Cervical Muscle Activity Research Articles

Memory-Guided Saccades and Non-Motor Symptoms Improve after Botulinum Toxin Therapy in Cervical Dystonia

Background/Objectives: Cervical dystonia (CD) is a condition characterized by involuntary activity of cervical muscles, which is often accompanied by various non-motor symptoms. Recent studies indicate impaired saccadic eye movements in CD. Local administration of botulinum toxin type A (BoNT/A), which causes temporary paralysis of the injected muscle, is the first-line treatment of focal dystonia, including CD. To our knowledge, concurrent observation of the effect of BoNT/A on smooth eye movements, voluntary saccades, memory-guided saccades, and antisaccades in CD has not yet been explored. The aim of this study was to assess the effect of BoNT/A on eye movements and non-motor symptoms in patients with CD, which, when altered, could imply a central effect of BoNT/A. Methods: Thirty patients with CD performed smooth pursuit, prosaccadic expression, memory-guided saccades, and antisaccade tasks; eye movements were recorded by an eye tracker. Motor and non-motor symptoms, including depression, anxiety, pain, disability, and cognitive changes prior to and after BoNT/A administration, were also evaluated. Results: The number of correct onward counts (p < 0.001), overall correct memory-guided saccades count (p = 0.005), motor symptoms (p = 0.001), and non-motor symptoms, i.e., anxiety (p = 0.04), depression (p = 0.02), and cognition (p < 0.001) markedly improved after BoNT/A administration. Conclusions: Memory-guided saccades, depression, and anxiety improve after BoNT/A in CD.

Evolving Dynamics of Neck Muscle Activation Patterns in Dental Students: A Longitudinal Study.

Cervical pain has been linked to increased motor unit activity, potentially associated with the initiation and progression of chronic neck pain. Therefore, this study aimed to compare the time-course changes in cervical superficial muscle activation patterns among dental students with and without neck pain throughout their initial semester of clinical training. We used an online Nordic Musculoskeletal Questionnaire for group allocation between neck pain (NP) (n = 21) and control group (CG) (n = 23). Surface electromyography (sEMG) of the sternocleidomastoid and upper bilateral trapezius was recorded before starting their clinical practice and after their first semester while performing a cranio-cervical flexion test (CCFT) in five increasing levels between 22 mmHg and 30 mmHg. After the first semester, both the CG (p < 0.001) and NP (p = 0.038) groups showed decreased sternocleidomastoid activation. The NP group exhibited a concomitant increase in upper trapezius coactivation (p < 0.001), whereas the muscle activation pattern in asymptomatic students remained unchanged (p = 0.980). During the first semester of clinical training, dental students exhibited decreased superficial flexor activity, but those with neck pain had increased co-contraction of the upper trapezius, likely to stabilize the painful segment. This altered activation pattern could be associated with further dysfunction and symptoms, potentially contributing to chronicity.

Sex differences in cervical disc height and neck muscle activation during manipulation of external load from helmets.

Neck pain associated with helmet-wear is an occupational health problem often observed in helicopter pilots and aircrew. Whether aircrew helmet wearing is associated with physiological and biomechanical differences between sexes is currently unknown. This study investigated neuromuscular activation patterns during different helmet-wearing conditions. The helmet load was manipulated through a novel Helmet Balancing System (HBS) in healthy, non-pilot male and female participants (n=10 each, age 19-45years) in two phases. Phase A assessed the acute effects of helmet-wear on neck muscles activation during head movements. Phase B examined changes in muscle activity and cervical disc height after wearing a helmet for 45 min. In Phase A, muscle activity was similar between sexes in many movements, but it was higher in female participants when wearing a helmet than in males. The HBS reduced muscle activity in both sexes. In Phase B, female participants exhibited a greater level of muscular fatigue, and male participants' cervical disc height was significantly decreased [5.7 (1.4) vs. 4.4 (1.5)mm, P<0.001] after continuous wearing. Both sexes showed no significant change in muscle fatigue and disc height [male: 5.0 (1.3) vs. 5.2 (1.4)mm, P=0.604] after applying HBS. These findings demonstrate sex-specific physiological and biomechanical responses to wearing a helmet. They may indicate different postural and motor control strategies, associated with different neck pain aetiologies in male and female aircrew, the knowledge of which is important to reduce or prevent musculoskeletal injuries associated with helmet wearing.

