Comparison of electrical and magnetic stimulations to assess quadriceps muscle function

2009 ◽  
Vol 106 (2) ◽  
pp. 701-710 ◽  
Author(s):  
Samuel Verges ◽  
Nicola A. Maffiuletti ◽  
Hugo Kerherve ◽  
Nicolas Decorte ◽  
Bernard Wuyam ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
High Frequency ◽  
Muscle Function ◽  
Vastus Lateralis ◽  
Intraclass Correlation ◽  
Femoral Nerve ◽  
Random Order ◽  
Quadriceps Muscle ◽  
Function Assessment

This study aimed to 1) compare electrical and magnetic stimulations for quadriceps muscle function assessment, and 2) ascertain whether the ratios of the second twitch elicited by supramaximal electrical and magnetic femoral nerve stimulation at 10 and 100 Hz (T210:100) and the total twitch force elicited by the same types of stimulations (Fpaired10:100) are equivalent to the standard low- to high-frequency force ratio associated with submaximal electrical tetanic stimulations (Ftet10:100). Quadriceps force and vastus lateralis EMG were recorded at rest ( n = 21 subjects), immediately after, and 30 min after a 30-min downhill run ( n = 10) when 1) supramaximal electrical nerve stimulation (ENS), 2) magnetic nerve stimulation (MNS) and 3) submaximal electrical muscle stimulation (EMS) were delivered in random order at 1 (single stimulation), 10, and 100 Hz (paired stimulations). Ten- and 100-Hz 500-ms tetani were also evoked with EMS to determine Ftet10:100. Before exercise, contractile properties with single and paired stimulations were similar for ENS and MNS (all intraclass correlation coefficients k > 0.90), but smaller for EMS ( P < 0.001). M-wave characteristics were also similar for ENS and MNS (all k > 0.90). After exercise, changes in all parameters did not differ between methods. With fatigue, the changes in Ftet10:100 were inconsistently correlated with the changes in T210:100 ( r2 = 0.24–0.73, P = 0.002–0.15) but better correlated with the changes in Fpaired10:100 (immediately after exercise: r2 = 0.80–0.83, P < 0.001; 30 min after exercise: r2 = 0.46–0.82, P = 0.001–0.03). We conclude that ENS and MNS provide similar quadriceps muscle function assessment, while Fpaired10:100 is a better index than T210:100 of low- to high-frequency fatigue of the quadriceps in vivo.

Optimization of Quadriceps Force Distribution for Minimization of Patellofemoral Contact Pressure During a Squat

2007 ◽  
Author(s):  
Aarthi S. Shankar ◽  
Trent M. Guess
Keyword(s):  
Contact Pressure ◽  
Vastus Lateralis ◽  
Rectus Femoris ◽  
Strong Relationship ◽  
Lateral Force ◽  
Quadriceps Muscle ◽  
Contact Forces ◽  
In Vivo Studies ◽  
Muscle Forces

Patellofemoral Pain (PFP) syndrome is a very common knee disorder. A possible cause may be excessive lateral force applied by the quadriceps and the patellar tendon producing an abnormal distribution of force and pressure within the patellofemoral joint [1]. EMG and in-vivo studies have been conducted to understand the function of the quadriceps and its relationship with PFP [2,3]. These studies suggest a strong relationship between muscle forces and PFP which originates from high lateral retropatellar contact forces. A dynamic computational model of the knee was developed which includes the quadriceps muscles Rectus Femoris (RF), Vastus Intermedius (VI), Vastus Lateralis (VL), and Vastus Medialis (VM) represented as force vectors. The model can predict retro-patellar contact pressures and the action of the individual quadriceps muscles based on the predicted pressures. The objective of this study was to develop a control system which could optimize the distribution of quadriceps muscle forces to minimize contact pressure between the patella and the femur of the knee during a squat.

