BACKGROUND: Measuring rate of torque development (RTD) and peak torque (PT) for hip muscle performance presents challenges in clinical practice. This study investigated the construct validity of a handheld dynamometer (HHD) versus an isokinetic dynamometer (IKD), and intra-rater repeated reliability for RTD and PT and their relationship in hip joint movements.
METHODS: Thirty healthy individuals (mean age = 30 ± 8 years, 13 males) underwent two test sessions in a single day. RTD (0-50, 0-100, 0-150, 0-200ms) and PT normalised to body mass in maximal voluntary isometric contractions were measured using a HHD and an IKD in hip flexion, extension, abduction, adduction, internal and external rotation.
RESULTS: For validity between the devices, RTD0-50 exhibited the largest significant systematic bias in all hip movements (3.41-11.99 Nm·s-1 kg-1) and widest limits-of-agreement, while RTD0-200 had the lowest bias (-1.33-3.99 Nm·s-1 kg-1) and narrowest limits-of-agreement. For PT, agreement between dynamometers was observed for hip flexion (0.08 Nm·kg-1), abduction (-0.09 Nm·kg-1), internal (-0.01 Nm·kg-1), and external rotation (0.05 Nm·kg-1). For reliability, intra-rater intraclass correlation coefficient (ICC2,1) ranged from moderate to good in RTD0-50 and RTD0-100 (0.5-0.88), and good to excellent in RTD0-150 and RTD0-200 (0.87-0.95) in all movements. The HHD displayed excellent intra-rater, relative reliability values (ICC2,1) in all movements (0.85-0.95). Pearson\'s correlation revealed good linear correlation between PT and RTD0-150 and RTD0-200 in all movements (r = .7 to .87, p = < .001).
CONCLUSIONS: Validity analysis demonstrated significant systematic bias and lack of agreement in RTD measures between the HHD and IKD. However, the HHD displays excellent to moderate intra-rater, relative reliability for RTD and PT measures in hip movements. Clinicians may use the HHD for hip muscle PT assessment but note, late phase RTD measures are more reliable, valid, and relate to PT than early phase RTD. Additionally, the correlation between RTD and PT at various time epochs was examined to better understand the relationship between these measures.

The reliability of the fixed-frame dynamometer for measuring isometric neck strength is established, but with limited field-based applications. This study aimed to establish the inter- and intra-session reliability of the peak force for neck flexors, extensors, and side flexors using the VALD ForceFrame and DynaMo and the force-time characteristics in the quadruped position (ForceFrame). Twenty-seven recreationally active males performed three repetitions of isometric neck flexion, extension, and side flexion over two sessions in random order using the VALD ForceFrame and DynaMo. Both devices demonstrated acceptable reliability, with the Forceframe ICC > 0.8 and CV% < 13.8% and the DynaMo ICC > 0.76 and CV% < 13.8%. No systematic or proportional differences were found using the Passing-Bablock procedure, and Bland-Altman analysis confirmed agreement across measures. Reliability was shown for right-side (ICC > 0.76) and left-side (ICC > 0.79) flexion and flexion (ICC > 0.75) across 50, 100, 150, and 200 ms. Statistical parametric mapping indicated no differences in ForceFrame-generated isometric force-time curves between sessions, though the CV was highest in the force development phase. The findings suggest that both tools can reliably assess neck strength, supporting their use in sports and clinical settings. However, assessment methods are not interchangeable, emphasising the need for standardised neck strength assessment approaches.

UNASSIGNED: The purpose of this study was to evaluate the associations of (1) individual absolute and body size normalized weakness cut-points, and (2) the collective weakness classifications on time to diabetes in Americans.
UNASSIGNED: We analyzed data from 9577 adults aged at least 50-years from the Health and Retirement Study. Diabetes diagnosis was self-reported. A handgrip dynamometer measured handgrip strength (HGS). Males with HGS <35.5 kg (absolute), <0.45 kg/kg (normalized to body weight), or <1.05 kg/kg/m2 (normalized to BMI) were categorized as weak. Females were classified as weak if their HGS was <20.0 kg, <0.337 kg/kg, or <0.79 kg/kg/m2. Compounding weakness included falling below 1, 2, or all 3 cut-points.
UNASSIGNED: Persons below the body weight normalized weakness cut-points had a 1.29 (95% confidence interval (CI): 1.15-1.47) higher hazard for incident diabetes, while those below the BMI normalized cut-points had a 1.30 (CI: 1.13-1.51) higher hazard. The association between absolute weakness and incident diabetes was insignificant (hazard ratio: 1.06; CI: 0.91-1.24). Americans below 1, 2, or all 3 collective weakness categories had a 1.28 (CI: 1.10-1.50), 1.29 (CI: 1.08-1.52), and 1.33 (CI: 1.09-1.63) higher hazard for the incidence of diabetes, respectively.
UNASSIGNED: Our findings indicate that while absolute weakness, which is confounded by body size, was not associated with time to diabetes, adjusting for the influence of body size by normalizing HGS to body weight and BMI was significantly associated with time to diabetes. This suggests that muscle strength, not body size, may be driving such associations with time to diabetes.

