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Fulltext Mechanomyography and Torque during FES-Evoked Muscle Contractions to Fatigue in Individuals with Spinal Cord Injury

Mohamad NZ, Hamzaid NA, Davis GM, Abdul Wahab AK, Hasnan N

Sensors (Basel), 2017 Jul 14;17(7).
PMID: 28708068 DOI: 10.3390/s17071627

A mechanomyography muscle contraction (MC) sensor, affixed to the skin surface, was used to quantify muscle tension during repetitive functional electrical stimulation (FES)-evoked isometric rectus femoris contractions to fatigue in individuals with spinal cord injury (SCI). Nine persons with motor complete SCI were seated on a commercial muscle dynamometer that quantified peak torque and average torque outputs, while measurements from the MC sensor were simultaneously recorded. MC-sensor-predicted measures of dynamometer torques, including the signal peak (SP) and signal average (SA), were highly associated with isometric knee extension peak torque (SP: r = 0.91, p < 0.0001), and average torque (SA: r = 0.89, p < 0.0001), respectively. Bland-Altman (BA) analyses with Lin's concordance (ρC) revealed good association between MC-sensor-predicted peak muscle torques (SP; ρC = 0.91) and average muscle torques (SA; ρC = 0.89) with the equivalent dynamometer measures, over a range of FES current amplitudes. The relationship of dynamometer torques and predicted MC torques during repetitive FES-evoked muscle contraction to fatigue were moderately associated (SP: r = 0.80, p < 0.0001; SA: r = 0.77; p < 0.0001), with BA associations between the two devices fair-moderate (SP; ρC = 0.70: SA; ρC = 0.30). These findings demonstrated that a skin-surface muscle mechanomyography sensor was an accurate proxy for electrically-evoked muscle contraction torques when directly measured during isometric dynamometry in individuals with SCI. The novel application of the MC sensor during FES-evoked muscle contractions suggested its possible application for real-world tasks (e.g., prolonged sit-to-stand, stepping,) where muscle forces during fatiguing activities cannot be directly measured.

Matched MeSH terms: Torque*
Fulltext An ultra-low power wireless sensor network for bicycle torque performance measurements

Gharghan SK, Nordin R, Ismail M

Sensors (Basel), 2015;15(5):11741-68.
PMID: 26007728 DOI: 10.3390/s150511741

In this paper, we propose an energy-efficient transmission technique known as the sleep/wake algorithm for a bicycle torque sensor node. This paper aims to highlight the trade-off between energy efficiency and the communication range between the cyclist and coach. Two experiments were conducted. The first experiment utilised the Zigbee protocol (XBee S2), and the second experiment used the Advanced and Adaptive Network Technology (ANT) protocol based on the Nordic nRF24L01 radio transceiver chip. The current consumption of ANT was measured, simulated and compared with a torque sensor node that uses the XBee S2 protocol. In addition, an analytical model was derived to correlate the sensor node average current consumption with a crank arm cadence. The sensor node achieved 98% power savings for ANT relative to ZigBee when they were compared alone, and the power savings amounted to 30% when all components of the sensor node are considered. The achievable communication range was 65 and 50 m for ZigBee and ANT, respectively, during measurement on an outdoor cycling track (i.e., velodrome). The conclusions indicate that the ANT protocol is more suitable for use in a torque sensor node when power consumption is a crucial demand, whereas the ZigBee protocol is more convenient in ensuring data communication between cyclist and coach.

Matched MeSH terms: Torque
Fulltext Investigating the Efficacy of Adhesive Tape for Drilling Carbon Fibre Reinforced Polymers

Prakash C, Pramanik A, Basak AK, Dong Y, Debnath S, Shankar S, et al.

