A test case: does the availability of visual feedback impact grip strength scores when using a digital dynamometer?

Population-specific equations of age-related maximum handgrip force: a comprehensive review

Background

The measurement of handgrip force responses is important in many aspects, for example: to complement neurological assessments, to investigate the contribution of muscle mass in predicting functional outcomes, in setting realistic treatment goals, evaluating rehabilitation strategies. Normative data about handgrip force can assist the therapist in interpreting a patient's results compared with healthy individuals of the same age and gender and can serve as key decision criteria. In this context, establishing normative values of handgrip strength is crucial. Hence, the aim of the this study is to develop a tool that could be used both in rehabilitation and in the prevention of work-related musculoskeletal disorders. This tool takes the form of population-specific predictive equations, which express maximum handgrip force as a function of age.

Methodology

In order to collect data from studies measuring maximum handgrip force, three databases were searched. The search yielded 5,058 articles. Upon the removal of duplicates, the screening of abstracts and the full-text review of potentially relevant articles, 143 publications which focussed on experimental studies on various age groups were considered as fulfilling the eligibility criteria. A comprehensive literature review produced 1,276 mean values of maximum handgrip force.

Results

A meta-analysis resulted in gender- and world region-specific (general population, USA, Europe and Asia) equations expressing maximum force as a function of age. The equations showed quantitative differences and trends in maximum handgrip force among age, gender and national groups. They also showed that values of maximum handgrip force are about 40% higher for males than for females and that age-induced decrease in force differs between males and females, with a proved 35% difference between the ages of 35 and 75. The difference was lowest for the 60-64 year olds and highest for the 18-25 year-olds. The equations also showed that differences due to region are smaller than those due to age or gender.

Conclusions

The equations that were developed for this study can be beneficial in setting population-specific thresholds for rehabilitation programmes and workstation exposure. They can also contribute to the modification of commonly used methods for assessing musculoskeletal load and work-related risk of developing musculoskeletal disorders by scaling their limit values.

Assessment of Motor Function in Peripheral Nerve Injury and Recovery

Introduction

Peripheral nerve injuries can be difficult to diagnose, treat, and monitor given their highly variable presentation. When the status of nerves is not accurately assessed, treatment may be delayed or overlooked and can result in lasting functional deficits. As our understanding of nerve repair and generation evolves, so will tools for evaluating both the functional and morphological status of peripheral nerves.

Objective

There is currently no single article which provides a detailed, comprehensive view of the literature comparing the clinical utility of various assessment modalities. Furthermore, there is no consensus on the optimal assessment algorithm for peripheral nerve injuries.

Methods

We performed a literature review using a comprehensive combination of keywords and search algorithm. The search was focused on clinical data regarding the assessment of peripheral nerves Results: This review may help to determine the appropriate tools that are currently available for monitoring nerve function both pre and postoperatively. Additionally, the review demonstrates possible roles and areas of improvement for each tool used to assess motor function.

Conclusion

As surgeons work to improve treatments for peripheral nerve injury and dysfunction, identifying the most appropriate existing measures of success and future directions for improved algorithms could lead to improved patient outcomes.

Investigating the Use of an Intermittent Sequential Pneumatic Compression Arm Sleeve for Recovery After Upper-Body Exercise

