Search

Introduction: Recurrent lower back pain (rLBP) and neuromuscular fatigue are independently thought to increase the risk of lower extremity (LE) injury. Volitional preemptive abdominal contraction (VPAC) is thought to improve lumbar spine and pelvis control in individuals with rLBP. The effects of VPAC on fatigued landing performance in individuals with rLBP are unknown. Objectives: To determine the effects of VPAC and LE fatigue on landing performance in a rLBP population. Design: Cross-sectional pretest-posttest cohort control design. Setting: A clinical biomechanics laboratory. Subjects: 32 rLBP (age 21.2 ± 2.7 y) but without current symptoms and 33 healthy (age 20.9 ± 2.3 y) subjects. Intervention(s) : (i) Volitional preemptive abdominal contraction using abdominal bracing and (ii) fatigue using submaximal free-weight squat protocol with 15% body weight until task failure was achieved. Main Outcome Measure(s): Knee and ankle angles, moments, electromyographic measurements from semitendinosus and vastus medialis muscles, and ground reaction force (GRF) were collected during 0.30 m drop-jump landings. Results: The VPAC resulted in significantly earlier muscle onsets across all muscles with and without fatigue in both groups (mean ± SD, 0.063 ± 0.016 s earlier; P ≤ .001). Fatigue significantly delayed semitendinosus muscle onsets (0.033 ± 0.024 s later; P ≤ .001), decreased GRF (P ≤ .001), and altered landing kinematics in a variety of ways. The rLBP group exhibited delayed semitendinosus and vastus medialis muscle onsets (0.031 ± 0.028 s later; P ≤ .001) and 1.8° less knee flexion at initial contact (P ≤ .008). Conclusion: The VPAC decreases some of the detrimental effects of fatigue on landing biomechanics and thus may reduce LE injury risk in a rLBP population. [ABSTRACT FROM AUTHOR]

Study Design: Prospective cohort study.Objective: Investigate the effect of surgical decompression and fusion on gait ground reaction forces (GRFs) parameters in patients with cervical spondylotic myelopathy (CSM) and to compare these values to those of healthy controls.Summary Of Background Data: Surgical intervention to alleviate spinal cord compression is typically recommended in cases of CSM. While the primary aim of surgery is to halt disease progression, the literature suggests that some symptomatic improvement is often observed postoperatively. Gait analysis via measurement of GRFs is a particularly sensitive means of quantifying changes in ambulatory function, but no comprehensive analysis has been published in the setting of CSM.Methods: Forty patients with symptomatic CSM underwent gait analysis with measurement of horizontal and vertical GRFs before and 3 months after surgery. Thirty healthy controls (H) underwent the same battery of tests. Comparisons were made between the pre- and postoperative profiles of patients with CSM as well as to that of the control group.Results: Before surgery, patients with CSM exhibited disturbances in GRF magnitudes: significantly greater maximum weight acceptance (Pre: 113.7 vs. H: 101.1% body weight [BW], P = 0.040) and push off forces (Pre: 112.2 vs. H: 101.4% BW, P = 0.044), and timing: maximum weight acceptance occurred earlier while mid-stance (Pre: 15.8 vs. H: 17.8% gait cycle [GC], P = 0.018), toe-off (Pre: 65.0 vs. H: 62.9% GC, P = 0.001), braking (Pre: 55.6 vs. H: 54.2% GC, P = 0.003), and propulsion occurred (Pre: 11.9 vs. H: 10.6% GC, P = 0.011) later compared with healthy controls. Surgery improved all GRF parameters (P < 0.039), but postoperative gait profiles did not completely normalize to levels observed in the control group.Conclusion: These observations combined with published data on gait muscle activation and gait patterns in CSM patients support the idea that patients with CSM have an altered gait profile consistent with a series of poorly controlled near falls. Surgical intervention was observed to produce improvements in but not complete resolution of these gait disturbances. These data provide a more comprehensive understanding of gait in the setting of CSM.