Materials (Basel), 2021 Mar 30;14(7).
PMID: 33808311 DOI: 10.3390/ma14071699

In the present research work, an effort has been made to explore the potential of using the adhesive tapes while drilling CFRPs. The input parameters, such as drill bit diameter, point angle, Scotch tape layers, spindle speed, and feed rate have been studied in response to thrust force, torque, circularity, diameter error, surface roughness, and delamination occurring during drilling. It has been found that the increase in point angle increased the delamination, while increase in Scotch tape layers reduced delamination. The surface roughness decreased with the increase in drill diameter and point angle, while it increased with the speed, feed rate, and tape layer. The best low roughness was obtained at 6 mm diameter, 130° point angle, 0.11 mm/rev feed rate, and 2250 rpm speed at three layers of Scotch tape. The circularity error initially increased with drill bit diameter and point angle, but then decreased sharply with further increase in the drill bit diameter. Further, the circularity error has non-linear behavior with the speed, feed rate, and tape layer. Low circularity error has been obtained at 4 mm diameter, 118° point angle, 0.1 mm/rev feed rate, and 2500 RPM speed at three layers of Scotch tape. The low diameter error has been obtained at 6 mm diameter, 130° point angle, 0.12 mm/rev feed rate, and 2500 rpm speed at three layer Scotch tape. From the optical micro-graphs of drilled holes, it has been found that the point angle is one of the most effective process parameters that significantly affects the delamination mechanism, followed by Scotch tape layers as compared to other parameters such as drill bit diameter, spindle speed, and feed rate.

Matched MeSH terms: Torque
The optimization of torque ripple reduction by using DTC-multilevel inverter

Tarusan SAA, Jidin A, Jamil MLM

ISA Trans, 2021 Apr 16.
PMID: 33931170 DOI: 10.1016/j.isatra.2021.04.005

Direct Torque Control (DTC) scheme introduces a robust and simple control of electrical drive. However, its shortcomings such as broad torque ripple and variable switching frequency have offered several improvements like Space Vector Modulation (SVM) strategy, multilevel inverter (MLI) topology, etc. The conventional DTC which is fed by the two-level inverter has limited voltage vector, results in some difficulties to optimize the operation, especially at low operating speed. In contrast to MLI, the abundant of voltage vector has provided various amplitudes and angles that can overcome the problem of conventional DTC. Thus, this paper introduces the selected optimal voltage vector obtained from five-level Cascaded H-Bridge (CHB) inverter that employs in DTC hysteresis-based to achieve better optimization that similar to the DTC-SVM. Initially, the research work begins with an investigation on the performance comparison between a DTC hysteresis-based between two-level inverter (conventional method) and a five-level CHB inverter (proposed method). Here, a DC generator acted as a load is employed to control the operating speed instead of the speed controller (speed controller is negligible). Hence, the DTC method is optimized by minimizing the torque ripple as well as retaining the torque control capability at constant torque region on several operating speed. The selected optimal vector from the look-up table DTC of five-level CHB inverter must be dynamically appropriate to any change of torque (increased or decreased torque). For simplicity, this paper will only discuss the experimental results for both topologies of drive system. From the experimental results, it is verified that the torque ripples by the proposed method have achieved 10% and 50% reduction at high and low operating speed respectively. It is found that the DTC hysteresis-based result simpler control method than DTC-SVM while maintaining similar output performance.

Matched MeSH terms: Torque
Crosstalk in Mechanomyographic Signals From Elbow Flexor Muscles During Submaximal to Maximal Isometric Flexion, Pronation, and Supination Torque Tasks

Talib I, Sundaraj K, Lam CK

J Biomech Eng, 2021 Jan 01;143(1).
PMID: 32691054 DOI: 10.1115/1.4047850

This study analyzed the crosstalk in mechanomyographic (MMG) signals from elbow flexors during isometric muscle actions from 20% to 100% maximum voluntary isometric contraction (MVIC). Twenty-five young, healthy, male participants performed the isometric elbow flexion, forearm pronation, and supination tasks at an elbow joint angle of 90 deg. The MMG signals from the biceps brachii (BB), brachialis (BRA), and brachioradialis (BRD) muscles were recorded using accelerometers. The cross-correlation coefficient was used to quantify the crosstalk in MMG signals, recorded in a direction transverse to muscle fiber axis, among the muscle pairs (P1: BB and BRA, P2: BRA and BRD, and P3: BB and BRD). In addition, the MMG RMS and MPF were quantified. The mean normalized RMS and mean MPF exhibited increasing (r > 0.900) and decreasing (r