Comparing Muscle Activity and Onset Time of Cervical and Thoracoscapular Muscles during Shoulder Flexion and Abduction in Individuals with and without Forward Head Posture

Comparing Muscle Activity and Onset Time of Cervical and Thoracoscapular Muscles during Shoulder Flexion and Abduction in Individuals with and without Forward Head Posture

Lumbar and Cervical Concurrent Muscle Activity Analysis During Hamstring Length Testing to Design a Customized Treatment Plan: An Observational Cross-Sectional Study.

Hamstring length plays a significant role in a spectrum of clinical entities, from injury prevention and gait dysfunction to posture correction. Evidence suggests that the prevalence of hamstring tightness (HT)/reduced length is increasing. Despite the number of available tests and treatment protocols, HT is still a functional diagnosis. This study's primary goal is to evaluate concurrent muscle (CM) usage during these testing procedures to design a unique, customized treatment protocol. The study was conducted in two stages. In phase 1, Active Straight Leg Raise (ASLR), Active Total Knee Extension (ATKE), and Active Seated Total Knee Extension (ASTKE) were carried out. Next, two pressure gauges (PGs) were placed to align with the natural lumbar and cervical curvatures while testing ASLR and ATKE. After analyzing the results for pressure gauge placement, phase 2 data were collected for tests ASLR and ATKE with PG. The results of ASLR and ATKE, both with and without PG, indicate a high prevalence rate, whereas the results of ASTKE show no prevalence. Changes in the PG values indicate CM usage. Dichotomization revealed that participants with normal test scores (non-HT group) had increased usage of CM work. Positive and negative changes in PG indicate the involved CM group. In regular practice, most healthcare professionals and fitness trainers prefer ASTKE due to the ease of the testing procedure. Directing co-professionals on their choice of tests is challenging, whereas providing knowledge about CM use paves the way for creating customized treatment plans.

The effect of craniocervical flexors endurance training on suprahyoid muscle activation in healthy adults: A randomised controlled trial.

Cervical posture affects swallowing function through contractile and non-contractile structures. Craniocervical flexor endurance training (CCFET), which focuses on the activation of deep cervical muscles, is used to ensure cervical posture stability. The aim of this study was to investigate the effect of CCFET on the suprahyoid muscles (SH), which play an important role in swallowing function. Eighty healthy individuals (52 female and 28 male, mean age 21.77 ± 1.81 years) were recruited and randomly assigned to groups that underwent either deep cervical flexor (DCF) training with a pressure biofeedback unit (CCFET group, n = 41) or no intervention (control group, n = 39). The intervention was applied for 4 weeks (five sessions per week). Static endurance and activation of DCF muscles (Craniocervical Flexion Test, CCFT), tragus-wall distance (TWD) for forward head posture and surface electromyographic (sEMG) activation of suprahyoid muscles were evaluated. The endurance and activation of the DCF muscles were significantly increased in the CCFET group (p = <.001). In the CCFET group, TWD significantly lower than the control group (p = <.001) Peak SH amplitude and mean SH amplitude were lower in the CCFET group compared to the control group (p = .013, p = .003). The study shows that 4 weeks of CCFET reduced SH muscle activation, allowing the same work to be done with fewer motor units. CCFET can be included in rehabilitation programs as an additional method that has an effect on the muscles involved in swallowing by providing cervical motor control.

