Hand osteoarthritis (OA) usually results in decreased strength and function of the hand and deficits in motor control. However, no data exists on the relationship among these symptomatological ...features of hand OA. Ten females with hand OA and ten matched, nondisabled control subjects participated in this study. The outcomes of the Moberg Pickup Test (MPUT) and other functional hand tests were correlated with the measures of grip force control obtained during the performance of a functional task of lifting and transporting a handheld object. Strong correlations existed between the MPUT and parameters of grip force control, such as latency (r = 0.85) and force at the moment of lift-off (r = 0.72), seen in these patients. The established strong correlation between the MPUT and parameters of grip force control might help researchers and clinicians better understand how deficits in controlling grip forces affect hand function in patients with hand OA.
Abstract To assess the electromyographic (EMG) activation of trunk muscle during exertions performed in one primary plane (sagittal, frontal, transverse), we previously proposed a protocol allowing ...minimizing out-of-plane efforts (coupled moments – CMs) with the use of a static dynamometer combined with a visual feedback system. The aims of this study were to go further by testing motor learning and reliability issues related to such a protocol. Three identical sessions were conducted, where maximal voluntary contractions and submaximal ramp contractions were performed in six different directions while standing in the dynamometer. Two feedback conditions were tested, the simple 1D-feedback in the primary plane and the full 3D-feedback in all planes simultaneously. Surface EMG signals were collected from back and abdominal muscles and EMG amplitude and CMs were computed during the ramp contractions. Providing a 3D feedback to minimize CMs did not improve EMG reliability or in other words, did not reduce the within-subject variability. Providing three assessment days had practically no effect (no learning) on CMs and EMG variables. Overall, the reliability of EMG was at best moderate. However, although this limits its use on an individual basis, it still allows within- and between-group comparisons for research applications.
To gain insight into the adaptive response of human tendon to paralysis, we compared the mechanical properties of the in vivo patellar tendon in six men who were spinal cord–injured (SCI) and eight ...age‐matched, able‐bodied men. Measurements were taken by combining dynamometry, electrical stimulation, and ultrasonography. Tendon stiffness and Young's modulus, calculated from force–elongation and stress–strain curves, respectively, were lower by 77% (P < 0.01) and 59% (P < 0.05) in the SCI than able‐bodied subjects. The cross‐sectional area (CSA) of the tendon was 17% smaller (P < 0.05) in the SCI subjects, but there was no difference in tendon length between the two groups. Our results indicate that paralysis causes substantial deterioration of the structural and material properties of tendon. This needs to be taken into consideration in the design of electrical stimulation protocols for rehabilitation and experimental purposes, and when interpreting changes in the contractile speed of paralyzed muscle. Muscle Nerve, 2005
Background:
Hip strength is associated with numerous orthopaedic and neuromuscular injuries and/or pathologies and may be assessed with a variety of anatomic testing positions and techniques. ...Isokinetic dynamometers are generally too cumbersome and intricate for efficient use in mass screenings (for prognostic studies of risk for injury) as well as with special populations. The reliability of isometric testing devices has demonstrated varied reliability, generally examining only 1 or 2 motions of the hip and reporting values of force, not torque. Consequently, there is a need for an efficient hip strength-testing device to quantify torque that tests subjects in 1 anatomic position, while evaluating multiple hip motions.
Hypothesis:
Evaluation of supine hip abduction, adduction, flexion, and extension torque using a new stabilized dynamometer system will produce good to excellent intra- and interexaminer reliability results.
Study Design:
A blinded, randomized, repeated-measures study design was used in this descriptive laboratory investigation.
Methods:
Supine isometric hip flexion, extension, abduction, and adduction torques were evaluated with a cage-stabilized dynamometer in 19 collegiate and professional-level ice hockey athletes by 2 investigators at 3 time intervals. Inter- and intrarater reliability was assessed.
Results:
Supine hip flexion, extension, abduction, and adduction torque was performed with good to excellent inter- and intrarater reliability (intraclass correlation coefficients ranging from 0.74 to 0.92 and 0.78 to 0.92, respectively) for all motions tested.
Conclusions:
We have developed an isometric hip strength-testing device that can be assembled around an examination table to efficiently and reliably evaluate torque developed for multiple motions of the hip.
Clinical Relevance:
This device and testing protocol may be used to efficiently evaluate hip strength in numerous settings; it allows decreased subject burden and increased comfort (which may be important following an injury in case-control investigations); and it may be well tolerated when testing athletes as well as special populations in the clinical setting.