Matched MeSH terms: Torque*
Fulltext Joint torque reduction of a three dimensional redundant planar manipulator

Yahya S, Moghavvemi M, Almurib HA

Sensors (Basel), 2012;12(6):6869-92.
PMID: 22969326 DOI: 10.3390/s120606869

Research on joint torque reduction in robot manipulators has received considerable attention in recent years. Minimizing the computational complexity of torque optimization and the ability to calculate the magnitude of the joint torque accurately will result in a safe operation without overloading the joint actuators. This paper presents a mechanical design for a three dimensional planar redundant manipulator with the advantage of the reduction in the number of motors needed to control the joint angle, leading to a decrease in the weight of the manipulator. Many efforts have been focused on decreasing the weight of manipulators, such as using lightweight joints design or setting the actuators at the base of the manipulator and using tendons for the transmission of power to these joints. By using the design of this paper, only three motors are needed to control any n degrees of freedom in a three dimensional planar redundant manipulator instead of n motors. Therefore this design is very effective to decrease the weight of the manipulator as well as the number of motors needed to control the manipulator. In this paper, the torque of all the joints are calculated for the proposed manipulator (with three motors) and the conventional three dimensional planar manipulator (with one motor for each degree of freedom) to show the effectiveness of the proposed manipulator for decreasing the weight of the manipulator and minimizing driving joint torques.

Matched MeSH terms: Torque
Fulltext Vertical play of straight wire appliance aids correction of gummy smile and bimaxillary incisor proclination with mini implant anchorage

Mohd Zambri M.M., Wan Nurazreena W.H.

Ann Dent, 2018;25(1):1-10.
MyJurnal

This report aimed to describe an effective biomechanics to control the upper incisors inclination during the
correction of gummy smile with bimaxillary proclinations. A 14-year-old female presented with a Class II
division I incisor relationship complicated with bimaxillary proclination on a Class 2 skeletal base. The lips
were incompetent, showing 7 mm of upper incisors at rest and 5mm maxillary gingival display on smiling
with normal upper lip length. Treatment involved extraction of all first permanent premolars followed by
upper and lower fixed appliances. Intrusion of the upper incisors with controlled labial crown torque was
accomplished with mini-implant anchorage placed bilaterally on the infrazygomatic crests with the retraction
forces above the centre of resistance using 0.019x0.025-in stainless steel archwire in 0.022-in slot. The
0.019x0.025-in stainless steel archwire in 0.022-in slot provided the vertical play to favour lingual crown
tipping despite having forces above the centre of resistance for concurrent anterior segment intrusion.

Matched MeSH terms: Torque
Fulltext Sensitivities of Rheological Properties of Magnetoactive Foam for Soft Sensor Technology

Norhaniza R, Mazlan SA, Ubaidillah U, Sedlacik M, Aziz SAA, Nazmi N, et al.