The Validity of Ultrasound Estimation of Muscle Volumes

2007 ◽  
Vol 23 (3) ◽  
pp. 213-217 ◽  
Author(s):  
Benjamin W. Infantolino ◽  
Daniel J. Gales ◽  
Samantha L. Winter ◽  
John H. Challis
Keyword(s):  
Vastus Lateralis ◽  
Intraclass Correlation ◽  
Accurate Method ◽  
Muscle Volume ◽  
Volume Estimation ◽  
Percentage Error ◽  
Ultrasound Images ◽  
Significant Difference ◽  
Hydrostatic Weighing

The purpose of this study was to validate ultrasound muscle volume estimation in vivo. To examine validity, vastus lateralis ultrasound images were collected from cadavers before muscle dissection; after dissection, the volumes were determined by hydrostatic weighing. Seven thighs from cadaver specimens were scanned using a 7.5-MHz ultrasound probe (SSD-1000, Aloka, Japan). The perimeter of the vastus lateralis was identified in the ultrasound images and manually digitized. Volumes were then estimated using the Cavalieri principle, by measuring the image areas of sets of parallel two-dimensional slices through the muscles. The muscles were then dissected from the cadavers, and muscle volume was determined via hydrostatic weighing. There was no statistically significant difference between the ultrasound estimation of muscle volume and that estimated using hydrostatic weighing (p> 0.05). The mean percentage error between the two volume estimates was 0.4% ± 6.9. Three operators all performed four digitizations of all images from one randomly selected muscle; there was no statistical difference between operators or trials and the intraclass correlation was high (>0.8). The results of this study indicate that ultrasound is an accurate method for estimating muscle volumes in vivo.

Determining the Force-Length-Velocity Relations of the Quadriceps Muscles: I. Anatomical and Geometric Parameters

1999 ◽  
Vol 15 (2) ◽  
pp. 182-190 ◽  
Author(s):  
John W. Chow ◽  
Warren G. Darling ◽  
James C. Ehrhardt
Keyword(s):  
Magnetic Resonance ◽  
Knee Flexion ◽  
Vastus Lateralis ◽  
Quadriceps Muscle ◽  
Vastus Lateralis Muscle ◽  
Moment Arm ◽  
Anatomical Position ◽  
Moment Arms ◽  
Effective Moment

The purpose of this study was to determine the coordinates of the origin and insertion, muscle volumes, lengths, lines of action, and effective moment arm of the quadriceps muscles in vivo using magnetic resonance imaging (MRI) and radiography for a pilot study involving musculoskeletal modeling. Two magnetic resonance scans were performed, and axial images were obtained for the left thigh of a female subject in the anatomical position to measure muscle volume, coordinates of the origin and insertion, and muscle belly length at the anatomical position of each quadriceps muscle. Six knee radiographs were used to determine the effective moment arm of the quadriceps force at different knee flexion angles. A combination of MRI and radiography data was used to compute the muscle lengths at different knee flexion angles. The coordinates of the vastus lateralis, muscle volumes of individual quadriceps muscles, and effective moment arms were clearly different from the corresponding values from cadaver data reported in the literature. These comparisons demonstrate the advantages of using personalized muscle parameters instead of those collected from cadavers and dry-bone specimens.

Effect of arterial oxygenation on quadriceps fatigability during isolated muscle exercise

2007 ◽  
Vol 292 (3) ◽  
pp. R1279-R1286 ◽  
Author(s):  
Keisho Katayama ◽  
Markus Amann ◽  
David F. Pegelow ◽  
Anthony J. Jacques ◽  
Jerome A. Dempsey
Keyword(s):  
Vastus Lateralis ◽  
Acute Hypoxia ◽  
Femoral Nerve ◽  
Quadriceps Muscle ◽  
Voluntary Contraction ◽  
Muscle Exercise ◽  
Myoelectrical Activity ◽  
Twitch Force ◽  
Relative Exercise Intensity ◽  
Before And After

