Transversus abdominis and the superficial abdominal muscles are controlled independently in a postural task

Relationship between respiratory muscle strength and dynamic balance in older persons requiring care or support: Focusing on the maximal single step length test and maximal double step length test as dynamic balance indices

BACKGROUND

Falls are a major health problem. The relationship between dynamic balance related to falls and respiratory muscle strength related to sarcopenia and frailty is poorly understood.

RESEARCH QUESTION

How do dynamic balance measures, such as maximal single step length test (MSL) and maximal double step length test (MDST), and respiratory muscle strength measures, such as maximal inspiratory (PImax) and maximal expiratory (PEmax), related to the requirement for long-term care or support in older people who live in the community?

METHODS

This was a cross-sectional study of 39 older people (17 men, 22 women) aged ≥ 65 years community-dwelling who were certified as requiring long-term care or support under the Japanese system. The participants' PImax, PEmax, MSL, and MDST results were recorded. The measurement data were evaluated using Pearson's correlation coefficients and multiple regression analysis.

RESULTS

MDST showed a positive correlation with PImax (r = 0.430, p = 0.006) but no correlation with PEmax. MSL showed no correlation with PImax or PEmax. A positive correlation was found between MDST and MSL (r = 0.851, p < 0.001), and multiple regression analysis with MDST as the dependent variable and PImax and MST as independent variables showed significant differences for MSL (p < 0.001) and PImax (p = 0.027).

SIGNIFICANCE

In older people requiring long-term care or support, MDST had a greater association with inspiratory muscle strength compared with MSL. These results suggest the importance of inspiratory muscle strength training and MDST assessment in the prevention of falls in older people requiring long-term care or support.

Relationship between walking speed, respiratory muscle strength, and dynamic balance in community-dwelling older people who required long-term care or support and used a daycare center

Background

Focusing on the relationship between frail older people and gait speed is vital to minimize the need for long-term care or increased support. The relationship between gait speed, respiratory muscle strength, and dynamic balance, is not well understood in older people requiring long-term care or support. Therefore, this study aimed to provide new insights into the relationship between gait speed, respiratory muscle strength, and dynamic balance in community-dwelling older people who required long-term care or support and used a daycare center.

Methods

This was a cross-sectional study of 49 community-dwelling older people (21 men, 28 women) aged ≥65 years who were certified as requiring long-term care or support under the Japanese system. The participants' maximal inspiratory pressure (PImax), maximal expiratory pressure (PEmax), walking speed (maximal and normal walking speed), and maximal double-step length test (MDST) results were recorded. The measurement data were evaluated using Pearson's correlation coefficient and multiple regression analysis.

Results

Pearson's correlation coefficient revealed correlations between PImax and the following: maximal walking speed (r = 0.606, p < 0.001), normal walking speed (r = 0.487, p < 0.001), and MDST (r = 0.435, p = 0.002). Correlations were also observed between PEmax and the following: maximal walking speed (r = 0.522, p < 0.001), normal walking speed (r = 0.467, p < 0.001), and MDST (r = 0.314, p = 0.028). Moreover, a correlation was found between MDST and both maximal walking speed and (r = 0.684, p < 0.001) and normal walking speed (r = 0.649, p < 0.001). The effect size was 0.379. Multiple regression analysis using a forced entry method with maximal walking speed as the dependent variable showed that maximal walking speed was significantly associated with MDST (p < 0.001) and PEmax (p = 0.036), with an effect size of 0.272. The model's adjusted coefficient of determination was 0.593 (p < 0.001). Multiple regression analysis using a forced entry method with normal walking speed as the dependent variable showed that normal walking speed was significantly associated with MDST (p < 0.001) and PEmax (p = 0.021), with an effect size of 0.272. The model's adjusted coefficient of determination was 0.497 (p < 0.001). Multiple regression analysis using a forced entry method with MDST as the dependent variable showed that MDST was significantly associated with PImax (p < 0.025), with an effect size of 0.243. The model's adjusted coefficient of determination was 0.148 (p = 0.017).

Conclusions

Respiratory muscle strength and dynamic balance were related to walking speed in older people requiring long-term care or support.

Effect of strengthening and weakening of abdominal and dorsal muscles on lumbar spine loads in parents of disabled children

Pain in the lower part of the back is one of the most common chronic illnesses globally. This work aimed to determine the impact of the reinforcement of particular groups of abdominal and dorsal muscles on the loads exerted on the lumbar section of the spine in 30 mothers of children with motor disabilities. An optical Ariel Performance Analysis System recorded and processed the kinematics data of everyday activities. Tests investigating the effects of the strengthening or weakening of abdominal and dorsal muscles on loading in the lumbar section of the spine utilized the AnyBody Modelling System. Input data for the simulations included mean values of body positions, while the effects of strengthening or weakening of muscles were simulated in the muscle forces model by introducing different values for muscle physiological cross-sectional area (PCSA). Simulations used decreasing or increasing PCSA values of abdominal muscles and the erector spinae. The analysis involved component and resultant force values on the lumbosacral joint (L5-S1) of the spine and intra-abdominal pressure values. The highest reduction of the resultant reaction value in L5-S1 was observed in the simulations that increased the PCSA of the transverse abdominal (TrA). Indeed, a double increase in the TrA cross-section caused a reduction of the resultant reaction in L5-S1 by 30% and the anterior-posterior and proximal-distal forces by approximately 20-30%. Increased PCSA of the erector spinae exerted higher loads on the spine. These results indicate that strengthening weakened abdominal muscles, particularly TrA, in parents of children with motor disabilities reduces lower spinal loads during daily activities.

Motion Analysis of Core Stabilization Exercise in Women: Kinematics and Electromyographic Analysis

As core stabilization exercise is essential for maintaining a stable spine and improving functional performance, understanding the activation of core muscles and the stabilization of the trunk and pelvis during such exercise is crucial. The purpose of this study was to investigate the muscle activation and stabilization of the lumbar–pelvic region during core stabilization exercise, with a specific focus on analyzing EMG and 3D motion kinematic data. The study aimed to understand how different tension settings on the reformer affect muscle activation and hip motion, as well as how these factors impact pelvic and trunk stability during the exercise. The reformer consists of a carriage that slides back and forth on rails, with springs providing resistance. The springs can be adjusted to vary the resistance level. Twenty-eight healthy women participating in this study were asked to perform ‘side splits’, a hip abduction exercise, on the reformer in both heavy and light tension settings. Activation of the internal oblique (IO), rectus abdominis (RA), multifidus (MU), costal lumbosacral (IL), gluteus medius (GM), and adductor muscles (AL) were measured using electromyography (EMG) and 3D motion. Kinematic data using an assay were also measured during exercise. GM, IO, and MU muscles were more active when heavy springs were used, and AL muscles were more active when light springs were used. Hip motion was more symmetrical when lighter springs were used with a greater range of hip motion. There was less pelvis and torso weight transfer and more torso and pelvis stability when the heavier springs were used. In this study, we confirmed that core stabilization exercise on an unstable surface activates the deep muscles of the abdomen and back and is effective for pelvic and trunk stabilization training.

Reliability of high-density surface electromyography for assessing characteristics of the thoracic erector spinae during static and dynamic tasks

PURPOSE

To establish intra- and inter-session reliability of high-density surface electromyography (HDEMG)-derived parameters from the thoracic erector spinae (ES) during static and dynamic goal-directed voluntary movements of the trunk, and during functional reaching tasks.

