Effect of low back pain on the muscles controlling the sitting posture

[Purpose] The purpose of the current study was to reveal the association between posture control and muscle activity by measuring the trunk and hip joint muscle activities in the upright and slump sitting positions in both the healthy participants and patients with recurrent lower back pain. [Participants and Methods] We recruited eleven patients of recurrent lower back pain and ten healthy participants. During the maintenance of the two types of posture, upright and slump, we collected the surface electromyography data. We assessed the following muscles: rectus abdominis, external oblique, thoracic erector spinae, lumbar erector spinae, internal oblique, lumbar multifidus, iliacus, serratus anterior, rectus femoris, tensor fascia latae, and gluteus maximus. We studied the differences in spinal–pelvic curvature and muscle activity between the upright and slump positions in each group. [Results] In the healthy group, comparison of the muscle activity in upright and slump positions for both the trunk (external oblique, internal oblique, lumbar erector spinae, and lumbar multifidus), and the hip muscles (iliacus and gluteus maximus) showed a significant decrease in activity in the slump position. In the group with recurrent lower back pain, although the external oblique, lumbar erector spinae and lumbar multifidus showed reduced activity in slump position, these values were smaller when compared to those in the healthy group. [Conclusion] This study aimed to clarify the relationship between posture (upright and slump) and the activity of the trunk and hip joint muscles in the healthy participants and the patients with recurrent lower back pain. The results indicated that postural changes caused by recurrent lower back pain significantly affected the activity of the muscles involved in controlling the posture.Key words: Sitting posture, Muscle control, Low back pain     

脑卒中偏瘫患者在坐位躯干旋转时躯干肌群表面肌电信号特征研究

目的:比较正常人及脑卒中偏瘫患者在躯干向左(瘫痪侧)及向右(非瘫痪侧)旋转过程中躯干浅表肌群的表面肌电信号特征。方法:选取17例脑卒中偏瘫患者及16例健康志愿者,采集2组受试者在躯干左旋(向瘫痪侧旋转)45°、右旋(向非瘫痪侧旋转)45°时腹直肌、腹外斜肌、胸段竖脊肌、腰段竖脊肌、背阔肌的表面肌电图均方根振幅(RMS)。结果:正常人在躯干向一侧旋转时对侧腹外斜肌RMS值大于转向侧(P0.01),转向侧胸段竖脊肌、背阔肌的RMS值大于对侧(P0.01);向左(瘫痪侧)旋转时脑卒中患者偏瘫侧腹外斜肌、胸段竖脊肌和背阔肌的RMS值低于正常组左侧(P0.01),非瘫痪侧腹外斜肌的RMS值低于正常组右侧(P0.01);向右(非瘫痪侧)旋转时脑卒中患者偏瘫侧腹外斜肌、胸段竖脊肌的RMS值小于正常组左侧(P0.01),偏瘫侧腰段竖脊肌的RMS值小于正常组左侧(P0.05),非瘫痪侧腹外斜肌、腰段竖脊肌和胸段竖脊肌的RMS值小于正常组右侧(P0.01)。结论:正常人在躯干旋转时胸段竖脊肌、背阔肌、腹外斜肌呈现明显的交叉性,转向侧的胸段竖脊肌、背阔肌的肌电活动明显增加,对侧的腹外斜肌肌电活动明显增加;而脑卒中患者则没有这种交叉性。     

Abdominal and erector spinae muscle activity during gait: the use of cluster analysis to identify patterns of activity