Effects of scapular treatment on chronic neck pain: a systematic review and meta-analysis of randomized controlled trials

BackgroundChronic neck pain (CNP) is a common public health problem that affects daily living activities and quality of life. There is biomechanical interdependence between the neck and scapula. Studies have shown that shoulder blade function might be related to chronic neck pain. We therefore evaluated the effects of scapular targeted therapy on neck pain and function in patients with CNP.MethodsDatabases, including MEDLINE (via PubMed), EMBASE (via Ovid), Ovid, Web of Science, and Scopus, were systematically searched for randomized controlled trials published in English investigating treatment of the scapula for CNP before July 16, 2023.ResultsA total of 313 participants were included from 8 RCTs. Compared with those in the control group, the intervention in the scapular treatment group exhibited greater improvement in pain intensity (standardized mean difference (SMD) = 2.55; 95% CI = 0.97 to 4.13; P = 0.002), with moderate evidence. Subgroup analysis for pain intensity revealed a significant difference between the sexes, with only the female population (SMD = 6.23, 95% CI = 4.80 to 7.65) showing better outcomes than those with both sexes (SMD = 1.07, 95% CI = 0.57 to 1.56) (p < 0.00001). However, moderate evidence demonstrated no improvement in neck disability after scapular treatment (SMD of 0.24[-0.14, 0.62] of Neck Disability Index or Northwick Park Neck Pain Questionnaire). No effect of scapular treatment was shown on the pressure pain threshold (PPT). The cervical range of motion (CROM) and electromyographic activity of neck muscles could not be conclusively evaluated due to limited support in the articles, and further study was needed. However, the patient’s head forward posture appeared to be corrected after scapular treatment.ConclusionScapular therapy was beneficial for relieving pain intensity in patients with CNP, especially in women. Head forward posture might also be corrected with scapular therapy. However, scapular therapy may have no effect on the PPT or neck disability. However, whether scapular therapy could improve CROM and cervical muscle activation in patients with CNPs had not been determined and needed further study.

Is adding dry needling to a standard care protocol beneficial in patients with chronic neck pain? A randomized placebo-controlled trial

PurposeTo evaluate the short-term effects of adding a dry needling therapy to a standard care protocol based on education, exercise and electrotherapy, compared to a sham procedure and to a standard care protocol in isolation in patients with chronic neck pain. Material and methodsA randomized placebo-controlled trial was performed. The participants in the dry needling group received a standard care protocol based on patient education, therapeutic exercise and electrotherapy, as well as two sessions of dry needling in the upper trapezius, levator scapulae, and/or sternocleidomastoid muscles. The participants in the sham dry needling group received the same standard care protocol and two sessions of sham dry needling. The participants in the control group received the same standard care protocol. The outcomes measured were pain intensity, pressure pain threshold, neck disability, range of movement, activation of deep cervical flexor muscles, kinesiophobia, pain catastrophizing, anxiety, and depression. ResultsNo significant group by time interactions were found for any of the outcome variables except for lower cervical spine range of movement (F = 3.79; p = 0.030). ConclusionThe addition of two sessions of dry needling in the superficial neck muscles to a standard protocol did not yield superior results compared to either the standard care alone or the standard care plus sham dry needling in patients with chronic neck pain in any outcome except for cervical range of movement.

Analysis of head-to-head impact in football with human finite element model considering pre-impact cervical muscle activation

Analysis of head-to-head impact in football with human finite element model considering pre-impact cervical muscle activation

Myopia & painful muscle form of temporomandibular disorders: connections between vision, masticatory and cervical muscles activity and sensitivity and sleep quality

