The coefficient of variation as a measure of sincerity of effort of grip strength, Part II: sensitivity and specificity

Multi-model assessment of potential natural vegetation to support ecological restoration

Ecological restoration is imperative for controlling desertification. Potential natural vegetation (PNV), the theoretical vegetation succession state, can guides near-natural restoration. Although a rising transition from traditional statistical methods to advanced machine learning and deep learning is observed in PNV simulation, a comprehensive comparison of their performance is still unexplored. Therefore, we overview the performance of PNV mapping in terms of 12 commonly used methods with varying spatial scales and sample sizes. Our findings indicate that the methodology should be carefully selected due to the variation in performance of different model types, with Area Under the Curve (AUC) values ranging from 0.65 to 0.95 for models with sample sizes up to 80% of the total sample size. Specifically, semi-supervised learning performs best with small sample sizes (i.e., 10 to 200), while Random Forest, XGBoost, and artificial neural networks perform better with large sample sizes (i.e., over 500). Further, the performance of all models tends to improve significantly as the sample size increases and the grain size of the crystals becomes smaller. Take the downstream Tarim River Basin, a hyper-arid region undergoing ecological restoration, as a case study. We showed that its potential restored areas were overestimated by 2-3 fold as the spatial scale became coarser, revealing the caution needed while planning restoration projects at coarse resolution. These findings enhance the application of PNV in the design of restoration programs to prevent desertification.

Evaluation of two methods of bone age assessment in peripubertal children in Zimbabwe

OBJECTIVES

Bone age (BA) measurement in children is used to evaluate skeletal maturity and helps in the diagnosis of growth disorders in children. The two most used methods are Greulich and Pyle (GP), and Tanner and Whitehouse 3 (TW3), both based upon assessment of a hand-wrist radiograph. To our knowledge no study has compared and validated the two methods in sub-Saharan Africa (SSA), and only a few have determined BA despite it being a region where skeletal maturity is often impaired for example by HIV and malnutrition. This study aimed to compare BA as measured by two methods (GP and TW3) against chronological age (CA) and determine which method is most applicable in peripubertal children in Zimbabwe.

METHODS

We conducted a cross-sectional study of boys and girls who tested negative for HIV. Children and adolescents were recruited by stratified random sampling from six schools in Harare, Zimbabwe. Non-dominant hand-wrist radiographs were taken, and BA assessed manually using both GP and TW3. Paired sample Student t-tests were used to calculate the mean differences between BA and chronological age (CA) in boys and girls. Bland-Altman plots compared CA to BA as determined by both methods, and agreement between GP and TW3 BA. All radiographs were graded by a second radiographer and 20 % of participants of each sex were randomly selected and re-graded by the first observer. Intraclass correlation coefficient assessed intra- and inter-rater reliability and coefficient of variation assessed precision.

RESULTS

We recruited 252 children (111 [44 %] girls) aged 8.0-16.5 years. The boys and girls were of similar mean ± SD CA (12.2 ± 2.4 and 11.7 ± 1.9 years) and BA whether assessed by GP (11.5 ± 2.8 and 11.5 ± 2.1 years) or TW3 (11.8 ± 2.5 and 11.8 ± 2.1 years). In boys BA was lower than CA by 0.76 years (95 % CI: -0.95, -0.57) when using GP, and by 0.43 years (95 % CI: -0.61, -0.24) when using TW3. Among the girls there was no difference between BA and CA by either GP [-0.19 years (95 % CI: -0.40, 0.03)] or TW3 [0.07 years (95 % CI: -0.16, 0.29)]. In both boys and girls, there were no systematic differences between CA and TW3 BA across age groups whereas agreement improved between CA and GP BA as children got older. Inter-operator precision was 1.5 % for TW3 and 3.7 % for GP (n = 252) and intra-operator precision was 1.5 % for TW3 and 2.4 % for GP (n = 52).