ABSTRACT

Cranston, AW and Driller, MW. Investigating the use of an intermittent sequential pneumatic compression arm sleeve for recovery after upper-body exercise. J Strength Cond Res 36(6): 1548-1553, 2022-The current study aimed to investigate the efficacy of an intermittent sequential pneumatic compression (ISPC) device placed on the arm after a fatiguing upper-body exercise circuit. Fifty resistance-trained athletes (37 males/13 females, mean ± SD; age = 27 ± 4 years) performed 3 physical performance tests (grip strength dynamometer, single-arm medicine ball throw, and preacher bench bicep curls to failure) before and after exercise, following a 30-minute recovery period. During the recovery period, subjects were randomly assigned an experimental arm, which was placed in the ISPC device, and a control arm (no device). Subjects completed a perceptual muscle soreness rating through palpation of 4 muscle groups in the upper body at the same time points and also 24 hours after recovery. There was a statistically significant interaction between conditions for the single-arm medicine ball throw (p < 0.01) in favor of the ISPC after the recovery period; however, the effect size was deemed trivial. There was a small but not statistically significant effect (d = 0.22, p > 0.05) for the bicep curls in favor of the ISPC and no significant difference for the grip strength (d = 0.09, p > 0.05). The perceptual muscle soreness scales resulted in significant differences between conditions immediately after and 24 hours after exercise across all muscle groups (p < 0.05), all in favor of the ISPC condition. This study supports the use of an upper-body ISPC device to reduce perceived muscle soreness for up to 24 hours after exercise, with negligible effects on physical performance when compared with a control trial.

Arthrodesis Versus Arthroplasty in Thumb Carpometacarpal Osteoarthritis: Impact on Maximal Voluntary Force, Endurance, and Accuracy of Pinch

PURPOSE

To investigate differences in pinch strength recovery among patients with first carpometacarpal joint osteoarthritis treated with either arthrodesis or suspension arthroplasty.

METHODS

Thirty-seven subjects who underwent arthrodesis or suspension arthroplasty for carpometacarpal osteoarthritis were included. Force exerted during maximal voluntary contraction (MVC) in a pinch task was measured. Maximal voluntary contraction was recorded using a haptic device equipped with a load cell from which an analog signal was acquired and digitized for visual feedback. Dynamic force was assessed by a task consisting of 10 repetitions, with a target of 70% of MVC. Endurance was assessed by the length of sustained pinch task at 30% of MVC. Task performance was quantified by mean distance and offset error from the target force as error indices, and standard deviation of force was used as index of force steadiness.

RESULTS

The arthrodesis group obtained considerably higher MVC values than the arthroplasty group. No notable differences were found for pinch endurance. The standard deviation for dynamic force was lower for arthroplasty, indicating greater force steadiness.

CONCLUSIONS

Arthrodesis is associated with greater pinch strength. Arthroplasty is associated with better pinch precision.

TYPE OF STUDY/LEVEL OF EVIDENCE

Therapeutic IV.

Handgrip as a measure of muscle strength and its physiological dependence on therapeutic variables: A randomized case

Clinical and medical data findings have traditionally been more representative of male than female subjects, and when combined, have not clearly differentiated between the groups. In this study there were no research questions initially contemplated, as the data were obtained from an educational setting, where participants completed tasks as part of a pedagogical program of preparation. The nature of the post-hoc analysis renders the study as a hypothesis-generating type rather than a hypothesis-testing one. It began as a cross-sectional quantitative analysis of performance on a task to explore the relationship between hand grip and three independent physiological variables. The data collected from all subjects were randomized since the total group of participants contained a disproportionate number of females as compared to males, this being a result of a demographic predominance of female students in a program of teacher preparation. Graphical analysis with the slope taken as a measure of hand grip dependence on three independent variables, and the correlation value used as a measure of association between variables yielded discernible differences. The grip strength dependence on the hand size as well as the wrist thickness show consistently significant differences for females only, with t test of significance (p < .001), and large effect size differences based on Cohen's d values of 3.08 and 1.92, respectively. The significance of the finding that female grip strength depends the most on wrist thickness has implications for rehabilitative and therapeutic settings.

