Transversus Abdominis/internal Oblique Research Articles

Effects of unilateral and bilateral lower extremity fatiguing exercises on postural control during quiet stance and self-initiated perturbation.

Postural control can be more difficult during muscle fatigue. Anticipatory postural adjustments (APAs) and compensatory postural adjustments (CPAs) are the two main postural strategies controlled by the central nervous system. Unchanged or early anticipatory onset together with altered activation magnitude during the APAs phase is observed in the trunk and thigh muscles following unilateral and bilateral fatiguing exercises. Thus far, no studies have compared the effect of such exercises on APAs and CPAs. This study compared the effects of these exercises performed at the same relative workload on center of pressure (COP)-based postural stability measures during quiet stance and electromyography (EMG)-based APAs and CPAs during self-initiated perturbation. Fifteen young male subjects completed the two separated fatiguing sessions; 50% of maximal voluntary contraction force obtained from the unilateral (dominant) and bilateral legs with five sets of 20 times lower limb exercise was respectively applied as unilateral and bilateral fatiguing protocols. Spatio-temporal COP parameters (sway velocity, total displacement, and envelope area) were used to evaluate postural stability, and spectral analysis was performed to estimate the distributions in COP power spectrum. EMG activities of transversus abdominis/internal oblique (TrA/IO) and lumbar multifidus (LMF) were recorded and analyzed during the APAs and CPAs phases. Increased sway velocity and total displacements occurred following both unilateral and bilateral fatiguing exercises; however, the envelope area was not affected. Further, early anticipatory onset of TrA/IO was found after bilateral than after unilateral fatiguing exercise. Co-activation index of the TrA/IO-LMF muscle pair during the CPAs phase increased following both fatiguing sessions. The results partly confirmed previously reported fatigue effects induced by unilateral and bilateral exercises on postural stability. It was observed that APAs onsets were altered differently following a unilateral or bilateral fatiguing exercise, whereas the alterations of CPAs were independent of fatigue conditions. Repetitive unilateral or bilateral fatiguing exercises in patients or athletes may differently alter the anticipatory component of postural control.

Abdominal muscle activity and pelvic motion according to active straight leg raising test results in adults with and without chronic low back pain

BackgroundActive Straight Leg Raise (ASLR) is a clinical test that challenges lumbopelvic stability and have been used in low back pain patients. There are reports of positive tests in asymptomatic individuals, however, it is not clear if they are false positives or a consequence of performing the test differently. ObjectivesTo compare abdominal muscles activity and pelvic motion during an ASLR between adults with chronic low back pain and asymptomatic participants with a positive and negative ASLR test. DesignCross-sectional study design. MethodNineteen volunteers with chronic nonspecific low back pain (LBP) and 19 asymptomatic, 12 with a negative ASLR (AG-) and 7 with a positive ASLR test (AG+) were assessed while performing an ASLR (dynamic postural challenge). Pelvic rotation and medio-lateral center of pressure displacement (COPml), as well as bilateral EMG abdominal muscles activity were assessed. Muscles asymmetry index were also analyzed. Kruskal-wallis test was used to compare groups (α = 0.05). ResultsBoth LBP and AG + displayed significantly less contralateral internal oblique/transversus abdominis (IO/TrA) muscle activation than AG- (p = 0.003 and p = 0.005, respectively) and also more asymmetry between sides in the IO/TrA than AG- (p = 0.022 and p = 0.004, respectively). No significant differences between LBP and AG+ were found (p > 0.05). ConclusionA positive ASLR test in an asymptomatic person could be more than a false positive, since IO/TrA muscle activation appears to be lower and more asymmetrical in people with a positive ASLR test, both with and without low back pain. Future studies may consider removing asymptomatic individuals with a positive ASLR.

Abdominal muscle activation: An EMG study of the Sahrmann five-level core stability test.