CONCLUSION

The TW3 BA method had better precision than GP and did not systematically differ from CA, meaning that TW3 is the preferred method of assessment of skeletal maturity in Zimbabwean children and adolescents. TW3 and GP methods do not agree for estimates of BA and therefore cannot be used interchangeably. The systematic differences in GP BA assessments over age means it is not appropriate for use in all age groups or stages of maturity in this population.

Comparing Statistics and Machine Learning to Detect Insincere Grip Force Testing Using Manugraphy

Background Currently, there are no tests that have been proven to be capable of rating an individual's grip force measurement as sincere or insincere. However, different parameters have been found to vary in grip force testing for maximal versus submaximal effort. A novel data analysis and processing approach might be key to improving these measurements. This study explores the use of a machine learning (ML) algorithm as a means to more accurately determine the sincerity or insincerity of grip force testing. The ML algorithm compares the hand's load distribution pattern with the information generated using conventional statistical methods. Methodology This study uses manugraphy data collected as part of a previous investigation that analyzed load distribution patterns of the right and left hands of 54 healthy subjects. The subjects underwent grip force testing using maximal or submaximal effort, and the percentage contributions of each of the seven defined anatomical areas of the hand were calculated with respect to the total load applied. The predictions based on the load distribution and its use for rating individual grip force measurements as sincere or insincere were compared with the results of conventional statistical methods (thresholds for a bi-manual area-to-area comparison) and an ML algorithm. Results Based on an area-to-area comparison, our method achieved a sensitivity of 54% and a specificity of 78% to detect insincere effort. A predictive ML model developed using these data was capable of recognizing submaximal effort based on the hand's load distribution pattern, determining a sensitivity of 94% and a specificity of 99%. Conclusions Compared to conventional methods, the use of an ML algorithm considerably improved the validity of manugraphy results in discerning the sincerity or insincerity of grip effort.

Generation gap, learning from the experience of compulsory remote architectural design studio

Physical design studio has been the mainstream method of architectural pedagogy for more than a century. Although the past two decades have brought forth emerging possibilities via advancements in digital communication, Virtual Design Studio (VDS) remained an experimental novelty until 2020. The interruption of face-to-face educational activities saw architecture schools facing a rapid paradigm shift because their studio-centred pedagogy retains intrinsic spatial qualities that are often attributed as critical dimensions of the learning process. This article explores the transition to the virtual design studio in a department of architecture after distance education became mainstream due to the global pandemic. The paper provides a comparison between students' and lecturers' points of view regarding different aspects of the virtual design studio. This addresses a potential generational gap concerning digital communication in a case study. A survey was administered to a group of architecture students who travelled back home and continued their education online and to the teachers of design studios who instructed VDS after the pandemic outbreak. The findings show the significant influence of effective communication, access to proper resources, maintenance of peer connections, and group works on the positive outcomes of the architectural design studio.

Muscle function impairment in cancer patients in pre-cachexia stage

Cancer cachexia has been reported to be directly responsible for at least 20% of cancer deaths. Management of muscle wasting in cancer-associated cachexia appears to be of pivotal importance for survival of patients. In this regard, it would be interesting to identify before its patent appearance eventual functional markers of muscle damage, to plan specific exercise protocols to counteract cachexia. The muscle function of 13 oncologic patients and 15 controls was analyzed through: i) analysis of the oxidative metabolism, indirectly evaluated trough dosage of blood lactate levels before and after a submaximal incremental exercise on a treadmill; ii) analysis of strength and, iii) endurance, in both lower and upper limbs muscles, employing an isokinetic dynamometer. Statistical analyses were carried out to compare the muscle activities between groups. Analysis of oxidative metabolism during the incremental exercise on a treadmill showed that patients performed a shorter exercise than controls. Lactate levels were significantly higher in patients both at baseline and after the task. Muscle strength analysis in patients group showed a reduction of Maximum Voluntary Contraction during the isometric contraction and, a tendency to fatigue during endurance task. Data emerging from this study highlight an impairment of muscle oxidative metabolism in subjects affected by a pre-cachexia stage of cancer. A trend of precocious fatigability and an impairment of muscle strength production were also observed. This evidence underlines the relevance of assessing muscle function in order to develop novel rehabilitative approaches able to counteract motor impairment and eventually to prevent cachexia in these patients.