The effect of various levels of oxygenation on quadriceps muscle fatigability during isolated muscle exercise was assessed in six male subjects. Twitch force (Qtw) was assessed using supramaximal magnetic femoral nerve stimulation. In experiment 1, maximal voluntary contraction (MVC) and Qtw of resting quadriceps muscle were measured in normoxia [inspired O2 fraction (FiO2) = 0.21, percent arterial O2 saturation (Sp[Formula: see text]) = 98.4%, estimated arterial O2 content (CaO2) = 20.8 ml/dl], acute hypoxia (FiO2 = 0.11, Sp[Formula: see text] = 74.6%, CaO2 = 15.7 ml/dl), and acute hyperoxia (FiO2 = 1.0, Sp[Formula: see text] = 100%, CaO2 = 22.6 ml/dl). No significant differences were found for MVC and Qtw among the three FiO2 levels. In experiment 2, the subjects performed three sets of nine, intermittent, isometric, unilateral, submaximal quadriceps contractions (62% MVC followed by 1 MVC in each set) while breathing each FiO2. Qtw was assessed before and after exercise, and myoelectrical activity of the vastus lateralis was obtained during exercise. The percent reduction of twitch force (potentiated Qtw) in hypoxia (−27.0%) was significantly ( P < 0.05) greater than in normoxia (−21.4%) and hyperoxia (−19.9%), as were the changes in intratwitch measures of contractile properties. The increase in integrated electromyogram over the course of the nine contractions in hypoxia (15.4%) was higher ( P < 0.05) than in normoxia (7.2%) or hyperoxia (6.7%). These results demonstrate that quadriceps muscle fatigability during isolated muscle exercise is exacerbated in acute hypoxia, and these effects are independent of the relative exercise intensity.

scholarly journals Exercise-induced AMPK activation does not interfere with muscle hypertrophy in response to resistance training in men

2014 ◽  
Vol 116 (6) ◽  
pp. 611-620 ◽  
Author(s):  
Tommy R. Lundberg ◽  
Rodrigo Fernandez-Gonzalo ◽  
Per A. Tesch
Keyword(s):  
Gene Expression ◽  
Glycogen Content ◽  
Citrate Synthase ◽  
Vastus Lateralis ◽  
Endurance Performance ◽  
Quadriceps Muscle ◽  
Muscle Size ◽  
Vastus Lateralis Muscle ◽  
Myostatin Gene

As aerobic exercise (AE) may interfere with adaptations to resistance exercise (RE), this study explored acute and chronic responses to consecutive AE (∼45 min cycling) and RE (4 × 7 maximal knee extensions) vs. RE only. Ten men performed acute unilateral AE + RE interspersed by 15 min recovery. The contralateral leg was subjected to RE. This exercise paradigm was then implemented in a 5-wk training program. Protein phosphorylation, gene expression, and glycogen content were assessed in biopsies obtained from the vastus lateralis muscle of both legs immediately before and 3 h after acute RE. Quadriceps muscle size and in vivo torque were measured, and muscle samples were analyzed for citrate synthase activity and glycogen concentration, before and after training. Acute AE reduced glycogen content (32%; P < 0.05) and increased ( P < 0.05) phosphorylation of AMPK (1.5-fold) and rpS6 (1.3-fold). Phosphorylation of p70S6K and 4E-BP1 remained unchanged. Myostatin gene expression was downregulated after acute AE + RE but not RE. Muscle size showed greater ( P < 0.05) increase after AE + RE (6%) than RE (3%) training. Citrate synthase activity (18%) and endurance performance (22%) increased ( P < 0.05) after AE + RE but not RE. While training increased ( P < 0.05) in vivo muscle strength in both legs, normalized and concentric torque increased after RE only. Thus AE activates AMPK, reduces glycogen stores, and impairs the progression of concentric force, yet muscle hypertrophic responses to chronic RE training appear not to be compromised.

scholarly journals A novel technique for nonvolitional assessment of quadriceps muscle endurance in humans