A TRIZ-driven conceptualisation of finger grip enhancer designs for the elderly

Background: Elderly people with severe finger weakness may need assistive health technology interventions. Finger weakness impedes the elderly in executing activities of daily living such as unbuttoning shirts and opening clothes pegs. While studies have related finger weakness with ageing effects, there appears to be no research that uses an algorithmic problem-solving approach such as the theory of inventive problem-solving (TRIZ) to recommend finger grip assistive technologies that resolve the issue of finger weakness among the elderly. Using TRIZ, this study aims to conceptualise finger grip enhancer designs for elderly people. Methods: Several TRIZ tools such as the cause-and-effect chain (CEC) analysis, engineering contradiction, physical contradiction, and substance-field analysis are used to conceptualise solutions that assist elderly people in their day-to-day pinching activities. Results: Based on the segmentation principle, a finger assistant concept powered by a miniature linear actuator is recommended. Specific product development processes are used to further conceptualise the actuation system. The study concluded that the chosen concept should use a DC motor to actuate fingers through tendon cables triggered by a push start button. Conclusions: Finger pinch degradation worsens the quality of life of the elderly. A finger grip enhancer that assists in day-to-day activities may be an effective option for elderly people, not only for their physical but also their mental well-being in society.

A Systematic Review of Radiolunate and Radioscapholunate Arthrodesis

Purpose

The aims of this systematic review were to examine the use of radiolunate (RL) or radioscapholunate (RSL) arthrodesis as surgical management for patients with advanced radiocarpal arthritis that failed conservative management and to assess postoperative outcomes.

Methods

We reviewed articles from PubMed, EMBASE, and Web of Science from inception through December 2019. We identified complete manuscripts written in English reporting on RL or RSL arthrodesis for treatment of wrist pathology that included the primary outcomes (pain or grip strength) and at least 2 secondary outcomes (range of motion, patient-reported outcomes, or nonunion). Data pooling was used to calculate weighted averages.

Results

We identified 2,252 articles and selected 13 for inclusion. Across all studies, RSL arthrodesis was performed for 180 patients (49% female; 45 years old) and RL for 94 (87% female; 50 years old). Both procedures exhibited improvements in pain score and grip strength. Both cohorts demonstrated postoperative changes in flexion-extension arc, flexion, extension, ulnar deviation, supination, and pronation after data pooling. The nonunion rate for RSL was 15% versus 2% for RL, whereas the rate of progression to total wrist arthrodesis for RSL and RL was 4% and 0%, respectively.

Conclusions

Both RL and RSL arthrodesis can be successfully used to manage debilitating radiocarpal arthritis by affording patients with pain reduction. Each has its own benefits, in which RSL arthrodesis provides a total arc of motion within the functional demands of most activities of daily living, and RL arthrodesis has low rates of nonunion and progression to total wrist arthrodesis. Further research is needed to compare the 2 surgeries directly and prospectively in comparable patient groups.

Type of study/level of evidence

Therapeutic III.

Influence of aging and visual feedback on the stability of hand grip control in elderly adults

Aging causes a gradual decrease in maximal grip strength and leads many elderly people to have to rely on visual feedback to compensate for poorer muscle strength in performing daily activities and preventing accidents. Previous studies have investigated age and visual feedback-related changes in grip strength. However, little is known about methods of determining the quality and stability of hand grip strength control in the elderly, which is important for understanding their ability to generate grip force when handling objects with and without visual feedback in daily living. Therefore, the purpose of this study was to investigate the influence of aging and visual feedback on the stability of hand grip control in both hands in elderly adults. Forty-four healthy elderly persons (age 80.5 ± 4.53 years) and 36 young adults (age 32.69 ± 16.48 years) were recruited to execute grip force stability tasks using both hands at a 2 kg target force level. To perform the grip force stability task, the participants were asked to hold the dynamometer tightly in an attempt to achieve the target force level under visual and non-visual feedback conditions. Strength performances (grip force and coefficient of variation values) and stability of strength control (deviation error, variation error and force stability index values) for hand grip force stability tasks were calculated and analyzed. Compared with the visual feedback condition, the stability of grip force control in the hands of the young and elderly groups were significantly reduced in the non-visual feedback condition by 23.5%-57.1% (p < .05). The elderly group also showed significantly worse hand grip strength performances and stability of hand strength control than the young adult group (p < .05). Aging and non-visual feedback reduced the hand grip force output and stability of grip strength control of the hands. This may reveal the difficulty with manipulating hand-held objects in the absence of visual feedback while performing activities of daily living among the elderly.

