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An isometric hand tester: Quantifying motor function in the hand
Abstract
The aim of this study was to develop and assess an isometric hand tester to measure multiple strength parameters of the muscles of the hand. Nineteen men and 22 women took part in a first study and 17 men were tested in a second one. Five different tests were developed: wrist flexion, wrist extension, metacarpophalangeal joint flexion, thumb adduction and proximal and distal interphalangeal joint flexion. Reliability was tested with an intraclass correlation coefficient for single measures. When the results from men and women were analysed separately, all tests except metacarpophalangeal joint flexion and thumb adduction produced intraclass correlation coefficients greater than 0.7. Combining the genders gave intraclass correlation coefficients greater than 0.9 except for metacarpophalangeal joint flexion and thumb adduction. After adjustments, intraclass correlation coefficients for metacarpophalangeal joint flexion and thumb adduction were between 0.70 and 0.83 in the second study. The new isometric hand tests improve the measurement of intrinsic and extrinsic hand muscle strength.
... Wrist flexion and extension strength have been previously assessed using different methods: Manual muscle testing (MMT) [3][4][5], hand-held dynamometry (HHD) [6,7], isokinetic dynamometry [8][9][10] and home-made dynamometers [11][12][13]. Advantages and disadvantages of these various methods have previously been discussed [14]. None of these methods is reliable and highly sensitive over a large range of strengths as well as being flexible for different upper limb dimensions or deformities (e.g. ...
Background
Wrist movements become impaired with disease progression in various neuromuscular disorders. With the development of new therapies, thorough measurement of muscle strength is crucial to document natural disease progression and to assess treatment efficacy. We developed a new dynamometer enabling wrist flexion and extension torque measurement with high sensitivity. The aims of the present study were to collect norms for healthy children and adults, to compute predictive equations, to assess the reliability of the measurements and to test the feasibility of using the device in patients with a neuromuscular disease.Methods
The peak isometric torque of wrist flexion and extension was measured with the MyoWrist dynamometer in 345 healthy subjects aged between 5 and 80 years old and in 9 patients with limb girdle muscle dystrophy type 2 C (LGMD2C) aged between 16 and 38 years old.ResultsPredictive equations are proposed for the wrist flexion and extension strength in children and adults. Intra-rater and inter-rater reliability was good with ICCs higher than 0.9 for both wrist flexion and extension. However, retest values were significantly higher by 4% than test results. The dynamometer was applied with no difficulty to patients with LGMD2C and was sensitive enough to detect strength as weak as 0.82 N.m. From our models, we quantified the mean strength of wrist extension in LGMD2C patients to 39¿±¿17% of their predicted values.Conclusions
The MyoWrist dynamometer provides reliable and sensitive measurement of both wrist flexion and extension torques. However, a training session is recommended before starting a study as a small but significant learning effect was observed. Strength deficit can be quantified from predictive equations that were computed from norms of healthy children and adults.
... Particularly, the intrinsic plus position can eval-uate a combination of interosseous and lumbrical muscle strength (Schreuders et al, 2006). Recently, Raschner et al. (2010) designed a new device using the force transducer to measure strength similar to the Rotterdam Intrinsic Hand Myometer (RHIM). In a MCP flexion test using this device, it shows a significantly higher correlation (r>.7∼.8). ...
The lumbrical muscles contribute to the intrinsic plus position, that is simultaneous metacarpophalangeal (MCP) flexion and interphalangeal (IP) extension. The strength of the lumbrical muscles is necessary for normal hand function. However, there is no objective and efficient method of strength measurement for the lumbrical muscles. In addition, previous studies have not investigated the measurement of the cross-sectional area (CSA) of the lumbrical muscles using ultrasonography (US) and the relationship between lumbrical muscle strength in the intrinsic plus position and the CSA. Therefore, the purpose of this study was to identify the measurement method of the CSA of the lumbrical muscles using US and to examine the relationship between maximal isometric strength and the CSA of lumbrical muscles. Nine healthy males participated in this study. Maximal isometric strength of the second, third, and fourth lumbrical muscles was assessed using a tensiometer in the intrinsic plus position which isolated MCP flexion and IP extension. The CSA of the lumbrical muscles was measured with an US. The US probe was applied on the palmar aspect of the metacarpal head with a transverse view of the hand in resting position. There was no significant difference between maximal isometric strength of the lumbrical muscles, but the fourth lumbrical muscle was stronger than the others. The CSA of the lumbrical muscles was significantly different and the fourth lumbrical muscle was significantly larger than the second lumbrical muscle. There was moderate to good correlation between maximal isometric strength and the CSA of the lumbrical muscles. Therefore, we conclude that maximal isometric strength of the lumbrical muscles was positively correlated to the CSA of the lumbrical muscle in each finger, while the measurement of the CSA of the lumbrical muscles, using US protocol in this study, was useful for measuring the CSA of the lumbrical muscles.