Sensors (Basel), 2021 Feb 28;21(5).
PMID: 33670872 DOI: 10.3390/s21051660

Magnetoactive (MA) foam, with its tunable mechanical properties and magnetostriction, has the potential to be used for the development of soft sensor technology. However, researchers have found that its mechanical properties and magnetostriction are morphologically dependent, thereby limiting its capabilities for dexterous manipulation. Thus, in this work, MA foam was developed with additional capabilities for controlling its magnetostriction, normal force, storage modulus, shear stress and torque by manipulating the concentration of carbonyl iron particles (CIPs) and the magnetic field with regard to morphological changes. MA foams were prepared with three weight percentages of CIPs, namely, 35 wt.%, 55 wt.% and 75 wt.%, and three different modes, namely, zero shear, constant shear and various shears. The results showed that the MA foam with 75 wt.% of CIPs enhanced the normal force sensitivity and positive magnetostriction sensitivity by up to 97% and 85%, respectively. Moreover, the sensitivities of the storage modulus, torque and shear stress were 8.97 Pa/mT, 0.021 µN/mT, and 0.0096 Pa/mT, respectively. Meanwhile, the magnetic dipolar interaction between the CIPs was capable of changing the property of MA foam from a positive to a negative magnetostriction under various shear strains with a low loss of energy. Therefore, it is believed that this kind of highly sensitive MA foam can potentially be implemented in future soft sensor systems.

Matched MeSH terms: Torque
Electrical stimulator with mechanomyography-based real-time monitoring, muscle fatigue detection, and safety shut-off: a pilot study

Naeem J, Hamzaid NA, Azman AW, Bijak M

Biomed Tech (Berl), 2020 Aug 27;65(4):461-468.
PMID: 32304295 DOI: 10.1515/bmt-2019-0191

Functional electrical stimulation (FES) has been used to produce force-related activities on the paralyzed muscle among spinal cord injury (SCI) individuals. Early muscle fatigue is an issue in all FES applications. If not properly monitored, overstimulation can occur, which can lead to muscle damage. A real-time mechanomyography (MMG)-based FES system was implemented on the quadriceps muscles of three individuals with SCI to generate an isometric force on both legs. Three threshold drop levels of MMG-root mean square (MMG-RMS) feature (thr50, thr60, and thr70; representing 50%, 60%, and 70% drop from initial MMG-RMS values, respectively) were used to terminate the stimulation session. The mean stimulation time increased when the MMG-RMS drop threshold increased (thr50: 22.7 s, thr60: 25.7 s, and thr70: 27.3 s), indicating longer sessions when lower performance drop was allowed. Moreover, at thr70, the torque dropped below 50% from the initial value in 14 trials, more than at thr50 and thr60. This is a clear indication of muscle fatigue detection using the MMG-RMS value. The stimulation time at thr70 was significantly longer (p = 0.013) than that at thr50. The results demonstrated that a real-time MMG-based FES monitoring system has the potential to prevent the onset of critical muscle fatigue in individuals with SCI in prolonged FES sessions.

Matched MeSH terms: Torque
Fulltext Preventing Hydrate Adhesion with Magnetic Slippery Surfaces

Ragunathan T, Xu X, Shuhili JA, Wood CD

ACS Omega, 2019 Oct 01;4(14):15789-15797.
PMID: 31592451 DOI: 10.1021/acsomega.9b01232

Hydrate formation is a common challenge in the oil and gas industry when natural gas is transported under cold conditions in the presence of water. Coatings are one of the solutions that have shown to be a promising approach to address this challenge. However, this strategy suffers from the intrinsic existence of a solid-liquid interface causing a high rate of hydrate nucleation and high hydrate adhesion strength. This proof-of-concept study highlights the performance of a magnetic slippery surface to prevent hydrate adhesion at atmospheric pressure using tetrahydrofuran hydrates. The coating consisted of a hydrocarbon-based magnetic fluid, which was applied to a metal surface to create an interface that lowered the hydrate adhesion strength on the surface. The performance of these new surfaces under static and dynamic (under fluid flow) conditions shows that the magnetic coating gel can be a potential inhibitor for hydrate adhesion as it reduced the torque value after the formation of hydrates.