Muscle function impairment in cancer patients in pre-cachexia stage

Cancer cachexia has been reported to be directly responsible for at least 20% of cancer deaths. Management of muscle wasting in cancer-associated cachexia appears to be of pivotal importance for survival of patients. In this regard, it would be interesting to identify before its patent appearance eventual functional markers of muscle damage, to plan specific exercise protocols to counteract cachexia. The muscle function of 13 oncologic patients and 15 controls was analyzed through: i) analysis of the oxidative metabolism, indirectly evaluated trough dosage of blood lactate levels before and after a submaximal incremental exercise on a treadmill; ii) analysis of strength and, iii) endurance, in both lower and upper limbs muscles, employing an isokinetic dynamometer. Statistical analyses were carried out to compare the muscle activities between groups. Analysis of oxidative metabolism during the incremental exercise on a treadmill showed that patients performed a shorter exercise than controls. Lactate levels were significantly higher in patients both at baseline and after the task. Muscle strength analysis in patients group showed a reduction of Maximum Voluntary Contraction during the isometric contraction and, a tendency to fatigue during endurance task. Data emerging from this study highlight an impairment of muscle oxidative metabolism in subjects affected by a pre-cachexia stage of cancer. A trend of precocious fatigability and an impairment of muscle strength production were also observed. This evidence underlines the relevance of assessing muscle function in order to develop novel rehabilitative approaches able to counteract motor impairment and eventually to prevent cachexia in these patients.

Influence of Maximal or Submaximal Effort on the Load Distribution of the Hand Analyzed by Manugraphy

PURPOSE

This study aims to investigate if the hands' load-distribution pattern differs during maximal and submaximal grip.

METHODS

Fifty-four healthy subjects used the 200-mm Manugraphy cylinder to assess the load-distribution pattern of both hands. On 2 testing days, the subjects performed grip-force testing: 1 hand with maximal effort and the other with submaximal effort. Sides changed for the second testing day. The whole contact area of the hand was sectioned into 7 anatomical areas, and the percent contribution of each area, in relation to the total load applied, was calculated. Maximal and submaximal efforts were compared across the 7 areas in terms of load contributions.

RESULTS

Comparing maximum effort of the left and right hand, the load distribution was very similar without statistically significant differences between the corresponding areas. Comparing the maximal and the submaximal effort for each hand, 4 (left) and 5 (right) of the 7 corresponding areas showed statistically significant differences. Comparing the right hand, performing with maximal effort, with the left hand, performing with submaximal effort, 5 areas varied significantly. With the right hand performing submaximal effort, all 7 anatomical areas were significantly different.

CONCLUSIONS

The load distribution of a healthy hand is different when performing with submaximal effort compared with maximal effort. To analyze a hand's load-distribution pattern, the opposite hand can be used as a reference.

CLINICAL RELEVANCE

The hand's load-distribution pattern may be a useful indication of submaximal effort during grip-force testing.

Upper-Body Strength Measures and Pop-Up Performance of Stronger and Weaker Surfers

