Spinal Muscle Activity Research Articles

Movement amplitude on the Functional Re-adaptive Exercise Device: deep spinal muscle activity and movement control

PurposeLumbar multifidus (LM) and transversus abdominis (TrA) show altered motor control, and LM is atrophied, in people with low-back pain (LBP). The Functional Re-adaptive Exercise Device (FRED) involves cyclical lower-limb movement against minimal resistance in an upright posture. It has been shown to recruit LM and TrA automatically, and may have potential as an intervention for non-specific LBP. However, no studies have yet investigated the effects of changes in FRED movement amplitude on the activity of these muscles. This study aimed to assess the effects of different FRED movement amplitudes on LM and TrA muscle thickness and movement variability, to inform an evidence-based exercise prescription.MethodsLumbar multifidus and TrA thickness of eight healthy male volunteers were examined using ultrasound imaging during FRED exercise, normalised to rest at four different movement amplitudes. Movement variability was also measured. Magnitude-based inferences were used to compare each amplitude.ResultsExercise at all amplitudes recruited LM and TrA more than rest, with thickness increases of approximately 5 and 1 mm, respectively. Larger amplitudes also caused increased TrA thickness, LM and TrA muscle thickness variability and movement variability. The data suggests that all amplitudes are useful for recruiting LM and TrA.ConclusionsA progressive training protocol should start in the smallest amplitude, increasing the setting once participants can maintain a consistent movement speed, to continue to challenge the motor control system.

Biomechanical analysis of INFINITY rehabilitation method for treatment of low back pain.

[Purpose] Low back pain is a pervasive problem in modern societies. Physical rehabilitation in treatment of low back pain should reduce pain, muscle tension and restore spine stability and balance. The INFINITY® rehabilitation method that is based on a figure of eight movement pattern was proved to be effective in low back pain treatment. The aim of the paper is to estimate the effect of a figure of eight motion on the L5/S1 load and lumbar spine muscle activation in comparison to other motion patterns. [Subjects and Methods] Three-dimensional model of lumbar spine musculoskeletal system is used to simulate effect of various load motion pattern induced by displacement of the center of gravity of the upper body. Four motion patterns were examined: lateral and oblique pendulum-like motion, elliptical motion and figure of eight motion. [Results] The simple pendulum-like and elliptical-like patterns induce harmonic muscle activation and harmonic spinal load. The figure of eight motion pattern creates high-frequency spinal loading that activates remodeling of bones and tendons. The figure of eight pattern also requires muscle activity that differs from harmonic frequency and is more demanding on muscle control and could also improve muscle coordination. [Conclusion] The results of the study indicate that complex motion pattern during INFINITY® rehabilitation might enhance the spine stability by influencing its passive, active and neural components.

Breast size impacts spine motion and postural muscle activation.

While it is generally accepted that large breast sizes in females contribute to back pain and poor posture, the effects of breast size on spinal motion and muscle activation characteristics are poorly understood. This study examined the relationship between breast size, spine motion, and trunk muscle activation. Fifteen university-aged females, free of back pain symptoms, were tested. Breast sizes were calculated, and three-dimensional spine motion and activation from five trunk muscles bilaterally were measured during standing and trunk flexion movements. Correlations between breast size and motion and muscle activation measures were assessed. Head and trunk angles were strongly, negatively correlated to breast size during upright standing; thoracic angles were moderately, positively correlated to breast size during thoracic flexion movements. Trunk muscles showed positive, moderate-strength relationships with breast size during upright standing and some trunk movements. These findings provide a preliminary indication that increasing breast sizes are associated with altered postures and increased muscle activation in a non-clinical population, and constitute a baseline for the study of females with a full range of breast sizes. Further research is required to confirm the generalizability of these findings to other sizes, in order to inform strategies for the prevention or reduction of back pain, as well as diagnosis, treatment, and rehabilitation techniques associated with breast size and back pain.

Musculoskeletal model of awkward carrying postures

Improper posture of carrying loads can cause low back disorders. This study investigates the impact of using a footstool in spinal force and muscle activity when: (1) pushing/pulling load farther/n...