2007 ◽  
Vol 103 (3) ◽  
pp. 739-746 ◽  
Author(s):  
E. B. Swallow ◽  
H. R. Gosker ◽  
K. A. Ward ◽  
A. J. Moore ◽  
M. J. Dayer ◽  
...  
Keyword(s):  
Magnetic Stimulation ◽  
Citrate Synthase ◽  
Fiber Type ◽  
Femoral Nerve ◽  
Quadriceps Muscle ◽  
Control Group ◽  
Chronic Obstructive ◽  
Type I ◽  
Myosin Heavy Chain Isoform

Assessment of quadriceps endurance is of interest to investigators studying human disease. We hypothesized that repetitive magnetic stimulation (rMS) of the intramuscular branches of the femoral nerve could be used to induce and quantify quadriceps endurance. To test this hypothesis, we used a novel stimulating coil to compare the quadriceps endurance properties in eight normal humans and, to confirm that the technique could be used in clinical practice, in eight patients with advanced chronic obstructive pulmonary disease (COPD). To validate the method, we compared in vivo contractile properties of the quadriceps muscle with the fiber-type composition and oxidative enzyme capacity. We used a Magstim Rapid2 magnetic nerve stimulator with the coil wrapped around the quadriceps. Stimuli were given at 30 Hz, a duty cycle of 0.4 (2 s on, 3 s off), and for 50 trains. Force generation and the surface electromyogram were measured throughout. Quadriceps twitch force, elicited by supramaximal magnetic stimulation of the femoral nerve, was measured before and after the protocol. Quadriceps muscle biopsies were analyzed for oxidative (citrate synthase, CS) and glycolytic (phosphofructokinase, PFK) enzyme activity and myosin heavy chain isoform protein expression. The time for force to fall to 70% of baseline (T70) was shorter in the COPD group than the control group: 55.6 ± 26.0 vs. 121 ± 38.7 s ( P = 0.0014). Considering patients and controls together, positive correlations were observed between T70 and the proportion of type I fibers ( r = 0.68, P = 0.004) and CS-to-PFK ratio (CS/PFK) ( r = 0.67, P = 0.005). We conclude that quadriceps endurance assessed using rMS is feasible in clinical studies.

Ventilation by external high-frequency oscillation in cats

1985 ◽  
Vol 58 (4) ◽  
pp. 1390-1399 ◽  
Author(s):  
H. E. Ward ◽  
J. Armengol ◽  
R. L. Jones
Keyword(s):  
High Frequency ◽  
Spontaneous Breathing ◽  
Random Order ◽  
High Frequency Oscillation ◽  
Chamber Pressure ◽  
Arterial Blood Gas ◽  
Arterial Blood ◽  
Residual Capacity ◽  
Highly Correlated

Eight anesthetized tracheostomized cats were placed in an 8.2-liter airtight chamber with the trachea connected to the exterior. Thirty-two combinations of high-frequency oscillations (HFO) (0.5–30 Hz; 25–100 ml) were delivered for 10 min each in random order into the chamber. Arterial blood gas tensions during oscillation were compared with control measurements made after 10 min of spontaneous breathing without oscillation when the mean arterial PCO2 (PaCO2) was 30.1 Torr. Ventilation due to spontaneous breathing (Vs) and oscillation (Vo) were derived from the chamber pressure trace and a pneumotachograph, respectively. As the oscillation frequency increased, oscillated tidal volume (Vo) decreased from a mean of 39 (0.5 Hz) to 3.3 ml (30 Hz) when 100 ml was delivered to the chamber. From 6–25 Hz, apnea occurred with Vo less than estimated respiratory dead space (VD); the minimum effective Vo/VD ratio was 0.37 +/- 0.05. Although Vo was maximal at 10 Hz at each oscillation volume, the lowest PaCO2 occurred at 2–6 Hz, and arterial PO2 rose as expected during hypocapnia. Above 10 Hz, PaCO2 was determined by Vo and was independent of frequency, whereas at lower frequencies, PaCO2 was related to Vo; below 6 Hz, PaCO2 varied inversely with the calculated alveolar ventilation. As oscillations became more effective, both PaCO2 and Vs fell progressively and were highly correlated; apnea occurred when PaCO2 was reduced by a mean of 4.5 Torr. Mean chamber pressure remained near zero up to 15 Hz, indicating functional residual capacity did not change. We conclude that externally applied HFO can readily maintain gas exchange in vivo, with Vo less than VD at frequencies over 2 Hz.