Parsonage, J, Secomb, JL, Sheppard, JM, Ferrier, BK, Dowse, RA, and Nimphius, S. Upper-body strength measures and pop-up performance of stronger and weaker surfers. J Strength Cond Res 34(10): 2982-2989, 2020-The primary purpose of this study was to investigate the reliability of the isometric push-up (IPU), dynamic push-up (DPU), and force plate pop-up (FP POP) as measures of upper-body isometric and dynamic strength qualities in surfing athletes. Furthermore, the study aimed to compare pop-up performance between stronger and weaker surfers. Eighteen female (n = 9) and male (n = 9) surfers (age = 28.1 ± 6.4 years, mass = 69.6 ± 10.4 kg, and height = 172.5 ± 6.7 cm) completed a battery of upper-body strength assessments, of which exhibited high between-day reliability: IPU, (coefficient of variation [CV%] = 4.7, intraclass correlation coefficient [ICC] = 0.96), DPU (CV% = 5.0, ICC = 0.90), and FP POP (CV% = 4.4, ICC = 0.90). Participants were subsequently split into stronger (n = 9) and weaker (n = 9) surfers based on normalized peak force (PF) attained in the IPU. Pop-up performance was measured both in the water and during the FP POP and was referred to as time to pop-up (TTP). Significant between-group differences were observed for normalized PF during IPU (d = 1.59, p < 0.01) and DPU (d = 0.94 p = 0.04). Although not significant, there was a large magnitude difference in FP POP (d = 0.80, p = 0.08) and FP TTP (d = 0.85, p = 0.07). Significant correlations were identified between normalized IPU PF and normalized DPU FP (r = 0.69, p = 0.03) and FP TTP (r = 0.73, p = 0.02) in the stronger group. The weaker group exhibited a significant inverse correlation between normalized IPU PF and in-water TTP (r = -0.77, p < 0.01). The results suggest improvements in pop-up performance may be elicited by improving dynamic strength for stronger surfers, whereas pop-up performance in weaker surfers may be elicited by improving maximum strength. The upper-body strength assessments provided a novel insight into strength qualities that are associated with in-water performance of surfers (TTP).

[Grip strength measurement : Significance and boundaries]

BACKGROUND

Grip strength measurement is a widely used method for clinical as well as scientific purposes. In hand surgery, it is an essential component in the diagnosis of disease, treatment sequences and assessment. In epidemiological studies, it is a good predictor of healthy ageing or disease progression.

PROBLEM

Measurement results and their interpretation can be influenced by many factors. The historical development of dynamometry, measurement technology and the standard values in various population groups are presented. Comparisons with standard values should only be made using current tables because the grip strength has changed in recent decades. Assessment of the voluntarily submaximal grip strength remains problematic. Proposals are made for how to assess grip strength during the evaluation.

Using the "visual target grip test" to identify sincerity of effort during grip strength testing

We devised a sincerity of effort assessment based on "tricking" a person into exerting maximal effort by providing incorrect visual feedback. The assessment involves deriving a target line from nonvisual peak gripping force, instructing participants to reach it with each grip repetition, and then secretly changing its position, which requires doubling the force necessary to reach it. Accordingly, participants are tricked into exerting more force than intended to reach the deceptive target line. We examined the validity of this test by comparing force values between "trick" and "non-trick" trials in 30 healthy participants. The study design used was a prospective cohort. Providing incorrect visual feedback caused significantly greater increases in force during submaximal effort (69%) than during maximal effort (28%). This test effectively detected submaximal effort (sensitivity=0.83 and specificity=0.93). Although this test is not safe for patients during initial therapy, it may be appropriate for patients who can safely exert maximal grip force.

LEVEL OF EVIDENCE

Not applicable.

Identifying sincerity of effort based on the combined predictive ability of multiple grip strength tests

STUDY DESIGN

Retrospective Cohort.

INTRODUCTION

Detecting sincerity of effort (SOE) of grip strength remains a frustrating and elusive task for hand therapists because there are no valid, reliable, or widely accepted assessments for identifying feigned effort. Some therapists use various combinations of different SOE tests in an attempt to identify feigned effort, but there is lack of evidence to support this practice.

PURPOSE

The present study examined the ability of a combination of three grip strength tests commonly used in the clinic to detect SOE: the five rung grip test, rapid exchange grip test, and coefficient of variation. A secondary purpose was to compare the predictive ability between the logistic and linear regression models.

METHODS

Healthy participants (n=146) performed the three SOE tests exerting both maximal and submaximal efforts. We compared the ability of two regression models, the logistic and linear models, to predict sincere versus insincere efforts.

RESULTS

Combining the three tests predicted SOE better than each test alone. Yet, the full logistic model, which was the best predictor of SOE, explained only 42% of variance and correctly classified only 58% of the efforts.

CONCLUSIONS

Our findings do not support the clinical practice of combining these three tests to detect SOE.

LEVEL OF EVIDENCE

Not applicable.