The measurement of isometric muscle torque with hand-held dynamometry is a technique little studied in the pediatric setting for the evaluation of maximal isometric muscle strength.
OBJECTIVE: to determine the reliability of hand-held dynamometry to obtain the maximal isometric torque of upper and lower limb muscle groups in Chilean children and adolescents.
METHODS: Crosssectional study. Seventy-two participants aged between 7 and 15 years were selected from a school in Talca. Maximal isometric torque was recorded in 15 muscle groups of upper and lower limbs through hand-held dynamometry. Intra- and inter-rater evaluation was used, applying the intraclass correlation coefficient (ICC) to determine the reliability of the tests and Bland-Altman plots to evaluate concordance.
RESULTS: The results demonstrated good to excellent inter-rater reliability (ICC = 0.850.98) and intra-rater reliability (ICC = 0.87-0.98). Only two groups, hip extensors and abductors, showed good inter-rater reliability (ICC = 0.85 and ICC = 0.88, respectively); and one group, the ankle dorsiflexors, showed good intra-rater reliability (ICC = 0.87). 100% of the tests presented at least 95.8% inter- and intra-rater agreement on the Bland-Altman plots.
CONCLUSIONS: The evaluation of isometric muscle torque using hand-held dynamometry is a reliable procedure for use in different growth periods.

UNASSIGNED: Grip strength is important for fine motor skills, and one of the measurement tools for grip strength is the Martin Vigorimeter (MV) dynamometer. Studies on establishing the reliability and validity of the MV in Koreans are limited. We aimed to establish the reliability and validity of the MV for grip strength measurement in healthy Korean adults by comparing it with the Jamar dynamometer, the standard tool used by the American Society of Hand Therapists.
UNASSIGNED: In total, 99 healthy participants (50 men and 49 women) were enrolled. Grip strength was measured using the Jamar dynamometer and MV. Reliability and validity were assessed using the intraclass correlation coefficient (ICC) and minimal detectable change (MDC). The correlation between the measurements of the instruments was analyzed using Pearson\'s correlation. The effect of hand anthropometry was evaluated, and the conversion equation between the instruments was calculated.
UNASSIGNED: MV showed excellent reliability (ICC > 0.90, p < 0.001) and validity with a high correlation (0.7 ≤ r < 0.9) with the Jamar dynamometer. The MDC was acceptable for detecting minimal clinically important differences (< 19.5%) in both instruments (Jamar: 3.4%-6.7%, MV: 3.8% to 6.3%). The grip strength measured using the MV was independent of hand anthropometry, unlike that using the Jamar dynamometer.
UNASSIGNED: This study provides insights into the relationship between the Jamar and MV instruments for measuring grip strength in Koreans. The MV is a viable alternative to the Jamar dynamometer in Koreans, offering not only reproducible and reliable measurements of grip strength but also the advantage of being unaffected by variations in hand anthropometry.

BACKGROUND: Frailty is a geriatric syndrome characterized by increased individual vulnerability with an increase in both dependence and mortality when exposed to external stressors. The use of Frailty Indices in routine clinical practice is limited by several factors, such as the cognitive status of the patient, times of consultation, or lack of prior information from the patient.
OBJECTIVE: In this study, we propose the generation of an objective measure of frailty, based on the signal from hand grip strength (HGS).
METHODS: This signal was recorded with a modified Deyard dynamometer and processed using machine learning strategies based on supervised learning methods to train classifiers. A database was generated from a cohort of 138 older adults in a transverse pilot study that combined classical geriatric questionnaires with physiological data.
METHODS: Participants were patients selected by geriatricians of medical services provided by collaborating entities.
RESULTS: To process the generated information 20 selected significant features of the HGS dataset were filtered, cleaned, and extracted. A technique based on a combination of the Synthetic Minority Oversampling Technique (SMOTE) to generate new samples from the smallest group and ENN (technique based on K-nearest neighbors) to remove noisy samples provided the best results as a well-balanced distribution of data.
CONCLUSIONS: A Random Forest Classifier was trained to predict the frailty label with 92.9% of accuracy, achieving sensitivities higher than 90%.

While resistance training promotes muscle hypertrophy and strength, accessibility of equipment is a barrier. This study evaluated a wearable VAriable Resistance Suit (VARS) as a novel and alternative method to achieve muscle strength improvement. It was hypothesized that by providing adjustable, bi-directional and speed dependent resistance, VARS can target specific muscles to improve muscle strength via an accessible and portable device. Twelve untrained healthy male adults (22.08 ± 4.1 years old) participated in an 8-week long resistance training using VARS to strengthen four muscles (biceps brachii, triceps brachii, biceps femoris, rectus femoris) of their non-dominant arm and leg using VARS. The results showed significant improvements in the muscle strength measured by isokinetic dynamometer - 49.9±9.6% increase in isokinetic force and 30.6±7.6% increase in isometric force. Muscle size and body composition were also assessed using ultrasound imaging and bioelectrical impedance analysis, which did not show significant changes. The study demonstrates the efficacy and feasibility of VARS as a resistance training tool to achieve muscle strength improvement and its potential extension to clinical populations.