METHODS

Twenty participants performed: 1) static trunk extension, 2) dynamic trunk forward and lateral flexion, and 3) multidirectional functional reaching tasks on two occasions separated by 7.5 ± 1.2 days. Muscle activity was recorded bilaterally from the thoracic ES. Root mean square (RMS), coordinates of the barycentre, mean frequency (MNF), and entropy were derived from the HDEMG signals. Reliability was determined with intraclass correlation coefficient (ICC), coefficient of variation, and standard error of measurement.

RESULTS

Good-to-excellent intra-session reliability was found for all parameters and tasks (ICC: 0.79-0.99), whereas inter-session reliability varied across tasks. Static tasks demonstrated higher reliability in most parameters compared to functional and dynamic tasks. Absolute RMS and MNF showed the highest overall reliability across tasks (ICC: 0.66-0.98), while reliability of the barycentre was influenced by the direction of the movements.

CONCLUSION

RMS and MNF derived from HDEMG show consistent inter-session reliability in goal-directed voluntary movements of the trunk and reaching tasks, whereas the measures of the barycentre and entropy demonstrate task-dependent reliability.

Core Synergies Measured with Ultrasound in Subjects with Chronic Non-Specific Low Back Pain and Healthy Subjects: A Systematic Review

Low back pain represents the leading cause of disability since 1990. In 90% of cases, it is classified as non-specific low back pain, being chronic in 10% of subjects. Ultrasound has proven to be an effective measurement tool to observe changes in the activity and morphology of the abdominal muscles. This article reviews which core synergies are studied with ultrasound in healthy subjects and with chronic non-specific low back pain. A systematic review was conducted on studies analyzing synergies between two or more core muscles. Publications from 2005 until July 2021 were identified by performing structured searched in Pubmed/MEDLINE, PEDro and WOS. Fifteen studies were eligible for the final systematic review. A total of 56% of the studies established synergies between the core muscles and 44% between the homo and contralateral sides of the core muscles. The most studied core synergies were transversus abdominis, internal oblique and external oblique followed by the rectus abdominis and the lumbar multifidus. No studies establishing synergies with diaphragm and pelvic floor were found. Eight studies were conducted in healthy subjects, five studies in subjects with chronic non-specific low back pain compared to healthy subjects and two studies in subjects with chronic non-specific low back pain.

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

BACKGROUND

Because 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/PURPOSE

This study investigated the association between deep abdominal muscles and fascial structures and transversus abdominis activation with age in healthy adults.

STUDY DESIGN

A cross-sectional study.

METHODS

Eighty-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).

RESULTS

The 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.

CONCLUSION

These 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 EVIDENCE

Level 2.

Effect of resistance exercises applying maximum expiration on the respiratory muscle strength of elderly women

BACKGROUND

Respiratory-muscle weakness is an important clinical problem. The respiratory system's health is a decisive factor in the physical and social life of the elderly. Changes in respiratory muscular strength and function activate the torso's adjustment ability, which affects daily activities.

OBJECTIVE

This study aimed to investigate the effects of resistance exercises combined with breathing exercises on the respiratory-muscle strength of elderly women.

METHOD

This study included 26 elderly woman, who were randomly divided into two sub-groups of 13 participants each. The experimental group performed breathing exercises and dynamic upper- and lower-extremity exercises, and the control group practiced only dynamic upper- and lower-extremity exercises. The maximum expiratory pressure (MEP) and maximum inspiratory pressure (MIP) were measured both before and at the end of the six-week study.

RESULTS

In both groups, both the post-test MIPs and MEPs were significantly higher than the pre-intervention ones (p< 0.05). For MIPs, the between-group difference was not statistically significant, either before the intervention or post-test (p> 0.05). For MEPs, the between-group difference was statistically significant at post-intervention points (p< 0.05).

CONCLUSION

The results showed that resistance exercises applying maximum expiration improved the respiratory-muscle strength of elderly women. These findings indicate that resistance exercises applying maximum expiration as described here in should be considered in patients who require breathing therapy, because the combination seems to significantly increase the strength of the respiratory muscles.

Interventional benefit of Pilates using Oov and mat on middle-aged women with lower urinary tract symptoms: emphasis on abdominal muscle thickness and muscular function

Lower urinary tract symptoms (LUTS) have been considered as clinically prevalent symptom in women, and can be ameliorated by the change of abdominal muscles and pelvic floor muscle (PFM). This study investigated the efficacy of Pilates program using Oov and mat on the change of abdominal muscle thickness, PFM function, and LUTS clinical score. 53 women experiencing LUTS were randomly assigned to Oov Pilates exercise group (OPEG) (n=20), mat Pilates exercise group (MPEG) (n= 16), and symptomatic control group (SCG) (n=17), respectively, and two groups using Oov and mat participated in 8-week Pilates program. Thickness of abdominal muscle, functional movement of PFM, and LUTS clinical score were measured from all groups. Thickness of rectus abdominis, internal oblique abdominis, transversus abdominis was significantly improved in OPEG (P<0.05), however, MPEG showed a significant change only in transversus abdominis (P<0.05). In all abdominal muscles, OPEG had a significantly improved abdominal muscle thickness compared to SCG (P<0.05). Functional movement of PFM in OPEG was significantly decreased (P<0.005), but not in MPEG and SCG. In LUTS clinical score, OPEG and MPEG showed a significantly abated symptoms in degree of voiding-related symptoms and discomfort (P<0.005), but not in SCG. Our study highlighted that Pilates using Oov can be an effective intervention to ameliorate the quantitative quality of abdominal muscle thickness and PFM, which ultimately provides the satisfied self-clinical index in degree of voiding-related symptoms and discomfort.

Liuzijue qigong versus traditional breathing training for patients with post-stroke dysarthria complicated by abnormal respiratory control: Results of a single-center randomized controlled trial

Objective:

The aim of the study was to investigate whether liuzijue qigong could improve the ability of respiratory control and comprehensive speech in patients with stroke dysarthria.

Design:

A randomized controlled trial.

Setting:

The research was carried out in the department of rehabilitation.

Participants:

Altogether, a total of 98 stroke patients with dysarthria participated in the study.

Interventions:

Patients were randomly divided into two groups (the experimental group: basic articulation + liuzijue qigong, 48 patients or the control group: basic articulation + traditional breathing training, 50 patients). All therapies were conducted once a day, five times a week for three weeks.

Main measures:

Primary outcome measure: Speech breathing level of the modified Frenchay Dysarthria Assessment. Secondary outcome measures: the modified Frenchay Dysarthria Assessment, maximum phonation time, maximal counting ability, /s/, /z/, s/z ratio, and the loudness level. All outcome measures were assessed twice (at baseline and after three weeks).

Results:

At three weeks, There were significant difference between the two groups in the change of speech breathing level (81% vs 66%, P = 0.011), the modified Frenchay Dysarthria Assessment (5.54 (4.68–6.40) vs 3.66 (2.92–4.40), P = 0.001), maximum phonation time (5.55 (4.92–6.18) vs 3.01(2.31–3.71), P < 0.01), maximal counting ability (3.08(2.45–3.71) vs 2.10 (1.53–2.67), P = 0.018), and /s/ (3.08 (2.39–3.78) vs 1.87 (1.23–2.51), P = 0.004), while no significant differences were found in the change of /z/ (3.08 (2.31–3.86) vs 2.10 (1.5–2.64), P = 0.08), s/z ratio (1.26 (0.96–1.55) vs 1.03 (0.97–1.09), P = 0.714), and the change of loudness level (69% vs 60%, P = 0.562).