Relationship Between Body Positioning, Muscle Activity, and Spinal Kinematics in Cyclists With and Without Low Back Pain: A Systematic Review.

Context:Low back pain is reported by more than half of cyclists. The pathomechanics and association of risk factors of lumbar spine overuse injuries in cycling are not clearly understood.Objective:To determine whether relationships exist between body positioning, spinal kinematics, and muscle activity in active cyclists with nontraumatic low back pain.Data Sources:In August of 2015 and April of 2016, a comprehensive search of the PubMed, CINAHL, Ovid MEDLINE, and Scopus databases was performed independently by 5 reviewers.Study Selection:Included articles consisted of biomechanical studies examining factors relating to low back pain in cyclists as agreed upon by group consensus.Study Design:Systematic review.Level of Evidence:Level 4.Data Extraction:Five reviewers appraised by consensus each article using the Downs and Black checklist.Results:Eight studies met criteria for this review. There is evidence that cyclists with lower handlebar heights displayed increased lumbosacral flexion angles during cycling. Core muscle activation imbalances, back extensor endurance deficits, and increased lumbar flexion while cycling were found to be present in cyclists with low back pain.Conclusion:Spinal and core muscle activation imbalances in a prolonged flexed posture associated with cycling may lead to maladaptive spinal kinematics and increased spinal stresses contributing to overuse low back pain.

Efectos de una técnica manual de tracción vertebral sobre el patrón de movimiento lumbo-pélvico y activación del erector espinal durante la flexo-extensión del tronco en pacientes con dolor lumbar

ObjectiveTo determine the behavior of the erector spinae and patterns lumbo-pelvic movement during flexion and extension movement of the trunk, following the application of a manual technique of lumbosacral decompression in patients with low back pain. Material and methods10 subjects with non-specific low back pain participated in the study. Surface electromyography recordings of the activity of the lumbar erector spinal muscles (L3 and L5, bilateral) and recordings of the lumbo-pelvic mobility were performed during trunk flexion and extension. These recordings were made before and after the application of the technique. ResultsAfter comparing the results of the parameters studied before and immediately after the manual technique no significant differences in either the behavior of the erector spinae, or the pattern of lumbar-pelvic movement found. ConclusionsThis study suggests that this manual technique of lumbosacral decompression, by itself, is not enough to produce immediate changes in patterns of lumbar-pelvic movement and activation of the erector spinae.

Relationship between neck acceleration and muscle activation in people with chronic neck pain: Implications for functional disability

BackgroundPrevious study has found that people with chronic neck pain moved with a consistently compromised acceleration/deceleration at their cervical and thoracic spines. This study examined the strength of the association between the electromyographic activities and the acceleration/deceleration of the cervical and thoracic spine, and its correlation with the functional disabilities in individuals with neck pain. MethodsTime history of the cervical and thoracic acceleration/deceleration and EMG activity was acquired in thirty-four subjects with chronic neck pain and thirty-four age- and gender-matched asymptomatic subjects during active neck movements. The strength of the association between the electromyographic activity of spinal muscles and the cervical and thoracic acceleration/deceleration was determined using cross-correlation method. Relationship between the strength of this association and the severity of the functional disabilities in neck pain group was examined using correlation analysis. FindingsThe strength of the association between cervical and thoracic acceleration/deceleration and electromyographic activities was significantly lower in neck pain group. Significant negative correlations were found between the functional disability level and the strength of this defined association in the symptomatic group. InterpretationThe compromised capability of the spinal muscles to produce acceleration/deceleration in the neck pain group may imply an impaired electromechanical coupling of these spinal muscles when performing neck movements. Significant negative correlation of the degree of functional disabilities suggests that the present approach can be used as an objective and specific evaluation of the dynamic performance of the spinal muscles and its relationship with the functional disabilities in neck pain subjects.

Efficacy of lumbar mobilization on postpartum low back pain in Egyptian females: A randomized control trial.