Matched MeSH terms: Torque
SVR modelling of mechanomyographic signals predicts neuromuscular stimulation-evoked knee torque in paralyzed quadriceps muscles undergoing knee extension exercise

Ibitoye MO, Hamzaid NA, Abdul Wahab AK, Hasnan N, Olatunji SO, Davis GM

Comput Biol Med, 2020 02;117:103614.
PMID: 32072969 DOI: 10.1016/j.compbiomed.2020.103614

BACKGROUND AND OBJECTIVE: Using traditional regression modelling, we have previously demonstrated a positive and strong relationship between paralyzed knee extensors' mechanomyographic (MMG) signals and neuromuscular electrical stimulation (NMES)-assisted knee torque in persons with spinal cord injuries. In the present study, a method of estimating NMES-evoked knee torque from the knee extensors' MMG signals using support vector regression (SVR) modelling is introduced and performed in eight persons with chronic and motor complete spinal lesions.
METHODS: The model was developed to estimate knee torque from experimentally derived MMG signals and other parameters related to torque production, including the knee angle and stimulation intensity, during NMES-assisted knee extension.
RESULTS: When the relationship between the actual and predicted torques was quantified using the coefficient of determination (R2), with a Gaussian support vector kernel, the R2 value indicated an estimation accuracy of 95% for the training subset and 94% for the testing subset while the polynomial support vector kernel indicated an accuracy of 92% for the training subset and 91% for the testing subset. For the Gaussian kernel, the root mean square error of the model was 6.28 for the training set and 8.19 for testing set, while the polynomial kernels for the training and testing sets were 7.99 and 9.82, respectively.
CONCLUSIONS: These results showed good predictive accuracy for SVR modelling, which can be generalized, and suggested that the MMG signals from paralyzed knee extensors are a suitable proxy for the NMES-assisted torque produced during repeated bouts of isometric knee extension tasks. This finding has potential implications for using MMG signals as torque sensors in NMES closed-loop systems and provides valuable information for implementing this method in research and clinical settings.

Matched MeSH terms: Torque
Fulltext Estimation of Electrically-Evoked Knee Torque from Mechanomyography Using Support Vector Regression

Ibitoye MO, Hamzaid NA, Abdul Wahab AK, Hasnan N, Olatunji SO, Davis GM

Sensors (Basel), 2016 Jul 19;16(7).
PMID: 27447638 DOI: 10.3390/s16071115

The difficulty of real-time muscle force or joint torque estimation during neuromuscular electrical stimulation (NMES) in physical therapy and exercise science has motivated recent research interest in torque estimation from other muscle characteristics. This study investigated the accuracy of a computational intelligence technique for estimating NMES-evoked knee extension torque based on the Mechanomyographic signals (MMG) of contracting muscles that were recorded from eight healthy males. Simulation of the knee torque was modelled via Support Vector Regression (SVR) due to its good generalization ability in related fields. Inputs to the proposed model were MMG amplitude characteristics, the level of electrical stimulation or contraction intensity, and knee angle. Gaussian kernel function, as well as its optimal parameters were identified with the best performance measure and were applied as the SVR kernel function to build an effective knee torque estimation model. To train and test the model, the data were partitioned into training (70%) and testing (30%) subsets, respectively. The SVR estimation accuracy, based on the coefficient of determination (R²) between the actual and the estimated torque values was up to 94% and 89% during the training and testing cases, with root mean square errors (RMSE) of 9.48 and 12.95, respectively. The knee torque estimations obtained using SVR modelling agreed well with the experimental data from an isokinetic dynamometer. These findings support the realization of a closed-loop NMES system for functional tasks using MMG as the feedback signal source and an SVR algorithm for joint torque estimation.

Matched MeSH terms: Torque
Fulltext The Development of Expanded Snack Product Made from Pumpkin Flour-Corn Grits: Effect of Extrusion Conditions and Formulations on Physical Characteristics and Microstructure