Background:Sahrmann five-level core stability test protocol has been used to evaluate the ability of the core muscles to stabilize the spine. However, validation studies on the Sahrmann protocol are limited.Objective:The purpose of this study was to compare the different levels of Sahrmann five-level core stability (levels 1–5) on the muscle activity of rectus abdominis (RA), external oblique (EO), and transverse abdominis/internal oblique (TrA/IO).Methods:Twenty-two asymptomatic male participants aged 21.3.59 years were recruited. Participants were instructed to perform maximum voluntary contraction (MVC) and five levels of Sahrmann five-level core stability test guided with a pressure biofeedback unit (PBU). The surface electromyography (EMG) data of each muscle during five levels of Sahrmann five-level core stability test were normalized as a percentage of MVC.Results:Results showed significant differences in the normalized EMGs of RA [(4) = 64.80, .001], EO [(4) = 58.11, .001], and TrA/IO [(4) = 56.00, .001] between the five levels of Sahrmann five-level core stability test. Post-hoc analysis revealed Sahrmann levels 5 and 3 have significantly higher abdominal EMG signals than levels 4, 2, and 1 (.001).Conclusion:In conclusion, the Sahrmann five-level core stability test differs according to the level of Sahrmann tests. Significantly higher abdominal muscle activities were observed during levels 3 and 5. Therefore, the classification exchange in levels 3 and 4 of the Sahrmann five-level core stability test should be reconsidered in the future.

Does athletic groin pain affect the muscular co-contraction during a change of direction

BackgroundGroin pain is one of the common problems in multidirectional sports. It seems that abnormal muscular activity and improper movement strategy led to prolongation and high rate of this injury. Therefore, the aim of this study was to Comparing the Average amplitude of Electromyography (AEMG), co-contraction ratio (CCR) of selected thigh and thoracic muscle during turning in individuals with chronic groin pain and healthy individuals. MethodsSurface electromyography was collected from the internal oblique/transversus abdominis (IO/TrA), multifidus (MF), adductor Longus (AL) and gluteus Medius (GM) for AEMG and CCR analyzed in 16-males with LSGP and 16-controls in four motion phases during 11 cycles of gait coupled with turning. ResultsResults revealed that in the AEMG apart from the third phase in the muscle of the IO/ Tr. A muscle and in the second phase in the MF muscle in the trunk and in the third phase in the muscle of the AL and the fourth phase in the GM foot Left There was a significant difference in other phases. There was a significant difference in the CCR, except in the second phase of the trunk and the fourth phase of the left foot in the rest of the phases. ConclusionsIt seems that in athletes with LSGP, have selective muscular activation and CCR have during turning, that may be resulting in compensatory strategies and movement control defects, which may be a useful tool to predict LSGP occurrence in players with a history of groin pain.

Comparison of Trunk Muscle Activity Between Traditional Plank Exercise and Plank Exercise With Isometric Contraction of Ankle Muscles in Subjects With Chronic Low Back Pain.

Choi, JH, Kim, DE, and Cynn, HS. Comparison of trunk muscle activity between traditional plank exercise and plank exercise with isometric contraction of ankle muscles in subjects with chronic low back pain. J Strength Cond Res 35(9): 2407-2413, 2021-This study aimed to compare the effects of 4 different ankle conditions on the activities of rectus abdominis (RA), external oblique (EO), transversus abdominis/internal oblique (TrA/IO), and erector spinae (ES) muscles during plank exercise in subjects with chronic low back pain (CLBP). Twenty-two subjects with CLBP participated in this study. The subjects performed the traditional plank and plank with 3 different ankle muscle contraction types (isometric contraction of ankle dorsiflexor, plantarflexor, and without ankle muscle contraction). Surface electromyography was used to measure the activities of RA, EO, TrA/IO, ES, tibialis anterior, and gastrocnemius muscles. A 1-way repeated-measures analysis of variance was used to assess the statistical significance of activities of the RA, EO, TrA/IO, and ES muscles. The activities of RA, EO, and TrA/IO muscles were significantly greater in the plank with isometric contraction of ankle dorsiflexor (PlankDF) than in the other 3 plank exercises. No significant difference in the activity of ES muscles was revealed during the 4 plank exercises. The activities of all abdominal muscles during PlankDF were significantly higher than those during the traditional plank, as well as during the plank with isometric contraction of ankle plantarflexor (PlankPF) and the plank without ankle muscular contraction (Plankw/o), and more than 60% of maximal voluntary isometric contraction was observed. Thus, PlankDF could be applied not only as a rehabilitation strategy for patients with decreased core stability owing to weakness of abdominal muscles but also as fitness program for improving core strength.