Low back pain (LBP) is a common complaint in the postnatal period. Physiotherapy has many techniques to apply for such cases. To investigate the effect of central postero-anterior (PA) lumbar mobilization on muscle activity in postpartum LBP. Forty-five females with chronic LBP at least three months postnatal. Participants divided randomly and equally into three groups. Group A (Study group) received PA lumbar mobilization plus traditional treatment which consisted of Ultrasonic and Infra-red. Group B (Placebo group) received placebo mobilization plus traditional treatment. Group C (Control group) received traditional treatment only. All patients received 3 sessions/week for 4 weeks. Pain intensity, functional disabilities and Surface EMG for recording para spinal muscle activity were measured before and after intervention. Statistical analysis was done by ANOVA and paired t-test. Central PA mobilization showed a significant reduction (P< 0.05) in the average surface EMG activity of the erector spinae musculature compared with the other groups as well as improvement in functional ability and reduction in pain intensity. A central PA mobilization significantly reduced pain intensity and surface EMG activity of erector spinae musculature as well as improvement in functional ability in mechanical low back pain in postnatal females.

Effects of movement from a postural maintenance position on lumbar hemodynamic changes.

[Purpose] To investigate the effects of movement from a postural maintenance position on lumbar hemodynamic changes, in order to prevent lower back pain and develop exercise therapy. [Subjects and Methods] Twenty-five healthy adults (mean age: 23.2 years) participated in the study. During flexion-extension exercise, the subjects moved their trunks gradually to a flexed position from an upright posture while sitting and standing, and then returned to and maintained an upright (re-upright) position. In the extension–flexion exercise, the subjects moved their trunks gradually from an upright posture to an extended position, and back while maintaining an upright (re-upright) position. Lumbar spinal muscle activity and hemodynamic changes were evaluated during both exercises. [Results] During the flexion and extension exercises, increased trunk-flexion angle caused increased muscle activity, decreased oxygenated hemoglobin in the multifidus muscle, and increased deoxygenated hemoglobin in the multifidus and lumbar erector spinae muscles. Moreover, the muscle activities were nearly the same in the re-upright and upright positions, and total hemoglobin also increased. [Conclusion] In both standing and sitting positions, holding the trunk in a flexed position causes ischemic hemodynamic changes in the multifidus muscle; however, the hyperemic response when returning the trunk to an extended position may improve circulation.

The Effects of Various Exercise-Based Interventions on Non-Specific Chronic Low Back Pain: A Systemic Review on Persian Studies

Introduction: Conservative treatment of patients with non-specific chronic low back pain (NCLBP); especially as exercise-based interventions, is a main part of rehabilitation program for such patients. This review study was designed to investigate the influences of exercise-based therapeutic intervention on patients with NCLBP in Persian studies. Materials and Methods: ISC (Islamic World Science Citation Center), Magiran, IranMedex, SID, and MedLib were selected as searching motor engines by using keywords including NCLBP, exercise-based therapy, Therapeutic exercise, Exercise therapy, and Corrective exercise training. Studies which used patients with acute or specific low back pain as subjects were excluded from the review process. Results: From 35 articles found, ten articles included in our study. They mainly concentrated on the effects of core stabilizing exercises and Pilates training on pain intensity, disability, function, balance, lumbar flexor and extensor muscles’ endurance, and electrical activity of abdominal and spinal muscles in individuals with NCLBP. Positive effect of core stabilizing exercises and Pilates training method on above-mentioned variables is confirmed in the literature. Conclusion: Exercise-based therapeutic interventions; especially as core stabilizing exercises or Pilates training can lead to reducing pain and improving function in patients with NCLBP; although designing and implementing clinical trials studies is essential due to relative poor quality of present articles to achieve more valid results.

Spinal muscle activity in simulated rugby union scrummaging is affected by different engagement conditions.