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.

Load distribution of the hand during cylinder grip analyzed by Manugraphy

STUDY DESIGN

Clinical measurement and basic research.

INTRODUCTION

Manugraphy allows assessing dynamically all forces applied perpendicular to a cylinder surface by the whole contact area of the hand with a high spatial resolution.

PURPOSE OF THE STUDY

To identify the physiological load distribution of the whole contact area of the hand during cylinder grip.

METHODS

A sample of 152 healthy volunteers performed grip force tests with 3 cylinder sizes of the Manugraphy system (novel, Munich, Germany) on 3 different days. The whole contact area of the hand was sectioned into 7 anatomic areas, and the percent contribution of each area in relation to the total load applied was calculated. The load distribution of the dominant and nondominant hands and with different cylinder sizes was compared. Furthermore, the load distribution between the finger phalanges of each finger was analyzed.

RESULTS

The results for the dominant and nondominant hands were in all 7 areas of the hand similar with the percent contribution differing within a range of 1%-4% (P > .138). Load distribution changed significantly with different cylinder sizes: all 7 areas differed between 1% and 7% with P < .001, most pronounced for the thumb. The load distribution of the phalanges showed that the contribution of the distal phalanges increased with ascending cylinder size, whereas the contribution of the proximal phalanges decreased. The interindividual variability of the load distribution pattern was noticeable.

DISCUSSION

For the clinical practice, Manugraphy might be a useful supplement to traditional grip force measurement for identifying the individual characteristics of a patient's dysfunction and monitoring the progress of hand rehabilitation.

CONCLUSIONS

There is no universal or typical load distribution pattern of the hand but only an individual pattern. To evaluate a compromised hand, it is permissible to compare it with the healthy opposite hand as a reference. Several cylinder sizes should be used for load distribution testing. Using smaller handles in the daily life can help to compensate impairment of the thumb and fingertips.

LEVEL OF EVIDENCE

2.

The Takei Handheld Dynamometer: An Effective Clinical Outcome Measure Tool for Hand and Wrist Function in Boxing

BACKGROUND

The aim of this article was to explore retrospectively the Takei dynamometer as a valid and reliable outcome measure tool for hand and wrist pathology in the Great Britain amateur boxing squad between 2010 and 2014.

METHODS

Longitudinal retrospective injury surveillance of the Great Britain boxing squad was performed from 2010 to 2014. The location, region affected, description, and duration of each injury were recorded by the team doctor and team physiotherapists. For each significant injury, we recorded hand grip scores using the Takei handheld dynamometer and compared the scores with baseline measures.

RESULTS

At the hand, fractures and dislocations were highly detected with an average difference of 40.2% ( P < .05) when comparing postinjury to baseline measures. At the wrist, carpometacarpal and carpal joint injuries were highly detected with an average difference of 32.6% ( P < .05). Other injuries provided varied results. In the absence of pathology, up to 15% difference between left and right scores can be considered normal with a predominance observed below 10%. A difference of 20% can be indicative of a form of pathology, although pathologies can also be present with lower difference or no apparent changes. A difference of >20% should be highly considered for significant pathology.

CONCLUSIONS

The Takei dynamometer is a valid and reliable outcome measure tool for hand and wrist pathologies in boxing. Our study highlights the importance of appropriate clinical tools to guide injury management in this sport.

Reliability of isometric subtalar pronator and supinator strength testing

BACKGROUND

Due to the specific anatomy of the subtalar joint with its oblique axis, isometric pronator and supinator strength is not well documented. The purpose of this study was to determine intra- and between-session reliability of pronator and supinator strength and lower leg muscle activity measurements during maximum voluntary isometric contractions (MVIC).