... The testing apparatus to measure finger flexor MVC and finger flexor endurance was a modified version of an existing testing apparatus developed by Raschner et al. (2010). For comparability reasons to the study of MacLeod et al. (2007), the modifications consisted of extending the upper profiles of the testing apparatus and building a wooden ledge using the alloy profiles as rails (Fig. 2). ...
Climbing performance relies to a great extent on the performance of the finger flexor muscles. Only a few studies investigated this performance in top class climbers and only one study compared gender-specific differences. This study investigated the climbing-specific finger flexor strength and endurance and related muscular oxygenation in 12 elite female and male climbers and 12 non-climbers. After the assessment of maximum voluntary finger flexor contraction (MVC), two isometric finger flexor endurance tests were performed at 40% MVC until exhaustion. A continuous isometric test was followed by an intermittent isometric test (10 s contraction, 3 s rest). Changes in oxygenation of finger flexor muscles were recorded using near infrared spectroscopy. MVC and strength-to-weight ratio were greater in climbers than non-climbers (P = 0.003; P < 0.001) and greater in men than women (P < 0.001; P = 0.002). Time to task failure for the intermittent test and the force-time integrals for the continuous and the intermittent test were also significantly greater in climbers (P = 0.030; P = 0.027; P = 0.005). During the intermittent test, re-oxygenation of the working muscles was faster in climbers (P < 0.05) without gender-specific differences. Close correlations were demonstrated between the best on-sight climbing performance and strength-to-weight ratio (r
2 = 0.946, P < 0.001) only in female climbers. The superior intermittent finger flexor endurance of climbers over non-climbers may be explained by the faster re-oxygenation of the finger flexor muscles during the short rest phases.
Sex differences in strength have been attributed to differences in body anthropometrics and composition; these factors are often ignored when generating workplace guidelines. These differences directly impact the upper extremity, leaving female workers exposed to injury risk. The wide range of tools and techniques for measuring upper extremity strength presents a challenge to ergonomists and work task designers; collating outcomes to provide a clear outlook of differences between males and females is essential and the purpose of this work. Four online databases were searched (PROSPERO ID: CRD42022339023 ) with a focus on articles assessing sex differences in wrist strength. A total of 2,378 articles were screened for relevancy; 25 full-text articles were included in this systematic review. Articles examined movement pairs (ulnar/radial deviation, pronation/supination, and flexion/extension), as well as contraction types (isometric and isokinetic) to observe sex differences in wrist strength. Across all articles, females produced ∼60–65% of male flexion/extension strength, ∼55–60% pronation/supination strength, and ∼60–70% ulnar/radial deviation strength. Overall, females presented lower strength-producing abilities than males, but when considering strength relative to body mass, male-female differences were less pronounced and occasionally females surpassed male strength metrics; typically, this occurred during flexion/extension, particularly in isokinetic contractions. This review has identified a scarcity of articles examining ulnar/radial deviation, pronation/supination, as well as isokinetic contractions; these are needed to supplement workplace exposure guidelines.
Background: Behcet's disease is predominantly an inflammatory disease with oral and genital ulcus, uveitis and erythema nodosum. It is a chronic disease with unprecetended remission and activation periods. Behçet's disease may also affect extremities in the form of arthritis, myositis, enthesis, tenosynovitis and dactylitis. The most affected joints are knee, wrist - hand, ankle and elbow. A history of sytemic inflammatory disease in a patient with a hand disease or a one who is a candidate for hand surgery may affect the surgical procedure and post-operative rehabilitation. Thus recognition of this condition is essential for the hand surgeon, physiotherapist, and the patient. Objective: To evaluate the impact of Beh\c{c}et's disease on grip and key pinch strength. Subjects: Fifty (31 male, 19 female) patients with Behçet's disease and 50 (32 male, 18 female) controls. Results: Hand grip and key pinch strength of Behçet's patients did not differ from that of normal subjects. Conclusions: Behçet's disease does not seem to affect grip and pinch strength.
