The measurement of muscle strength in patients with peripheral neuromuscular disorders

Comparison of telerehabilitation versus home-based video exercise in patients with Duchenne muscular dystrophy: a single-blind randomized study

Introduction

Patients with Duchenne muscular dystrophy (DMD) have lost their access to on-site rehabilitation due to the COVID-19 pandemic. Telerehabilitation can be a viable approach for these patients to protect their muscle strength and functional status. The aim of this study is to compare telerehabilitation with home-based video exercises.

Patients and methods

Male, ambulatory DMD patients were randomized into telerehabilitation and video-exercise groups. Nineteen patients were included in the final analyses. Telerehabilitation consisted of live online exercises, while video exercise implemented a pre-recorded video as a home-based program. Both programs spanned 8 weeks, three times a week. Patients’ muscle strength with a hand-held dynamometer, Quick Motor Function Test, North-Star Ambulatory Assessment (NSAA), 6-Minute Walk Test (6MWT) and Caregiver Burden were recorded before and after treatment.

Results

The 6MWT of the telerehabilitation group was391.26 ± 95.08 m before and387.75 ± 210.93 after treatment (p = 0.94) and 327.46 ± 103.88 m before treatment and313.77 ± 114.55 after treatment in video group (p = 0.63). The mean NSAA score of the telerehabilitation group were26.70 ± 8.04 before treatment and 25.20 ± 11.33 after treatment (p = 0.24). In the video group scores were 21.66 ± 6.65 before to 22.00 ± 8.61 after treatment (p = 0.87). There were no significant changes between groups at the end of the treatments. The telerehabilitation group's neck extension, bilateral shoulder abduction, and left shoulder flexion, bilateral knee flexion and extension, bilateral ankle dorsiflexion, and left ankle plantar flexion strength improved significantly and were better than the video group (p < 0.05 for all measurements).

Conclusion

A telerehabilitation approach is superior in improving muscle strength than a video-based home exercise, but none of the programs improved functional outcomes in ambulatory patients with DMD.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13760-022-01975-4.

Quantitative assessment of elbow flexion by handheld dynamometry in brachial plexus palsy

The purpose of this study was to assess the relative and absolute reliability of a handheld dynamometer when used for examining elbow flexion power in patients with brachial plexus palsy. The assessment of the intra-rater and inter-rater reliability coefficients for the handheld dynamometer was done using the stationary Kin-Com® dynamometer as the reference standard. We determined the measurement errors and checked the systematic biases of the handheld dynamometer. The inter-rater and intra-rater reliabilities of the handheld dynamometer had a very high intraclass correlation coefficient. The values of handheld dynamometer readings had a high correlation to Kin-Com® readings. The Medical Research Council grading was a comparatively inaccurate method for quantitative assessment of motor power. We conclude that a handheld dynamometer measurement is more precise and reliable than the Medical Research Council grading for measuring recovery of elbow flexion in patients with brachial plexus palsy. Level of evidence: III.

Assessment of lower extremity muscle mass, muscle strength, and exercise therapy in elderly patients with diabetes mellitus

The increase in the proportion of elderly people in the population is one of the most remarkable sociodemographic phenomena of the twenty-first century. The number of patients with diabetes is also increasing worldwide with this demographic change. Given these facts, consideration of the problems the general elderly population is facing in the management of diabetes is essential. In this review article, we focus on sarcopenia, which is the decrease in lower extremity muscle mass and muscle strength accompanying aging, describe the relationship between sarcopenia and diabetes, and highlight the specific factors through which diabetes contributes to loss of muscle strength. The quantitative methods for evaluating lower extremity muscle strength will also be described. These methods hold the key to assessing the effectiveness of exercise therapy and optimizing the assessment of the degree of autonomy in the activities of daily living. Exercise is one of the basic treatments for type 2 diabetes and may also prevent and improve sarcopenia. This review discusses the aspects common to the two health conditions and elucidates the effectiveness and necessity of exercise as a preventive measure against diabetes among the elderly.

Strength Testing in Motor Neuron Diseases

Loss of muscle strength is a cardinal feature of all motor neuron diseases. Functional loss over time, including respiratory dysfunction, inability to ambulate, loss of ability to perform activities of daily living, and others are due, in large part, to decline in strength. Thus, the accurate measurement of limb muscle strength is essential in therapeutic trials to best understand the impact of therapy on vital function. While qualitative strength measurements show declines over time, the lack of reproducibility and linearity of measurement make qualitative techniques inadequate. A variety of quantitative measures have been developed; all have both positive attributes and limitations. However, with careful training and reliability testing, quantitative measures have proven to be reliable and sensitive indicators of both disease progression and the impact of experimental therapy. Quantitative strength measurements have demonstrated potentially important therapeutic effects in both amyotrophic lateral sclerosis and spinobulbar muscular atrophy, and have been shown feasible in children with spinal muscular atrophy. The spectrum of both qualitative and quantitative strength measurements are reviewed and their utility examined in this review.