Electrical Nerve Localization

2004 ◽  
Vol 100 (6) ◽  
pp. 1526-1530 ◽  
Author(s):  
Admir Hadzic ◽  
Jerry D. Vloka ◽  
Richard E. Claudio ◽  
Nihad Hadzic ◽  
Daniel M. Thys ◽  
...  
Keyword(s):  
Nerve Stimulation ◽  
Motor Response ◽  
Femoral Nerve Block ◽  
Femoral Nerve ◽  
Random Order ◽  
Electrical Stimulus ◽  
Constant Current ◽  
Current Duration ◽  
Nerve Localization ◽  
Mixed Nerve

Background Recommendations regarding the technical aspects of nerve stimulator-assisted nerve localization are conflicting. The objectives of this study were to determine whether the placement of the cutaneous electrode affects nerve stimulation and to determine the duration and intensity of an electrical stimulus that allows nerve stimulation with minimal discomfort. Methods Ten healthy volunteers underwent an interscalene and a femoral nerve block. After obtaining a clearly visible motor response of the biceps (interscalene) and quadriceps (femoral) muscles at the minimal current (0.1 ms, 2 Hz), the position of the cutaneous electrode was varied. Next, the duration of the stimulating current was set at 0.05, 0.1, 0.3, 0.5, or 1.0 ms, in random order. Intensity of the motor response and discomfort on stimulation were recorded. Results The minimal current at which a visible motor response was obtained was 0.32 +/- 0.1 mA (0.23-0.38 mA) for the inter-scalene block and 0.29 +/- 0.1 mA (0.15-0.4 mA) for the femoral block. Changing the position of the return electrodes did not result in any change in the grade of the motor response or in the current required to maintain it. Currents of longer duration caused discomfort and more forceful contraction at a lower current intensity as compared with currents of shorter duration (P &lt; 0.01). When the current was adjusted to maintain the same visible motor response, there was no significant discomfort among studied current durations. Conclusion Site of placement of the cutaneous electrode is not important when constant current nerve stimulators are used during nerve localization in regional anesthesia. There is an inverse relation between the current required to obtain a visible motor response and current duration. Selecting a current duration between 0.05 and 1.0 ms to specifically stimulate sensory or motor components of a mixed nerve does not seem to be important in clinical practice.

Аpplying of high-frequency monopolar diathermocoagulation in the treatment of chronic pulpitis

2020 ◽  
Vol 1 (12) ◽  
pp. 40-42
Author(s):  
F. Yu. Daurova ◽  
D. I. Tomaeva ◽  
S. V. Podkopaeva ◽  
Yu. A. Taptun
Keyword(s):  
Root Canal ◽  
High Frequency ◽  
Antibacterial Effect ◽  
Comparison Group ◽  
Poor Quality ◽  
Endodontic Treatment ◽  
Root Canals ◽  
The Third ◽  
Before And After

Relevance: the reason for the development of complications in endodontic treatment is poor-quality instrumental treatment root canals.Aims: a study of the animicrobial action and clinical efficacy of high-frequency monopolar diathermocoagulation in the treatment of chronic forms of pulpitis.Materials and methods: 102 patients with various chronic forms of pulpitis were divided into three groups of 34 patients each. In the first two groups, high-frequency monopolar diathermocoagulation was used in endodontic treatment in different modes. In the third group, endodontic treatment was carried out without the use of diathermocoagulation (comparison group). The root canal microflora in chronic pulpitis in vivo was studied twice-before and after diathermocoagulation.Results: it was established that high-frequency monopolar diathermocoagulation in the effect mode is 3, power is 4 (4.1 W) and effect is 4, power is 4 (5.4 W) with an exposure time of 3 seconds, it has a pronounced antibacterial effect on all presented pathogenic microflora obtained from the root canals of the teeth.

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