The intra-and inter-tester reliability for measurement of handgrip strength and indexgrip strength using the Jamar dynamometer was investigated in 32 healthy volunteers, and the intra-tester reliability in 13 patients with cervical radiculopathy. The results from the reliability studies showed that handgrip and indexgrip strength measured with the Jamar dynamometer is a reliable method (ICC values 0.85–0.98) and can be recommended for use in clinical practice. Age-and sex-specii c reference values for handgrip strength and indexgrip strength were measured with the Jamar dynamometer in 101 randomly selected healthy volunteers, aged 25–64 years. The results from the reference value study showed that sex is a more important determinant of hand strength than age, height and body weight. The reference values for hand strength improve the potential for objective evaluation of patients with arm/hand disorders caused by cervical radiculopathy.
To assess the inter-rater and intra-rater reliability and validity of the original and a modified Medical Research Council scale for testing muscle strength in radial palsy.
Prospective, randomized validation study.
Thirty-one patients with peripheral paresis of radial innervated forearm muscles were included.
Wrist extension, finger extension and grip strength were evaluated by manual muscle testing. Dynamometric measurement of grip strength was performed. Pair-wise weighted kappa coefficients were calculated to determine inter-rater and intra-rater reliability. The 2 scores were compared using the signed-rank test. Spearman's correlation coefficients of the maximal relative force measurements with the median (over-raters) Medical Research Council and modified Medical Research Council scores were calculated to determine validity.
Inter-rater agreement of the Medical Research Council scale (finger extension: 0.77; wrist extension: 0.78; grip strength: 0.78) and the modified Medical Research Council scale (finger extension: 0.81; wrist extension: 0.78; grip strength: 0.81) as well as intra-rater agreement of the Medical Research Council scale (finger extension: 0.86; wrist extension: 0.82; grip strength: 0.84) and the modified Medical Research Council scale (finger extension: 0.84, wrist extension: 0.81; grip strength: 0.88) showed almost perfect agreement. Spearman's correlation coefficients of the maximal relative force measurements with the median Medical Research Council and modified Medical Research Council score were both 0.78.
Medical Research Council and modified Medical Research Council scales are measurements with substantial inter-rater and intra-rater reliability in evaluating forearm muscles.
Two studies are reported that investigated the effect of warm-up exercises on maximal grip strength. Warm-up, a submaximal rehearsal or practice of an intended activity or event, is used to enhance athletic performance and reduce injury. Previous research on lower extremity performance has not found that activities designed to produce a warm-up effect increased strength. We hypothesized that subjects who engaged in mild warm-up exercises would have higher maximal grip force than would subjects with no warm-up period. The hypothesis was supported by both studies. The increase in grip strength due to warm-up was statistically and clinically significant (an increase of about 1 standard deviation).
Testing grip strength is a popular assessment used by occupational therapists in a range of clinical settings. It is fast, easy to perform, reliable and produces a result which is simple to record. Results of grip strength testing have been used to determine a baseline measure of performance against which change can be compared, as well as comparison of results to normative data. This article reviews the literature associated with the measurement of grip strength. It addresses the purposes of grip strength measurement; the instruments used and their reliability and accuracy; the testing position and protocol suggested for use and aspects of these which may influence results; the use of normative data and factors which influence grip strength, including age, gender and occupation; and various methods to determine level or sincerity of effort. Recommendations are made regarding these issues to enable clinicians to conduct grip strength assessments and interpret the results with confidence.
This study compared the Jamar and Rolyan hydraulic dynamometers to determine their concurrent validity with known weights as well as their inter-instrument reliability and concurrent validity for measuring grip strength in a clinical setting. Thirty females and 30 males were tested on these two grip strength measurement devices using a repeated measure design. Results showed that the Jamar and Rolyan dynamometers have acceptable concurrent validity with known weights (that is, correlation coefficients were r ≥ 0.9994), excellent inter-instrument reliability (that is, intraclass correlation coefficients ranged from 0.90 to 0.97) and strong concurrent validity (that is, no significant differences between dynamometers' scores). Data indicate that Jamar and Rolyan dynamometers measure grip strength equivalently and can be used interchangeably. Thus, therapists using the Rolyan dynamometer are justified in using published normative data, which were collected with the Jamar dynamometer. Copyright © 2002 Whurr Publishers Ltd.