OBJECTIVE: To describe patterns of muscle activation during gait in selected abdominal and lumbar muscles using cluster analysis. PARTICIPANTS: A sample of convenience of 38 healthy adult volunteers.Outcome measures. Electromyographic activity from the right internal and external obliques, rectus abdominis and lumbar erector spinae were recorded, and the root mean square values for each muscle were calculated throughout the stride in 5% epochs. These values were normalised to maximum effort isometric muscle contractions. Cluster analysis was used to identify groups of subjects with similar patterns of activity and activation levels. RESULTS: Cluster analysis identified two patterns of activity for the internal oblique, external oblique and rectus abdominis muscles. In the lumbar erector spinae, three patterns of activity were observed. In most instances, the patterns observed for each muscle differed in the magnitude of the activation levels. In rectus abdominis and external oblique muscles, the majority of subjects had low levels of activity (<5.0% of a maximum voluntary contraction) that were relatively constant throughout the stride cycle. In the internal oblique and the erector spinae muscles, more distinct bursts of activity were observed, most often close to foot-strike. The different algorithms used for the cluster analysis yielded similar results and a discriminant function analysis provided further evidence to support the patterns observed. CONCLUSIONS: Cluster analysis was useful in grouping subjects who had similar patterns of muscle activity. It provided evidence that there were subgroups that might otherwise not be observed if a group ensemble was presented as the "norm" for any particular muscle's role during gait. RELEVANCE: The identification of common variations in muscle activity may prove valuable in identifying individuals with electromyographic patterns that might influence their chances of sustaining injury. Alternatively, clusters may provide important information related to muscle activity in those that do well or otherwise after a particular injury.     

Reliability of ultrasound measurement of the lateral abdominal and lumbar multifidus muscles in individuals with chronic low back pain: A cross-sectional test-retest study

ObjectivesUltrasound (US) imaging has been suggested to evaluate the morphology and function of trunk muscles; however, little is known about the reliability of the US measures in patients with chronic low back pain (CLBP). This study aimed to evaluate intrarater reliability of US imaging of the lateral abdominal and lumbar multifidus muscles in individuals with nonspecific CLBP.MethodsIn this cross-sectional study, intrarater within-day and between-day reliability of US measurements of the transversus abdominis, internal oblique, external oblique and lumbar multifidus (at the L3-L4, L4-L5, and L5-S1 levels) muscles were obtained on both sides. The resting and contracted thickness and contraction ratio of each muscle were measured in 21 individuals with nonspecific CLBP.ResultsAll US measurements of the lateral abdominal and lumbar multifidus muscles demonstrated good to excellent within-day (Intraclass correlation coefficients (ICCs: 0.80–0.98) and between-day (ICCs: 0.80–0.97) reliability. The standard error of the measurement (SEMs) and minimal detectable change (MDCs) of the lateral abdominal muscles on both sides ranged 0.5–1.6 mm and 0.4–4.4 mm, respectively. The SEMs and MDCs of the LM muscles on both sides ranged 1.1–2.7 mm and 2.86–7.49 mm, respectively.ConclusionThe findings indicate that US imaging has good to high intrarater within- and between-day reliability for assessing absolute thickness and contraction ratio of the trunk muscles on both right and left sides in patients with nonspecific CLBP. The vertical alignment of the US transducer is a reliable method for assessing the lateral abdominal muscles.     

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.Key words: Spinal stability muscles, Position, Forced respiratory maneuvers     

Application of Ultrasonography in the Assessment of Abdominal and Lumbar Trunk Muscle Activity in Participants With and Without Low Back Pain: A Systematic Review

ObjectiveThe purpose of this study was to systematically review the literature regarding which condition (task, position, or contraction type), changes in muscle thickness could be interpreted as muscle activity of trunk muscles.MethodsStudies that assessed the correlation between changes in muscle thickness measured with ultrasonography (US) and electromyography (EMG) activity were included. Only the data related to abdominal and lumbar trunk muscles in participants with or without low back pain were extracted. The PubMed, ScienceDirect, Ovid MEDLINE, Scopus, Springer, and Cumulative Index to Nursing and Allied Health Literature databases were searched from inception to August 2018. Two independent raters appraised the quality of the included studies using the Critical Appraisal Skills Program checklist.ResultsFourteen studies were included. The results revealed significant correlations between US and EMG measures for the lumbar multifidus and erector spinae muscle during most contraction levels and postures. For transverse abdominis and internal oblique, US and EMG measures were correlated during low load abdominal drawing or bracing. The correlations were influenced by trunk position for higher intensities of contraction. For the external oblique muscle, correlation was observed only during trunk rotation.ConclusionChanges in muscle thickness should not be interpreted as muscle activity for all tasks, positions, and contraction types. Only during prime movement tasks performed with isometric contraction could muscle thickness change be considered as muscle activity. Also, upright postures influenced the relationship between changes in muscle thickness and muscle activity for abdominal muscles.     