In the assessment of hand and upper limb function, detecting sincerity of effort (SOE) for grip strength is of major importance to identifying feigned loss of strength. Measuring maximal grip ...strength with a dynamometer is very common, often combined with calculating the coefficient of variation (CV), a measure of the variation over the three grip strength trials. Little data is available about the relevance of these measurements in patients with median nerve impairment due to the heterogeneity of patient groups. This study examined the reliability of grip strength tests as well as the CV to detect SOE in healthy subjects. The power distribution of the individual fingers and the thenar was taken into account. To assess reliability, the measurements were performed in subjects with a median nerve block to simulate a nerve injury. The ability of 21 healthy volunteers to exert maximal grip force and to deliberately exert half-maximal force to simulate reduced SOE in a power grip was examined using the Jamar® dynamometer. The experiment was performed in a combined setting with and without median nerve block of the same subject. The force at the fingertips of digits 2–5 and at the thenar eminence was measured with a sensor glove with integrated pressure receptors. For each measurement, three trials were recorded subsequently and the mean and CV were calculated. When exerting submaximal force, the subjects reached 50–62% of maximal force, regardless of the median nerve block. The sensor glove revealed a significant reduction of force when exerting submaximal force (P1 sensor) with (P<0.032) and without median nerve block (P<0.017). An increase in CV at submaximal force was found, although it was not significant. SOE can be detected with the CV at the little finger at using a 10% cut-off (sensitivity 0.84 and 0.92 without and with median nerve block, respectively). These findings suggest low reliability of the power grip measurement with the Jamar® dynamometer, as well as that of the CV for detecting SOE. However, the combination of finger forces including the thenar area and the CV at the little finger could lead to better reliability for detecting feigned reduction of grip strength. The methods were as reliable in subjects with a median nerve block as in healthy subjects.
Dans l’évaluation de la fonction de la main du membre supérieur, il est primordial de détecter la sincérité de l’effort (SDE) lors de la force de poigne pour identifier les pertes feintes de force. La mesure de la force maximale de poigne avec un dynamomètre est très répandue, souvent combinée au calcul du coefficient de variations (CV), une mesure de la variation lors de trois essais répétés successivement de la force de poigne. Peu de données sont disponibles concernant la pertinence de ces mesures chez les patients présentant une pathologie du nerf médian, en raison de l’hétérogénéité des groupes de patients. Le présent travail a évalué la fiabilité des tests de force de poigne et le CV pour détecter la SDE chez les sujets sains. La distribution de la puissance selon les différents doigts et l'éminence thénar a été prise en compte. Les mesures ont également été réalisées chez les mêmes sujets après un bloc du nerf médian simulant un groupe de patients présentant une lésion nerveuse pour en évaluer la fiabilité. Dans cette étude, 21 volontaires sains ont été examinés quant à leur capacité à développer une force de poigne maximale et une force de poigne délibérément diminuée de sa moitié pour simuler une SDE lors d’une prise de poigne évaluée avec le dynamomètre JAMAR. L’expérimentation a été réalisée avec et sans bloc du nerf médian chez le même sujet. De plus, la force développée aux pulpes des doigts 2 à 5 et au niveau de l’éminence thénar a été mesurée à l’aide d’un gant sensitif équipé de capteurs de pression. Pour chaque mesure, trois essais ont été enregistrés successivement, la moyenne et le CV ont été calculés. Lors de la prise de force avec le dynamomètre JAMAR chez les sujets exerçant une force submaximale, les patients développaient 50 à 62 % de la force maximale, même après bloc du nerf médian. En mesurant de la force développée au niveau de l’éminence thénar par le gant sensitif, on constatait une réduction significative de la force lorsque que le sujet exerçait une force submaximale (capteur P1), avec (p<0,032) et sans bloc du nerf médian (p<0,017). On enregistrait également une augmentation du CV lors des prises à force submaximale, bien qu’elle ne soit pas significative. Il était possible de détecter la SDE et le CV au petit doigt avec un seuil de 10 % (sensibilité 0,84 et 0,92, respectivement sans et avec bloc du nerf médian). Ces expérimentations suggèrent une faible fiabilité des mesures de la force de poigne avec le dynamomètre JAMAR ainsi que celle du CV pour la détection de la SDE. Cependant, sa combinaison de la mesure des forces exercées par les doigts et l’éminence thénar et le CV au niveau du petit doigt pourrait améliorer la fiabilité lors du repérage d’une réduction feinte de force de poigne. La fiabilité de ces méthodes chez les sujets après bloc du nerf médian était comparable à celles des sujets sains.