OBJECTIVE: Occupational therapy practitioners need modern tools for the assessment of maximal grip strength in clinical and remote settings.
OBJECTIVE: To establish the (1) interrater reliability and (2) precision of the GripAble among three raters with different expertise in occupational therapy when testing healthy participants, and to (3) evaluate the relative reliabilities of different approaches to estimating grip strength (i.e., one trial, mean of two trials, and the mean of three trials).
METHODS: Measurement study.
METHODS: Minnesota Translational Musculoskeletal and Occupational Performance Research Lab, University of Minnesota, Minneapolis.
METHODS: Thirty volunteers, age ≥18 yr, without any hand problems.
METHODS: Using GripAble, three occupational therapy raters with varied experience measured the maximal grip strength of the dominant and nondominant hands of all participants. Using the mean of three trials when testing grip strength with GripAble adds precision.
RESULTS: GripAble has excellent interrater reliability (i.e., intraclass correlation coefficient > .75) and acceptable precision (minimal detectable change < 15%) among healthy adults.
CONCLUSIONS: GripAble allows occupational therapy practitioners with different experiences to assess grip strength in healthy hands quickly, precisely, and with excellent reliability. Additional research is needed on its psychometrics in clinical populations and capacities in remote monitoring and exergaming. Plain-Language Summary: The results of this study show that grip strength, an important biomarker and commonly assessed construct in occupational therapy, can be evaluated reliably, precisely, and rapidly with GripAble. The use of GripAble by occupational therapy practitioners in clinical settings may help to build an infrastructure for remote measurements and exergaming interventions in the future.

Background and Objectives: Biodex System® is an advanced dynamometer used for testing various biomechanical parameters of muscles. Test outcomes allow for the identification of muscle pathology and consequently lead to a clinical diagnosis. Despite being widely used for the testing and rehabilitation of the human musculoskeletal system, no universal and acceptable protocol for wrist examination has been proposed for patients with wrist pathology. In this study, the authors aim to identify the most appropriate protocol for testing the biomechanical parameters of flexors and extensors of the wrist. Materials and Methods: A group of 20 patients with symptomatic tennis elbow and 26 healthy volunteers were examined using three different protocols: isokinetic, isometric and isotonic. Protocol order for each study participant was assigned at random with a minimum of a 24 h break between protocols. All protocol parameters were set according to data obtained from a literature review and an earlier pilot study. Following completion of each protocol, participants filled out a questionnaire-based protocol, assessing pain intensity during the exam, difficulty with exam performance and post-exam muscle fatigue. Results: The isotonic protocol showed the best patient tolerance and the highest questionnaire score. There was a significant difference (p < 0.05) between the three protocols in average pain intensity reported by study participants. All participants completed the isotonic protocol, but not all patients with symptomatic tennis elbow were able to complete the isometric and isokinetic protocols. The isotonic protocol was deemed \"difficult but possible to complete\" by study participants. Conclusions: The isotonic protocol is most suitable for testing the flexors and extensors of the wrist. It gives the most biomechanical data of all protocols, is well tolerated by patients and rarely causes pain during examination even in symptomatic participants.

BACKGROUND: Sarcopenia is associated with many adverse outcomes in patients with cirrhosis. The tools currently in use for assessing sarcopenia have numerous flaws. We evaluated the utility of portable ultrasonography and a dynamometer for the bedside assessment of sarcopenia and its implications in hospitalized cirrhosis patients.
METHODS: A dynamometer was used to test the hand-grip strength (HGS) and ultrasound was used to measure the thickness of the forearm and quadriceps muscles. HGS value < 27 kg for men and < 16 kg for women was taken as significant according to the European Working Group on Sarcopenia in Older People (EWGSOP2) criteria. The lower normal limit of muscle mass (5th percentile) was determined on 100 matched healthy controls.
RESULTS: According to the EWGSOP2 criteria and HGS values, the prevalence of sarcopenia and probable sarcopenia among 300 cirrhosis patients were 56% and 62.3%, respectively. HGS alone identified sarcopenia in 88.9% of patients, while overestimated it in 6.3% of cases. The prevalence rate of sarcopenic obesity was 11%. Compared to patients without sarcopenia, sarcopenic patients had more complications of cirrhosis such as ascites, variceal bleeding, hepatic encephalopathy, spontaneous bacterial peritonitis, sepsis, hepatorenal syndrome and refractory ascites. In-hospital (p = 0.037), three-month (p < 0.001), and six-month (p < 0.001) mortality rates were all higher among sarcopenic patients. On cox regression survival analysis, overall six-month mortality was significantly higher in sarcopenic patients compared to patients without sarcopenia (hazard ratio, 6.37; 95% confidence interval, 3.15-12.8, p < 0.001).
CONCLUSIONS: Bedside assessment of sarcopenia using a portable ultrasound machine and a dynamometer detects liver cirrhosis patients with high risk of complications and mortality.