Conclusions:

Liuzijue qigong, combined with basic articulation training, could improve the respiratory control ability, as well as the comprehensive speech ability of stroke patients with dysarthria.

Trial registration:

ChiCTR-INR-16010215.

Experimentally induced low back pain influences brain networks activity

Purpose of this study was to answer the question whether the recognized patterns of brain activity are likely to change under the influence of experimentally induced low back pain (LBP), and also to determine the functional networks of the brain engaged in this process. Twenty healthy subjects (8 women) participated. An experimental design was applied with repeated measurements of the blood oxygen level-dependent (BOLD) signal from the brain during two different voluntary contractions of the abdominal muscles without and with experimentally induced LBP. Brain areas showing significant differences in activity were identified and ascribed to the three functional neuronal brain networks: default mode network (DMN), pain matrix (PM), and sensorimotor (SM) areas. After implementation of the experimental painful stimulus the overall level of brain activity appears to be higher. No higher brain deactivations are seen in painful conditions and no higher activations in pain-free conditions. During isolated-type of muscular contraction a slight tendency to DMN deactivation may be observed.

Differences in Activity of the Brain Networks During Voluntary Motor Tasks Engaging the Local and Global Muscular Systems of the Lower Trunk

Low back pain constitutes a multidimensional problem of largely unknown origin. One of the recent theories explaining its frequent occurrence includes speculative statements on patterns of central nervous system activity associated with the control of so-called local and global muscles of the lower trunk. The objective of the study was to verify whether there is a difference in the activity of the brain during selective, voluntary contraction of the local and global abdominal muscles as assessed by functional MRI. Twenty healthy subjects participated. An experimental design was applied with repeated measurements of the blood-oxygen-level-dependent signal from the brain during voluntary contraction of the local and global abdominal muscles, performed in random order. Prior to registration, a 2-week training period was introduced, aiming to master the experimental motor tasks. The magnetic resonance imaging (MRI) data were processed using the FMRIB Software Library (Oxford, UK). Brain areas showing significant activations/deactivations were identified and averaged across all participants, and intercondition differential maps were computed. Areas of significant intercondition differences were linked to the corresponding anatomical structures and ascribed to the default mode functional brain network and to the sensorimotor network. Contraction of the local abdominal muscles elicited more pronounced activity of the brain cortex, basal ganglia, and cerebellum. This suggests that motor control of the abdominal musculature consists of two modes of brain activity and that control of the local muscles may be a more challenging task for the brain. Moreover, contraction of the local muscles elicited more distinct deactivation of the default mode network, which may have implications for diagnostics and therapy of low back pain.

Feedforward activation of the quadratus lumborum during rapid shoulder joint abduction

This study aimed to clarify the difference in the onset of EMG activity between eight trunk muscles, including the anterior (QL-a) and posterior (QL-p) layers of the quadratus lumborum during rapid shoulder joint abduction. Thirteen healthy men participated in this study. Electromyography of the QL-a, QL-p, transversus abdominis (TrA), internal oblique (IO), external oblique (EO), rectus abdominis (RA), lumbar multifidus (LMF), lumbar erector spinae (LES) on non-movement side, and middle deltoid (MD) on the movement side were measured. Subjects who were standing in a relaxed position performed rapid shoulder abduction with the dominant hand after light stimulus with or without a 3 kg wrist weight. Two-way ANOVA (muscles × weight conditions) was used to compare the onset of trunk muscles relative to that of MD. There was a significant main effect of the muscles. The onset of the QL-a, QL-p, and TrA was significantly earlier than that of the IO, EO, LMF, and LES (P < 0.01). This result suggests that the activities of the QL-a, QL-p, and TrA have a crucial role in controlling the center of mass within the base of support and stabilizing the lumbar spine in the coronal plane during shoulder abduction.

Role of Ultrasound in Low Back Pain: A Review

Low back pain is one of most common musculoskeletal disorders around the world. One major problem clinicians face is the lack of objective assessment modalities. Computed tomography and magnetic resonance imaging are commonly utilized but are unable to clearly distinguish patients with low back pain from healthy patients with respect to abnormalities. The reason may be the anisotropic nature of muscles, which is altered in function, and the scans provide only structural assessment. In view of this, ultrasound may be helpful in understanding the disease as it is performed in real-time and comprises different modes that measure thickness, blood flow and stiffness. By the use of ultrasound, patients with low back pain have been found to differ from healthy patients with respect to the thickness and stiffness of the transversus abdominis, thoracolumbar fascia and multifidus. The study results are currently still not conclusive, and further study is necessary to validate. Future work should focus on quantitative assessment of these tissues to provide textural, structural, hemodynamic and mechanical studies of low back pain. This review highlights the current understanding of how medical ultrasound has been used for diagnosis and study of low back pain and discusses potential new applications.

The Effects of Instruction Manipulation on Motor Performance Following Action Observation

The effects of action observation (AO) on motor performance can be modulated by instruction. The effects of two top-down aspects of the instruction on motor performance have not been fully resolved: those related to attention to the observed task and the incorporation of motor imagery (MI) during AO. In addition, the immediate vs. 24-h retention test effects of those instruction’s aspects are yet to be elucidated. Forty-eight healthy subjects were randomly instructed to: (1) observe reaching movement (RM) sequences toward five lighted units with the intention of reproducing the same sequence as fast and as accurate as possible (Intentional + Attentional group; AO+At); (2) observe the RMs sequence with the intention of reproducing the same sequence as fast and as accurate as possible and simultaneously to the observation to imagine performing the RMs (Intentional + attentional + MI group; AO+At+MI); and (3) observe the RMs sequence (Passive AO group). Subjects’ performance was tested before and immediately after the AO and retested after 24 h. During each of the pretest, posttest, and retest, the subject performed RMs toward the units that were activated in the same order as the observed sequence. Occasionally, the sequence order was changed by beginning the sequence with a different activated unit. The outcome measures were: averaged response time of the RMs during the sequences, difference between the response time of the unexpected and expected RMs and percent of failures to reach the target within 1 s. The averaged response time and the difference between the response time of the unexpected and expected RMs were improved in all groups at posttest compared to pretest, regardless of instruction. Averaged response time was improved in the retest compared to the posttest only in the Passive AO group. The percent of failures across groups was higher in pretest compared to retest. Our findings suggest that manipulating top-down aspects of instruction by adding attention and MI to AO in an RM sequence task does not improve subsequent performance more than passive observation. Off-line learning of the sequence in the retention test was improved in comparison to posttest following passive observation only.

Effects of elastic band resistance exercises with breathing techniques on pulmonary function in female seniors

The purpose of this study was to investigate the effects of elastic-band resistance exercises combined with breathing techniques on pulmonary function in female seniors. Forty-five female seniors 65 years or older were recruited from a welfare center and assigned to an experimental (n=23) or control (n=22) group. The experimental group used an elastic band with a resistance exercises while concurrently using specific breathing techniques. The control group conducted the same resistance tasks without the respiration exercises. Respiratory function data were collected before and after the 6-week intervention. The experimental group showed a significant increase in forced vital capacity (FVC), forced expiratory volume 1 sec (FEV₁), and in FEV₁ as a percentage of FVC. In addition, there were significant differences in the FVC and FEV₁ levels between groups. The results show that resistance accompanied by breathing techniques positively affects senior respiratory function when an elastic band is used for exercise.