Using the force-time curve to determine sincerity of effort in people with upper extremity injuries

This was a prospective cohort study. In a previous study, the slopes of the force-time (F-T) curve were shown to differentiate between maximal and submaximal grip effort in healthy participants. The objective of the study was to examine if the slopes of the F-T curve can determine the sincerity of effort in people with upper extremity injuries. Forty participants with unilateral upper extremity injury performed maximal and submaximal grip efforts. The F-T curve was recorded, and the slopes of the force-generation and force-decay phases were calculated. Repeated-measures analysis of variance revealed significantly steeper slopes for maximal than those for submaximal efforts. However, receiver operating characteristic curves showed that, at best, the slope of the force-generation phase yielded overall error rates of 55% for women and 60% for men. Therefore, sensitivity and specificity values were insufficient to effectively differentiate maximal from submaximal efforts. The slopes of the F-T curve did not validly measure the sincerity of effort in participants with upper extremity injury, perhaps, because they were protective of their injured hand and, thus, exerted only submaximal effort even at their best grip attempt.

LEVEL OF EVIDENCE

Not applicable.

Creating a clinically useful data collection form for the DASH questionnaire

PURPOSE

We generated a clinically useful data collection form for the Disabilities of the Arm, Shoulder, and Hand (DASH) questionnaire. This data collection form is designed to aid in measuring change and goal setting.

METHOD

Rasch analysis was used to generate three data collection forms for constructs on the DASH (gross motor, fine motor, and symptoms; N = 960). A form was completed to represent the findings from 1 study participant. Admission and discharge data were illustrated for one of the three sections (gross motor activity). Possible goals were indicated on the admission form. The discharge form illustrates whether these goals have been achieved.

RESULTS

Figures illustrate the utility of the forms in observing functional change from admission to discharge and how the forms aid in goal setting.

CONCLUSION

Use of the data collection form has many positive implications. This type of form could aid in goal setting and treatment planning.

A comparison of the ability of two upper extremity assessments to measure change in function

STUDY DESIGN

Retrospective Measurement Comparison.

INTRODUCTION

Upper extremity musculoskeletal disorders affect millions, thus, discerning optimal assessments for measuring change in upper extremity function is critical.

PURPOSE OF THE STUDY

To compare responsiveness (ability to measure change) of the Disabilities of Arm, Shoulder, and Hand (DASH) and Upper Extremity Functional Index (UEFI).

METHODS

Statistical analyses included Rasch analysis to place the instruments on the same scale, analysis of variance to compare change scores, correlations to compare change scores with global ratings, and the use of receiver operating characteristic (ROC) curves to determine meaningful change scores and overall error.

RESULTS

Change scores on the DASH and UEFI and correlations between change scores and global ratings were similar. Areas under the ROC curves for the DASH and UEFI were 67% and 65%, respectively.

CONCLUSIONS

Neither assessment has a clear advantage over the other when measuring clinical change.

LEVEL OF EVIDENCE

Not applicable.

Validity and Critical Driving Errors of On-Road Assessment for Older Drivers

OBJECTIVES. We examined the validity of our on-road driving assessment to quantify its outcomes.

METHOD. Older drivers (N = 127) completed a driving assessment on a standardized road course. Measurements included demographics, driving errors, and driving test outcomes; a categorical global rating score (pass–fail); and the sum of maneuvers (SMS) score (0–273).

RESULTS. There were significant differences in the SMS (F = 29.9, df = 1 p ≤ .001) between drivers who passed the driving test and those who failed. The SMS cutoff value of 230 points was established as the criterion because it yielded the most optimal combination of sensitivity (0.91) and specificity (0.87). The strongest predictors of failure were adjustment to stimuli and lane maintenance errors.

CONCLUSION. The SMS differentiated between passing and failing drivers and can be used to inform clinical decision making.