EFFECTS OF INDIVIDUALLY STRUCTURED TRUNK TRAINING ON BODY FUNCTION AND STRUCTURES IN CHILDREN WITH SPASTIC CEREBRAL PALSY: A STRATIFIED RANDOMIZED CONTROLLED TRIAL

Purpose: This study aimed to investigate the effects of trunk training on body function and structures of children with spastic cerebral palsy (CP). Methods: Children included in this study were classified according to the Gross Motor Function Classification System (GMFCS) and divided into two groups by stratified randomization based on their GMFCS levels and ages. A total of 36 children with bilateral spastic CP were recruited for this study, and 19 children (4 females, 15 males, age=8.81±3.92 years) were included in the trunk training group, and 17 children (6 females, 11 males, age=10.44±4.63 years) were included in the control group. Muscle tone of upper and lower extremity muscles was assessed using the Modified Tardieu Scale (MTS), and muscle activation of the trunk muscles was assessed using Surface Electromyography during rest (sEMG minimum) and forward reaching (sEMG maximum) at baseline and after an eight-week intervention. Results: When the therapy-induced changes were considered, it was seen that there was no difference in muscle tone in both groups (p>0.05). The sEMG maximum scores for erector spinae muscles (p=0.025 for right and p=0.006 for left) improved in the trunk training group. There was no change in the sEMG scores of lumbar multifidus, M. rectus abdominis, internal oblique-transversus abdominis, external oblique, and M. gluteus maximus muscles (p>0.05). Conclusion: Individually-structured trunk training is a promising method to increase activation of trunk extensors. This intervention can be used safely without the risk of increasing muscle tone of upper and lower extremities in children with CP.

Surface electromyography comparison of the abdominal hypopressive gymnastics against the prone bridge exercise

Objectives: Abdominal hypopressive gymnastics (AHG) is a little-researched method designed to train the muscles of the abdominal wall and pelvic floor under low stress. This study’s objective is to compare levels of muscle activation in AHG against prone bridge by surface electromyography (sEMG) of the abdominal wall muscles.
 Methods: Twenty healthy subjects were enrolled to measure the muscle activity of the rectus abdominis (RA), transversus abdominis/internal oblique (Tra/IO), and external oblique (EO) during three exercises: prone bridge (PB), orthostatic hypopressive (OH), and hypopressive bridge (HB). Root mean square values normalized to the PB (%PB) as a baseline were used to compare the PB against OH and HB.
 Results: The median PB ratio (%PB) for the Tra/IO showed –10.31% and +59.7% activation during OH and the HB, respectively, whereas the RA showed –77.8% and +19.3% and the EO –39.8% and +9.8%. Significant differences were found for all muscles except the Tra/IO during the OH.
 Conclusion: This study’s results suggest that hypopressive exercises facilitate the activation of the Tra/IO similar to bridge exercises while simultaneously reducing RA and EO activity. This suggests that hypopressive training is a valid alternative for activating the abdominal muscles, isolating the Tra/IO at low intra-abdominal pressure.

The onset of deep abdominal muscles activity during tasks with different trunk rotational torques in subjects with non-specific chronic low back pain

BackgroundAlthough delayed onset of the deep abdominal muscles activity in subjects with non-specific chronic low back pain (CLBP) has been suggested to be related to trunk rotational torque, no study has examined the onsets associated with non-specific CLBP during a variety of tasks with different trunk rotational torque. The aim of this study is to compare the onsets of deep abdominal muscles activity among tasks with different trunk rotational torques in subjects with and without non-specific CLBP. MethodsTwelve subjects with non-specific CLBP and 13 control subjects were included. They performed 8 types of upper limb movements. The onsets of muscular activity of bilateral internal oblique-transversus abdominis (IO-TrA) and trunk rotational torque due to the upper limb movements were measured using a surface electromyography and a three-dimensional motion analysis system. ResultsIn non-specific CLBP group, right IO-TrA activities were significantly delayed during tasks with left trunk rotational torque compared with the control (P < 0.05), while onsets of the left IO-TrA activities were significantly later than those of the control during tasks with right rotational torque of the trunk (P < 0.05). There were no significant differences in onsets of both sides IO-TrA during tasks without trunk rotational torque between non-specific CLBP and control groups (P > 0.05). ConclusionsThe onsets of IO-TrA activities in subjects with non-specific CLBP were delayed during tasks with rotational torque of the trunk in the opposite direction, suggesting a possibility that delayed onset of the deep abdominal muscles during rotational torque of the trunk might be etiology of chronic low back pain.