The Effects of Sling Exercise Using Vibration on Trunk Muscle Activities of Healthy Adults

[Purpose] This study compared the effects of sling exercises with and without vibration on the muscular activity of the internal oblique (IO), rectus abdominis (RA), multifidus (MF), and erector spinae (ES) muscles of healthy adults. [Methods] Eleven healthy university students (11 men) with a mean age of 22.8 years were enrolled in this study. Subjects performed supine and prone bridge exercises with the knees flexed using a sling suspension system with and without vibration. The amplitudes of the EMG activities of selected trunk muscles (internal oblique, rectus abdominis, erector spinae, multifidus) were recorded. Two types of exercise conditions were executed in a random sequence for 5 seconds each. The signals detected from the middle 3 seconds (after discarding the signals of the first and the last one seconds) were used in the analysis. A 3-minute break was given after each exercise to minimize muscle fatigue. [Results] During the supine bridge exercise with vibration, the activities of the IO, RA, MF, and ES muscles were significantly higher than those of the supine bridge exercise without vibration. Additionally, during the prone bridge exercise with vibration, the activities of the IO, RA, MF, and ES were significantly higher than those of the prone bridge exercise without vibration. [Conclusion] Sling exercises with vibration improved the trunk muscle activities of healthy adults compared to the sling exercises without vibration. The information presented here is important for clinicians who use lumbar stabilization exercises as an evaluation tool or a rehabilitation exercise.Key words: Sling exercise, Vibration, Trunk muscle     

Lumbar posture biomechanics and its influence on the functional anatomy of the erector spinae and multifidus

Abstract

Background:

Lumbar posture has a significant impact on the functional biomechanics of the erector spinae and multifidus muscles, which has implications for the loads placed on the tissues of the lumbar spine.

Objectives:

The objective of this review is to discuss the effects of lumbar posture on the functional biomechanics of the different divisions of the erector spinae and the multifidus muscle and its importance when developing clinical interventions.

Methods:

This review used the search engines PubMed, EBSCO, CINAHL and SCOPUS to identify studies investigating erector spinae and multifidus muscle architecture and the influence of lumbar posture on the biomechanical properties of these muscles and the resulting impact on spinal loading.

Results:

Changes in lumbar curvature alter muscle fascicle obliquity, lever arm distances, the length–tension relationships and muscle volume of the different divisions of erector spinae and multifidus, which impact on the spine's ability to resist moments and shear forces.

Conclusion:

Changes in lumbar posture influence the functional biomechanics of the different divisions of erector spinae and the multifidus muscles. Therapists should develop low back interventions that avoid end range of lumbar postures and optimise the functional biomechanics of the erector spinae and multifidus muscles and minimise loading on the lumbar spine.     

Effects of slouching and muscle contraction on the strain of the iliolumbar ligament

The study consisted of biomechanical modelling and in vitro experiments. The objective of the study was to find a mechanical cause of acute low back pain (LBP) in everyday situations. The precise mechanism producing LBP is still under discussion. Most biomechanical studies link the concepts of stooped postures and buckling instability of the spine under high compressive load. No biomechanical model addresses situations with small or neglectable compressive spinal load. The proposed conceptual model describes strain on the iliolumbar ligaments (ILs) when slouching from standing upright. Delayed or absent recruitment of back muscles that protect against hyperkyphosis of the lumbar spine is a conditional factor. Erector spinae and multifidus muscle forces are included, representing a bifurcation in back muscle force: one part acting on the iliac bones and one part acting on the sacrum. The multifidus muscle action on the sacrum may produce nutation which can be counteracted by pelvic floor muscles, which would link back problems and pelvic floor problems. The effect of simulated muscle tension on the ILs and the L5-S1 intervertebral disc angle was measured using embalmed specimens. Forces were applied to simulate erector spinae and sacral part of multifidus tension, bilateral up to 100 N each. Strain gauge sensors registered elongation of the ILs. Explorative biomechanical model calculations show that dynamic slouching, driven by upper body weight and (as an example) rectus abdominis muscle force may produce failure load of the spinal column and the ILs. The quasi-static test on embalmed specimens showed a significant increase of IL elongation with simulated rectus abdominis muscle force. Adding erector spinae or multifidus muscle tension eased the ILs. Sudden slouching of the upright trunk may create failure risk for the spine and ILs. This loading mode may be prevented by controlling loss of lumbar lordosis with erector spinae and multifidus muscle force.     

