scholarly journals Impact of Lockdown during COVID-19 Pandemic on Central Activation, Muscle Activity, Contractile Function, and Spasticity in People with Multiple Sclerosis

2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Luis Andreu-Caravaca ◽  
Domingo J. Ramos-Campo ◽  
Linda H. Chung ◽  
Pedro Manonelles ◽  
Oriol Abellán-Aynés ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Muscle Activity ◽  
Neural Control ◽  
Contractile Function ◽  
Knee Extensor ◽  
Knee Extensors ◽  
Maximum Voluntary Isometric Contraction ◽  
Central Activation ◽  
The Impact ◽  
Muscle Contractile

Background. People with multiple sclerosis (MS) suffer from symptoms related to neural control, such as reduced central activation, lower muscle activity, and accentuated spasticity. A forced 9-week home confinement related to COVID-19 in Spain may have worsened these symptoms. However, no study has demonstrated the impact of home confinement on neuromuscular mechanisms in the MS population. This study was aimed at analyzing the effects of a 9-week home confinement on central activation, muscle activity, contractile function, and spasticity in MS patients. Methods. Eighteen participants were enrolled in the study. Left and right knee extensor maximum voluntary isometric contraction (MVIC), maximal neural drive via peak surface electromyography (EMG) of the vastus lateralis, central activation ratio (CAR), and muscle contractile function via electrical stimulation of the knee extensor muscles, as well as spasticity using the pendulum test, were measured immediately before and after home confinement. Results. Seventeen participants completed the study. CAR significantly decreased after lockdown ( ES = 1.271 , p < 0.001 ). Regarding spasticity, there was a trend to decrease in the number of oscillations ( ES = 0.511 , p = 0.059 ) and a significant decrease in the duration of oscillations ( ES = 0.568 , p = 0.038 ). Furthermore, in the left leg, there was a significant decrease in the first swing excursion ( ES = 0.612 , p = 0.027 ) and in the relaxation index ( ES = 0.992 , p = 0.001 ). Muscle contractile properties, MVIC, and EMG variables were not modified after confinement. Conclusions. The results suggest that a home confinement period of 9 weeks may lead to an increase in lower limb spasticity and a greater deficit in voluntary activation of the knee extensors.

scholarly journals Effects of long-term resistance training and simultaneous electro-stimulation on muscle strength and functional mobility in multiple sclerosis

2010 ◽  
Vol 17 (4) ◽  
pp. 468-477 ◽  
Author(s):  
Tom Broekmans ◽  
Machteld Roelants ◽  
Peter Feys ◽  
Geert Alders ◽  
Domien Gijbels ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Resistance Training ◽  
Muscle Strength ◽  
Controlled Trial ◽  
Knee Extensor ◽  
Functional Mobility ◽  
Knee Extensors ◽  
Strength Analysis ◽  
Control Group

Background: Resistance training studies in multiple sclerosis (MS) often use short intervention periods. Furthermore, training efficiency could be optimized by unilateral training and/or electrical stimulation. Objective: To examine the effect(s) of unilateral long-term (20 weeks) standardized resistance training with and without simultaneous electro-stimulation on leg muscle strength and overall functional mobility. Methods: A randomized controlled trial involving 36 persons with MS. At baseline (PRE) and after 10 (MID) and 20 (POST) weeks of standardized (ACSM) light to moderately intense unilateral leg resistance training (RESO, n = 11) only or resistance training with simultaneous electro-stimulation (RESE, n = 11, 100 Hz, biphasic symmetrical wave, 400 µs), maximal isometric strength of the knee extensors and flexors (45°, 90° knee angle) and dynamic (60–180°/s) knee-extensor strength was measured and compared with a control group (CON, n = 14). Functional mobility was evaluated using the Timed Get Up and Go, Timed 25 Foot Walk, Two-Minute Walk Test, Functional Reach and Rivermead Mobility Index. Results: Maximal isometric knee extensor (90°, MID: +10 ± 3%, POST: +10 ± 4%) in RESO and knee flexor (45°, POST: +7 ± 4%; 90°, POST: +9 ± 5%) in RESE strength increased ( p < 0.05) compared with CON but RESO and RESE did not differ. Also, impaired legs responded positively to resistance training (unilateral leg strength analysis) and functional reaching increased significantly in RESO (+18%) compared with CON. Dynamic muscle strength and the remaining functional mobility tests did not change. Conclusion: Long-term light to moderately intense resistance training improves muscle strength in persons with MS but simultaneous electro-stimulation does not further improve training outcome.