Comparison of Modular Control during Smash Shot between Advanced and Beginner Badminton Players.

This study investigated muscle synergy during smash shot in badminton and compared synergies of advanced players (more than 7 years experience) and beginner players (less than 3 years experience). The dominant hand of all players was the right side. Muscle activities were recorded on both sides of the rectus abdominis, external oblique (EO), internal oblique/transversus abdominis (IO/TrA), and erector spinae. Additionally, the right side of the biceps brachii, triceps brachii, flexor carpi radialis, flexor carpi ulnaris, and flexor digitorum profundus muscle activities were recorded. All data was obtained using surface electromyography. Synergy was extracted from electromyography signals using nonnegative matrix factorization. Extracted synergies in each group were compared using scalar product (SP) which is the similarity index. As a result, two synergies were extracted in the beginner players and three synergies were extracted in advanced players. Beginner and advanced players had one synergy in common (SP = 0.86) that was mainly on the left side of the EO. It activated in the early stroke and had a role of side bending from the left to hit the shuttlecock at a higher point. Another synergy that had coactivation of the IO/TrA and forearm muscles at impact was extracted only for advanced players and it may enhance the smash shot performance in badminton.

Improved compensatory postural adjustments of the deep abdominals following exercise in people with chronic low back pain

The purpose of this study was to determine if 8 weeks of exercise affects motor control in people with chronic low back pain (CLBP), measured by anticipatory (APAs) and compensatory postural adjustments (CPAs). APAs and CPAs were measured prior to and following 8 weeks in two groups of people with CLBP: an exercise group (n=12) who attended three exercise sessions per week for 8 weeks; and a non-exercise control group (n=12) who were advised to continue their usual activities for the duration of the study. APAs and CPAs were recorded during unilateral arm flexion, bilaterally from rectus abdominis (RA), transverse abdominis/internal oblique (TA/IO), and erector spinae (ES) via surface electromyography. Analysis of muscle onsets and APA amplitudes suggests APAs did not change for either group. Ipsi-lateral TA/IO CPAs increased for the exercise group and ipsi-lateral TA/IO CPAs decreased for the control group. Only exercise promoted a pattern of TA/IO activity during CPAs similar to healthy individuals, suggesting improved control of rotational torques. These results show motor control improvement following exercise in people with CLBP, highlighted by improved side specific control of TA/IO.

Reflex-mediated dynamic neuromuscular stabilization in stroke patients: EMG processing and ultrasound imaging.

Postural core instability is associated with poor dynamic balance and a high risk of serious falls. Both neurodevelopmental treatment (NDT) and dynamic neuromuscular stabilization (DNS) core stabilization exercises have been used to improve core stability, but the outcomes of these treatments remain unclear. This study was undertaken to examine the therapeutic effects of NDT and DNS core stabilization exercises on muscular activity, core stability, and core muscle thickness. Ten participants (5 healthy adults; 5 hemiparetic stroke patients) were recruited. Surface electromyography (EMG) was used to determine core muscle activity of the transversus abdominis/internal oblique (TrA/IO), external oblique (EO), and rectus abdominis (RA) muscles. Ultrasound imaging was used to measure transversus abdominals/internal oblique (TrA/IO) thickness, and a pressure biofeedback unit (PBU) was used to measure core stability during the DNS and NDT core exercise conditions. Data are reported as median and range and were compared using nonparametric Mann - Whitney U test and Wilcoxon signed rank test at p< 0.05. Both healthy and hemiparetic stroke groups showed greater median EMG amplitude in the TrA/IO muscles, core stability, and muscle thickness values during the DNS exercise condition than during the NDT core exercise condition, respectively (p< 0.05). However, the relative changes in the EMG amplitude, core stability, and muscle thickness values were greater during the DNS exercise condition than during the NDT core exercise condition in the hemiparetic stroke patient group (p< 0.05). Our novel results provide the first clinical evidence that DNS is more effective than NDT in both healthy and hemiparetic stroke subjects to provide superior deep core muscle activation, core stabilization, and muscle thickness. Moreover, such advantageous therapeutic benefits of the DNS core stabilization exercise over the NDT exercise were more apparent in the hemiparetis stroke patients than normal controls.

