONCLUSION

The most common procedures used for sEMG were identified. Methodological studies with objective comparisons were fundamental for improving standardization, given the impossibility of recommendations from this review.

Effect of hip position and breathing pattern on abdominal muscle activation during curl-up variations

Recent studies have indicated that applying different breathing pattern and changes of extremity positions could be a useful way of performing challenging exercises that include coactivation of the abdominal muscles. The aim of this study was to investigate the effects of changes of breathing pattern and hip position on abdominal muscle activity during curl-up exercises. Surface electromyography responses of the rectus abdominis (RA), internal oblique (IO), external oblique (EO) muscles and rectus femoris (RF), and Borg rating of perceived exertion (Borg RPE) score were investigated during the curl up exercises. A total of 20 healthy, physically active male volunteers completed two hip positions (45° and 90° hip flexion) and three breath types (slow expiration, maximal inspiration, and maximal expiration) for curl-up variations. The curl-up with 90° of hip flexion significantly increased the muscular activities of IO, EO, RF, and Borg RPE score (P<0.05). The curl-up with maximal expiration significantly elevated the IO and EO activity, compared to other breathing conditions. There were no significant difference in RA activities (P>0.05). The present study showed both the hip position and breathing pattern affect abdominal muscle activities during the curl-up exercise, especially of the oblique muscles. Among the breathing patterns investigated herein, the curl-up with maximum expiration produced greater activation of the oblique muscles compared to slow expiration and maximum inspiration.

Correlation between forward head posture, respiratory functions, and respiratory accessory muscles in young adults

BACKGROUND

Forward head posture (FHP) causes changes in the strengths and rigidities of cervical muscles.

OBJECTIVE

The aim of this study was to investigate correlations between FHP and respiratory functions and the muscle activities of respiratory accessory muscles in young adults in their 20s.

METHODS

A volunteer sample of 33 healthy young adults participated in this study. Craniovertebral angle (CVA), cranial rotational angle (CRA), vital capacity (VC), forced vital capacity (FVC), forced expiratory volume at 1 second (FEV1), peak expiratory flow (PEF), maximal voluntary ventilation (MVV), and sternocleidomastoid (SCM) and upper trapezius activity ratios were measured.

RESULTS

Significant positive correlations were found between CVA and VC, FVC, FEV1, PEF, and MVV, and a significant negative correlation was found between CVA and SCM activity ratio. Significant negative correlations existed between CRA and VC and FVC, and significant positive correlations between CRA and SCM and upper trapezius activity ratios.

CONCLUSION

FHP may act to lower respiratory functions, and thus, the maintenance of correct head posture is required to prevent such functional reductions.

Effects of Shoulder Taping on Discomfort and Electromyographic Responses of the Neck While Texting on a Touchscreen Smartphone

Background

Prolonged neck flexion during smartphone use is known as a factor of neck pain and alteration of neck muscle activity. Studies on the effects of shoulder taping on neck discomfort and neck muscle responses while texting on a smartphone are still lacking. The aim of this study was to examine the effects of shoulder taping on neck discomfort using a numerical rating scale, and neck muscle activity and fatigue using a surface electromyography during a texting task on a touchscreen smartphone.

Methods

Twenty-five healthy adolescents used the dominant hand to perform a 30-minute texting task using a touchscreen smartphone at two separate times under one of the following two conditions: taping across the upper trapezius muscle and no taping. Neck discomfort, normalized root mean square, and normalized median frequency slopes for upper trapezius, cervical erector spinae, and sternocleidomastoid muscles were recorded.

Results

The results revealed that shoulder taping provided significantly lower neck discomfort than no taping (p < 0.001). However, shoulder taping did not significantly alter normalized root mean square and normalized median frequency slope values of all muscles when compared with no taping controls.

Conclusion

Shoulder taping reduces neck discomfort but does not affect neck muscle activity and fatigue while texting on a touchscreen smartphone.