Is Pelvic Floor Dysfunction Associated With Development of Transient Low Back Pain During Prolonged Standing? A Protocol

Background

Prolonged standing has been associated with an increased prevalence of low back pain (LBP) and is recognized as a potential workplace hazard for employees such as retail staff, assembly line workers, and healthcare personnel. Low back pain is more prevalent in women than in men, and disability due to LBP is worse in women with severe urinary incontinence. However, it is unclear whether pelvic floor dysfunction observed in stress urinary incontinence is a risk factor for LBP. The main purpose of this study is to determine whether co-activation patterns between the pelvic floor and abdominal muscles during a 2-hour prolonged standing task predict transient LBP in women with and without stress urinary incontinence.

Methods

In this is prospective cohort study, 60 female volunteers will stand in a confined area for 2 hours (120 minutes) while performing tasks such as, 'computer work' and 'small object assembly'. The primary outcome measure is transient LBP, which will be monitored every 10 minutes using a numeric pain rating scale. Surface electromyography (EMG) will be collected from the gluteus medius and internal oblique/transverse abdominis muscles, and an intravaginal electrode will be used to monitor pelvic floor muscle activity. The EMG signals will be divided into 12 10-minute blocks to assess changes in co-activation over time. Cross-correlation analyses will be used to quantify co-activation between the muscle pairs (e.g. pelvic floor and internal oblique/transverse abdominis), and the coefficient of co-activation will be expressed as a percentage for each block. A mixed-model regression analysis will be used to determine whether co-activation patterns can predict transient LBP during the prolonged standing task.

Discussion

The primary objective of this research is to improve current understanding regarding the role of pelvic floor muscles in the onset of LBP and the potential association between stress urinary incontinence and LBP. These findings have the potential to inform prevention and rehabilitation programmes for women with stress urinary incontinence and LBP.

Trial registration

ACTRN12618000446268 [Protocol Version 2].

Abdominal girth as an index of muscle tension during abdominal hollowing: Selecting the optimal training intensity for the transversus abdominis muscle

The abdominal hollowing technique is used for training the transversus abdominis (TrA). However, the optimal intensity of hollowing is still unclear. The objective of the present study is to verify the validity of estimating the tension of the TrA by measuring the girth of the abdomen with a tape and to determine the optimum intensity of hollowing to effectively train the TrA. Sixteen healthy males performed hollowing with an intensity of 0%, 25%, 50%, 75%, and 100%, estimated from the girth of the abdomen. The shear elastic modulus was measured for the rectus abdominis (RA), external oblique (EO), internal oblique (IO), and TrA at all intensities via ultrasonic shear wave elastography. The shear elastic modulus was considered as the index of the tension of the abdominal muscles at each intensity, and the ratio of the TrA to RA, EO, and IO respectively was calculated as the index of TrA selectivity. As the intensity of hollowing increased, the girth of abdomen decreased and tension of all the four muscles increased. The ratio of TrA to the RA, EO, and IO did not exhibit a significant variation among hollowing intensities of 25% to 100%. It is rational to estimate the tension of the TrA by measuring the girth of the abdomen. Moreover, considering both TrA contraction intensity and selectivity, abdominal hollowing performed at maximum intensity was effective for the maximum contraction training of the TrA.

Difference of the thickness and activation of trunk muscles during static stoop lift at different loads between subjects with and without low back pain

BACKGROUND

Patients suffering from low back pain (LBP) have been reported to alter muscle contraction strategies.

OBJECTIVE

To compare activity and thickness of the trunk muscles (external oblique (EO), internal oblique (IO), transversus abdominis (TrA), and lumbar multifidus (LM)) during static stoop lift at different lifting loads between the subjects with and without LBP.

METHODS

Twenty eight subjects with LBP and twenty eight healthy subjects were recruited. The stoop lifting was performed in three conditions in 0%, 10%, and 20% of body weight.

RESULTS

The activity of EO (F= 9.513) and IO (F= 7.781) was significantly increased with increasing lifting loads in subjects with LBP (p< 0.05) but not significantly in subjects without LBP. The activity of the LM (F= 124.980) was significantly increased in response to lifting loads in both groups (p< 0.05). The percent change of TrA (F= 8.797) and LM (F= 48.170) muscles thickness was significantly increased with increasing lifting loads in both groups (p< 0.05). The percent change of TrA (F= 3.780) and LM (F= 16.314) muscles thickness in subjects without LBP was greater than those in subjects with LBP at all three lifting loads (p< 0.05).

CONCLUSIONS

The results of this study suggest that more activation of EO in subjects with LBP may contribute to increase the compressive force on the lumbar spine during stoop lift. Also, less activation of TrA and LM in subjects with LBP may contribute to decrease the lumbar stabilization during stoop lift.

Effect of breathing exercises combined with dynamic upper extremity exercises on the pulmonary function of young adults

BACKGROUND

The abdominal muscles, upper extremities, and diaphragm work in synergy to maintain trunk stability during breathing.

OBJECTIVE

This study aimed to investigate the effects of a breathing technique combined with dynamic upper extremity exercise on the pulmonary function of healthy adults.

METHOD

Forty male participants in their 20s were recruited and randomly divided into two groups of 20 participants each: the experimental group performed a dynamic upper extremity exercise with breathing, and the control group only performed the breathing exercise. The experimental duration was 4 weeks, and both groups performed each training three times per a week. We performed pulmonary function test.

RESULTS

Forced vital capacity increased significantly in both groups after the training period, but it was not significantly different between the two groups. Similarly, the forced expiratory volume at one second was not significantly different after training, but was significantly different between the two groups. In contrast, the peak expiratory flow did not show any significant within-group or between-group difference.

CONCLUSION

Consequently, we came up with result that breathing exercise with dynamic upper extremity exercise improves pulmonary function. Our findings indicate that the breathing and dynamic upper extremity exercise described here should be considered in patients who require breathing therapy, since it seems to have beneficial effects on pulmonary function.

The effect of stabilization exercises on diaphragm muscle thickness and movement in women with low back pain

BACKGROUND

Diaphragm is an important component of spinal stability. In presence of low back pain, there may be some alterations in this muscle like other muscles that are responsible for lumbal stabilization.

OBJECTIVE

This study aims to assess the effects of stabilization exercises on diaphragm muscle thickness and motion along with lumbopelvic stability.

METHODS

Twenty-one women with low back pain participated in the study. Stabilization exercises including motor control training were performed on treatment group (n= 11). In control group (n= 10), strentghening exercises were peformed for back muscles, abdominal muscles and hip muscles. The patients underwent a total of 30 sessions of treatment, 3 days in a week for 10 weeks. The diaphragm muscle thickness and motion was evaluated using ultrasound (US), and lumbopelvic stability was evaluated using lumbopelvic stability tests.

RESULTS

After the treatment, in the treatment group, increase in diaphragm thickness and improvement in lumbopelvic stability were statically significant (p< 0.05). However, there were no significant changes in diaphragm motion in both groups (p> 0.05).

CONCLUSIONS

As a result, stabilization exercises increase diaphragm muscle thickness and improve lumbopelvic stability in women with low back pain. Therefore, stabilization exercises should be considered as a part of the treatment program in low back pain.