Effects of trunk stability on isometric knee extension muscle strength measurement while sitting

[Purpose] This study aimed to investigate the effect of trunk stability on isometric knee extension muscle strength measurement while sitting by performing simultaneous measurements with a handheld dynamometer (HHD) and an isokinetic dynamometer (IKD) in the same seated condition. [Subjects and Methods] The subjects were 30 healthy volunteers. Isometric knee extension muscle strength was simultaneously measured with a HHD and an IKD by using an IKD-specific chair. The measurement was performed twice. Measurement instrument variables and the number of measurements were examined by using the analysis of variance and correlation tests. [Results] The measurement instrument variables and the number of measurements were not significantly different. The correlation coefficients between the HHD and IKD measurements were ≥0.96. [Conclusion] Isometric knee extension muscle strength measurement using the HHD in the sitting position resulted in a lower value than that using the IKD, presumably because of the effect of trunk stability on the measurement. In the same seated posture with trunk stability, no significant difference in measurement values was observed between the HHD and IKD. The present findings suggest that trunk stability while seated during isometric knee extension muscle strength measurement influenced the HHD measurement.

Validity and reliability of isometric muscle strength measurements of hip abduction and abduction with external hip rotation in a bent-hip position using a handheld dynamometer with a belt

[Purpose] This study aimed to investigate the relatedness, reliability, and validity of isometric muscle strength measurements of hip abduction and abduction with an external hip rotation in a bent-hip position using a handheld dynamometer with a belt. [Subjects and Methods] Twenty healthy young adults, with a mean age of 21.5 ± 0.6 years were included. Isometric hip muscle strength in the subjects’ right legs was measured under two posture positions using two devices: a handheld dynamometer with a belt and an isokinetic dynamometer. Reliability was evaluated using an intra-class correlation coefficient (ICC); relatedness and validity were evaluated using Pearson’s product moment correlation coefficient. Differences in measurements of devices were assessed by two-way ANOVA. [Results] ICC (1, 1) was ≥0.9; significant positive correlations in measurements were found between the two devices under both conditions. No main effect was found between the measurement values. [Conclusion] Our findings revealed that there was relatedness, reliability, and validity of this method for isometric muscle strength measurements using a handheld dynamometer with a belt.

Reasons for persistent disability in Guillain-Barre syndrome

The reasons for persistent disability in 10 Guillain-Barre syndrome patients were investigated. Patients were assessed between 11 and 35 months after disease onset with impairment, disability and handicap scales, a standard neurological examination and nerve conduction studies. All patients showed persistent limb weakness which affected independence in self-care in three patients and the pursuit of leisure and work activities in eight patients. The implications for clinical practice are discussed.

Use of myometry in the assessment of neuropathic weakness: testing for reliability in clinical practice

The myometer has been recommended as a quantitative method of measuring muscle strength in clinical practice. The reliability of the myometer was tested in a clinical environment by physiotherapists and a form incorporating the testing positions was designed. An intensive training programme for examiners was instigated and piloted on normal subjects. The study tested the reliability of paired examiners in recording the muscle strength of 20 Guillain-Barre syndrome patients at different stages in their recovery. Ten patients were tested in the first experiment. The error rate between observers was large and unacceptable. Procedures for improving reliability were implemented. Testing was repeated on 10 more patients but no improvement in reliability was observed. The implications for clinical practice are discussed.

Does an early home-based progressive resistance training program improve function following total hip replacement? Results of a randomized controlled study

BACKGROUND

In-hospital progressive resistance training (PRT) has been shown to be an effective method of rehabilitation following hip surgery. The aim of this study was to assess whether a home-based PRT program would be beneficial in improving patients' muscle strength and physical function compared to standard rehabilitation.

METHODS

Subjects (n = 49) either received home-based PRT rehabilitation (n = 25) or standard rehabilitation (n = 24) in a prospective single blinded randomized trial carried out over a two-year period. The primary outcome measure was the maximal voluntary contraction of the operated leg quadriceps (MVCOLQ) with secondary measures of outcome being the sit to stand score (ST), timed up and go (TUG), stair climb performance (SCP), the 6 min walk test (6MWT), and lean mass of the operated leg (LM).