What is a Suitable Pressure for the Abdominal Drawing-in Maneuver in the Supine Position Using a Pressure Biofeedback Unit?

[Purpose] The aim of this study was to determine the appropriate pressure variation for performing a successful abdominal drawing-in maneuver (ADIM). The abdominal muscle thickness variations and contraction ratios were examined in relation to pressure variations using a Pressure Biofeedback Unit (PBU) during an ADIM in the supine position. [Methods] The PBU was placed identically between the lumbar lordosis of 20 healthy subjects (12 males and 8 females) and the pressure of the PBU was maintained at 40 mmHg. Then, while the subjects performed ADIM at four random pressure variations (0, 2, 4, or 6 mmHg), the thicknesses of the transversus abdominis (TrA), the internal oblique abdominal muscle (IO), and the external oblique abdominal muscle (EO) were measured using ultrasonography. [Results] Pressure increases of 0–2 mmHg resulted in significant decreases in IO and EO thicknesses compared to pressure increases of 6 mmHg. Increases of 0–2 mmHg also resulted in significant decreases in IO+EO and EO contraction ratios compared to pressure increases of 6 mmHg, while the preferential activation ratio of the TrA was significantly increased. [Conclusion] Compared to the other pressure increases, an increase of 0–2 mmHg effectively regulated the thicknesses and contraction ratios of superficial muscles such as IO and EO, rather than the thickness and contraction ratio of the TrA, showing high and indirect preferential activation ratios for TrA. Therefore, for successful ADIM, rather than using large PBU pressure increases, exercises that promote slight increases of around 0–2 mmHg from a baseline of 40 mmHg are desirable.Key words: Pressure biofeedback unit, Abdominal drawing-in maneuver, Pressure variation     

Normative parameters and anthropometric variability of lumbar muscle stiffness using ultrasound shear-wave elastography

BackgroundQuantifying stiffness of the lumbar spine musculature using shear-wave elastography (SWE) maybe beneficial in the diagnosis and treatment of non-specific low back pain (LBP). The primary purpose of this study was to establish normative parameter and variance estimates of lumbar spine muscle stiffness at rest and during submaximal contraction levels using SWE in healthy individuals. A second aim was to determine the relationship between lumbar spine muscle stiffness and a variety of demographic, anthropometric, and medical history variables.MethodsThis cross-sectional study included stiffness measurements of the lumbar musculature in 120 asymptomatic individuals using ultrasound SWE. The lumbar erector spinae muscle was measured during rest only and lumbar multifidus muscle was measured during rest and during submaximal contraction using a prone contralateral arm lift. Statistical comparisons of shear modulus were made between sex (male vs. female) and muscle condition (erector spinae rest, lumbar multifidus rest, lumbar multifidus contracted) using 2 × 3 repeated measures analysis of variance (ANOVA). Univariate associations between shear modulus and age, sex, BMI, activity level, and history of back pain were assessed using correlation analysis.FindingsShear modulus at rest was approximately 4 kPa for the erector spinae muscles and approximately 6 kPa for the lumbar multifidus muscles. Shear modulus substantially increased during contraction, and varied by sex, BMI, and self-reported activity level, with men and more active individuals generally having stiffer muscles.InterpretationVariability in shear modulus of the lumbar musculature may be mediated through a combination of muscle size and contractile state, which is consistent with our findings of higher stiffness in the more postural lumbar multifidi muscles, during contraction, and in larger and more active individuals. These findings should inform and be accounted for in future comparative clinical studies.     