Biomechanical studies of rugby union scrummaging have focused on kinetic and kinematic analyses, while muscle activation strategies employed by front-row players during scrummaging are still unknown. The aim of the current study was to investigate the activity of spinal muscles during machine and live scrums. Nine male front-row forwards scrummaged as individuals against a scrum machine under "crouch-touch-set" and "crouch-bind-set" conditions, and against a two-player opposition in a simulated live condition. Muscle activities of the sternocleidomastoid, upper trapezius, and erector spinae were measured over the pre-engagement, engagement, and sustained-push phases. The "crouch-bind-set" condition increased muscle activity of the upper trapezius and sternocleidomastoid before and during the engagement phase in machine scrummaging. During the sustained-push phase, live scrummaging generated higher activities of the erector spinae than either machine conditions. These results suggest that the pre-bind, prior to engagement, may effectively prepare the cervical spine by stiffening joints before the impact phase. Additionally, machine scrummaging does not replicate the muscular demands of live scrummaging for the erector spinae, and for this reason, we advise rugby union forwards to ensure scrummaging is practiced in live situations to improve the specificity of their neuromuscular activation strategies in relation to resisting external loads.

The effects of bag style on muscle activity of the trapezius, erector spinae and latissimus dorsi during walking in female university students.

Back pain is common in adolescents which has been associated with carrying a bag. However, there is little research examining the effects of bag style in female adolescents. The aim of the study was to investigate the effects of different bag conditions on muscle activity of the trapezius, erector spinae and latissimus dorsi muscles in female university students during walking. Twelve female university students walked on a treadmill for 5 minutes at 1.1 m/s during five conditions; control, 1 strapped rucksack, 2 strapped rucksack, ipsilateral shoulder strap and contralateral shoulder strap, each containing 10% bodyweight. Electromyography for the trapezius, erector spinae and latissimus dorsi was recorded for the last 30 s of each condition. Two-way ANOVA and paired t-tests were used to identify differences between right and left muscles and between bag conditions. Results showed that muscle activity of the left trapezius was significantly higher than the right trapezius during the 1 strap rucksack condition. For the left trapezius, the 2 strapped rucksack and the control condition had significantly lower muscle activity compared to the 1 strapped rucksack and the ipsilateral shoulder strap. For the left erector spinae muscle, there was significantly greater muscle activity when wearing the contralateral shoulder strap compared to the control. For the right erector spinae, significantly lower muscle activity was observed when wearing the 2 strapped rucksack compared to the ipsilateral shoulder strap and contralateral shoulder strap. There were no significant differences in muscle activity of the latissimus dorsi muscles between any of the bag conditions. These findings suggest that a two strapped rucksack should be used when carrying loads to reduce spinal muscle activity which may, in turn, reduce reports of back pain in female adolescents.

A minimal dose of electrically induced muscle activity regulates distinct gene signaling pathways in humans with spinal cord injury.

Paralysis after a spinal cord injury (SCI) induces physiological adaptations that compromise the musculoskeletal and metabolic systems. Unlike non-SCI individuals, people with spinal cord injury experience minimal muscle activity which compromises optimal glucose utilization and metabolic control. Acute or chronic muscle activity, induced through electrical stimulation, may regulate key genes that enhance oxidative metabolism in paralyzed muscle. We investigated the short and long term effects of electrically induced exercise on mRNA expression of human paralyzed muscle. We developed an exercise dose that activated the muscle for only 0.6% of the day. The short term effects were assessed 3 hours after a single dose of exercise, while the long term effects were assessed after training 5 days per week for at least one year (adherence 81%). We found a single dose of exercise regulated 117 biological pathways as compared to 35 pathways after one year of training. A single dose of electrical stimulation increased the mRNA expression of transcriptional, translational, and enzyme regulators of metabolism important to shift muscle toward an oxidative phenotype (PGC-1α, NR4A3, IFRD1, ABRA, PDK4). However, chronic training increased the mRNA expression of specific metabolic pathway genes (BRP44, BRP44L, SDHB, ACADVL), mitochondrial fission and fusion genes (MFF, MFN1, MFN2), and slow muscle fiber genes (MYH6, MYH7, MYL3, MYL2). These findings support that a dose of electrical stimulation (∼10 minutes/day) regulates metabolic gene signaling pathways in human paralyzed muscle. Regulating these pathways early after SCI may contribute to reducing diabetes in people with longstanding paralysis from SCI.