The effects of Pilates breathing trainings on trunk muscle activation in healthy female subjects: a prospective study

[Purpose] To investigate the effects of Pilates breathing on trunk muscle activation. [Subjects and Methods] Twenty-eight healthy female adults were selected for this study. Participants’ trunk muscle activations were measured while they performed curl-ups, chest-head lifts, and lifting tasks. Pilates breathing trainings were performed for 60 minutes per each session, 3 times per week for 2 weeks. Post-training muscle activations were measured by the same methods used for the pre-training muscle activations. [Results] All trunk muscles measured in this study had increased activities after Pilates breathing trainings. All activities of the transversus abdominis/internal abdominal oblique, and multifidus significantly increased. [Conclusion] Pilates breathing increased activities of the trunk stabilizer muscles. Activation of the trunk muscle indicates that practicing Pilates breathing while performing lifting tasks will reduce the risk of trunk injuries.

Correlation and compatibility between surface respiratory electromyography and transesophageal diaphragmatic electromyography measurements during treadmill exercise in stable patients with COPD

PURPOSE

To evaluate the compatibility and correlation between noninvasive surface respiratory electromyography and invasive transesophageal diaphragmatic electromyography measurements as facilitating indicators of neural respiratory drive (NRD) evaluation during treadmill exercise.

PATIENTS AND METHODS

Transesophageal diaphragmatic electromyogram activity (EMGdi,es) and surface inspiratory electromyogram (EMG) activity, including surface diaphragmatic EMG activity (EMGdi,sur), surface parasternal intercostal muscle EMG activity (EMGpara), and surface sternocleidomastoid EMG activity (EMGsc), were detected simultaneously during increasing exercise capacity in 20 stable patients with COPD. EMGdi,es, EMGdi,sur, EMGpara, and EMGsc were quantified using the root mean square (RMS) and were represented as RMSdi,es, RMSdi,sur, RMSpara, and RMSsc, respectively.

RESULTS

There was a significant association between EMGdi,es and EMGdi,sur (r=0.966, p<0.01), EMGpara (r=0.967, p<0.01), and EMGsc (r=0.956, p<0.01) in the COPD patients during exercise. Bland-Altman plots showed that the lowest mean bias value was between EMGdi,es and EMGpara compared with the bias values between EMGdi,es and the other two EMG parameters. In comparing the estimation of EMGdi,es, we observed the lowest bias values (-1%) and the lowest limits of agreement values (-10% to -12%). Intraclass correlation coefficient (ICC) between EMGdi,es and EMGdi,sur was 0.978 (p<0.01), between EMGdi,es and EMGpara was 0.980 (p<0.01), and between EMGdi,es and EMGsc was 0.868 (p<0.01).

CONCLUSION

RMSdi,sur, RMSpara, and RMSsc could provide useful physiological markers of NRD in COPD. RMSpara shows the best compatibility and correlation with transesophageal diaphragmatic electromyography during treadmill exercise in stable patients with COPD.

Effect of neck flexion restriction on sternocleidomastoid and abdominal muscle activity during curl-up exercises

[Purpose] The purpose of this study was to investigate the effect of neck flexion restriction on sternocleidomastoid (SCM), rectus abdominis (RA), and external oblique (EO) muscle activity during a traditional curl-up exercise and a curl-up with neck flexion restriction. [Subjects] In total, 13 healthy male subjects volunteered for this study. [Methods] All subjects performed a traditional curl-up exercise and a curl-up exercise in which neck flexion was restricted by the subject's hand. Surface electromyography (EMG) signals were recorded from the SCM, RA, and EO during the curl-up. [Results] There was significantly lower EMG activity of the SCM during the curl-up exercise with neck flexion restriction compared to the traditional curl-up exercise. Conversely, the activity of the RA and EO muscles was significantly higher in the curl-up exercise with neck flexion restriction than in the traditional curl-up exercise. [Conclusion] Neck flexion restriction is recommended to prevent excessive activation of superficial cervical flexors during the curl-up exercise.