Nor NM, Carr A, Hardacre A, Brennan CS

Foods, 2013 May 14;2(2):160-169.
PMID: 28239106 DOI: 10.3390/foods2020160

Pumpkin products confer natural sweetness, desirable flavours and β-carotene, a vitamin A precursor when added as ingredients to extruded snacks. Therefore, a potential use for dried pumpkin flour is as an ingredient in ready-to-eat (RTE) snack foods. Growth in this market has driven food manufacturers to produce a variety of new high value snack foods incorporating diverse ingredients to enhance the appearance and nutritional properties of these foods. Ready-to-eat snacks were made by extruding corn grits with 5%, 10%, 15% and 20% of pumpkin flour. Snacks made from 100% corn grits were used as control products for this work. The effect of formulation and screw speeds of 250 rpm and 350 rpm on torque and specific mechanical energy (SME, kWh/kg), physical characteristics (expansion ratio, bulk density, true density and hardness) and the microstructure of the snacks were studied. Increasing the screw speed resulted in a decrease of torque for all formulations. When pumpkin flour was added the specific mechanical energy (SME) decreased by approximately 45%. Increasing the percentage of pumpkin flour at the higher screw speed resulted in a harder texture for the extruded products. X-ray tomography of pumpkin flour-corn grit snacks showed that increased levels of pumpkin flour decreased both the bubble area and bubble size. However, no significant differences (p > 0.05) in bubble wall thickness were measured. By understanding the conditions during extrusion, desirable nutritional characteristics can be incorporated while maximizing expansion to make a product with low bulk density, a fine bubble structure and acceptable organoleptic properties.

Matched MeSH terms: Torque
Fulltext Parallelogram linkage leg structure for stabilized walking gaits in humanoid robot

Firdaus Sukarman, Mohd Ghazali Mohd Hamami, Mazleenda Mazni, Muhammad Amir Mat Shah, Ahmad Faidzal Khodori

Journal of Advanced Research in Applied Sciences and Engineering Technology, 2017;9(1):22-31.
MyJurnal

The utilization of parallelogram structure in a small-sized humanoid robot consists of two parallel platforms that are linked serially in each leg. The thigh and shank of each leg consists of two servomotors as actuator and linked in parallel platform. By using parallel mechanism in leg structure, foot sole surface is always parallel to the walking surface at any point. Even it looks unnatural to human-like walking motion, the expected result is the robot can maintain it posture while walking and at the point foot sole touch the walking surface, unnecessary vibrates can be modulated at the certain level to remain its balance. The effectiveness and the performance of the proposed parallel platforms are experimented by using zero moment point (ZMP) method by taking various scenario data from pressure sensors attached at the footsole. Planned walking gait is introduced to be identical in terms of foot steps length and width of each leg swing. As the results, in terms of load in each actuator, required torque at servomotors can be reduced because two servomotors are used simultaneously in one parallel system. Stable walking gait can be predicted as the quantity of error falls within the error ranges from the published walking gait patterns.

Matched MeSH terms: Torque
Fulltext A Facile and Flexible Method for On-Demand Directional Speed Tunability in the Miniaturised Lab-on-a-Disc

Tan MK, Siddiqi A, Yeo LY

Sci Rep, 2017 07 27;7(1):6652.
PMID: 28751783 DOI: 10.1038/s41598-017-07025-x

The Miniaturised Lab-on-a-Disc (miniLOAD) platform, which utilises surface acoustic waves (SAWs) to drive the rotation of thin millimeter-scale discs on which microchannels can be fabricated and hence microfluidic operations can be performed, offers the possibility of miniaturising its larger counterpart, the Lab-on-a-CD, for true portability in point-of-care applications. A significant limitation of the original miniLOAD concept, however, is that it does not allow for flexible control over the disc rotation direction and speed without manual adjustment of the disc's position, or the use of multiple devices to alter the SAW frequency. In this work, we demonstrate the possibility of achieving such control with the use of tapered interdigitated transducers to confine a SAW beam such that the localised acoustic streaming it generates imparts a force, through hydrodynamic shear, at a specific location on the disc. Varying the torque that arises as a consequence by altering the input frequency to the transducers then allows the rotational velocity and direction of the disc to be controlled with ease. We derive a simple predictive model to illustrate the principle by which this occurs, which we find agrees well with the experimental measurements.