Training Status and Gender Effects on Sternocleidomastoid and Abdominal Muscles Activity during Curl-Up Exercise with Different Respiratory Cycle

Objective: This study aims to investigate sternocleidomastoid muscle (SCM) during curl-up exercise with different inspiration and expiration cycle among subject with different training status and gender, and the abdominal muscles in the targeted area. Methods: 24 healthy subjects volunteered to participate in the study. The data were gathered from bilateral SCM, rectus abdominis (RA), external oblique (EO) and transversus abdominis/internal oblique (TrA/IO) muscles via surface electromyography (EMG). Results: The analysis of all the data gathered from the participants shows that the muscle activation in EO right, TrA/IO right, TrA/IO left and RA right during curl-up exercise with expiration is higher than activation during curl-up exercise with inspiration. A comparison of sedentary and mean scores of participants during curl-up exercise with expiration did not reveal any significant difference. A comparison of mean scores of men and women during curl-up exercise with expiration showed that the scores derived from females’ EO left and RA right muscles is higher than the scores derived from the same muscles group of males. However, when the average scores of male and female participants in the curl-up movement with inspiration were compared, the scores derived from the same muscle group of females is higher than that of males’. Conclusion: As there is no difference between genders and the contraction rates of SCM muscle, no gender-specific suggestions can be made about respiration during curl-up for the health of neck and cervical zone

The effect of inspiratory and expiratory loads on abdominal muscle activity during breathing in subjects “at risk” for the development of chronic obstructive pulmonary disease and healthy

The abdominal muscle activity has been shown to be variable in subjects with chronic obstructive pulmonary disease (COPD) when respiratory demand increases and their recruitment pattern may change the mechanics, as well as the work and cost of breathing. The scientific evidence in subjects “at risk” for the development of COPD may be important to understand the natural history of this disease. This study aims to evaluate the effect of inspiratory and expiratory loads on the abdominal muscle activity during breathing in subjects “at risk” for the development of COPD and healthy. Thirty-one volunteers, divided in “At Risk” for COPD (n=17; 47.71±5.11years) and Healthy (n=14; 48.21±6.87years) groups, breathed at the same rhythm without load and with 10% of the maximal inspiratory or expiratory pressures, in standing. Surface electromyography was performed to assess the activation intensity of rectus abdominis (RA), external oblique and transversus abdominis/internal oblique (TrA/IO) muscles, during inspiration and expiration. During inspiration, in “At Risk” for COPD group, RA muscle activation was higher with loaded expiration (p=0.016); however, in Healthy group it was observed a higher activation of external oblique and TrA/IO muscles (p<0.050). During expiration, while in “At Risk” for COPD group, RA muscle activation was higher with loaded inspiration (p=0.009), in Healthy group TrA/IO muscle showed a higher activation (p=0.025). Subjects “at risk” for the development of COPD seemed to have a specific recruitment of the superficial layer of ventrolateral abdominal wall for the mechanics of breathing.

Abdominal muscle activity during breathing in different postures in COPD “Stage 0” and healthy subjects

This study aims to evaluate the effect of different postures on the abdominal muscle activity during breathing in subjects “at risk” for the development of chronic obstructive pulmonary disease (COPD) and healthy. Twenty-nine volunteers, divided in “At Risk” for COPD (n=16; 47.38±5.08years) and Healthy (n=13; 47.54±6.65years) groups, breathed at the same rhythm in supine, standing, tripod and 4-point-kneeling positions. Surface electromyography was performed to assess the activation intensity of rectus abdominis, external oblique and transversus abdominis/internal oblique (TrA/IO) muscles, during inspiration and expiration. From supine to standing, an increased activation of all abdominal muscles was observed in “At Risk” for COPD group; however, in Healthy group, TrA/IO muscle showed an increased activation. In both groups, the TrA/IO muscle activation in tripod and 4-point kneeling positions was higher than in supine and lower than in standing. Subjects “at risk” for the development of COPD seemed to have a specific recruitment of the superficial layer of ventrolateral abdominal wall for the synchronization of postural function and mechanics of breathing.