Intrarater Reliability of Shear Wave Elastography for the Quantification of Lateral Abdominal Muscle Elasticity in Idiopathic Scoliosis Patients

ObjectiveTo date, studies evaluating the reliability of shear wave elastography (SWE) measures of the lateral abdominal muscles (LAMs) in adolescent patients with idiopathic scoliosis (AIS) have never been performed. The aim of the study was to assess the intrarater reliability of SWE and thickness of the LAMs at rest and during isometric contraction (10% of maximal voluntary contraction).MethodsThis was a single-group, repeated-measures intrarater reliability study. Twenty-four patients with AIS between ages 10 and 17 years took part in the study. Two and 3 repeated SWE measurements were recorded in the supine resting position and during isometric contraction, respectively. Two sessions were performed with a 7-day interval.ResultsBy using the mean of 2 measures in the supine, resting position, intraexaminer reliability point estimates (intraclass correlation coefficient [ICC]_3.2) ranged from 0.75 to 0.84 for external oblique, internal oblique, and transversus abdominis muscles. During the isometric contraction, the ICC_3.3 results ranged from 0.70 to 0.83. The ICC results for muscle thicknesses in both conditions ranged from 0.89 to 0.96.ConclusionMeasurements of LAM elasticity are reliable in patients with AIS. The superficial fat layer did not influence the measurement error between 2 sets of measurements in the examined adolescent population. The images extracted from SWE can successfully be used to assess LAM thicknesses with high reliability.     

The lumbar multifidus: does the evidence support clinical beliefs?

The contribution of the trunk muscles to spinal stability is well established. There is convincing evidence for the role of multifidus in spinal stability. Recently, emphasis has shifted to the deep fibres of this muscle (DM) and five key clinical beliefs have arisen: (i) that DM stabilizes the lumbar spine whereas the superficial fibres of lumbar multifidus (SM) and the erector spinae (ES) extend and/or rotate the lumbar spine, (ii) that DM has a greater percentage of type I (slow twitch) muscle fibres than SM and ES, (iii) that DM is tonically active during movements of the trunk and gait, whereas SM and ES are phasically active, (iv) that DM and the transversus abdominis (TrA) co-contract during function, and (v) that changes in the lumbar paraspinal muscles associated with LBP affect DM more than SM or ES. This paper reviews the biomechanical, electromyographic, histochemical and morphological data that underpin these beliefs. Although there is support for the importance of the lumbar multifidus and the specific contribution of this muscle to intervertebral control, several of the clinical beliefs have little or no support and require further evaluation. These findings have implications for clinical practice.     

Comparison of Abdominal Muscle Thickness with Vaginal Pressure Changes in Healthy Women

[Purpose] The purpose of this study was to verify the efficacy of a pelvic floor muscle exercise program by comparing subjects’ muscle thickness with changes in vaginal pressure. [Subjects] Two groups of female participants without a medical history of pelvic floor muscle dysfunction were evaluated. The mean age of Group I was 33.5 years and that of Group II was 49.69 years. [Methods] The participants were instructed to perform a pelvic floor muscle contraction. While measuring the vaginal pressure of the pelvic floor muscle, biofeedback was given on five levels, and the thicknesses of the transversus abdominis, external oblique, and internal oblique muscles were measured with ultrasound. [Results] The thickness of the transversus abdominis muscle was significantly increased at 30 cmH₂O in Group I, and at 20 cmH₂O in Group II. The thickness of the internal oblique abdominal muscle significantly increased at maximum contraction in Group II. [Conclusion] Different abdominal muscles contracted depending on vaginal pressure. The result may be used to create and implement an exercise program that effectively strengthens the pelvic floor muscles.Key words: Pelvic floor muscle contraction, Vaginal pressure, Abdominis muscle     

A Comparison of Flexi-bar and General Lumbar Stabilizing Exercise Effects on Muscle Activity and Fatigue