Matched MeSH terms: Torque
Fulltext A review on the global widespread of TTV infection among humans population

Nur Syazwani Jarkasi, Zamberi Sekawi, Cheah, Yoke Kqueen, Zulkefley Othman

The Pertanika Journal of Scholarly Research Reviews, 2018;4(1):10-24.
MyJurnal

Torque Teno Virus (TTV) is a human-infected virus that is present ubiquitously in nature. Globally, it infects up to 95% of the healthy individuals without any clinical manifestations. The widely used laboratory diagnosis of TTV infection is Polymerase chain reaction (PCR). Nevertheless, several other methods have been developed. The rapid growth of TTV variants over time has posed a challenge in estimating the global TTV infection as none of the PCR protocol has the ability to detect the entire spectrum of TTV variants. Multiple TTV epidemiological studies have been conducted among Asian population, whereas other continents showed a limited number of studies. The horizontal and vertical transmission of TTV among humans population, as well as interspecies transmission are potentially related to the global widespread of TTV infection.

Matched MeSH terms: Torque teno virus
Fulltext Relationship between isokinetic leg strength and knee frontal plane projection angle during single leg squat among male junior athletes

Mail, M.S.Z., Mohd Azhar, N., Affandi, N.F., Shaharudin, S., Agrawal, S., Chee, L.M.

JUMMEC, 2019;22(2):43-48.
MyJurnal

Background: Those with increased dynamic knee valgus are vulnerable to increased risk of non-contact knee
injuries. However, studies on the top down kinetic chain of lower limb mechanics during dynamic motions
such as single leg squat (SLS) among trained males were scarce.

Objective: The objective of the study was to evaluate the relationship between isokinetic hip and knee strength
and frontal plane projection angle (FPPA) of the knee joint during SLS.

Methods: Thirty-two male junior athletes (twelve cyclists, ten runners and ten squash players) were screened
for excessive dynamic knee valgus (DKV) prior to participation. Only those within the normal value of DKV were
included. Their hip and knee isokinetic strength in sagittal plane were evaluated at 60º/s of angular velocity
for both legs using dynamometer. Two dimensional knee FPPA was evaluated during SLS at 60º of knee flexion.
Pearson correlation was evaluated between knee FPPA during SLS and isokinetic leg strength.

Results: Correlations between knee FPPA and hip and knee isokinetic strength were not statistically significant
except between knee flexion peak torque/body weight (r = -0.35, p = 0.05) and hamstring to quadriceps ratio
(r = -0.39, p = 0.03) of non-dominant leg.

Conclusions: Isokinetic hip and knee strength and knee FPPA during SLS was correlated only for non-dominant
leg during SLS among male junior athletes. DKV during SLS may be reduced through strengthening the muscles
around hip and knee joints.

Matched MeSH terms: Torque
Effect of compatibilizer on the dynamic mechanical and electrical properties of kaolin clay reinforced EPDM rubber

Gautam Sarkhel, Sanjay Manjhi

Sains Malaysiana, 2013;42:495-501.

Industrial pollution issue and dark colour of carbon black, clay based non black filler are getting more importance for reinforcing elastomer. EPDM-Kaolin composites with various maleated EPDM concentration have been prepared by mixing on a two roll mill. The rheometry data showed the optimum cure time increases with increasing compatibilizer concentration without decreasing torque value indicating that acidic functional groups comes from compatibilizer could retard cure rate and increase the optimum cure time rather than change in the ultimate cure state. As the filler
concentration increases, the edge to edge and face to edge interaction between filler and EPDM increases and the free volume between EPDM molecules is reduced, the storage modulus increases. Moreover, the dynamic mechanical analysis also showed the increase in glass transition temperature with increase in filler concentration due to the inter-tubular diffusion of EPDM inside the clay. It was also observed that with increasing filler concentration, the resistivity and dielectric strength decreases and moreover with increasing compatibilizer concentration the resistivity decreases due to better dispersion of filler helps to build conduction path. The morphological study also revealed that homogeneity of filler dispersion increases with increase in compatibilizer concentration.