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A prospective cohort study.Objective: The aim of this study was to quantify the amount of sway associated with maintaining a balanced posture in a group of untreated cervical spondylotic myelopathy (CSM) patients.Summary Of Background Data: Balance is defined as the ability of the human body to maintain its center of mass (COM) within the base of support with minimal postural sway. Sway is the movement of the COM in the horizontal plane when a person is standing in a static position. CSM patients have impaired body balance and proprioceptive loss.Methods: Thirty-two CSM patients performed a series of functional balance tests a week before surgery. Sixteen healthy controls (HCs) performed a similar balance test. Patients are instructed to stand erect with feet together and eyes opened in their self-perceived balanced and natural position for a full minute. All test subjects were fitted to a full-body reflective markers set and surface electromyography (EMG).Results: CSM patients had more COM sway in the anterior-posterior (CSM: 2.87 cm vs. C: 0.74 cm; P = 0.023), right-left (CSM: 5.16 cm vs. C: 2.51 cm; P = 0.003) directions as well as head sway (anterior-posterior - CSM: 2.17 cm vs. C: 0.82 cm; P = 0.010 and right-left - CSM: 3.66 cm vs. C: 1.69 cm; P = 0.044), more COM (CSM: 44.72 cm vs. HC: 19.26 cm, p = 0.001), and head (Pre: 37.87 cm vs. C: 19.93 cm, P = 0.001) total sway in comparison to controls. CSM patients utilized significantly more muscle activity to maintain static standing, evidenced by the increased trunk and lower extremity muscle activity (multifidus, erector spinae, rectus femoris, and tibialis anterior, P < 0.050) during 1-minute standing.Conclusion: In symptomatic CSM patients, COM and head total sway were significantly greater than controls. Individuals with CSM exhibit more trunk and lower extremity muscle activity, and thus expend more neuromuscular energy to maintain a balanced, static standing posture. This study is the first effort to evaluate global balance as a dynamic process in this patient population.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A prospective cohort study.Objective: To examine the relationship of fear-avoidance beliefs and neuromuscular activity during gait in adult degenerative scoliosis (ADS) patients.Summary Of Background Data: Among patients with chronic spine pain, fear-avoidance beliefs are predictive of poor surgical outcomes. Fear-avoi occurs when patients perceive that movement will worsen underlying physical problems. This process leads them to restrict activity, which further heightens emotional distress. Patients with ADS have previously been shown to have an altered gait pattern. Electromyography is evolving into a useful tool to further our understanding of the pathologic manifestations of ADS during gait.Methods: Fifty ADS patients completed the Tampa Scale for Kinesiophobia (TSK) questionnaire and the Fear Avoidance Beliefs Questionnaire (FABQ). Surface electromyography electrodes were bilaterally placed on trunk and lower extremity muscles. Each patient performed a series of over-ground gait trials at a self-selected comfortable speed. Pearson Product Correlation analysis was used to determine the relationship between the self-reported fear of movement measures and the neuromuscular gait analysis biomechanical data.Results: The TSK total score and the FABQ physical were correlated with muscle onset of the External Oblique (P = 0.005), Gluteus Maximus (P = 0.018), Multifidi (P = 0.017), Erector Spinae (P = 0.014), Rectus Femoris (i = 0.008), Semitendinosus (P = 0.012), Tibilais Anterior (P = 0.012), and Medial Gastrocnemius (P = 0.010). Furthermore, the TSK total score, FABQ physical portion were correlated with muscle peak activity of Medial Gastrocnemius (P = 0.007), Multifidi (P = 0.014), and Tibilais Anterior (i = 0.050) and time to peak muscle activity of the Medial Gastrocnemius (P = 0.006) and Semitendinosus P = 0.038.Conclusion: This study demonstrates a strong correlation between neuromuscular gait parameters and fear-avoidance of movement which may reflect ADS patient experiences during ambulation. Further, it demonstrates that there are different aspects of fear-avoidance that may influence gait parameters. This study extends previous research on the role of fear-avoidance to include patients with spinal deformity.