RESULTS

Twenty-six patients completed follow up at 1 year (n = 13 per group) for the final comparative analysis. All the outcome measures showed marked progressive improvements from the baseline measures at 9-12 months post op (Estimated effect (std error); p value)- MVCOLQ 26.50 (8.71) N p = 0.001; ST 1.37 (0.33) p = 0.0001; TUG -1.44 (0.45) s p =0.0001; SCP -3.41(0.80)s p = 0.0001; 6MWT 45.61 (6.10)m p = 0.0001; LM 20 (204)g p = 0.326) following surgery for both groups. Overall, there was no significant effect for participation in the exercise regime compared with standard care for all outcomes assessed.

CONCLUSIONS

Overall, this study demonstrated that there is no significant difference between the two groups for participation in the home-based PRT exercise programme when compared to standard care for all outcomes.

TRIAL REGISTRATION

ISRCTN 1309951. Registered February 2011.

Intrarater reliabilities of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer for geriatric and stroke patients

[Purpose] This study aimed to verify the appropriate number of measurements and the intrarater reliabilities of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD) for geriatric and stroke patients. [Subjects and Methods] The subjects were 40 inpatients, who were divided into two groups: 20 stroke patients in the stroke group (SG), and 20 geriatric patients in the no-stroke group (N-SG). Measurements were performed three times using an HHD with a belt. The reliability was verified using Bland-Altman analysis and the intraclass correlation coefficient (ICC). [Results] ICC (1, 1) was >0.9. A systematic bias was not observed between the first and second measurement values except for the right side in N-SG. A systematic bias between the maximum value obtained during the first and second measurements and third measurement value was observed on the left side in N-SG, and on the non-paralyzed side in SG: the third measurement values were small in both cases. [Conclusion] Intrarater reliabilities were high for shoulder horizontal adductor strength measurements using an HHD with a belt for geriatric and stroke patients. Taking the systematic bias into consideration, these findings suggest that the required number of measurements is two.

Absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer

[Purpose] The aim of this study was to verify the absolute reliability of shoulder joint horizontal adductor muscle strength measurements using a handheld dynamometer (HHD). [Subjects and Methods] The subjects were 33 healthy college students. The measurements were made three times with the HHD fixed using a belt (BFHHD) or with the examiner's hand (conventional method; HFHHD). The absolute reliability of measurements was verified using Bland-Altman analysis, both in the all subjects group and a group of subjects showing measurements less than a fixed limit of 30 kgf. [Results] In the <30 kgf group, a systematic bias was not observed, and BFHHD values were greater than HFHHD values. BFHHD values in the all subjects group showed a systematic bias; the 3rd measurement value was less than the maximum value obtained during the 1st and 2nd measurements. [Conclusion] For obtaining an acceptable value during clinical measurements of horizontal adductor muscle strength, single measurements obtained using an HFHHD in the case of a <30 kgf group and the maximum value of two measurements obtained using a BFHHD are reliable.

Test-retest reliability of isometric shoulder muscle strength measurement with a handheld dynamometer and belt

[Purpose] The aim of this study was to develop a method of measuring isometric shoulder joint muscle strength using a handheld dynamometer with a belt and investigate its test-retest reliability. [Subjects] The subjects comprised 40 healthy adults. [Methods] Six types of isometric shoulder muscle strength were measured twice, and reliability was assessed. [Results] The intraclass correlation coefficient (1, 1) values ranged from 0.976 to 0.902. The result of a Bland-Altman analysis showed differences in the types of errors between measurement items. [Conclusion] The relative reliability of isometric shoulder muscle measurement using a handheld dynamometer with a belt was high. However, analysis of absolute reliability revealed errors that may affect interpretation of values; therefore, it was considered that adapting the greater of two measurement values is appropriate.

Reliability of isometric knee extension muscle strength measurements made by a hand-held dynamometer and a belt: a comparison of two types of device

[Purpose] The purpose of the present study was to compare the reliability of 2 hand-held dynamometers (HHD-1, 2) with different designs, by performing isometric knee muscle extension measurements two times each. [Subjects] The subjects were 40 young healthy adults. [Methods] The reliability of the measurements was examined using Bland-Altman analysis. [Results] Bland-Altman analysis found a fixed bias in measurements made by HHD-1 with an average limits of agreement (LOA) value of −2.1 kgf. For HHD-2, only random errors were detected, and the minimal detectable change (MDC) was 11.4 kgf. Fixed biases were observed between the two devices with an average LOA value of 2.2 kgf. When the bodyweight ratio was used, fixed biases were observed in measurements made by both devices, and the average value of LOA was −0.03 kgf/kg. The comparison of the two devices revealed only random errors, and MDC was 0.22 kgf/kg. [Conclusion] For HHD measurements using these two devices, the appropriate number of measurements is two times, and comparison of measurement values between the two devices should be avoided.