불안정한 지지면에서의 균형운동이 건강한 성인의 폐활량에 미치는 효과: 사전 연구

Purpose : This study attempts to examine the effect of the balance exercise on the unstable surfaces for the vital capacity in healthy adults. Methods : A total of 13 subjects was randomly divided into a breathing exercise training group (n=7) and a breathing and balance exercise training group (n=6). Changes in vital capacity and respiratory muscle activity were measured before and after the intervention. The intervention was performed three times a week for four weeks. Forced vital capacity (FVC), forced expiratory volume at one second (FEV1) and maximal voluntary ventilation (MVV) were used as measurement tools for the vital capacity test. Electromyography (EMG) was also used to examine respiratory muscle activity. Result : The breathing exercise training group showed significant improvement in terms of FVC, FEV1 and external oblique (EO), and transverse abdominis/internal oblique (TrA/IO) of MVV. The breathing and balance exercise training group showed significant improvement in terms of FVC, MVV and EO, TrA/IO of FVC and rectus abdominis (RA), EO, and TrA/IO of MVV. However, in comparing changes in vital capacity and respiratory muscle activity before and after the training, the breathing exercise training group and the breathing and balance exercise training group showed a significant difference in terms of MVV. Conclusion : This study is as a preliminary study to find out the relation between a balance exercise and a vital capacity, it is considered to require a further study with several revisions of subjects, duration and time for an intervention.

Preparatory brain activity and anticipatory postural adjustments accompanied by externally cued weighted-rapid arm rise task in non-specific chronic low back pain patients and healthy subjects.

ObjectiveCortical reorganization is one of the most plausible mechanisms underlying impairment of anticipatory postural adjustments (APAs) in low back pain (LBP) patients. In order to clarify changes in corticomotor neurophysiology, APAs were assessed by using electromyography (EMG) and electroencephalography (EEG).MethodsAn equal number (29) of nonspecific LBP patients and healthy subjects performed unilateral rapid arm movements in response to auditory imperative stimulus preceded by warning stimulus within 2 s interstimulus interval. Burst onset activity was calculated in relation to the activity of anterior deltoid for bilateral transverse abdominis/internal oblique (TrA/IO), and also postural muscles on left side, including rectus abdominis, external oblique (E.O), erector spinae and medial head of gastrocnemius (Gc.M). Contingent negative variation (CNV) potentials were recorded by scalp EEG, and the area under receiver operating characteristic curve (AUC) was analyzed.ResultsIn LBP patients, there was a significant onset delay for E.O and bilateral TrA/IO, but a significant earlier activity for Gc.M (for both P < 0.05). The CNV parameters were considerably greater in LBP patients (P < 0.01). The AUC was significant just for left TrA/IO and E.O muscles (P < 0.05).ConclusionsThe CNV amplitudes were increased, and APA onset times re-organized to be delayed at the trunk and early at the distal limb in LBP cases. These findings support the hypothesis about reorganized activity of cerebral cortex in LBP patients.

Influence of chronic low back pain and fear of movement on the activation of the transversely oriented abdominal muscles during forward bending

Introduction: Chronic low back pain (CLBP) and fear of movement (kinesiophobia) are associated with an overactivation of paravertebral muscles during forward bending. This impairs spine motor control and contributes to pain perpetuation. However, the abdominal muscles activation is engaged too in spine stabilization but its modulation with kinesiophobia remains unknown. Our study tested whether CLBP and kinesiophobia affected the activation pattern of abdominal muscles during trunk flexion/extension. Methods: Surface electromyographical recordings of the internal oblique/transversus abdominis (IO/TrA) and external oblique (EO) muscles were analyzed in 12 people with CLBP and 13 pain-free subjects during low-velocity forward bending back and forth from erected posture. Tampa Scale of Kinesiophobia was also administrated. Results: IO/TrA activation, but not EO, was modulated across the phases of movement in both groups, i.e. maximal at onset of flexion and end of extension, and minimal at full flexion. In CLBP group only, IO/TrA activation was increased near to full trunk flexion and in correlation with kinesiophobia. Conclusions: The phase-dependence of IO/TrA activation during trunk flexion/extension in standing may have a role in spine motor control. The influence of kinesiophobia in CLBP should be further investigated as an important target in CLBP management.