Is abdominal hollowing exercise using real-time ultrasound imaging feedback helpful for selective strengthening of the transversus abdominis muscle?: A prospective, randomized, parallel-group, comparative study

Despite the importance of strengthening of the transversus abdominis (TrA) muscle in individuals with low back pain, the effect of real-time ultrasound imaging on maintenance in selective strengthening of abdominal hallowing exercise (AHE) performance has not been investigated. So, the aim of this study was to investigate the effects of AHE with real-time ultrasound imaging feedback on selective reinforcing the TrA muscle.Twenty healthy subjects were enrolled prospectively and randomized to train AHE for 2 weeks either by conventional feedback (group A) or by visual feedback from real-time ultrasound imaging additional to conventional feedback (group B). The changes in thickness of TrA, internal oblique abdominal muscle (IO), and external oblique abdominal muscle (EO) were measured using the ultrasonography. The changes in muscle activities of TrA-IO and EO were measured using surface electromyography.The thickness of TrA, IO, and EO muscles in resting was not significantly changed in both groups A and B. However, the ratio of root mean square (RMS) values of TrA-IO/EO muscles, which mirrors selective contraction of TRA-IO muscles against EO muscle, was significantly higher in group B than in group A.In healthy subjects, training with AHE using real-time ultrasound imaging feedback may be a useful additional method to conventional feedback for strengthening the TrA muscles selectively.

Gait in patients with adolescent idiopathic scoliosis. Effect of surgery at 10 years of follow-up

PURPOSE

To assess radiological and gait biomechanical changes before, at one and 10 years after surgery in AIS patients.

METHODS

This clinical prospective study included fifteen adult women (mean[SD] age: 26 [1] years) diagnosed with thoraco-lumbar/lumbar AIS and operated 10 years ago. Clinical, radiological and gait variables, including kinematics, electromyography (EMG), mechanics and energetics were compared between presurgery (S0), 1 year (S1) and 10 years (S2) postsurgery period using a one way repeated measure ANOVA.

RESULTS

The Cobb angle of the scoliosis curve was reduced by 55% at 1 year postsugery but only by 37% at 10 years postsurgery suggesting a loss of 32% over time. Frontal plumb line C7-S1 distance was significantly improved by surgery (-44%) and remained stable at 10 years postsurgery. Lower limb kinematics was not affected by the surgery at long term. Excessive bilateral activation of lombo-pelvic muscles, observed before surgery, decreased significantly at S1 and S2 period. Mechanical energy increased significantly between S0, S1 and S2 session, without any change for the energetic variables.

CONCLUSIONS

Between 1 and 10 years post-surgery, thoraco-lumbar/lumbar AIS women showed a few decompensation of the curve without any change of the improved frontal body balance. Lower limbs and pelvic motion, during gait, was not affected by the surgery. But presurgical excessive EMG activity of the lumbo-pelvic muscle and reduced mechanical energy produced to walk get similar to normal patterns. Only the oxygen consumption remained excessive probably due to physical deconditioning or postural instability.

Audiovisual Biofeedback-Based Trunk Stabilization Training Using a Pressure Biofeedback System in Stroke Patients: A Randomized, Single-Blinded Study

The purpose of this study was to assess the effects of audiovisual biofeedback-based trunk stabilization training using a pressure biofeedback system (PBS) in stroke patients. Forty-three chronic stroke patients, who had experienced a stroke more than 6 months ago and were able to sit and walk independently, participated in this study. The subjects were randomly allocated to an experimental group (n = 21) or a control group (n = 22). The experimental group participated in audiovisual biofeedback-based trunk stabilization training for 50 minutes/day, 5 days/week, for 6 weeks. The control group underwent trunk stabilization training without any biofeedback. The primary outcome of this study was the thickness of the trunk muscles. The secondary outcomes included static sitting balance ability and dynamic sitting balance ability. The thickness of the trunk muscles, static sitting balance ability, and dynamic sitting balance ability were significantly improved in the experimental group compared to the control group (p < 0.05). The present study showed that trunk stabilization training using a PBS had a positive effect on the contracted ratio of trunk muscles and balance ability. By providing audiovisual feedback, the PBS enables accurate and effective training of the trunk muscles, and it is an effective method for trunk stabilization.

Breathing changes accompanying balance improvement during biofeedback

The aim of this study was to determine whether respiration would be altered during visual biofeedback condition while standing on a foam surface. Fifty young, healthy subjects (24 men, 26 women) were divided into a spirometry group, in which additional spirometry analysis was performed, and a control group. All subjects were tested in two conditions: 1) standing on a foam surface and 2) standing on a foam surface with visual biofeedback (VF) based on the centre of pressure (CoP). CoP amplitude and velocity in anterior-posterior (Aap, Vap) and medial-lateral (Aml, Vml) directions were measured by the force platform. Breathing movements were recorded by two pairs of 3D accelerometers attached on the upper chest (upper chest breathing - UCB) and the lower chest (lower chest breathing - LCB). Results showed that significant decreases of CoP amplitude and velocity in both directions were accompanied by a significant decrease of lower chest breathing, and an increase of LCB frequency was seen during VF condition compared to control condition in both groups. Moreover, a significant decrease in tidal volume and increased breathing frequency during VF condition were confirmed by spirometric analysis. Reduced breathing movements and volumes as well as increased breathing frequency are probably part of an involuntary strategy activated to maximize balance improvement during VF condition.

Effect of breathing maneuver combined with upper extremity exercise on respiratory capacity in healthy adult men

[Purpose] This study aimed to determine the effect of the breathing maneuver combined with dynamic motion of the upper limbs on respiratory capacity in healthy adult men. [Subjects and Methods] Twenty-four healthy adult men participated in this study. Subjects were randomly assigned to a control group (n=12) or an experimental group (n=12). The subjects in the control group performed the breathing maneuver without the upper extremity exercise. The subjects in the experimental group performed upper extremity exercise with the breathing maneuver three times a week for 4 weeks. Outcomes were measured using maximum inspiratory and expiratory pressures. [Results] There was a significant difference in maximum inspiratory and expiratory pressures before and after intervention in the experimental group and the control group. In addition, there was a significant difference in maximal expiratory pressure between groups after intervention. [Conclusion] The results of this study suggest the respiration maneuver combined with upper extremity exercise could be used as a program for clinical respiration training.

Directional preference of activation of abdominal and paraspinal muscles during position-control tasks in sitting

Controversy exists in the literature regarding antagonist activity of trunk muscles during different types of trunk loading, and the direction-specificity of activation of trunk muscles, particularly the deeper trunk muscles. This study aimed to systematically compare activation of a range of trunk muscles between directions of statically applied loads, and to consider the impact of breathing in this activation. In a semi-seated position, 13 healthy male participants resisted moderate inertial loads applied to the trunk in eight different directions. Intramuscular electromyography was recorded from eight abdominal and back muscles on the right side during 1s prior to peak inspiration/expiration. All muscles demonstrated a directional preference of activation. No muscle displayed antagonistic activation during loading conditions of an intensity that exceded that recorded in upright sitting without a load. During these moderate intensity sustained efforts, trunk muscle activation varied little between respiratory phases. Antagonistic muscle activation of amplitude equivalent to the activation recorded in upright sitting without load is sufficient to maintain control of the spine during predictable and sustained low load tasks.

Analysis of muscle activity during active pelvic tilting in sagittal plane

BACKGROUND

Pelvic tilting is performed to improve lumbopelvic flexibility or retrain the motor control of local muscles. However, few studies investigated the activity of local muscles during pelvic tilting.