Muscle Contractile Function and Neural Control after Repetitive Endurance Cycling

2010 ◽  
Vol 42 (1) ◽  
pp. 206-212 ◽  
Author(s):  
EMMA Z. ROSS ◽  
WARREN GREGSON ◽  
KAREN WILLIAMS ◽  
COLIN ROBERTSON ◽  
KEITH GEORGE
Keyword(s):  
Neural Control ◽  
Contractile Function ◽  
Endurance Cycling ◽  
Muscle Contractile

scholarly journals The relationship between upper leg muscle strength and walking capacity in persons with multiple sclerosis

2012 ◽  
Vol 19 (1) ◽  
pp. 112-119 ◽  
Author(s):  
Tom Broekmans ◽  
Domien Gijbels ◽  
Bert O. Eijnde ◽  
Geert Alders ◽  
Ilse Lamers ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Resistance Training ◽  
Muscle Strength ◽  
Knee Extensor ◽  
Knee Extensors ◽  
Regression Analyses ◽  
Walking Capacity ◽  
Disability Status ◽  
Leg Muscle ◽  
Flexor Strength

Background: In persons with multiple sclerosis (PwMS) resistance training improves muscle strength but effects on walking capacity are inconsistent. Objective: The objective was to determine the relation between different types of upper leg muscle strength measurements and walking capacity in PwMS. Methods: An observational cross-sectional study design was applied. Upper leg muscle strength of 52 PwMS (Expanded Disability Status Scale, EDSS range 1.5–6.5) was measured using isometric (knee extensors and flexors) and isokinetic (knee extensors) dynamometry. Walking capacity was assessed using the Timed 25-Foot Walk, Timed Up and Go and Two Minute Walk Test. Subgroups with mild (EDSS 1.5–4.0, n=31) and moderate (EDSS 4.5–6.5, n=21) ambulatory dysfunction were distinguished, and results were hypothesized to differ depending on multiple sclerosis (MS)-related disability status. Correlation and regression analyses were performed on the data of the most affected leg. Results: Greatest ( r: 0.2–0.7) and significant Pearson correlation coefficients were found in the moderate compared to mild MS subgroup. Within knee extensor measurements, it was found that isokinetic endurance strength related best to walking capacity. When comparing maximal isometric strength measurements, knee flexors ( r: 0.5–0.7) related better to walking capacity than knee extensors ( r: 0.1–0.4). Regression analyses confirmed endurance knee extensor strength (~25 %) and isometric knee flexor strength (~40%) as main predictors for walking capacity. Conclusion: Resistance training protocols may consider inclusion of exercises focusing on endurance knee extensor and isometric knee flexor strength when aiming to enhance walking capacity in persons with moderate ambulatory dysfunction.

scholarly journals Number of Synergies Impacts Sensitivity of Gait to Weakness and Contracture

2021 ◽  
Author(s):  
Elijah C. Kuska ◽  
Naser Mehrabi ◽  
Michael H. Schwartz ◽  
Katherine M. Steele
Keyword(s):  
Muscle Weakness ◽  
Muscle Activity ◽  
Neural Control ◽  
Control Strategies ◽  
Knee Extensor ◽  
Musculoskeletal Impairments ◽  
Small Set ◽  
Hip Flexor ◽  
Impairment Severity ◽  
Insight Into

Muscle activity during gait can be described by a small set of synergies, weighted groups of muscles, that are often theorized to reflect underlying neural control. For people with neurologic injuries, like in cerebral palsy or stroke, even fewer (e.g., < 5) synergies are required to explain muscle activity during gait. This reduction in synergies is thought to reflect simplified control strategies and is associated with impairment severity and treatment outcomes. Individuals with neurologic injuries also develop secondary musculoskeletal impairments, like weakness or contracture, that can also impact gait. The combined impacts of simplified control and musculoskeletal impairments on gait remains unclear. In this study, we use a musculoskeletal model constrained to synergies to simulate unimpaired gait. We vary the number of synergies (3-5), while simulating muscle weakness and contracture to examine how altered control impacts sensitivity to muscle weakness and contracture. Our results highlight that reducing the number of synergies increases sensitivity to weakness and contracture. For example, simulations using five-synergy control tolerated 40% and 51% more knee extensor weakness than those using four- and three-synergy control, respectively. Furthermore, the model became increasingly sensitive to contracture and proximal muscle weakness, such as hamstring and hip flexor weakness, when constrained to four- and three-synergy control. However, the models sensitivity to weakness of the plantarflexors and smaller bi-articular muscles was not affected by the number of synergies. These findings provide insight into the interactions between altered control and musculoskeletal impairments, emphasizing the importance of incorporating both in future simulation studies.