[Purpose] The objective of this study was to compare the effects of flexi-bar training and general lumbar stabilization training on muscle activity and fatigue. [Methods] Twenty normal persons participated in this study. After warm up and a Maximum Voluntary Isomeric Contraction (MVIC) test, participants performed bridging exercise, quadruped lumbar stabilization exercise on quadruped and curl-up, with and without the flexi-bar training, each exercise lasting for 30 seconds. Electromyography was used for the assessment of the muscle activity and fatigue of the rectus abdominis, erector spinae, external oblique and internal oblique muscles. [Results] The bridging and quadruped exercises with the flexi-bar elicited significant increases in the muscle activates of the muscle groups. The curl-up exercise with the flexi-bar showed significant differences in external oblique and internal oblique muscle activities compared to the exercise without the flexi-bar. Muscle fatigue showed different results depending on the exercise. [Conclusion] Generally, flexi-bar exercise induced greater muscle activation and fatigue. However, because there were differences of effect dependent on the posture, we should prescribe the appropriate exercise for the target muscles.Key Words: Flexi-bar, Trunk stability, Vibration training     

Relationship between paraspinal muscle cross-sectional area and relative proprioceptive weighting ratio of older persons with lumbar spondylosis

[Purpose] The purpose of this study was to examine the relationship between the paraspinal muscle cross-sectional area and the relative proprioceptive weighting ratio during local vibratory stimulation of older persons with lumbar spondylosis in an upright position. [Subjects] In all, 74 older persons hospitalized for lumbar spondylosis were included. [Methods] We measured the relative proprioceptive weighting ratio of postural sway using a Wii board while vibratory stimulations of 30, 60, or 240 Hz were applied to the subjects’ paraspinal or gastrocnemius muscles. Back strength, abdominal muscle strength, and erector spinae muscle (L1/L2, L4/L5) and lumbar multifidus (L1/L2, L4/L5) cross-sectional areas were evaluated. [Results] The erector spinae muscle (L1/L2) cross-sectional area was associated with the relative proprioceptive weighting ratio during 60Hz stimulation. [Conclusion] These findings show that the relative proprioceptive weighting ratio compared to the erector spinae muscle (L1/L2) cross-sectional area under 60Hz proprioceptive stimulation might be a good indicator of trunk proprioceptive sensitivity.Key words: Relative proprioceptive weighting ratio, Erector spinae muscle cross-sectional area, Older persons with lumbar spondylosis     

Effects of abdominal belts on intra-abdominal pressure, intra-muscular pressure in the erector spinae muscles and myoelectrical activities of trunk muscles

OBJECTIVE: To evaluate the effects of abdominal belts on lifting performance, muscle activation, intra-abdominal pressure and intra-muscular pressure of the erector spinae muscles. DESIGN: Simultaneous measurement of intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles was performed during the Valsalva maneuver and some isometric lift exertions. BACKGROUND: While several hypotheses have been suggested regarding the biomechanics of belts and performance has been found to increase when lifting with belts, very little is known about the modulating effects on trunk stiffness. At present, there is no reason to believe that spine tolerance to loads increases with belts. METHODS: An abdominal belt designed for weightlifting was used. Intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and myoelectric activities of trunk muscles (erector spinae, rectus abdominis and external oblique) were measured simultaneously during the Valsalva maneuver as well as three types of isometric lifting exertions (arm, leg and torso lift). A paired t-test was used to analyze for statistical differences between the two conditions (without-belt and with-belt) in intra-abdominal pressure, intra-muscular pressure of the erector spinae muscles and in the integrated EMG of the trunk muscles. RESULTS: Intra-muscular pressure of the erector spinae muscles increased significantly by wearing the abdominal belt during Valsalva maneuvers and during maximum isometric lifting exertions, while maximum isometric lifting capacity and peak intra-abdominal pressure were not affected. Integrated EMG of rectus abdominis increased significantly by wearing the abdominal belt during Valsalva maneuvers (after full inspiration) and during isometric leg lifting. CONCLUSIONS: Wearing abdominal belts raises intra-muscular pressure of the erector spinae muscles and appears to stiffen the trunk. Assuming that increased intra-muscular pressure of the erector spinae muscles stabilizes the lumbar spine, wearing abdominal belts may contribute to the stabilization during lifting exertions.     