PURPOSE

The purpose of this study was to investigate muscle activity during anterior and posterior pelvic tilting.

METHOD

Twelve healthy males (age, 22.6 ± 1.4 years) participated. Fine-wire electrodes were inserted into the bilateral lumbar multifidus (MF) and transversus abdominis (TrA). Surface electrodes were used to record activity of the bilateral rectus abdominis, external oblique, and erector spinae (ES), and the unilateral right latissimus dorsi, gluteus maximus, semitendinosus, and rectus femoris muscles. The electromyographic activities during anterior and posterior pelvic tilting in a standing position were recorded and expressed as a percentage of the maximum voluntary contraction (%MVC) for each muscle.

RESULTS

The activities of the bilateral MF (right: 23.9 ± 15.9 %MVC, left: 23.9 ± 15.1 %MVC) and right ES (19.0 ± 13.3 %MVC) were significantly greater than those of the other muscles during anterior pelvic tilting. The activity of the left TrA (14.8 ± 16.4 %MVC) was significantly greater than that of the other muscles during posterior pelvic tilting.

CONCLUSIONS

The results suggested that the MF and ES are related to anterior pelvic tilting. The activity of the TrA, which was classified as a local muscle, was greater during posterior pelvic tilting. This study indicated that local muscles such as the MF and TrA may be related to pelvic tilting.

Pelvic floor muscle contraction and abdominal hollowing during walking can selectively activate local trunk stabilizing muscles

BACKGROUND

Trunk muscle exercises are widely performed, and many studies have been performed to examine their effects on low back pains. However, the effect of trunk muscles activations during walking with pelvic floor muscle contraction (PFMC) and abdominal hollowing (AH) has not been clarified.

OBJECT

To investigate whether walking with PFMC and AH is more effective for promoting local trunk muscle activation than walking without PFMC and AH.

METHODS

Twenty healthy men (28.9 ± 3.14 years, 177.2 ± 4.25 cm, 72.1 ± 6.39 kg, body mass index 22.78 ± 2.38 kg/m2) were participated in this study. Surface electrodes were attached over the multifidus (MF), lumbar erector spinae (LES), thoracic erector spinae (TES), transverse abdominus-internal oblique abdominals (TrA-IO), external oblique abdominals (EO), and rectus abdominus (RA). The amplitudes of electromyographic signals were measured during a normal walking with and without PFMC and AH.

RESULT

PFMC and AH while walking was found to result in significant bilateral increases in the normalized maximum voluntary contraction (MVC) of MFs and TrA-IOs (p< 0.05). Ratios of local muscle activity to global muscle activities were increased while performing PFMC and AH during normal walking. Bilateral TrA-IO/EO activity ratios were significantly increased by PFMC and AH (p< 0.05).

CONCLUSION

Performance of the PFMC and AH during walking resulted in significantly more recruitment of local trunk muscles. This study suggests that PFMC and AH during normal daily walking improves activation of muscles responsible for spinal dynamic stabilization and might be useful if integrated into low back disability and pain physical rehabilitation efforts.

Deep abdominal muscle thickness measured under sitting conditions during different stability tasks

[Purpose] This study was conducted to investigate ultrasonically determined changes in the thickness of the transversus abdominis and internal oblique muscles during different sitting conditions. [Subjects and Methods] Twenty healthy men volunteered to participate in this study. Four different sitting conditions including (A) sitting, (B) sitting with left hip flexion, (C) sitting with an abdominal hollowing maneuver (AHM), and (D) sitting with an AHM and left hip flexion, were used. Subjective exercise difficulty was evaluated. [Results] Transversus abdominis and internal oblique muscle thicknesses significantly differed between conditions, with significantly greater thickness between positions from (A) to (D). Stability of the surface when sitting had no effect on the muscle thickness of the transversus abdominis. By contrast, sitting on an unstable surface caused an increase in muscle thickness of the internal oblique in each condition. The subjects reported progressively increasing difficulty in performing each exercise in a stable position from (A) to (D), while the difficulty in an unstable position was significantly different between (A) and (B), and between (C) and (D). [Conclusion] Our findings suggest that task (B) on a stable surface should be chosen for maximal activation of transversus abdominis without inducing overactivation of the internal oblique muscle.

Trunk muscles contribute as functional groups to directionality of reaching during stance

Muscle activity preceding the onset of voluntary movement has been shown to reduce centre of mass (CoM) displacement and stabilise the body during self-induced 'perturbations'. However, based on recent findings in the lower limb, where preparatory muscle activity creates the dynamics necessary for the initiation of movement, this study sought to investigate whether trunk musculature acted consistently to minimise the displacement of the CoM, or in contrast, contribute to the movement. While standing, nine healthy participants made single-step (point-to-point) reaching movements to 13 visual targets throughout a 180° range (target interval = 15°). Full-body kinematics and electromyographic activity from 'focal' arm and 'postural' trunk muscles were analysed for a preparatory phase of 250-ms preceding movement onset (termed pPA). Akin to lower limb findings, direction-specific patterns of anticipatory trunk muscle activity accompanied the onset of rotational kinematics and CoM acceleration in the direction of the desired target. When arranged in terms of peak activation, we found functionally relevant groupings aligned to either ipsi-, central or contra-lateral reaching directions. Contrary to traditional approaches, which focus on CoM stabilisation, this spatial recruitment was in favour of assisting initiation of movement. Such activity suggests that the central nervous system may rely on synergic patterns of muscle activation within an undistinguishable and shared focal/postural motor command for functional voluntary movements.

Trunk Muscle Activation at the Initiation and Braking of Bilateral Shoulder Flexion Movements of Different Amplitudes

The aim of this study was to investigate if trunk muscle activation patterns during rapid bilateral shoulder flexions are affected by movement amplitude. Eleven healthy males performed shoulder flexion movements starting from a position with arms along sides (0°) to either 45°, 90° or 180°. EMG was measured bilaterally from transversus abdominis (TrA), obliquus internus (OI) with intra-muscular electrodes, and from rectus abdominis (RA), erector spinae (ES) and deltoideus with surface electrodes. 3D kinematics was recorded and inverse dynamics was used to calculate the reactive linear forces and torque about the shoulders and the linear and angular impulses. The sequencing of trunk muscle onsets at the initiation of arm movements was the same across movement amplitudes with ES as the first muscle activated, followed by TrA, RA and OI. All arm movements induced a flexion angular impulse about the shoulders during acceleration that was reversed during deceleration. Increased movement amplitude led to shortened onset latencies of the abdominal muscles and increased level of activation in TrA and ES. The activation magnitude of TrA was similar in acceleration and deceleration where the other muscles were specific to acceleration or deceleration. The findings show that arm movements need to be standardized when used as a method to evaluate trunk muscle activation patterns and that inclusion of the deceleration of the arms in the analysis allow the study of the relationship between trunk muscle activation and direction of perturbing torque during one and the same arm movement.

Evaluating eccentric hip torque and trunk endurance as mediators of changes in lower limb and trunk kinematics in response to functional stabilization training in women with patellofemoral pain

BACKGROUND

Altered movement patterns of the trunk and lower limbs have been associated with patellofemoral pain (PFP). It has been assumed that increasing the strength of the hip and trunk muscles would improve lower limb and trunk kinematics in these patients. However, evidence in support of that assumption is limited.

PURPOSE

To determine whether increases in the strength of hip muscles and endurance of trunk muscles in response to functional stabilization training will mediate changes in frontal plane lower limb kinematics in patients with PFP.