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Balance is defined as the ability of the human body to maintain its center of mass (COM) within the base of support with minimal postural sway. Sway is the movement of the COM in the horizontal plane when a person is standing in a static position. Cervical spondylotic myelopathy (CSM) patients have impaired body balance and proprioceptive loss. PURPOSE To quantify the amount of sway associated with maintaining a balanced posture within the cone of economy (COE) in a group of untreated CSM patients and compare them to matched healthy controls. STUDY DESIGN/SETTING A prospective cohort study. PATIENT SAMPLE Thirty-two CSM patients and sixteen healthy controls (HC). OUTCOME MEASURES Center of mass (COM) and head sway, spine and lower extremityIntegrated Electromyography (iEMG). METHODS Thirty-two CSM patients performed a series of functional balance tests a week before surgery. Sixteen healthy controls (HC) performed a similar balance test. The functional balance test was essentially a Romberg's test in which the patients are required to stand erect with feet together and eyes opened in their self-perceived balanced and natural position for a full minute. All test subjects were fitted to a full body reflective markers set and surface EMG. RESULTS CSM patients presented more center of mass (COM) sway in the anterior-posterior (CSM: 2.87 vs. C: 0.74cm; p=.023) and right-left (CSM: 5.16 vs. C: 2.51cm; p=.003) directions and head sway (anterior-posterior – CSM: 2.17 vs. C: 0.82cm; p=.010 and right-left – CSM: 3.66 vs. C: 1.69cm; p=.044) and more COM (CSM: 44.72cm vs. HC: 19.26cm, p=.001) and head (Pre: 37.87cm vs. C: 19.93cm, p=.001) total sway in comparison to the healthy controls. CSM patients expended statistically significantly more muscle activity to maintain static standing, as manifest by increased muscle activity in their Multifidus (CSM: 22.25mV vs. HC: 12.39mV, p=.038), Erector Spinae (CSM: 26.76mV vs. HC: 14.41mV, p=.044), Rectus Femoris (CSM: 29.05mV vs. HC: 16.07mV, p=.037), and Tibialis Anterior(CSM: 23.06mV vs. HC: 14.48mV, p=.048) muscles during one minute standing in comparison to healthy control. CONCLUSIONS In symptomatic CSM patients, COM and head total sway were significantly greater than controls. Individuals with CSM exhibit more trunk and lower extremity muscle activity, and thus expend more energy to maintain a balanced, static standing posture. While most of the balance research in patients with spinal disorders is done based on static x-rays and mostly focused on sagittal spinal alignment, this study is the first effort to evaluate global balance as a dynamic process. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Gait impairment is a hallmark of cervical spondylotic myelopathy (CSM) and has been shown to affect quality of life. Some studies describe the gait as spastic, while others suggest a paretic component. Further electromyographic (EMG) characterization of the gait cycle may help elucidate the true neuromuscular pathology with implications on prognosis and rehabilitation techniques. PURPOSE To compareneuromuscular activity in CSM patients to healthy, age-matched controls. STUDY DESIGN/SETTING Nonrandomized, prospective, concurrent control cohort study. PATIENT SAMPLE Forty patients with symptomatic CSM prior to any surgical intervention and 25 healthy controls. OUTCOME MEASURES Integrated electromyography (iEMG), peak EMG, time to peak EMG, mean power frequency and time of muscle onset. METHODS Forty patients with symptomatic CSM prior to any surgical intervention and 25 healthy controls had neuromuscular activity measured during a series of over-ground gait trials at a self-selected speed. External Oblique (EO), Multifidus (Mf), Erector Spinae (ES), Rectus Femoris (RF), Semitendinosus (ST), Tibialis Anterior (TA), Medial Gastrocnemius (MG) and Medial Deltoid (MD) were assessed. Differences in integrated electromyography (iEMG), peak EMG, time to peak EMG, mean power frequency and time of muscle onset were assessed using one-way ANOVA. RESULTS Compared to controls, patients with CSM demonstrated significantly less activation amplitude of the EO (0.72±0.79 vs. 1.52±2.05mV; p=.034), ST (3.02±5.37 vs. 5.86±9.19mV; p=.05), and MD (0.876±0.81 vs. 2.6±3.77mV; p=.008). They demonstrated significantly higher peak EMG muscle activity in the MD (0.06±0.044 vs. 0.03±0.021mV; p=.031) and significantly longer time to peak EMG muscle activity in the Mf (20.2±8.5 vs. 16.8±8.9ms, p=0.050), ES (18.2±6.7 vs. 8.9±7.2ms; p<.001), ST (26.3±7.2 vs. 22.4±6.8ms; p=.037), TA (14.7±7.4 vs. 11.0±7.4ms; p=.050) and MD (24.2±8.5 vs. 9.2±6.6ms p<.001). There was no difference in time of onset of muscle activity during gait. CONCLUSIONS Patients with CSM often present with a gait disturbance that has significant implications on quality of life. This study's findings demonstrate difficulty with muscular recruitment in lower extremity stabilizing musculature, coupled with increased peak EMG activity in the MD, representing compensatory mechanisms in the upper extremities, as well. This study contributes to existing knowledge on EMG muscle activity in patients with untreated CSM and will be useful in future studies investigating neuromuscular function in patients with CSM after surgical decompression. [ABSTRACT FROM AUTHOR]