Trunk extensor muscle fatigue influences trunk muscle activities

Trunk muscles fatigue is one of the risk factors in workplaces and daily activities. Loads would be redistributed among active and passive tissues in a non-optimal manner in fatigue conditions. Therefore, a single tissue might be overloaded with minimal loads and as a result the risk of injury would increase. The goal of this paper was to assess the electromyographic response of trunk extensor and abdominal muscles after trunk extensor muscles fatigue induced by cyclic lifting task. This was an experimental study that twenty healthy women participated. For assessing automatic response of trunk extensor and abdominal muscles before and after the fatigue task, electromyographic activities of 6 muscles: thorasic erector spine (TES), lumbar erector spine (LES), lumbar multifidus (LMF), transverse abdominis/ internal oblique (TrA/IO), rectus abdominis (RA) and external oblique (EO) were recorded in standing position with no load and symmetric axial loads equal to 25% of their body weights. Statistical analysis showed that all the abdominal muscles activity decreased with axial loads after performing fatigue task but trunk extensor activity remained constant. Results of the current study indicated that muscle recruitment strategies changed with muscle fatigue and load bearing, therefore risks of tissue injury may increase in fatigue conditions.

The influences of position and forced respiratory maneuvers on spinal stability muscles.

[Purpose] The purposes of this study were to investigate the influences of position on %MVIC of spinal stability muscles to establish for the most effective breathing pattern for activation of spinal stability muscles in order to provide an additional treatment method for use in spinal stability exercise programs. [Subjects and Methods] Thirty-three healthy subjects performed quiet breathing and four different forced respiratory maneuvers (FRM); [pursed lip breathing (PLB), diaphragmatic breathing (DB), combination breathing (CB) and respiration muscle endurance training (RMET)] in both standing and sitting positions. %MVIC of them (the multifidus (MF), erector spinae (ES), internal oblique/transversus abdominis (IO/TrA), external oblique (EO), rectus abdominis (RA) measured. [Results] IO/TrA, MF and EO showed greater activation in standing than in sitting, while RA and ES showed greater activation in sitting than in standing. RMET induced significantly greater activation of spinal stability muscles then other breathing patterns. %MVIC changes of muscle activities induced by FRM were independent of position with a few exceptions. [Conclusion] The increased respiratory demands of FRM induced greater activation of spinal stability muscles than QB. RMET was found to be the most effective breathing pattern for increasing the activation of the spinal stability muscles.

Core Muscle Activity during TRX Suspension Exercises with and without Kinesiology Taping in Adults with Chronic Low Back Pain: Implications for Rehabilitation.

This study aimed to examine the effects of kinesiology taping (KT) and different TRX suspension workouts on the amplitude of electromyographic (EMG) activity in the core muscles among people with chronic low back pain (LBP). Each participant (total n = 21) was exposed to two KT conditions: no taping and taping, while performing four TRX suspension exercises: (1) hamstring curl, (2) hip abduction in plank, (3) chest press, and (4) 45-degree row. Right transversus abdominis/internal oblique (TrAIO), rectus abdominis (RA), external oblique (EO), and superficial lumbar multifidus (LMF) activity was recorded with surface EMG and expressed as a percentage of the EMG amplitude recorded during a maximal voluntary isometric contraction of the respective muscles. Hip abduction in plank increased TrAIO, RA, and LMF EMG amplitude compared with other TRX positions (P < 0.008). Only the hamstring curl was effective in inducing a high EMG amplitude of LMF (P < 0.001). No significant difference in EMG magnitude was found between the taping and no taping conditions overall (P > 0.05). Hip abduction in plank most effectively activated abdominal muscles, whereas the hamstring curl most effectively activated the paraspinal muscles. Applying KT conferred no immediate benefits in improving the core muscle activation during TRX training in adults with chronic LBP.