STUDY DESIGN

Controlled laboratory study.

METHODS

Thirty-one female athletes were randomized to either a functional stabilization training group that emphasized strengthening of the trunk and hip muscles or a standard training group that emphasized stretching and quadriceps strengthening. Patients attended a baseline assessment session, followed by 8 weeks of intervention, and were then reassessed at the end of the intervention period. The potential mediators that were evaluated included eccentric torque of hip muscles and endurance of the trunk muscles. The outcome variables were the lower limb and trunk kinematics in the frontal plane assessed during a single-legged squat task.

RESULTS

The eccentric strength of the gluteus muscles showed a mediation effect ranging from 18% to 32% on changes to frontal plane kinematics (decreased ipsilateral trunk inclination, pelvis contralateral depression, and hip adduction excursions) observed in the functional stabilization training group after intervention.

CONCLUSION

Although the mediation effects were small, the results suggest that improvements in the strength of the gluteus muscles can influence the frontal plane movement patterns of the lower limb and trunk in women with PFP.

CLINICAL RELEVANCE

Patients with PFP might benefit from strengthening of the hip muscles to improve frontal plane lower limb and trunk kinematics during functional tasks.

Effects of different types of contraction in abdominal bracing on the asymmetry of left and right abdominal muscles

[Purpose] The purpose of this study was to investigate the effective strength levels of abdominal muscle contraction using the bracing contraction method. [Subjects] The experiment was conducted with 31 healthy male (M=15) and female (F=16) adults attending D University in Busan; all participants had less than obesity level BMI (BMI<30). [Methods] Bracing contraction was performed by the subjects in the hook-lying position at maximum and minimum pressure levels, five times each, using a Pressure Biofeedback Unit (PBU), and the mean measurement value was calculated. The maximum pressure level was set at 100% and the half maximum pressure level was set at 50%. Each subject’s left and right abdominal muscle thicknesses were then measured by ultrasound imaging in each state: at rest, 100% contraction, and 50% contraction. [Results] No significant differences were found between the left and right sides of the transversus abdominis (TrA) at rest, 50%, or 100% contraction. The external oblique abdominis (EO) and internal oblique abdominis (IO) showed no significant difference at rest or at the 50% contraction. However, a significant difference was noted at 100% contraction for the EO and IO. [Conclusion] Application of abdominal contraction using bracing can achieve symmetry in the left and right abdominal muscles at less than the maximum contractile strength. The occurrence of asymmetry in the left and right abdominal muscles at the maximum contractile strength suggests that the most suitable contractile strength in this exercise is less than the maximum contractile strength.

Effect of abdominal drawing-in maneuver during hip extension on the muscle onset time of gluteus maximus, hamstring, and lumbar erector spinae in subjects with hyperlordotic lumbar angle

Background

The abdominal drawing-in maneuver (ADIM) is used to prevent abnormal movements of the lumbar spine and pelvis during therapeutic exercises. This study compared the effects of ADIM on the muscle onset time of the hamstring, gluteus maximus, and erector spinae muscles during prone hip extension exercise in subjects with or without hyperlordotic lumbar angle. Forty healthy adults (18 male, 22 female) were recruited for this study.

Methods

The lumbar lordotic angles and pelvic tilt angles of the subjects were measured using the Avaliação postural analysis software. The subjects were divided into two groups: the lumbar hyperlordotic angle (LHLA) and lumbar normal lordotic angle (LNLA) groups. The muscle contraction onset time of the hamstring, gluteus maximus, and erector spinae were assessed using surface electromyography.

Results

During ADIM application, the muscle contraction onset time of the gluteus maximus was significantly increased in the LHLA group compared with the LNLA group.

Conclusions

ADIM application during prone hip extension was more effective for gluteus maximus onset time in the LHLA group. Therefore, ADIM during prone hip extension may be useful for gluteus maximus training in individuals with lumbar hyperlordosis.

Trunk muscle activity is modified in osteoporotic vertebral fracture and thoracic kyphosis with potential consequences for vertebral health

This study explored inter-relationships between vertebral fracture, thoracic kyphosis and trunk muscle control in elderly people with osteoporosis. Osteoporotic vertebral fractures are associated with increased risk of further vertebral fractures; but underlying mechanisms remain unclear. Several factors may explain this association, including changes in postural alignment (thoracic kyphosis) and altered trunk muscle contraction patterns. Both factors may increase risk of further fracture because of increased vertebral loading and impaired balance, which may increase falls risk. This study compared postural adjustments in 24 individuals with osteoporosis with and without vertebral fracture and with varying degrees of thoracic kyphosis. Trunk muscle electromyographic activity (EMG) associated with voluntary arm movements was recorded and compared between individuals with and without vertebral fracture, and between those with low and high thoracic kyphosis. Overall, elderly participants in the study demonstrated co-contraction of the trunk flexor and extensor muscles during forwards arm movements, but those with vertebral fractures demonstrated a more pronounced co-contraction than those without fracture. Individuals with high thoracic kyphosis demonstrated more pronounced alternating flexor and extensor EMG bursts than those with less kyphosis. Co-contraction of trunk flexor and extensor muscles in older individuals contrasts the alternating bursts of antagonist muscle activity in previous studies of young individuals. This may have several consequences, including altered balance efficacy and the potential for increased compressive loads through the spine. Both of these outcomes may have consequences in a population with fragile vertebrae who are susceptible to fracture.

The functional coupling of the deep abdominal and paraspinal muscles: the effects of simulated paraspinal muscle contraction on force transfer to the middle and posterior layer of the thoracolumbar fascia

The thoracolumbar fascia (TLF) consists of aponeurotic and fascial layers that interweave the paraspinal and abdominal muscles into a complex matrix stabilizing the lumbosacral spine. To better understand low back pain, it is essential to appreciate how these muscles cooperate to influence lumbopelvic stability. This study tested the following hypotheses: (i) pressure within the TLF's paraspinal muscular compartment (PMC) alters load transfer between the TLF's posterior and middle layers (PLF and MLF); and (ii) with increased tension of the common tendon of the transversus abdominis (CTrA) and internal oblique muscles and incremental PMC pressure, fascial tension is primarily transferred to the PLF. In cadaveric axial sections, paraspinal muscles were replaced with inflatable tubes to simulate paraspinal muscle contraction. At each inflation increment, tension was created in the CTrA to simulate contraction of the deep abdominal muscles. Fluoroscopic images and load cells captured changes in the size, shape and tension of the PMC due to inflation, with and without tension to the CTrA. In the absence of PMC pressure, increasing tension on the CTrA resulted in anterior and lateral movement of the PMC. PMC inflation in the absence of tension to the CTrA resulted in a small increase in the PMC perimeter and a larger posterior displacement. Combining PMC inflation and tension to the CTrA resulted in an incremental increase in PLF tension without significantly altering tension in the MLF. Paraspinal muscle contraction leads to posterior displacement of the PLF. When expansion is combined with abdominal muscle contraction, the CTrA and internal oblique transfers tension almost exclusively to the PLF, thereby girdling the paraspinal muscles. The lateral border of the PMC is restrained from displacement to maintain integrity. Posterior movement of the PMC represents an increase of the PLF extension moment arm. Dysfunctional paraspinal muscles would reduce the posterior displacement of the PLF and increase the compliance of the lateral border. The resulting change in PMC geometry could diminish any effects of increased tension of the CTrA. This study reveals a co-dependent mechanism involving balanced tension between deep abdominal and lumbar spinal muscles, which are linked through the aponeurotic components of the TLF. This implies the existence of a point of equal tension between the paraspinal muscles and the transversus abdominis and internal oblique muscles, acting through the CTrA.