METHODS

Pronator and supinator peak torques (PT), with and without supplementary visual muscle strength biofeedback (FB), and muscular activities of peroneus longus (PL) and tibialis anterior (TA) were assessed twice 3 days apart by the same examiner in 21 healthy young male adults (mean age: 27.6 years; SD = 3.9). Limits of agreement (LoA) and minimum detectable change (MDC) were evaluated.

RESULTS

By applying FB, reliability of both pronator and supinator PT was improved: LoA were reduced from 32% to 26% and from 20% to 18% and MDC from 20% to 15% and from 16% to 12% in supinator and pronator PT, respectively. Learning effects in pronator and supinator PT (p < 0.05), which were present without FB, were eliminated using FB. Except for TA during pronation, muscle activities showed low reliability indicated by LoA of 51% to 79%.

CONCLUSIONS

Using supplementary biofeedback, isometric subtalar pronator and supinator strength testing is reliable in healthy subjects. LoA of 18% and 26% have to be exceeded for pronator and supinator PT, respectively, to detect relevant effects in repeated measures.

Grip force monitoring on the hand: Manugraphy system versus Jamar dynamometer

INTRODUCTION

For clinical grip force assessment, the Jamar dynamometer is a wide accepted tool. Users have to be aware that this method does not represent all grip efforts applied. The Manugraphy system is a tool that measure total grip force as well as identify load distribution patterns of the hand while gripping cylinders wrapped with calibrated capacitive matrix sensor mats. The aim of this study was to validate an assessment setting of the Manugraphy system for clinical use. Further, the relationship and difference between the Manugraphy system and the Jamar dynamometer were investigated.

MATERIALS AND METHODS

At two study centers, 152 healthy volunteers performed grip force tests with a digital Jamar dynamometer using handle positions 3 and 4 and the novel(®) Manugraphy system using two cylinders with circumferences of 150 and 200 mm. The subjects performed grip force testing with both devices on three different days. The intra- and inter-day variability for both methods was evaluated. To compare the values of both systems, the Spearman correlation coefficient was calculated.

RESULTS

The force values, as measured by the sensor matrix, were higher than those of the Jamar dynamometer. Analyses showed significant positive correlations between values obtained by the two measurement methods (p < 0.001). There was no significant inter-day variation for the 200-mm cylinder of the Manugraphy system. For the 150-mm cylinder, a significant variation was observed at center B, but not at A. Nevertheless, the fluctuation of the grip force values obtained with the Manugraphy system was equal or better than those obtained with the Jamar dynamometer.

CONCLUSIONS

The force values, obtained using the two systems, have a high correlation but are not directly comparable. Both systems allow valid and constant grip force measurement. As the sensor mat detects all forces applied perpendicularly to the cylinder surface, it characterizes grip force better than the Jamar dynamometer. In addition, information about load distribution of the hand is gained.

Reliability of the pinch strength with digitalized pinch dynamometer

OBJECTIVE

To examine the intra-rater, inter-rater, and inter-instrumental reliability of the digitalized pinch muscle strength dynamometer.

METHOD

Thirty normal subjects were examined for pinch strength, using both the Preston pinch gauge and the digitalized pinch dynamometer. The participants performed all pinch strength tests in the seated position as recommended by the American Society of Hand Therapists (ASHT). Three successive measurements were taken for each hand. The mean of the three trials was used for data analysis. The pinch strength tests performed used a repeated measure design and measurements were taken by each rater.

RESULTS

The relationship between the Preston pinch gauge and the digitalized pinch dynamometer in pinch strength was reliable (the ICC were 0.821 and 0.785 in rater 1 and rater 2 respectively). The relationship between the first session and second session in pinch strength using the digitalized pinch dynamometer was reliable (the ICC were 0.872 and 0.886 in rater A and rater B respectively). The relationship between rater A and rater B in pinch strength using the digitalized pinch dynamometer was reliable (the ICC was 0.754).

CONCLUSION

The pinch strength measurement using the digitalized pinch dynamometer is reliable within the rater and between raters. Thus, the Preston pinch gauge and the digitalized dynamometer measure grip strength equivalently, and can be used interchangeably.