scholarly journals Standardizing fatigue-resistance testing during electrical stimulation of paralysed human quadriceps muscles, a practical approach

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Martin Schmoll ◽  
Ronan Le Guillou ◽  
David Lobato Borges ◽  
Charles Fattal ◽  
Emerson Fachin-Martins ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Knee Extension ◽  
Electrode Configuration ◽  
Resistance Testing ◽  
Positive Effects ◽  
Significant Difference ◽  
Dynamic Contractions ◽  
Isometric Torque

Abstract Background Rapid onset of muscular fatigue is still one of the main issues of functional electrical stimulation (FES). A promising technique, known as distributed stimulation, aims to activate sub-units of a muscle at a lower stimulation frequency to increase fatigue-resistance. Besides a general agreement on the beneficial effects, the great heterogeneity of evaluation techniques, raises the demand for a standardized method to better reflect the requirements of a practical application. Methods This study investigated the fatigue-development of 6 paralysed quadriceps muscles over the course of 180 dynamic contractions, evaluating different electrode-configurations (conventional and distributed stimulation). For a standardized comparison, fatigue-testing was performed at 40% of the peak-torque during a maximal evoked contraction (MEC). Further, we assessed the isometric torque for each electrode-configuration at different knee-extension-angles (70°–170°, 10° steps). Results Our results showed no significant difference in the fatigue-index for any of the tested electrode-configurations, compared to conventional-stimulation. We conjecture that the positive effects of distributed stimulation become less pronounced at higher stimulation amplitudes. The isometric torque produced at different knee-extension angles was similar for most electrode-configurations. Maximal torque-production was found at 130°–140° knee-extension-angle, which correlates with the maximal knee-flexion-angles during running. Conclusion In most practical applications, FES is intended to initiate dynamic movements. Therefore, it is crucial to assess fatigue-resistance by using dynamic contractions. Reporting the relationship between produced torque and knee-extension-angle can help to observe the stability of a chosen electrode-configuration for a targeted range-of-motion. Additionally, we suggest to perform fatigue testing at higher forces (e.g. 40% of the maximal evoked torque) in pre-trained subjects with SCI to better reflect the practical demands of FES-applications.

scholarly journals Comparison of Apical Transportation, Centering Ability and Cyclic Fatigue Resistance of Four Rotary File Systems

2015 ◽  
Vol 03 (01) ◽  
pp. 012-019
Author(s):  
Ankita Sood ◽  
Varun Jindal ◽  
Ajay Chhabra ◽  
Arvind Arora ◽  
Ankur Vats
Keyword(s):  
Fatigue Resistance ◽  
Fatigue Testing ◽  
File Systems ◽  
Cyclic Fatigue ◽  
Root Canal Preparation ◽  
Maxillary Molars ◽  
Apical Transportation ◽  
Significant Difference ◽  
Before And After ◽  
Canal Transportation

Abstract Aim: The aim of this study was to evaluate the apical transportation, centering ability and cyclic fatigue resistance of Hero shaper, Twisted file, Hyflex file and RACE rotary file systems. Methods: Mesiobuccal roots of eighty maxillary molars were divided into four groups and instrumented with Hero shaper, Twisted file, Hyflex file and RACE rotary file systems with a final apical size being 25/.04. Apical deviation was assessed by the radiographic platform method that enables obtaining superimposed images of the first and last instrument used in root canal preparation in the same radiograph. Apical transportation was measured in millimeters with the aid of the AUTOCAD 2008 software. Forty canals were sectioned at 7mm from the apex and stereomicroscopic Images were taken at 6x magnification before and after instrumentation for evaluation of centering ability. The cyclic fatigue testing was conducted with the instrumentrotating freely at angles of curvature of 45 degree. Total 10 instruments were tested in each group. The instruments were rotated at 400rpm using the X-smart motor (Dentsply, Maillefer) until fracture occurred. Results: There was no statistically significant difference between the four groups in apical transportation and centering ability whereas twisted files showed the maximum cyclic fatigue resistance. Conclusion: The different rotary file systems provided minimum canal transportation and the twisted file performed significantly better in terms of cyclic fatigue resistance.

scholarly journals Assessment of the role of cross section on fatigue resistance of rotary files when used in reciprocation

2016 ◽  
Vol 10 (04) ◽  
pp. 541-545 ◽  
Author(s):  
Vadhana Sekar ◽  
Ranjith Kumar ◽  
Suresh Nandini ◽  
Suma Ballal ◽  
Natanasabapathy Velmurugan
Keyword(s):  
Cross Section ◽  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Dynamic Testing ◽  
Cyclic Fatigue ◽  
Reciprocating Motion ◽  
Continuous Rotation ◽  
Significant Difference ◽  
Post Hoc