Comparison Between Isometric and Concentric Motor Fatigability in Persons With Multiple Sclerosis and Healthy Controls – exploring central and peripheral contributions of motor fatigability

2021 ◽  
pp. 154596832110175
Author(s):  
Tobias Gaemelke ◽  
Morten Riemenschneider ◽  
Ulrik Dalgas ◽  
Tue Kjølhede ◽  
Cuno Rasmussen ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Regression Analysis ◽  
Knee Extensor ◽  
Voluntary Contraction ◽  
Voluntary Activation ◽  
Knee Extensors ◽  
Healthy Controls ◽  
Isokinetic Dynamometer ◽  
Interpolated Twitch Technique ◽  
Group Regression

Background Motor fatigability (i.e. contraction-induced reduction in muscle strength) from a concentric task associate stronger to walking and perception of fatigue in persons with multiple sclerosis (pwMS), compared with an isometric task. However, the central and peripheral contributions of motor fatigability between these tasks have not been investigated. Objective Compare the central and peripheral contributions of motor fatigability in the knee extensors in a sustained isometric fatigability protocol versus a concentric fatigability protocol and in pwMS versus healthy controls (HCs). Methods Participants (n=31 pwMS; n=15 HCs) underwent neuromuscular testing before and immediately after two knee extensor fatigability tasks (sustained isometric and concentric) in an isokinetic dynamometer. Neuromuscular testing of fatigability consisted of maximal voluntary contraction, voluntary activation (central/neural contributor), and resting twitch (peripheral/muscular contributor) determined by the interpolated twitch technique. Results Sustained isometric and concentric fatigability protocols resulted in motor fatigability for both pwMS and HCs, with no between-protocols differences for either group. Regression analysis showed that motor fatigability variance in pwMS was mainly attributed to central fatigability in the sustained isometric protocol and to both central and peripheral fatigability in the concentric protocol. In HCs, the variance in sustained isometric and concentric fatigability were attributed to both peripheral and central fatigability. Conclusion Central and peripheral contributions of motor fatigability differed between sustained isometric and concentric protocols as well as between pwMS and HCs. These between-protocol differences in pwMS provide a neuromuscular dimension to the reported difference in the strength of associations of concentric and isometric tasks to walking and perception of fatigue in pwMS.

scholarly journals EFFECTS OF ELASTIC WRAP ON MUSCLE ACTIVITY AND ISOMETRIC FORCE OF KNEE EXTENSORS

2018 ◽  
Vol 24 (4) ◽  
pp. 295-299
Author(s):  
Fábio Sisconeto de Freitas ◽  
Willy Andrade Gomes ◽  
Paulo Henrique Marchetti
Keyword(s):  
Muscle Activity ◽  
Repeated Measures ◽  
Isometric Force ◽  
Vastus Lateralis ◽  
Knee Extension ◽  
Peak Force ◽  
Knee Extensors ◽  
Level Of Evidence ◽  
Maximum Voluntary Isometric Contraction ◽  
Total Body Mass

ABSTRACT Introduction: The elastic knee wrap (EKW) is a device used by powerlifters, weightlifters and subjects undergoing strength training with the aim of stabilizing the knee joint and increasing the development of strength (carryover effect). Objective: To compare the effects of elastic knee wrap use on muscular activity of the vastus lateralis (VL) and on knee extension force during maximum voluntary isometric contraction (MVIC) on the knee extensor chair. Methods: The study included 18 healthy male strength trained (>1 year) subjects (age: 25.56 ± 4.84 years, total body mass: 81.83 ± 8.73 kg, height: 176 cm ± 5.17). Three five-second maximum voluntary isometric contractions (MVICs) of the knee extensors were performed with a 10-second interval between attempts, for each experimental condition: control (C), with elastic knee wrap (EKW), and with tensor (T). The performance of the knee extensors and VL muscle activity were evaluated. A repeated measures ANOVA was used to compare the dependent variables (carryover, peak force, IEMG and Impulse). Results: For carryover, the use of EKW presented a higher value (74.21%) than the control condition (p <0.001, d = 0.96) and was 79.37% higher than the tensor (p <0.001, d = 0.97). Peak force was 12.2% higher in condition C compared to EKW (p = .018, d = 0.71). For impulse, the control condition presented an increase of 8% compared to EKW use (p = .015, d = 0.62). No significant differences were observed for IEMG. Conclusion: Elastic knee wrap use increased strength production capacity during knee extension. The removal of the mechanical effect originating from carryover during MVIC reduces the strength performance of the knee extensors, but not the muscular activation of the VL. Level of Evidence I; Therapeutic studies - Investigation of treatment results.