The main aim of this study is to evaluate the effects of painful muscle form of temporomandibular disorders and myopia on the connections between the visual organ, the bioelectrical activity and sensitivity of the masticatory and cervical muscles, and sleep quality. Subjects were divided into 4 groups (Myopia & TMDs, Myopia (Without TMDs), Emmetropic & TMDs and Emmetropic (Without TMDs)). The study was conducted in the following order of assessment: examination for temporomandibular disorders, assessment of the muscle activity by electromyograph, pressure pain thresholds examination, ophthalmic examination and completion of the Pittsburgh Sleep Quality Index. It was observed that the Myopia & TMDs group had higher muscle tenderness, higher resting and lower functional muscle bioelectrical activity. The visual organ is clinical related to the masticatory and cervical muscles. TMDs and myopia alter masticatory and cervical muscle activity. The thickness of the choroid in people with myopia is related to muscle tenderness. TMDs and myopia impair sleep quality. It is recommended to determine the number of people with refractive error and its magnitude in the sEMG study in order to be able to replicate the research methodology.

Cervical muscle parameters and allodynia in migraine and cervical pain-A controlled study.

Neck pain is common among individuals with migraine, but there is a lack of information of how this comorbidity can be associated with cervical muscle function. This controlled cross-sectional study aimed to compare cervical muscle function, activity, and sensitization in women with migraine, neck pain, both, and neither. This study included women, between 18 and 55 years old, with either episodic migraine with or without aura, without any concomitant headache diagnosis; chronic neck pain, with at least moderate intensity and mild disability; or neither headache nor neck pain. Pain pressure threshold, allodynia, muscle strength, and endurance and cervical muscles activity were evaluated. One hundred subjects, with mean age of 30.4 years old, were stratified by diagnosis (n = 25 per group) and by self-reported pain during tests. Lower endurance during flexion was observed for migraine and neck pain (34s) relative to neck pain alone (45s), migraine (40s), and controls (58s) (p = 0.04). For extensor endurance, means were 142s, 166s, 215s, and 270s, respectively (p < 0.001). Endurance times were impacted by the presence of test-induced pain decreasing about 40%-53% of the performance. Diagnostic groups did not differ significantly in strength (p > 0.05), but all pain groups presented significantly higher proportion of test-induced pain, lower muscle activity during the maximal isometric voluntary contractions, and lower pressure pain thresholds. Patients with migraine, chronic neck pain, and the association of both present altered cervical muscle function and activity. Also, test-induced pain impacts significantly on neck muscles endurance. The diagnosis of migraine and chronic neck pain is associated with altered function and activity of the cervical muscles. However, the test-induced pain had an important contribution to worse cervical muscle endurance. This suggests that the therapeutic approach should focus on de-sensitization of the trigeminal-cervical complex when dealing with the comorbidity of migraine and cervical pain.

Cervical proprioception in Parkinson's disease and its correlation with manual dexterity function.

Cervical proprioception has a crucial role in posture and movement control. The study aimed to determine the relationship of cervical proprioception, cervical muscle strength and endurance with manual dexterity and hand strength in individuals with idiopathic Parkinson's disease (PD). Twenty individuals with PD (mean age:63.9 years) and 20 healthy individuals as a control group (mean age: 61.9 years) were recruited. Cervical joint position error (JPE), static endurance of neck muscles, activation of deep cervical flexor muscles (Craniocervical Flexion Test-CCFT), manual dexterity using Purdue Pegboard Test (PPT), cognitive and motor task on PPT, finger tapping test (FTT) and pinch-grip strength were assessed. Cervical JPE was significantly higher in individuals with PD than controls (p<0.05). The strength and endurance of the cervical muscles were significantly decreased in individuals with PD (p<0.05). There was a significant negative correlation of cervical JPE measurements with PPT, cognitive and motor tasks on PPT in the PD group (p<0.05). There was a significant negative correlation of the endurance of cervical flexor muscles with PPT and cognitive task on PPT (p<0.05). In addition, a significant positive correlation was found between cervical flexor endurance and hand strength in the PD group (p<0.05). Cervical proprioception and the strength and endurance of cervical muscles decrease in individuals with PD compared to healthy individuals. Impairment of cervical proprioception appears to be associated with poorer upper extremity performance. Detailed evaluation of the cervical region in PD may be useful in determining the factors affecting upper extremity function.