Changes in Activation of Abdominal Muscles at Selected Angles During Trunk Exercise by Using Ultrasonography

OBJECTIVE

To investigate the changes of activation of the abdominal muscles depending on exercise angles and whether the activation of rectus abdominis differs according to the location, during curl up and leg raise exercises, by measuring the thickness ratio of abdominal muscles using ultrasonography.

METHODS

We examined 30 normal adults without musculoskeletal problems. Muscle thickness was measured in the upper rectus abdominis (URA), lower rectus abdominis (LRA), obliquus externus (EO), obliquus internus (IO), and transversus abdominis (TrA), at pre-determined angles (30°, 60°, 90°) and additionally at the resting angle (0°). Muscle thickness ratio was calculated by dividing the resting (0°) thickness for each angle, and was used as reflection of muscle activity.

RESULTS

The muscle thickness ratio was significantly different depending on the angles in URA and LRA. For curl up-URA p=0 (30°<60°), p=0 (60°>90°), p=0.44 (30°<90°) and LRA p=0.01 (30°<60°), p=0 (60°>90°), p=0.44 (30°>90°), respectively, by one-way ANOVA test-and for leg raise-URA p=0 (30°<60°), p=0 (60°<90°), p=0 (30°<90°) and LRA p=0.01 (30°<60°), p=0 (60°<90°), p=0 (30°<90°), respectively, by one-way ANOVA test-exercises, but not in the lateral abdominal muscles (EO, IO, and TrA). Also, there was no significant difference in the muscle thickness ratio of URA and LRA during both exercises. In the aspect of muscle activity, there was significant difference in the activation of RA muscle by selected angles, but not according to location during both exercises.

CONCLUSION

According to this study, exercise angle is thought to be an important contributing factor for strengthening of RA muscle; however, both the exercises are thought to have no property of strengthening RA muscle selectively based on the location.

Comparison between the effectiveness of expiration and abdominal bracing maneuvers in maintaining spinal stability following sudden trunk loading

The purpose of this study was to clarify the effectiveness of expiration and abdominal bracing maneuvers in response to sudden trunk loading in healthy subjects. Fifteen healthy male subjects were anteriorly loaded under different experimental conditions. Tests were conducted at rest and while performing each of the stabilization maneuvers (expiration and abdominal bracing) at 15% of the maximal voluntary isometric contraction of the internal oblique muscle. Subjects had no knowledge of the perturbation timing. An electromyographic biofeedback system was used to control the intensity of internal oblique muscle activation. Muscular pre-activation of three trunk muscles (internal oblique, external oblique, and L3 erector spinae muscles) and lumbar acceleration in response to loading were measured. The expiration and abdominal bracing maneuvers promoted torso co-contraction, reduced the magnitude of lumbar acceleration, and increased spinal stability compared to the resting condition. There were no differences between the expiration and abdominal bracing maneuvers in the pre-activation of the three trunk muscles or in lumbar acceleration in response to loading. It appears that both expiration and abdominal bracing maneuvers are effective in increasing spinal stability in response to sudden anterior loading.

Slow Expiration Reduces External Oblique Muscle Activity during Maximum Trunk Flexion

[Purpose] The purpose of this study was to demonstrate the effects of expiration on abdominal muscle activity during maximum trunk flexion. [Subjects] Twenty-one healthy university students (10 men, 11 women) participated in this study. [Methods] Electromyography (EMG) was used to quantify the activity of the right rectus abdominis, external oblique, and internal oblique muscles. The paired t-test was used to examine the significance of differences in the abdominal muscles between maximum trunk flexion with breath holding and slow expiration. [Results] There was a significantly lower EMG activity in the external oblique muscle during maximum trunk flexion with slow expiration. [Conclusion] The results of this study indicate that slow expiration reduces external oblique muscle activity during maximum trunk flexion performed by healthy young subjects.