Robot-assisted gait training in multiple sclerosis: a pilot randomized trial

2007 ◽  
Vol 14 (2) ◽  
pp. 231-236 ◽  
Author(s):  
S. Beer ◽  
B. Aschbacher ◽  
D. Manoglou ◽  
E. Gamper ◽  
J. Kool ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Effect Size ◽  
Knee Extensor ◽  
Gait Training ◽  
Walking Distance ◽  
Robot Assisted ◽  
Knee Extensor Strength ◽  
Walking Velocity ◽  
The Impact

Objective To evaluate feasibility and perform an explanatory analysis of the efficacy of robot-assisted gait training (RAGT) in MS patients with severe walking disabilities (Expanded Disability Status Scale [EDSS] 6.0—7.5) in a pilot trial. Methods Prospective, randomized, controlled clinical trial comparing RAGT with conventional walking training (CWT) in a group of stable MS patients ( n = 35) during an inpatient rehabilitation stay, 15 sessions over three weeks. All patients participated additionally in a multimodal rehabilitation program. The primary outcome measure was walking velocity and secondary measures were 6-minwalking distance, stride length and knee-extensor strength. All tests were performed by an external blinded assessor at baseline after three weeks and at follow-up after six months. Additionally, Extended Barthel Index (EBI) at entry and discharge was assessed (not blinded), and acceptance/convenience of RAGT rated by patients (Visual Analogue Scale [VAS]) was recorded. Results Nineteen patients were randomly allocated to RAGT and 16 patients to CWT. Groups were comparable at baseline. There were 5 drop-outs (2 related directly to treatment) in the RAGT group and 1 in the CWT group, leaving 14 RAGT patients and 15 CWT patients for final analysis. Acceptance and convenience of RAGT as rated by patients were high. Effect sizes were moderate to large, although not significant, for walking velocity (0.700, 95% CI -0.089 to 1.489), walking distance (0.401, 95% CI - 0.370 to 1.172) and knee-extensor strength (right: 1.105, 95% CI 0.278 to 1.932, left 0.650, 95% CI -0.135 to 1.436) favouring RAGT. Prepost within-group analysis revealed an increase of walking velocity, walking distance and knee-extensor strength in the RAGT group, whereas in CWT group only walking velocity was improved. In both groups outcome values returned to baseline at follow-up after six months ( n = 23). Conclusions Robot-assisted gait training is feasible and may be an effective therapeutic option in MS patients with severe walking disabilities. Effect size calculation and prepost analysis suggest a higher benefit on walking velocity and knee-extensor strength by RAGT compared to CWT. Due to several limitations, however, our results should be regarded as preliminary. Post hoc power calculation showed that two groups of 106 patients are needed to demonstrate a significant moderate effect size of 0.4 after three weeks of RAGT. Thus, further studies with a larger number of patients are needed to investigate the impact of this new treatment option in MS patients. Multiple Sclerosis 2008; 14: 231—236. http://msj.sagepub.com

scholarly journals Estradiol's beneficial effect on murine muscle function is independent of muscle activity

2011 ◽  
Vol 110 (1) ◽  
pp. 109-115 ◽  
Author(s):  
Sarah M. Greising ◽  
Kristen A. Baltgalvis ◽  
Allison M. Kosir ◽  
Amy L. Moran ◽  
Gordon L. Warren ◽  
...  
Keyword(s):  
Muscle Activity ◽  
Wheel Running ◽  
Contractile Function ◽  
Isometric Force ◽  
Hindlimb Suspension ◽  
Female Mice ◽  
Hindlimb Muscles ◽  
Ovariectomized Mice ◽  
Isometric Forces ◽  
Muscle Contractile

Estradiol (E2) deficiency decreases muscle strength and wheel running in female mice. It is not known if the muscle weakness results directly from the loss of E2 or indirectly from mice becoming relatively inactive with presumably diminished muscle activity. The first aim of this study was to determine if cage activities of ovariectomized mice with and without E2 treatment differ. Ovariectomized mice were 19–46% less active than E2-replaced mice in terms of ambulation, jumping, and time spent being active ( P ≤ 0.033). After E2-deficient mice were found to have low cage activities, the second aim was to determine if E2 is beneficial to muscle contractility, independent of physical activities by the mouse or its hindlimb muscles. Adult, female mice were ovariectomized or sham-operated and randomized to receive E2 or placebo and then subjected to conditions that should maintain physical and muscle activity at a constant low level. After 2 wk of hindlimb suspension or unilateral tibial nerve transection, muscle contractile function was assessed. Soleus muscles of hindlimb-suspended ovariectomized mice generated 31% lower normalized (relative to muscle contractile protein content) maximal isometric force than suspended mice with intact ovaries ( P ≤ 0.049). Irrespective of whether the soleus muscle was innervated, muscles from ovariectomized mice generated ∼20% lower absolute and normalized maximal isometric forces, as well as power, than E2-replaced mice ( P ≤ 0.004). In conclusion, E2 affects muscle force generation, even when muscle activity is equalized.

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