Effects of abdominal hollowing during stair climbing on the activations of local trunk stabilizing muscles: a cross-sectional study

Objective

To examine using surface electromyography whether stair climbing with abdominal hollowing (AH) is better at facilitating local trunk muscle activity than stair climbing without AH.

Methods

Twenty healthy men with no history of low back pain participated in the study. Surface electrodes were attached to the multifidus (MF), lumbar erector spinae, thoracic erector spinae, transverse abdominus - internal oblique abdominals (TrA-IO), external oblique abdominals (EO), and the rectus abdominis. Amplitudes of electromyographic signals were measured during stair climbing. Study participants performed maximal voluntary contractions (MVC) for each muscle in various positions to normalize the surface electromyography data.

Results

AH during stair climbing resulted in significant increases in normalized MVCs in both MFs and TrA-IOs (p<0.05). Local trunk muscle/global trunk muscle ratios were higher during stair climbing with AH as compared with stair climbing without AH. Especially, right TrA-IO/EO and left TrA-IO/EO were significantly increased (p<0.05).

Conclusion

Stair climbing with AH activates local trunk stabilizing muscles better than stair climbing without AH. The findings suggest that AH during stair climbing contributes to trunk muscle activation and trunk stabilization.

Variables associated with performance of an active limb movement following within-session instruction in people with and people without low back pain

Modification of a movement pattern can be beneficial in decreasing low back pain (LBP) symptoms. There is variability, however, in how well people are able to modify performance of a movement. What has not been identified is the factors that may affect a person's ability to modify performance of a movement. We examined factors related to performance of active hip lateral rotation (HLR) following standardized instructions in people with and people without LBP. Data were collected during performance of HLR under 3 conditions: passive, active, and active instructed. In people with LBP, motion demonstrated during the passive condition (r = 0.873, P < 0.001), motion demonstrated during the active condition (r = 0.654, P = 0.008), and gender (r = 0.570, P = 0.027) were related to motion demonstrated during the active-instructed condition. Motion demonstrated during the passive condition explained 76% (P < 0.001) of the variance in motion demonstrated during the active-instructed condition. A similar relationship did not exist in people without LBP. The findings of the study suggest that it may be important to assess motion demonstrated during passive HLR to determine how difficult it will be for someone with LBP to modify the performance of HLR. Prognosis should be worst for those who display similar movement patterns during passive HLR and active-instructed HLR.

The effect of transversus abdominis activation on exercise-related transient abdominal pain

OBJECTIVES

Exercise-related transient abdominal pain (ETAP) affects 40-60% of the physically active population, is detrimental to performance but of unknown aetiology. Excessive movement of abdominal peritoneum is one proposed mechanism. Transversus abdominis (TrA) function may play a role reducing in the incidence of Exercise-related transient abdominal pain via the tensioning of the thoracolumbar fascia or increasing intra-abdominal pressure. The aim of this study is to identify any relationship between transversus abdominis function and exercise-related transient abdominal pain, hypothesing that those with stronger transversus abdominis will have lower incidence of exercise-related transient abdominal pain.

DESIGN

Observational study design.

METHODS

Trunk muscle strength was measured clinically using the functional Sahrmann test. Contraction of transversus abdominis was measured by ultrasound imaging of resting muscle size and calculating the change in thickness with a voluntary contraction. Participants completed questionnaires describing any exercise-related transient abdominal pain symptoms, and were divided into four groups dependent upon frequency of any symptoms (never, yearly, monthly and weekly). Between group differences were analysed using analysis of covariance, with Bonferroni correction adjusting for age and training of participants using STATA. Poisson regression determined incident rate ratios for relevant variables.

RESULTS

Data was obtained from fifty runners (28 male, 25.8 ± 7.0 years). Sahrmann test score and frequency of Exercise-related transient abdominal pain were significantly different between groups (p=0.002) with asymptomatic runners having significantly higher Sahrmann test scores (stronger muscles) than weekly and yearly Exercise-related transient abdominal pain groups (p=0.001, p=0.02). There were significant between group differences for resting transversus abdominis thickness (p=0.034) but not for transversus abdominis thickness change (p=0.555).

CONCLUSIONS

Participants who had stronger trunk muscles and larger resting Transversus abdominis size experienced Exercise-related transient abdominal pain less.

'The core': understanding it, and retraining its dysfunction

"Core stability training" is popular in both the therapeutic and fitness industries but what is actually meant and understood by this concept? And does everyone need the same training approach? This paper examines the landscape of 'the core' and its control from both a clinical and research perspective. It attempts a comprehensive review of its healthy functional role and how this is commonly changed in people with spinal and pelvic girdle pain syndromes. The common clinically observable and palpable patterns of functional and structural change associated with 'problems with the core' have been relatively little described. This paper endeavors to do so, introducing a variant paradigm aimed at promoting the understanding and management of these altered patterns of 'core control'. Clinically, two basic subgroups emerge. In light of these, the predictable difficulties that each group finds in establishing the important fundamental elements of spino-pelvic 'core control' and how to best retrain these, are highlighted. The integrated model presented is applicable for practitioners re-educating movement in physiotherapy, rehabilitation, Pilates, Yoga or injury prevention within the fitness industry in general.

An investigation of abdominal muscle recruitment for sustained phonation in 25 healthy singers

OBJECTIVES

The purpose of this study was to investigate the baseline muscle thickness and recruitment patterns of the transversus abdominis muscle (TAM) and the internal oblique muscle (IOM) during semisupine phonation in a group of healthy performers.

STUDY DESIGN

This was a 2 × 3×2 within-group, repeated-measure study in which 25 professional vocalists--12 male and 13 female performed a series of sustained pitches in differing vocal qualities. Measurements were taken with ultrasound (Sonosite Micromaxx Ultrasound System) of the baseline thickness and % recruitment during voicing, of two deep abdominal muscles--TAM and the IOM. Correlations between TAM and IOM absolute change scores, TAM and IOM percentage change scores, and changes in muscle thickness (absolute and percentage) and age were examined using Spearman's correlations. Gender differences in the four types of change scores within each combination of pitch and quality were conducted with one-way analysis of variances. Differences in muscle thickness change 1) absolute scores and 2) percentage change in TAM and IOM, by pitch and quality (and their interactions) were analyzed using linear mixed models, using restricted maximum likelihood estimations, employing a Toeplitz variance-covariance matrix structure in SPSS (IBM, 2011). Post hoc analyses for independent variable group differences used Sidak's correction for multiple comparisons. Alpha level was set to 0.05.

RESULTS

In terms of absolute contractions (changes in the actual millimeter thickness of the muscle), the IOM was greater than the TAM. However in terms of percentage changes in muscles during phonation, the TAM was always greater than the IOM. The TAM as a percentage change was recruited preferentially and significantly in most vocal qualities tested. Although there were differences in muscle mass and recruitment patterns between genders, and males had thicker muscle mass at rest, differences due to muscle mass were not conclusive.

CONCLUSIONS

Overall this study supports the argument that the peri-abdominal muscles do indeed play a role in supporting the "performing" or athletic voice in healthy subjects, and will hopefully act as a database for further research in individuals with healthy and injured voices.