BACKGROUND CONTEXT Adult degenerative scoliosis (ADS) patients frequently suffer from impairments in mobility. Surgical intervention for ADS mostly improves gait, balance and other health-related quality of life scores. Previous literature demonstrates that the central nervous system (CNS) might use an organization of muscle synergies to control a wide range of activities, for example walking. Instead of controlling each muscle individually, the CNS groups the muscles and activates many them with a single control signal. Hence, neuromuscular synergies may indicate the ability of the CNS in generating independent control signals. Less number of muscle synergies during walking emphasizes inability of the CNS to generate as many independent control signals. The higher number of synergies represents the higher gait complexity since more number of control inputs are required to achieve the same task. PURPOSE To compare number of walking muscle synergies in ADS patients both before and 3 months postsurgery. STUDY DESIGN/SETTING A prospective concurrent control cohort study. PATIENT SAMPLE A total of 13 ADS patients. OUTCOME MEASURES Gait complexity by number of muscle synergies. METHODS Clinical gait analysis was performed one week prior and 3 months postsurgery. Five walking trials were performed at comfort speed. Surface electromyography (EMG) electrodes were placed and recorded bilaterally from 16 trunk and lower extremity muscles: external oblique, gluteus maximus, multifidus, erector spinae, rectus femoris, semitendinosus, tibialis anterior, medial gastrocnemius. EMG data was collected at 2,000 Hz, filtered, rectified, and normalized. The processed EMG was mathematically broken into synergies and their activation ratio (from 100%). The higher number of synergies always reduces the residual error between the reconstructed EMG and the original EMG. The required number of synergies were defined as the minimum number of synergies that could reconstruct EMG signals with subtracting 5% error ([EMGoriginal -EMGreconstructed] = e, e/EMGoriginal <5%). A paired t test was used to test the hypothesis (α=0.05) using SPSS. RESULTS Clinical gait analysis was performed one week prior and 3 months postsurgery. Five walking trials were performed at comfort speed. Surface electromyography (EMG) electrodes were placed and recorded bilaterally from 16 trunk and lower extremity muscles: external oblique, gluteus maximus, multifidus, erector spinae, rectus femoris, semitendinosus, tibialis anterior and medial gastrocnemius. EMG data was collected at 2,000 Hz, filtered, rectified and normalized. The processed EMG was mathematically broken into synergies and their activation ratio (from 100%). The higher number of synergies always reduces the residual error between the reconstructed EMG and the original EMG. The required number of synergies were defined as the minimum number of synergies that could reconstruct EMG signals with subtracting 5% error {(EMGoriginal -EMGreconstructed) = e, e/EMGoriginal <5%). A paired t test was used to test the hypothesis (α=0.05) using SPSS. CONCLUSIONS This study shows an increase in gait complexity by increase in number of synergies following a surgical alignment in ADS patients. More number of synergies postsurgery shows a more elaborate gait pattern since more number of synergies (modules) are required to rebuild the EMG signals, in addition to improvements in ability of the CNS in generating more number of independent or rich control signals. As an example, inability of poststroke patients in generating independent control signals for gait makes their CNS to activate numerous muscles with a single signal (at the same time), causing unwanted co-contractions that hinders their normal gait. We recommend that spine care providers use gait analysis as part of their clinical evaluation to provide an objective measure of function and to better understand the effects of the disease and its treatment on their patients' gait, function, and, ultimately, quality of life. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs. [ABSTRACT FROM AUTHOR]