An Investigation of the Association between Transversus Abdominis Myofascial Structure and Activation with Age in Healthy Adults using Ultrasound Imaging

BackgroundBecause of their importance in core stability, training the deep abdominal muscles, fascial structures and particularly the transversus abdominis, is a key component of many sport and physical therapy programs. However, there are gaps in knowledge about age-related changes in the structure and activation capacity of these muscles.Hypothesis/PurposeThis study investigated the association between deep abdominal muscles and fascial structures and transversus abdominis activation with age in healthy adults.Study designA cross-sectional study.MethodsEighty-six adults aged 18 to 77 participated in this study. An ultrasound image of their transversus abdominis, internal oblique, external oblique and associated fasciae was first captured at rest, then during a contraction of the transversus abdominis. Bivariate correlation analyses and hierarchical analyses were performed (significance level: p < 0.05).ResultsThe thickness of these three muscles decreases with age (ρ = -0.66 for external oblique, -0.51 for internal oblique and -0.58 for transversus abdominis), whereas the thickness of their fasciae increases (ρ = 0.39 for the fascia of external oblique, 0.54 for the fascia between internal oblique and external oblique, and 0.74 for the fascia between internal oblique and transversus abdominis). Transversus abdominis activation decreases with age (r =-0.44). Age accounts for 19.5% of the variance in transversus abdominis activation.ConclusionThese results demonstrate that normal aging is associated with changes in deep abdominal myofascial structures and transversus abdominis activation. Assessment of these metrics can provide valuable baseline information for physical therapists involved in rehabilitation and strengthening programs targeting older individuals.Level of evidenceLevel 2     

Effect of abduction and external rotation of the hip joint on muscle onset time during prone hip extension with knee flexion

[Purpose] This study investigated the effect of hip position on muscle onset time during prone hip extension with knee flexion. [Subjects] The study included 21 healthy male volunteers. [Methods] Muscle onset times of the right gluteus maximus, right hamstrings, bilateral lumbar erector spinae, and bilateral lumbar multifidus were measured using surface electromyography during right hip extension with knee flexion in the prone position. Measurements were made with the hip in 3 positions: (1) neutral, (2) abduction, and (3) abduction and external rotation. [Results] Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and with hip abduction and external rotation compared with that with the hip in the neutral position. Gluteus maximus onset relative to the hamstrings was significantly earlier with hip abduction and external rotation compared with that with hip abduction. The bilateral multifidus and left lumbar erector spinae onset times relative to the hamstrings were significantly earlier with hip abduction and external rotation compared with those with hip abduction and with the hip in the neutral position. [Conclusion] Abduction and external rotation of the hip during prone hip extension with knee flexion is effective for advancing the onset times of the gluteus maximus, bilateral multifidus, and contralateral lumbar erector spinae.Key words: Prone hip extension with knee flexion, Hip joint position, Muscle onset time     

Comparative analysis of trunk muscle activities in climbing of during upright climbing at different inclination angles

[Purpose] This study was performed to provide evidence for the therapeutic exercise approach through a compative analysis of muscle activities according to climbing wall inclination. [Subjects and Methods] Twentyfour healthy adult subjects without climbing experience performed static exercises at a therapeutic climbing at with various inclination angles (0°, 10°, 20°), and the activities of the trunk muscles (rectus abdominis, obliquus externus abdominis, obliquus internus abdominis, erector spinae) were measured using surface electromyography (EMG) for 7 seconds. [Results] Significant differences were found between the inclination angles of 10° and 0°, as well as 20° in the rectus abdominis, obliquus internus abdominis, right obliquus externus abdominis, and right erector spinae. [Conclusion] Based on measurements of trunk muscle activity in a static climbing standing position at different angles, significant changes in muscle activity appear to be induced at 10 degrees. Therefore, the results appear to provide clinically relevant evidence.Key words: Climbing, Trunk muscle activity