ABSTRACT Objective: The purpose of this study was to assess the role of cross section on cyclic fatigue resistance of One Shape, Revo-S SU, and Mtwo rotary files in continuous rotation and reciprocating motion in dynamic testing model. Materials and Methods: A total of 90 new rotary One Shape, Revo-S SU, and Mtwo files (ISO size 25, taper 0.06, length 25 mm) were subjected to continuous rotation or reciprocating motion. A cyclic fatigue testing device was fabricated with 60° angle of curvature and 5 mm radius. The dynamic testing of these files was performed using an electric motor which permitted the reproduction of pecking motion. All instruments were rotated or reciprocated until fracture occurred. The time taken for each instrument to fracture was recorded. All the fractured files were analyzed under a scanning electron microscope (SEM) to detect the mode of fracture. Statistical analysis was performed using one-way ANOVA, followed by Tukey's honestly significant difference post hoc test. Results: The time taken for instruments in reciprocating motion to fail under cyclic loading was significantly longer when compared with groups in continuous rotary motion. There was a statistically significant difference between Mtwo rotary and the other two groups in both continuous and reciprocating motion. One Shape rotary files recorded significantly longer duration to fracture resistance when compared with Revo-S SU files in both continuous and reciprocating motion. SEM observations showed that the instruments of all groups had undergone a ductile mode of fracture. Conclusion: Reciprocating motion improved the cyclic fatigue resistance of all tested groups.

scholarly journals Activation of human quadriceps femoris muscle during dynamic contractions: effects of load on fatigue

2000 ◽  
Vol 89 (3) ◽  
pp. 926-936 ◽  
Author(s):  
Samuel C. K. Lee ◽  
Cara N. Becker ◽  
Stuart A. Binder-Macleod
Keyword(s):  
Electrical Stimulation ◽  
Muscle Fatigue ◽  
Skeletal Muscles ◽  
Average Power ◽  
Knee Extension ◽  
Limiting Factor ◽  
Functional Activities ◽  
Dynamic Contractions ◽  
Shortening Contractions ◽  
Femoris Muscle

Muscle fatigue is both multifactorial and task dependent. Electrical stimulation may assist individuals with paralysis to perform functional activities [functional electrical stimulation (FES), e.g., standing or walking], but muscle fatigue is a limiting factor. One method of optimizing force is to use stimulation patterns that exploit the catchlike property of skeletal muscle [catchlike-inducing trains (CITs)]. Although nonisometric (dynamic) contractions are important parts of both normal physiological activation of skeletal muscles and FES, no previous studies have attempted to identify the effect that the load being lifted by a muscle has on the fatigue produced. This study examined the effects of load on fatigue during dynamic contractions and the augmentation produced by CITs as a function of load. Knee extension in healthy subjects was electrically elicited against three different loads. The highest load produced the least excursion, work, and average power, but it produced the greatest fatigue. CIT augmentation was greatest at the highest load and increased with fatigue. Because CITs were effective during shortening contractions for a variety of loads, they may be of benefit during FES applications.

A comparison of the biomechanical stability of pedicle-lengthening screws and traditional pedicle screws

2018 ◽  
Vol 100-B (4) ◽  
pp. 516-521 ◽  
Author(s):  
L. Qian ◽  
C. Jiang ◽  
P. Sun ◽  
D. Xu ◽  
Y. Wang ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Fatigue Testing ◽  
Lumbar Vertebrae ◽  
Pedicle Screws ◽  
Cyclic Fatigue ◽  
Resistance Testing ◽  
Mineral Density ◽  
Biomechanical Stability ◽  
Pull Out ◽  
Fixation Stability

Aims The aim of this study was to compare the peak pull-out force (PPF) of pedicle-lengthening screws (PLS) and traditional pedicle screws (TPS) using instant and cyclic fatigue testing. Materials and Methods A total of 60 lumbar vertebrae were divided into six groups: PLS submitted to instant pull-out and fatigue-resistance testing (groups A1 and A2, respectively), TPS submitted to instant pull-out and fatigue-resistance testing (groups B1 and B2, respectively) and PLS augmented with 2 ml polymethylmethacrylate, submitted to instant pull-out and fatigue-resistance testing (groups C1 and C2, respectively). The PPF and normalized PPF (PPFn) for bone mineral density (BMD) were compared within and between all groups. Results In all groups, BMD was significantly correlated with PPF (r = 0.83, p < 0.001). The PPFn in A1 was significantly less than in B1 (p = 0.006) and C1 (p = 0.002). The PPFn of A2 was significantly less than in B2 (p < 0.001) and C2 (p < 0.001). The PPFn in A1, B1, and C1 was significantly greater than in A2 (p = 0.002), B2 (p = 0.027), and C2 (p = 0.003). There were no significant differences in PPFn between B1 and C1, or between B2 and C2. Conclusion Pedicle lengthening screws with cement augmentation can provide the same fixation stability as traditional pedicle screws and may be a viable clinical option. Cite this article: Bone Joint J 2018;100-B:516–21.