Using the force-time curve to detect maximal grip strength effort

Currently, there are no universally accepted assessment methods for detecting insincere effort during grip strength testing. We examined the validity of the slopes of the force-time curve (during force-generation and force-decay phases) as indicative of sincerity of effort. Thirty healthy subjects performed both maximal and submaximal grip strength trials. The test administrator was blinded as to the nature of the effort. A force-time curve was generated for each individual trial. The slopes of the force-generation phase and the force-decay phase were calculated. Both slopes were significantly steeper for the maximal than the submaximal efforts (p</=0.0001). Sensitivity and specificity analyses revealed that the slope of the force-generation phase was a more effective assessment of sincerity of effort for women, whereas the slope of the force-decay phase was a more effective assessment for men. The most notable finding was that for the force-decay phase, for slope cutoff values of -0.75 and -1.0, none of the men who exerted maximal effort were mistakenly identified as exerting a submaximal effort, whereas only 7% of the men who exerted submaximal effort were incorrectly identified as exerting a maximal effort. Thus, the slopes of the force-time curve are valid and effective in detecting sincerity of effort in healthy subjects. This study represents the first step in establishing the feasibility and validity of a new sincerity of effort assessment using the slopes of the force-time curve. Future research is needed to establish the validity and effectiveness of this sincerity of effort assessment in people with hand injury.

An analysis of symmetry of torque strength of the forearm under resisted forearm rotation in normal subjects

PURPOSE

To establish normative pronation and supination torque values in right-handed adults without evidence of upper-extremity dysfunction or impairment in the forearm positions of neutral, pronation, and supination.

METHODS

Fifty-one normal right-handed participants ages 22 to 45 years were enrolled and tested in this study using a custom device that incorporated a torque cell and a grip system that produced a digital recording of the peak torque during maximal resisted pronation and supination in positions of neutral forearm rotation, 60 degrees pronation, and 60 degrees supination.

RESULTS

The greatest peak torque strength for both male and female participants was found during resisted pronation in the supinated position. The peak torque values averaged 11.9 +/- 3.7 N.m on the right side and 10.4 +/- 3.3 N.m on the left side for men, and 6.0 +/- 1.4 N.m on the right side and 5.0 +/- 1.2 N.m on the left side for women. The weakest torque strengths were resisted pronation in the pronated position and resisted supination in the supinated position.

CONCLUSIONS

Torque strength measurements are reliable and should be collected when treating patients with forearm dysfunction. Maximal torque follows the same pattern related to hand dominance as grip strength. Men generate average torque strengths that are approximately twice the magnitude of those generated by women.

Analysis of the statistical methods used to detect submaximal effort with the five-rung grip strength test

Controversy exists in the literature concerning the ability of the five-rung grip test to identify submaximal effort. The purpose of this study was to analyze four methods commonly used to evaluate the shape of the curve generated by maximal versus submaximal efforts. Thirty hand therapy patients performed the five-rung grip test maximally and submaximally with both their injured and uninjured hands. Grip strength scores were recorded at each of the five-rung positions. Next, four methods were used to analyze the data 1) visual analysis, 2) analysis of variance, 3) normalization, and 4) calculation of the standard deviation across the five strength scores. Analysis by all methods demonstrated that there were no differences between the injured hand exerting maximal effort and the uninjured hand exerting submaximal effort. In all four methods, the five-rung grip strength test was unable to distinguish between the injured hand exerting maximal effort and the uninjured hand exerting submaximal effort. The results suggest that the five-rung grip strength test should not be used to determine sincerity of effort in people with hand injuries, and that the shape of the curve generated by the five-rung grip strength test may not be related to level of effort but rather to the amount of force generated by the gripping hand.

Critical issues in the use of muscle testing for the determination of sincerity of effort