Local dynamic stability of spine muscle activation and stiffness patterns during repetitive lifting.

To facilitate stable trunk kinematics, humans must generate appropriate motor patterns to effectively control muscle force and stiffness and respond to biomechanical perturbations and/or neuromuscular control errors. Thus, it is important to understand physiological variables such as muscle force and stiffness, and how these relate to the downstream production of stable spine and trunk movements. This study was designed to assess the local dynamic stability of spine muscle activation and rotational stiffness patterns using Lyapunov analyses, and relationships to the local dynamic stability of resulting spine kinematics, during repetitive lifting and lowering at varying combinations of lifting load and rate. With an increase in the load lifted at a constant rate there was a trend for decreased local dynamic stability of spine muscle activations and the muscular contributions to spine rotational stiffness; although the only significant change was for the full state space muscle activation stability (p < 0.05). With an increase in lifting rate with a constant load there was a significant decrease in the local dynamic stability of spine muscle activations and the muscular contributions to spine rotational stiffness (p ≤ 0.001 for all measures). These novel findings suggest that the stability of motor inputs and the muscular contributions to spine rotational stiffness can be altered by external task demands (load and lifting rate), and therefore are important variables to consider when assessing the stability of the resulting kinematics.

Assessment of standing balance deficits in people who have undergone anterior cruciate ligament reconstruction using traditional and modern analysis methods

Modern methods of assessing standing balance such as wavelet and entropy analysis could provide insight into postural control mechanisms in clinical populations. The aim of this study was to examine what effect anterior cruciate ligament reconstruction (ACLR) has on traditional and modern measures of balance. Ninety subjects, 45 who had undergone ACLR and 45 matched controls, performed single leg static standing balance tests on their surgical or matched limb on a Nintendo Wii Balance Board. Data were analysed in the anterior–posterior axis of movement, which is known to be affected by ACLR. The traditional measures of path velocity, amplitude and standard deviation were calculated in this plane. Additionally, sample entropy and discrete wavelet transform derived assessment of path velocity in four distinct frequency bands related to (1) spinal reflexive loops and muscle activity, (2) cerebellar, (3) vestibular, and (4) visual mechanisms of postural control were derived. The ACLR group had significantly increased values in all traditional measures and all four frequency bands. No significant difference was observed for sample entropy. This indicated that whilst postural sway was amplified in the ACLR group, the overall mechanism used by the patient group to maintain balance was similar to that of the control group. In conclusion, modern methods of signal analysis may provide additional insight into standing balance mechanisms in clinical populations. Future research is required to determine if these results provide important and unique information which is of benefit to clinicians.

Altered spinal kinematics and muscle recruitment pattern of the cervical and thoracic spine in people with chronic neck pain during functional task

Knowledge on the spinal kinematics and muscle activation of the cervical and thoracic spine during functional task would add to our understanding of the performance and interplay of these spinal regions during dynamic condition. The purpose of this study was to examine the influence of chronic neck pain on the three-dimensional kinematics and muscle recruitment pattern of the cervical and thoracic spine during an overhead reaching task involving a light weight transfer by the upper limb. Synchronized measurements of the three-dimensional spinal kinematics and electromyographic activities of cervical and thoracic spine were acquired in thirty individuals with chronic neck pain and thirty age- and gender-matched asymptomatic controls. Neck pain group showed a significantly decreased cervical velocity and acceleration while performing the task. They also displayed with a predominantly prolonged coactivation of cervical and thoracic muscles throughout the task cycle. The current findings highlighted the importance to examine differential kinematic variables of the spine which are associated with changes in the muscle recruitment in people with chronic neck pain. The results also provide an insight to the appropriate clinical intervention to promote the recovery of the functional disability commonly reported in patients with neck pain disorders.