Wheelchair basketball is the most popular exercise activity among individuals with spinal cord injury (SCI). The purpose of this study was to investigate muscular endurance and fatigue in wheelchair ...basketball athletes with SCI using surface electromyography (SEMG) and maximal torque values. SEMG characteristics of 10 wheelchair basketball players (WBP) were compared to 13 able-bodied basketball players and 12 sedentary able-bodied subjects. Participants performed sustained isometric elbow flexion at 50% maximal voluntary contraction until exhaustion. Elbow flexion torque and SEMG signals were recorded from three elbow flexor muscles: biceps brachii longus, biceps brachii brevis and brachioradialis. SEMG signals were clustered into 0.5-s epochs with 50% overlap. Root mean square (RMS) and median frequency (MDF) of SEMG signals were calculated for each muscle and epoch as traditional fatigue monitoring. Recurrence quantification analysis was used to extract the percentage of determinism (%DET) of SEMG signals. The slope of the %DET for basketball players and WBP showed slower increase with time than the sedentary able-bodied control group for three different elbow flexor muscles, while no difference was observed for the slope of the %DET between basketball and WBP. This result indicated that the athletes are less fatigable during the task effort than the nonathletes. Normalized MDF slope decay exhibited similar results between the groups as %DET, while the slope of the normalized RMS failed to show any significant differences among the groups (
p
> 0.05). MDF and %DET could be useful for the evaluation of muscle fatigue in wheelchair basketball training. No conclusions about special training for WBP could be determined.
The hip adductor muscle group plays an important role in both movement and stability at the hip joint in many athletic pursuits. Injury to this muscle group has been reported in a number of sports, ...among them, ice hockey, soccer, Australian football, and swimming. The identification of muscle characteristics that predispose a muscle to injury is an important step in developing conditioning programs to reduce injury risk. Muscle strength and range of motion are 2 parameters that may influence injury risk. The aim of this review was to examine the relationship between hip adductors' strength, flexibility, and injury risk. Strength testing has involved isokinetic or hand-held dynamometry. Flexibility has usually been assessed by goniometry during maximal hip abduction. An association has been reported between adductor strength deficits and injury for ice hockey players. Low adductor flexibility has also been identified as a risk factor for injury in soccer players. An intervention program that strengthened the hip adductors had some success in reducing injury risk for ice hockey players. There is some low- to moderate-level evidence from cohort studies to suggest that flexibility and strength are related to injury risk in particular sports and that an intervention program may be effective in reducing injury risk. Higher level evidence from randomized controlled trials is required to firmly establish the link between hip adductor flexibility, strength, and injury.
Abstract This paper compares geometry-based knee axes of rotation (transepicondylar axis and geometric center axis) and motion-based functional knee axes of rotation (fAoR). Two algorithms are ...evaluated to calculate fAoRs: Gamage and Lasenby's sphere fitting algorithm (GL) and Ehrig et al.'s axis transformation algorithm (SARA). Calculations are based on 3D motion data acquired during isokinetic dynamometry. AoRs are validated with the equivalent axis based on static MR-images. We quantified the difference in orientation between two knee axes of rotation as the angle between the projection of the axes in the transversal and frontal planes, and the difference in location as the distance between the intersection points of the axes with the sagittal plane. Maximum differences between fAoRs resulting from GL and SARA were 5.7° and 15.4 mm, respectively. Maximum differences between fAoRs resulting from GL or SARA and the equivalent axis were 5.4°/11.5 mm and 8.6°/12.8 mm, respectively. Differences between geometry-based axes and EA are larger than differences between fAoR and EA both in orientation (maximum 10.6°).and location (maximum 20.8 mm). Knee joint angle trajectories and the corresponding accelerations for the different knee axes of rotation were estimated using Kalman smoothing. For the joint angles, the maximum RMS difference with the MRI-based equivalent axis, which was used as a reference, was 3°. For the knee joint accelerations, the maximum RMS difference with the equivalent axis was 20°/s2. Functional knee axes of rotation describe knee motion better than geometry-based axes. GL performs better than SARA for calculations based on experimental dynamometry.
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