scholarly journals PO-166 Neuromuscular Fatigue after maximal Concentric and Eccentric Contractions of Knee Extensor

2018 ◽  
Vol 1 (4) ◽  
Author(s):  
Shenpeng Xu ◽  
Ying Wang ◽  
Wan Chen
Keyword(s):  
Electrical Stimulation ◽  
Knee Flexion ◽  
Low Frequency ◽  
Knee Extensor ◽  
Knee Extension ◽  
Neuromuscular Fatigue ◽  
Peripheral Fatigue ◽  
Concentric Exercise ◽  
Significant Difference ◽  
Low Frequency Fatigue

Objective The aim of this study was to investigate after different maximal contractions concentric and eccentric would cause different neuromuscular fatigue of knee extensor.  Methods Ten healthy young men(21≤age≤24) who were not adapted by electrical stimulation were the subjects.The subjects were asked to arrive at the laboratory in three weeks at the same time of every week to avoid the effects of biological rhythms.Each subject performed three group maximal contractions on the ISOMED2000 isokinetic muscle tester according to the requirements.The subjects performed the same neuromuscular function test before and after exercise.The centripetal motion scheme:3*30,M1(knee flexion)-CON,M2(knee extension)-CON.angular velocity is 60 °,interval 30s in each group.Centrifugal motion scheme:3*30,M1(knee flexion)-ECC,M2(knee extension)-ECC.angular velocity is 60 °,interval 30s in each group.  Results The decrease rate of peak torque after concentric exercise was 55.93±13.20%, which was significantly higher than that after centrifugal exercise (20.06 ±11.06%, P < 0.01)The total work of the concentric movement was 8737.20±1543.43J, which was significantly smaller than that of the centrifugal exercise group (14312.20±2978.31J, P < 0. 01).The decline rate of MVC in concentric exercise was 24.89 ±10.54 and that in centrifugal exercise was 19.32±9.90,there was no significant difference between the two groups. Double Twitch induced a very significant decrease in PT-SSR RFD-SSN RHD-SS (P<0.01).There was no significant difference in VA decline rate.PAP decreased from 142.82±14.55% to 125.23±11.36 after concentric exercise, and after eccentric exercise PAP decreased from 141.1215.72% to 126.02 ±10.45.  Conclusions The neuromuscular fatigue caused by two kinds of exercise. Peripheral fatigue accounted for 39.19% after concentric exercise and 23.59% after centrifugal exercise,but there was little difference in the degree of central fatigue.All of them showed low frequency fatigue, and the low frequency fatigue after centrifugal exercise was more obvious. Key World:Neuromuscular fatigue; Electrical stimulation; High-frequency fatigue; Low-frequency fatigue; PAP.

scholarly journals Effect of Hydrogen Peroxide on Cyclic Fatigue Resistance of NiTi Endodontic Files

2020 ◽  
Vol 29 (04) ◽  
pp. 246-248
Author(s):  
Huma Sarwar ◽  
◽  
Meshal M Meshal M Naeem ◽  
Sumaiya Shabbir ◽  
Sania Riaz ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Fatigue Resistance ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Resistance Testing ◽  
P Value ◽  
Group I ◽  
Significant Difference ◽  
Group Ii ◽  
Dent Assoc