Over the past 20 years, there have been numerous attempts to identify methodologies that are capable of the determination of sincerity of effort during muscle testing. The ensuing paper reviewed this literature and drew several conclusions. Injured patients and healthy volunteers do produce less force and more variable force while performing submaximal contractions than maximal contractions. However, submaximal efforts during strength testing can be reproduced and the use of force variability is not adequate to distinguish sincerity of effort. Visual examination of the shape of force output curves is also not adequate for distinguishing sincerity of effort. Furthermore, much of the research using strength ratios, difference scores, and an assortment of different parameters derived during strength testing has not established reliable and clinically useful methods of differentiating effort levels. Methods examining motion variability, radial/ulnar force output ratios, difference scores of eccentric-concentric ratios, and electromyography offer some promise, but numerous critical issues need to addressed. The use of the coefficient of variation, for example, is statistically untenable given the number of trials appropriate for clinical samples. Several studies have inadequate sample size to number of variable ratios. Many studies have questionable or at least unknown generalizability to patient samples and actual functional capacity. It is critical that other explanatory variables such as fear of injury, pain, medications, work satisfaction, and other motivational factors be considered. It is our opinion that there is not sufficient empirical evidence to support the clinical application of muscle testing to determine sincerity of effort.

Effectiveness of the Five–Handle Position Grip Strength Test in Detecting Sincerity of Effort in Men and Women

OBJECTIVE

The five-handle position (five-rung) test is used to determine sincerity of effort of grip strength. However, there is a controversy in the literature concerning its validity and effectiveness. The purpose of the study was to investigate whether test results are affected by the amount of strength exerted by the gripping hand and to determine the test's effectiveness.

DESIGN

A total of 30 hand therapy patients performed the five-rung grip test both maximally and submaximally with both the injured and uninjured hands. The standard deviation across the five strength trials was used to measure the shape of the curve. Sensitivity and specificity values were calculated for each sex.

RESULTS

The repeated measures analyses of variance revealed that average strength and the standard deviation were greater for men than for women, for maximal effort than for submaximal effort, and for the injured hand in comparison with the healthy hand. The most optimal standard deviation cutoff value was 8.5 (sensitivity, 0.70; specificity, 0.83), and the proportional area under the receiver operator characteristic curve was greater for the men (89%) than for women (80%).

CONCLUSIONS

The shape of the curve generated by the five-rung test was strength dependent; thus, the test may yield biased results when assessing sincerity of effort in people with weakened hands. The five-rung test was less effective for women than for men. Thus, we recommend that the five-rung test not be used to detect sincerity of effort.

Reliability and validity of the BTE-Primus grip tool

This study was designed to examine the reliability and validity of the newly designed grip tool of the Baltimore Therapeutic Equipment (BTE)-Primus and to investigate the effects of body position (sit versus stand), handedness, and fatigue on grip strength. The subjects performed maximal grip strength tests using the Jamar dynamometer and the BTE-Primus. Intraclass correlation coefficients were calculated for test-retest reliability and criterion-related validity. A repeated measures analysis of covariance was conducted to reveal differences in grip strength between instruments, body positions, hands, and sessions. The BTE-Primus grip tool was found to be reliable (r = 0.97 to 0.98) and valid (r = 0.95 to 0.96). There were no significant differences in grip strength scores between the Jamar and the BTE-Primus or between sitting and standing. Grip strength scores of the right hand were significantly greater than those of the left hand, and grip strength scores in the first session were significantly greater than those in the second session. The results of this study indicate that clinicians can use the BTE-Primus grip attachment at the second handle setting and know that is reliable, valid, and comparable to the second-handle setting of the Jamar dynamometer.

Simultaneous bilateral testing: validation of a new protocol to detect insincere effort during grip and pinch strength testing

The detection of feigned weakness in hand grip strength assessment is difficult. The authors review several proposed methods and their weaknesses. A comparison of unilateral testing and simultaneous bilateral testing with the Jamar dynamometer and the Baseline pinch gauge is demonstrated as a solution. An experiment involved 100 asymptomatic subjects who were tested twice, once under instructions to give a full effort and once under instructions to feign weakness. Seven statistical criteria of noncompliance were chosen. Defining noncompliance as failing two or more of the seven criteria, 99% of the instructed noncompliant subjects were correctly classified as noncompliant. No subjects were incorrectly classified as noncompliant during instructed compliant testing. Twelve subjects failed on a single criterion. On retesting, all but one were correctly classified. One subject in the instructed noncompliant group passed all criteria. Accuracy was 99.5%, including retesting of the 12 "gray-zone" subjects.