The purpose of this investigation was to determine the relationship between isometric measures of muscular function at two different joint angles and dynamic performance. Thirteen experienced weight trainers performed two isometric tests in a bench press position, at elbow angles of 90 and 120°. Performance was assessed by a one repetition maximum (1-RM) bench press and a series of upper body bench press throws at loads of 15, 30, and 60% of the 1-RM load. The results clearly show that changing the joint angle from 120 to 90° improved the relationship between most of the tests and performance by more than 100%, possibly due to differences in motor unit recruitment patterns and differing muscle mechanics (e.g., length-tension), at varying joint angles. It was suggested that the best angle at which to assess isometric function may be the joint angle at which peak force is developed in the performance of interest.
The purpose of this investigation was to determine the relationship between isometric measures of muscular function at two different joint angles and dynamic performance. Thirteen experienced weight trainers performed two isometric tests in a bench press position, at elbow angles of 90 and 120°. Performance was assessed by a one repetition maximum (1-RM) bench press and a series of upper body bench press throws at loads of 15, 30, and 60% of the I-RM load. The results clearly show that changing the joint angle from 120 to 90° improved the relationship between most of the tests and performance by more than 100%, possibly due to differences in motor unit recruitment patterns and differing muscle mechanics (e.g., length-tension), at varying joint angles. It was suggested that the best angle at which to assess isometric function may be the joint angle at which peak force is developed in the performance of interest.
Grip strength and pinch strength measurements are often used to assess hand function. However, both measure a number of muscle groups in combination, and grip strength in particular is dominated by extrinsic hand muscles. The Rotterdam Intrinsic Hand Myometer (RIHM) was recently introduced to measure the force that individual fingers and thumb can exert in different directions. The aim of this study was to establish the reliability of these measurements with use of the RIHM in children.
Sixty-three healthy children between 4 and 12 years of age participated in this study. The RIHM was used to measure thumb palmar abduction, thumb opposition, thumb flexion at the metacarpal-phalangeal (MP) joint, index finger abduction, and little finger abduction. A retest was performed with an average test-retest interval of 26 days.
For the thumb, palmar abduction strength had intraclass correlation coefficients (ICCs) of .98 for both hands. For both thumb opposition and flexion at the MP joint, ICCs were .97 for the dominant hands and .98 for the nondominant hands. Index finger abduction had ICCs of .94 and .95 and little finger abduction had ICCs of .90 and .92 for the dominant and nondominant hands, respectively. The smallest detectable differences for dominant and nondominant hands respectively were thumb palmar abduction, 15% and 15%; thumb opposition, 12% and 9%; thumb flexion (at the MP joint), 12% and 9%; abduction of the index finger, 17% and 17%; and little finger abduction, 26% and 26%.
We found that the RIHM was reliable for use in children. Intraclass correlation coefficients and smallest detectable differences were comparable with those obtained with use of the RIHM in adults and with values found for pinch and grip strength in children. Because the RIHM measures more specific aspects of hand function than grip and pinch, adding the RIHM to measurement protocols may contribute to a more complete overview of a child's hand function.
This study evaluated the effectiveness of a patient-oriented, hand rehabilitation programme compared to a standard programme regarding functional outcomes, return to work, patient satisfaction and costs. Patients were recruited in two consecutive cohorts. One cohort received the standard treatment programme (n = 75) and the other a programme based on principles of patient orientation (n = 75). Data were collected at the beginning and end of rehabilitation and 6 months after discharge. Clinical variables included range of motion, grip and pinch strength. Self-reported measures included pain, upper extremity functioning, health status, satisfaction and job situation. Analysis of variance for repeated measurements was used to calculate the main effects. The patient-oriented group showed more favourable results with respect to DASH scores (P <.05), pain (P <.001) and patient satisfaction (P <.0001). More patients returned to their former jobs and time off sick was reduced. We concluded that the patient-oriented approach was more effective and cost-saving.