Analysis of abnormal muscle activities in patients with loss of cervical lordosis: a cross-sectional study

BackgroundThis study aimed to detect the differences in cervical muscle activation patterns in people with versus without cervical lordosis and explore the possible mechanism of cervical pain originating therein.MethodsThis cross-sectional design included 39 participants without and 18 with normal cervical lordosis. Muscular activation was measured for 5 s in both groups using surface electromyography. Subsequently, the root mean square (RMS) of muscle amplitude was obtained at the bilateral splenius capitis, upper and lower parts of the splenius cervicis, upper and lower parts of the semispinalis cervicis, sternocleidomastoid, upper trapezius, and rhomboid muscles in five cervical positions: 0° (resting), 30° of flexion, 30° of extension, 60° of extension, and upon a 1-kg load on the head in a resting posture.ResultsThe RMS values of the upper trapezius muscle at all postures and the rhomboid muscles at 60° of extension were significantly lower in the loss of lordosis than control group. Comparing the RMS ratio of each posture to the resting position, the ratio of the upper trapezius at flexion was significantly higher and that of the rhomboids at 60° of extension and upon loading was significantly lower in the loss of lordosis than control group. Moreover, the pattern changes in the RMS values according to posture showed a similar shape in these two muscles, and lower in the loss of lordosis than the normal group.ConclusionsThe loss of normal cervical alignment may correlate with predisposed conditions such as reduced muscle activation of the trapezius and rhomboid muscle, and may also provoke over-firing of the upper trapezius muscle, possibly increasing neck musculoskeletal pain.Trial registration.Clinicaltrials.gov, registration number: NCT03710785.

Neck muscle activation in response to eye movement depends on sitting posture and is modified in whiplash associated disorders: Cross-sectional study

BackgroundActivity of specific neck muscles is modulated by eye movement. This activity modulation is exaggerated in people with whiplash associated disorders (WAD), but it is unknown whether it is impacted by sitting posture. ObjectiveThis study investigated; (i) whether activity of cervical muscles differs with spinal posture; (ii) whether the effect of eye gaze direction (horizontal/vertical) on neck muscle activity differs between postures, and (iii) whether these effects differ between individuals with and without WAD. MethodsIn three seated postures (normal relaxed, head forward, sit tall) electromyography (EMG) was recorded right obliquus capitis inferior (OI), multifidus (MF), splenius capitis (SP) and left sternocleidomastoid (SCM) with fine-wire and surface electrodes in ten healthy controls and nine with WAD. Electro-oculography recorded eye movements. ResultsIn controls, EMG was less for extensor muscles in Sit Tall than Head Forward, but higher in SCM. Only SC EMG modulated with eye movement. When WAD participants adopted similar sitting postures several responses were different; compared to Normal Relaxed posture OI EMG was less in Head Forward; MF EMG was less in Sit Tall; and SC was less in Head Forward and Sit Tall. Neck muscles in WAD were generally more sensitive to eye movement, except SC which did not modulate. ConclusionsThese finding support the hypothesis that neck muscle activity is influenced by spinal posture and eye movement. In WAD, this relationship is distorted and the response to eye movement is increased. SignificanceThese observations have potential implications for clinical management of individuals with WAD.

Evaluation of surface electromyography of selected neck muscles during the whiplash mechanism in aware and unaware conditions due to safe punching in kickboxing