Matched MeSH terms: Torque
Fulltext Analysis of anthropometrics and mechanomyography signals as forearm flexion, pronation and supination torque predictors

Talib I, Sundaraj K, Hussain J, Lam CK, Ahmad Z

Sci Rep, 2022 Sep 27;12(1):16086.
PMID: 36168025 DOI: 10.1038/s41598-022-20223-6

This study aimed to analyze anthropometrics and mechanomyography (MMG) signals as forearm flexion, pronation, and supination torque predictors. 25 young, healthy, male participants performed isometric forearm flexion, pronation, and supination tasks from 20 to 100% maximal voluntary isometric contraction (MVIC) while maintaining 90° at the elbow joint. Nine anthropometric measures were recorded, and MMG signals from the biceps brachii (BB), brachialis (BRA), and brachioradialis (BRD) muscles were digitally acquired using triaxial accelerometers. These were then correlated with torque values. Significant positive correlations were found for arm circumference (CA) and MMG root mean square (RMS) values with flexion torque. Flexion torque might be predicted using CA (r = 0.426-0.575), a pseudo for muscle size while MMGRMS (r = 0.441), an indication of muscle activation.

Matched MeSH terms: Torque
Torque and mechanomyogram relationships during electrically-evoked isometric quadriceps contractions in persons with spinal cord injury

Ibitoye MO, Hamzaid NA, Hasnan N, Abdul Wahab AK, Islam MA, Kean VS, et al.

Med Eng Phys, 2016 Aug;38(8):767-75.
PMID: 27289541 DOI: 10.1016/j.medengphy.2016.05.012

The interaction between muscle contractions and joint loading produces torques necessary for movements during activities of daily living. However, during neuromuscular electrical stimulation (NMES)-evoked contractions in persons with spinal cord injury (SCI), a simple and reliable proxy of torque at the muscle level has been minimally investigated. Thus, the purpose of this study was to investigate the relationships between muscle mechanomyographic (MMG) characteristics and NMES-evoked isometric quadriceps torques in persons with motor complete SCI. Six SCI participants with lesion levels below C4 [(mean (SD) age, 39.2 (7.9) year; stature, 1.71 (0.05) m; and body mass, 69.3 (12.9) kg)] performed randomly ordered NMES-evoked isometric leg muscle contractions at 30°, 60° and 90° knee flexion angles on an isokinetic dynamometer. MMG signals were detected by an accelerometer-based vibromyographic sensor placed over the belly of rectus femoris muscle. The relationship between MMG root mean square (MMG-RMS) and NMES-evoked torque revealed a very high association (R(2)=0.91 at 30°; R(2)=0.98 at 60°; and R(2)=0.97 at 90° knee angles; P<0.001). MMG peak-to-peak (MMG-PTP) and stimulation intensity were less well related (R(2)=0.63 at 30°; R(2)=0.67 at 60°; and R(2)=0.45 at 90° knee angles), although were still significantly associated (P≤0.006). Test-retest interclass correlation coefficients (ICC) for the dependent variables ranged from 0.82 to 0.97 for NMES-evoked torque, between 0.65 and 0.79 for MMG-RMS, and from 0.67 to 0.73 for MMG-PTP. Their standard error of measurements (SEM) ranged between 10.1% and 31.6% (of mean values) for torque, MMG-RMS and MMG-PTP. The MMG peak frequency (MMG-PF) of 30Hz approximated the stimulation frequency, indicating NMES-evoked motor unit firing rate. The results demonstrated knee angle differences in the MMG-RMS versus NMES-isometric torque relationship, but a similar torque related pattern for MMG-PF. These findings suggested that MMG was well associated with torque production, reliably tracking the motor unit recruitment pattern during NMES-evoked muscle contractions. The strong positive relationship between MMG signal and NMES-evoked torque production suggested that the MMG might be deployed as a direct proxy for muscle torque or fatigue measurement during leg exercise and functional movements in the SCI population.

Matched MeSH terms: Torque*

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