Influence of visual feedback on force–EMG curves from spinally innervated versus trigeminally innervated muscles

ObjectiveWe compared the influence of visual feedback between spinal and trigeminal muscle activity. DesignTwelve subjects participated in two tasks: a finger pinch and a tooth clench task and performed a series of muscle activations with visual feedback as a training task and two series without visual feedback as pre- and post-training tasks. Five target force levels at 10%, 20%, 40%, 60% and 80% maximal voluntary contraction were performed in each series for both tasks. During all series electromyographic (EMG) activity and force were recorded. Target force–actual force and target force–EMG curves were compared with and without visual feedback for both tasks. The variability in each series was determined as the coefficient of variation (CV) from the EMG and force recordings. ResultsAlthough positive linear relationships were found between the target force level and the actual force value, and target force level and root mean square (RMS)-EMG amplitude from the tooth clenching task, the curves calculated from the finger pinch task were not completely linear. CVs of the actual force value and CVs of the RMS-EMG amplitude in both masseter and temporalis muscles were significantly influenced by visual feedback (P<0.001). However, the CVs of the RMS-EMG amplitude in right abductor pollicisbrevis and right first dorsal interosseous muscles were not significantly influenced by the three series. ConclusionsThe influence of visual feedback was different between spinally innervated and trigeminally innervated muscles, and the specific mechanism of force execution from muscle activity appears to be different between the tasks.

Effects of Push-up Exercise with Hip Adduction on the COP Deviation and the Serratus Anterior and L1 Paraspinal Muscles

[Purpose] This study investigated the effect of push-up exercise with hip adduction on the COP deviation and SA and L1 spinal muscle activation. [Subjects] Twelve males aged 20–30 years were recruited. [Methods] We measured the COP deviation and SA and L1 spinal muscle activities during push-up exercise with and without hip adduction [Results] The COP deviation significantly decreased and the SA and L1 spinal muscles were significantly increased during push-ups with hip adduction when compared with push-ups without hip adduction. [Conclusion] We thought that the push-up exercise with hip adduction might help to selectively strengthen the SA.

Lumbar spinal loads and muscle activity during a golf swing

This study estimated the lumbar spinal loads at the L4–L5 level and evaluated electromyographic (EMG) activity of right and left rectus abdominis, external and internal obliques, erector spinae, and latissimus dorsi muscles during a golf swing. Four super VHS camcorders and two force plates were used to obtain three-dimensional (3D) kinematics and kinetics of golf swings performed by five male collegiate golfers. Average EMG levels for different phases of golf swing were determined. An EMG-assisted optimization model was applied to compute the contact forces acting on the L4–L5. The results revealed a mean peak compressive load of over six times the body weight (BW) during the downswing and mean peak anterior and medial shear loads approaching 1.6 and 0.6 BW during the follow-through phases. The peak compressive load estimated in this study was high, but less than the corresponding value (over 8 BW) reported by a previous study. Average EMG levels of different muscles were the highest in the acceleration and follow-through phases, suggesting a likely link between co-contractions of paraspinal muscles and lumbar spinal loads.

Effect of load carriage on spinal compression

Backpack is commonly carried either posteriorly or anteriorly. Although load carriage has been shown to have significant effects on postural alignment and spinal muscle activity, its effect on spinal loading was not studied. The objective of this study is to investigate the effect of different load carriage methods on spinal loading over time via the measurement of spinal compression. Eight male adults participated in this study. They were asked to carry a load equivalent to 15% of their body weight either anteriorly or posteriorly for 20 min followed by 10 min of unloading. Their statures were measured before load carriage and every 2 min after carrying the load. The sequence of loading conditions was randomized and the participants took a 20-min rest with Fowler’s posture for spinal length recovery prior to each testing condition. The amount of spinal compression was found to be associated with carrying duration. Spinal compression during anterior carriage was larger than that of posterior carriage. There was a mild recovery of spinal compression after the removal of the carried load for both the anterior and posterior carriage conditions. Relevance to industry Short-term putting a backpack anteriorly might be useful for temporarily relieving postural changes induced by posterior carriage. However, prolonged anterior carriage is not recommended. The effects of load carriage on spinal compression should be considered in the design of a load carriage system with load partially or completely positioned in the front