BackgroundKickboxing is considered as a combat sport in progress, in which injuries are frequent and significant, and close injury monitoring is highly recommended. Sports injuries to the head and neck are estimated to cause 70% deaths and 20% permanent disabilities although they are much less common than those to the limbs. Whiplash mechanism involves the rapid extension (opening) and flexion (bending) of neck. The purpose of the current study was to investigate the electromyographic activity of selected muscles in the whiplash mechanism in aware and unaware conditions of the safe punching in kickboxing so that we can design special exercises.MethodIn the present study, 24 male kickboxing athletes aged 18–40 years were selected based on a purposive sampling method. The surface electromyography (EMG) signals of muscles were recorded with and without awareness of safe punching by using a nine-channel wireless EMG device. Additionally, a nine-channel 3D inertial measurement unit (IMU, wireless,) was utilized to determine the acceleration, kinematics, and angular velocity of the subjects’ head. The statistical dependent t-test was applied to compare the EMG activity of each muscle, as well as its participation ratio.ResultsThe results of statistical analysis represented a significant increase in the EMG activity of sternocleidomastoid (p = 0.001), upper trapezius (p = 0.001) and cervical erector spinae muscles (p = 0.001), as well as the neck extension and flexion angles between the athletes aware (open eyes) and unaware (closed eyes) of the safe punching.ConclusionIn this study, the EMG activity of the sternocleidomastoid, upper trapezius, and cervical erector spine muscles in the aware condition was significantly different from the activity under unaware condition. In fact, the intended muscles exhibited significantly different behaviors in preventing extension and flexion in the two conditions.

Isometric chin tuck exercise with and without scapular postural correction for patients with chronic neck pain: a longitudinal study

Background/Aims Chronic neck pain is common in individuals with poor posture and motor control impairments. There has been increased interest in scapular postural correction in conjunction with the isometric chin tuck exercise. The aim of this study was to investigate the clinical efficacy of scapular postural correction while performing isometric chin tuck exercises for the improvement of neck pain, neck and shoulder alignment and superficial neck muscle activity in patients with chronic neck pain. Methods A total of 32 participants with chronic, non-specific neck pain were randomly divided into two groups (groups A and B, both n=16), who performed isometric chin tuck exercises alone or isometric chin tuck with scapular postural correction respectively. The participants were instructed to perform five sets of the exercise with 10 repetitions for 6 weeks. Measurements were taken pre- and post-intervention to determine Neck Disability Index scores, postural parameters (head, cervical and shoulder angle) and superficial cervical muscle activity (sternocleidomastoid, anterior scalene, splenius capitis). Analysis of covariance was used to compare the post-intervention scores. Results Significant differences were observed between groups A and B in the cervical angle (F1,29=4.538, P=0.042) and shoulder angle (F1,29=8.357, P=0.007), when compared to baseline values. Both group A (t=12.097, P&lt;0.001) and group B (t=8.032, P&lt;0.001) showed a significant reduction in Neck Disability Index scores compared to baseline scores. Both group A and group B showed a significant decrease in sternocleidomastoid (group A: t=6.637, P&lt;0.001; group B: t=10.143, P&lt;0.001), anterior scalene (group A, t=5.484, P&lt;0.001; group B, t=8.063, P&lt;0.001), and splenius capitis (group A, t=8.591, P&lt;0.001; group B, t=8.258, P&lt;0.001) muscle activity compared to baseline values. Conclusions Isometric chin tuck alone and isometric chin tuck combined with scapular postural correction both showed significant reductions in neck pain and superficial neck muscle activity. Additional scapular postural correction training significantly increased the cervical angle and decreased the shoulder angle.

Motor neuron involvement threatens survival in spinocerebellar ataxia type 1.

Motor neuron involvement threatens survival in spinocerebellar ataxia type 1.

The Influence of Visual Input on Electromyographic Activity and Patterns of Masticatory and Cervical Spine Muscles in Emmetropic Caucasian Subjects by Gender

(1) Background: The objective of the research was to analyze the change of visual input on electromyographic activity and patterns of masticatory and cervical spine muscles in emmetropic Caucasian subjects by gender. Supposedly, visual input should not influence activity and electromyographic patterns of masticatory and cervical spine muscles in emmetropic Caucasian subjects by gender. (2) Methods: After applying the inclusion criteria, 50 emmetropic Caucasian subjects were included in the study. Four muscle pairs were analyzed: the temporalis muscle (TA), the masseter muscle (MM), the digastric muscle (DA), and the sternocleidomastoid muscle (SCM), during resting and functional activity. (3) Results: It was observed that there were no significant statistical differences in activity and bioelectrical patterns between open and closed eyes in women and men, with the exception of clenching on dental cotton rollers in DA-left and DA mean between tests in women. The observed statistical results had a small effect size, successively equal to 0.32 and 0.29. (4) Conclusions: Changes in the influence of visual input do not affect electromyographic activity and patterns of masticatory and cervical spine muscles in emmetropic Caucasian women and men.