OBJECTIVE: To investigate the effect of nickel titanium rotary endodontic file immersion in hydrogen peroxide on cyclic fatigue resistance. METHODOLOGY: Twenty Six Protaper Universal (Dentsply Maillerfier) F1 files were randomly divided into two experimental groups. In Group I, Protaper universal variable taper F1 files were immersed in normal saline where as in Group II, the files were soaked in hydrogen peroxide (6% w/v) for 2 hours at 37°C. Cyclic fatigue of each file was checked by recording the number of rotations required to break a file in a 90°curve with a 5 mm radius. For statistical analysis of data, Two-way ANOVA was applied. A p value of <0.05 was considered significant. RESULT: Out of Twenty Six, Six files fractured spontaneously after immersion in hydrogen peroxide. Twenty files were subjected to fracture resistance testing. Statistically significant difference in cyclic fatigue resistace between the two groups was found (p=0.002). The files soaked in Group II required less revolutions to fracture than the ones immersed Group I. CONCLUSION: The immersion of NiTi endodontic files in hydrogen peroxide significantly reduces cyclic fatigue resistance. Therefore, immersion of the NiTi endodontic files in hydrogen peroxide solution for removal of clogged debris should be discouraged. KEYWORDS: Cyclic fatigue, Endodontic instruments, Hydrogen peroxide, NiTi HOW TO CITE: Sarwar H, Naeem MM, Shabbir S, Riaz S, Afaq H, Shabbir J. Effect of hydrogen peroxide on cyclic fatigue resistance of NiTi endodontic files. J Pak Dent Assoc 2020;29(4):246-248.

Effect of Neuromuscular Electrical Stimulation on Swallowing Process in Stroke Patient with Neurogenic Dysphagia

1970 ◽  
Vol 1 (1) ◽  
pp. 44-53
Author(s):  
Ruth Ariyani ◽  
Widjajalaksmi ◽  
Luh K Wahyuni ◽  
Susyana Tamin ◽  
Saptawati Bardosono
Keyword(s):  
Electrical Stimulation ◽  
Voice Quality ◽  
Neuromuscular Electrical Stimulation ◽  
Neurogenic Dysphagia ◽  
Stroke Patients ◽  
Cough Reflex ◽  
Voluntary Cough ◽  
Pharyngeal Phase ◽  
Significant Difference ◽  
Quasi Experimental

Objective: The aim of this study to determine the therapeutic effect of Neuromuscular Electrical Stimulation (NMES) on pharyngeal phase of swallowing for stroke patients with neurogenic dysphagia,and to see the effect of NMES in reducing the incidence of standing secretion, residue, penetration and aspiration.Methods: It is a quasi-­experimental study design. 10 stroke patients with neurogenic dysphagia in Cipto Mangunkusumo hospital, Jakarta, 40-­80 years old with hemodynamically stable, cooperative and will be get NMES therapy for 4 weeks. Pre and Post treatment assessment caompared using a modified MASA test (The Mann Assessment of Swallowing Ability) and FEES examination (Flexible Endoscophic Evaluation of Swallowing). Analysis of change scores using Wilcoxon test.Results:The obtain average age of patients 59.80+9.705 years. Significant difference seen in the pharyngeal phase of swallowing increased score of gag reflex, velum elevation, cough reflex, voluntary cough, voice quality, pharynx response, pharyngeal constrictor contraction and vocal cord adduction (p<0.005).Also seen significant reduction in the incidence of standing secretion, residue and penetration (p<0.005), but not significantly in the incidence of aspiration (p=0083).Conclusions: NMES increased the pharyngeal phase of swallowing, reduced the incidence of standing secretion, residue and penetration of stroke patients with neurogenic dysphagia, but have not able to reduced aspiration.Keywords :Neuromuscular Electrical Stimulation (NEMS), neurogenic dysphagia, MASA test (The Mann Assessment of Swallow ing Ability), FEES examination (Flexible Endoscophic Evaluation of Swallowing), swallowing process.

INFLUENCE OF FOOT INSOLE ON THE GAIT PERFORMANCE IN SUBJECTS WITH FLAT FOOT DISORDER

2019 ◽  
Vol 19 (06) ◽  
pp. 1950050
Author(s):  
M. T. KARIMI ◽  
R. B. TAHMASEBI ◽  
B. SATVATI ◽  
F. FATOYE
Keyword(s):  
Range Of Motion ◽  
Ankle Joint ◽  
Lower Limb ◽  
Walking Speed ◽  
Force Plate ◽  
Flat Foot ◽  
Gait Performance ◽  
Positive Effects ◽  
Significant Difference ◽  
Foot Disorder

Flat foot is the most common foot disorder that influences the alignment of the lower limb structure. It is controversial whether the use of foot insole influences kinetic and kinematic of the leg or not. Therefore, this study investigated the influence of foot insole on the gait performance in subjects with flat foot disorder. A group of flat foot subject was recruited into this study (the number of subjects was 15). The motion of the leg joints was determined using the Qualysis motion analysis system. Moreover, the force applied on the lower limb was recorded by a Kistler force plate. The range of motion of the lower limb joints, the moments applied on the lower limb joints and force transmitted through the leg were the parameters used in this study. The difference between these parameters during walking with and without insole was evaluated using the paired [Formula: see text]-test. Significant value was set at [Formula: see text]. There was no significant difference between the range of motion of ankle joint while walking with and without insole. However, the medial directed force applied on the leg decreased significantly [Formula: see text]. The use of foot insole did not influence the moments transmitted through the hip and knee joints. The walking speed of the subjects improved while walking with foot insole. Use of foot insole influenced the magnitude of the force applied on the leg and the adductor moment of ankle joint due to its influence on foot alignment. As the walking speed of the improved subjects follows the use of insole, it can be concluded that it may have a positive effects on the performance of flat foot subjects.

A comparative study of the acute effects of knee brace vs. kinesiotape on selected isokinetic strength variables of the knee muscles

2021 ◽  
pp. 1-6
Author(s):  
Ali Kerim Yilmaz ◽  
Mehmet Vural ◽  
Mustafa Özdal ◽  
Menderes Kabadayi
Keyword(s):  
Knee Injuries ◽  
Knee Extension ◽  
Acute Effects ◽  
Post Injury ◽  
Kinesio Tape ◽  
Knee Strength ◽  
Significant Difference ◽  
S Peak ◽  
Male Subjects ◽  
Methods Of Treatment

BACKGROUND: Different methods of treatment for preventing knee injuries, enhancing knee strength and minimising post-injury risks have been explored. Among these methods, Kinesio tape (KT) and knee braces (KB) are commonly used. OBJECTIVE : To investigate the acute effects of KT and KB on isokinetic knee strength parameters. METHODS: A total of 15 healthy sedentary male subjects voluntarily participated in the study. Concentric isokinetic knee extension (EX) and flexion (FLX) strength were measured at three sessions: 1. Baseline 2. with KT (’KT’) 3. with KB (’KB’). Tests were performed at 60, 180 and 240∘/s. Peak moment (PM), Hamstring/Quadriceps ratio (HQR), and joint angle at peak moment (JAPM) were measured. RESULTS: ‘KT’ and ‘KB’ were associated with increase in PMEX, PMFLX, HQR at 60 and 240∘/s (p< 0.05) and increased JAPMEX. No significant difference was observed at 180∘/s (p> 0.05). CONCLUSION: In healthy individuals, ‘I’ shape KT and KB positively affect EX and FLX strengths and HQR, especially at low angular velocity.

scholarly journals Effect of synchronous irrigation on cyclic fatigue of nickel-titanium instrument in the dynamic and static models

2021 ◽  
Vol 19 ◽  
pp. 228080002098740
Author(s):  
Haiyun Liu ◽  
Yanfeng Li ◽  
Guangquan Chai ◽  
Yuan Lv ◽  
Changjian Li ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Flow Rate ◽  
Dynamic Control ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Control Group ◽  
Time To Failure ◽  
Dynamic Tests ◽  
Significant Difference ◽  
Experimental Group

Objective: To evaluate the effect of synchronous water irrigation on the fatigue resistance of nickel-titanium instrument. Methods: A standardized cyclic fatigue test models were established, and five types of nickel-titanium instruments (PTU F1, WO, WOG, RE, and M3) were applied. Each instrument was randomly divided into two groups ( N = 12). There was synchronous water irrigation in the experimental group, and no water irrigation in the control group. Besides, ProTaper Universal F1 was randomly divided into 10 groups ( N = 20). In the static group, nickel-titanium instruments were divided into one control group (no irrigation, N = 20) and six experimental group (irrigation, N = 20) based on different flow rate, angle and position; while in the dynamic group, instruments were divided into one control group (no irrigation, N = 20) and two experimental group (irrigation, N = 20) based on different flow rate. The rotation time (Time to Failure, TtF) of instruments was recorded and analyzed. Results: According to the static experiments, the TtF of instruments in all experimental groups was significantly higher than that in the static control group. Besides, the dynamic tests of PTU F1 showed that the TtF in the experimental group was significantly higher than that in the dynamic control group. Compared with control group, the TtF in the experimental groups increased by at least about 30% and up to 160%. The static and dynamic tests of PTU F1 showed that the TtF of nickel-titanium instrument in all experimental groups was significantly higher than that in the control group. However, there was no significant difference between any two experimental groups. Conclusion: Regardless of dynamic or static model, TtF with irrigation was longer than that with non-irrigation, indicating that synchronous irrigation can increase the fatigue resistance of nickel-titanium instrument. However, different irrigation conditions may have the same effect on the fatigue resistance.

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