Effects of typing positions on the upper trapezius and neck extensor muscles electromyography in office employees: A single-blind cross-sectional study.

Holding incorrect postures over a long period could lead to chronic nonspecific neck pain (CNNP) in office employees. The present study aimed to evaluate the effects of different typing positions on the activity of the neck extensor and upper trapezius (UT) muscles of office employees diagnosed with CNNP. This assessor-blinded cross-sectional study was performed on 22 female subjects with the mean age of 39.95±5.30 years. The neck extensors and UT muscle activities of the participants were assessed in the upright, forward, and slouching postures by electromyography (EMG). In addition, neck proprioception and the performance of the cervical stabilizer muscles were evaluated using an inclinometer and biofeedback pressure unit, respectively. A significant difference was observed between the cervical erector spine (CES) and UT muscle activities in the upright, forward, and slouching typing positions (P < 0.05). In addition, a difference was observed between the upright and slouching postures in these muscles. A positive correlation was denoted between CES muscle activity in the slouching and forward postures and the activation index of neck muscles (P < 0.05). Furthermore, a significant, negative correlation was observed between the UT muscle activity in the slouching posture and neck proprioception (P < 0.05). A positive correlation was also noted between the pain index and repositioning error rates (P < 0.05). CES muscle activity increased in a forward head posture, which could damage neck proprioception through causing early fatigue and stimulating a cumulative damage cycle.

The relationship between spinal alignment and activity of paravertebral muscle during gait in patients with adult spinal deformity: a retrospective study

BackgroundSpinal alignment in patients with adult spinal deformity (ASD) changes between rest and during gait. However, it remains unclear at which point the compensated walking posture breaks down and how muscles respond. This study used time-synchronized electromyography (EMG) to investigate the relationship between dynamic spinal alignment and muscle activity during maximum walking duration to reveal compensation mechanisms.MethodsThis study collected preoperative three-dimensional gait analysis data from patients who were candidates for corrective surgery for ASD from April 2015 to May 2019. We preoperatively obtained dynamic spinal alignment parameters from initiation to cessation of gait using a motion capture system with time-synchronized surface integrated EMG (iEMG). We compared chronological changes in dynamic spinal alignment parameters and iEMG values 1) immediately after gait initiation (first trial), 2) half of the distance walked (half trial), and 3) immediately before cessation (last trial).ResultsThis study included 26 patients (22 women, four men) with ASD. Spinal sagittal vertical axis distance during gait (SpSVA) increased over time (first vs. half vs. last, 172.4 ± 74.8 mm vs. 179.9 ± 76.8 mm vs. 201.6 ± 83.1 mm; P < 0.001). Cervical paravertebral muscle (PVM) and gluteus maximus activity significantly increased (P < 0.01), but thoracic and lumbar PVM activity did not change. Dynamic spinal alignment showed significant correlation with all muscle activity (cervical PVM, r = 0.41–0.54; thoracic PVM, r = 0.49–0.66; gluteus maximus, r = 0.54–0.69; quadriceps, r = 0.46–0.55) except lumbar PVM activity.ConclusionSpinal balance exacerbation occurred continuously in patients with ASD over maximum walking distance and not at specific points. To maintain horizontal gaze, cervical PVM and gluteus maximus were activated to compensate for a dynamic spinal alignment change. All muscle activities, except lumbar PVM, increased to compensate for the spinal malalignment over time.