Limits of the manipulative-fixed method for measurement of shoulder joint horizontal adduction muscle strength using a handheld dynamometer

[Purpose] The aim of this study was to verify the limit of isometric muscle strength of shoulder joint horizontal adduction using handheld dynamometer (HHD) manipulated by hand (referred to as the manipulative-fixed method). [Subjects and Methods] The subjects were 33 healthy college students. The examiner was a healthy college student. Shoulder joint horizontal adductor muscle strength was measured using HHD with the subject in the supine position. The belt-fixed and manipulative-fixed methods were used to secure the HHD sensor unit. The limitations of the manipulative-fixed method were assessed by simple regression analysis, in which the participants were divided into 2 groups according to a branch point. The slope of the straight line of the graph was visualized. [Results] Single regression analysis of the <30 kgf group revealed significant results. The results of single regression of the >30 kgf group were not significant. [Conclusion] The manipulative-fixed method is simple to perform. However, there exists the possibility that the actual muscle strength is not measurable by this method. The measurement limit of the shoulder horizontal adduction strength with the manipulative-fixed method was 30 kgf in the case of the examiner in the present study. The fixed limit was also found to influence in the muscle strength of the upper limbs.

Reliability of Isometric Knee Extension Muscle Strength Measurements of Healthy Elderly Subjects Made with a Hand-held Dynamometer and a Belt

[Purpose] The purpose of this study was to examine the reliability of three isometric knee extension strength measurements (IKE) made with a hand-held dynamometer (HHD) and a belt of healthy elderly living in the community as subjects. [Subjects] The subject cohort consisted of 186 healthy elderly people, aged 65 to 79 years, living in local communities. [Methods] IKE of the leg subjects used to kick a ball was measured. IKE of each subject was measured three times using an HHD-belt at intervals of 30 seconds. The reliability of the larger of the first two measurements (LV2) as well as the third measurement (3V) was investigated. [Results] The intraclass correlation coefficients [ICC (1, 1)] for LV2 and 3V were 0.955. Bland-Altman analysis showed a fixed bias, and the limits of agreement ranged from -5.6 to 4.6. [Conclusion] The ICC results show that the test-retest reproducibility of IKE measurements of healthy elderly subjects using an HHD-belt is high. However, Bland-Altman analysis showed a fixed bias, suggesting the need for three measurements.

The validity of plantarflexor strength measures obtained through hand-held dynamometry measurements of force

PURPOSE/BACKGROUND

Hand-held dynamometers are commonly used to assess plantarflexor strength during rehabilitation. The purpose of this study was to determine the concurrent validity of measuring plantarflexion force using a hand-held dynamometer (HHD) as compared to an electromechanical dynamometer as the gold standard. The hypothesis was that plantarflexor forces obtained using a hand-held dynamometer would not show absolute agreement with a criterion standard.

DESIGN

Concurrent validity assessment for a diagnostic strength testing device.

SETTING

Institutional clinic and research laboratory.

PARTICIPANTS

Volunteer sample of healthy university students (N=20, 10 women, 10 men; 25.9±4.1 years).

MAIN OUTCOME MEASURES

Maximal plantarflexion strength was measured using both a HHD and an electromechanical dynamometer (EMD) as a criterion measure.

RESULTS

Plantarflexor force measures with the HHD were significantly different (p<0.01) and not correlated with plantarflexor forces measured using the EMD for either limb (R(2) ≤ 0.09).

CONCLUSIONS

Plantarflexor strength measurements acquired using HHD are different from those acquired using an EMD and are likely influenced by the strength of the examiner.

LEVEL OF EVIDENCE

Prospective cohort study, level II.

Isokinetic testing in patients with neuromuscular diseases: a focused review

OBJECTIVE

This literature review aimed to study the use of isokinetic testing in patients with neuromuscular diseases (NMDs) and to identify directions for future research of isokinetic testing.

DESIGN

The MEDLINE (January 1, 1965, to July 1, 2010), Cumulative Index to Nursing and Allied Health (1980 to May 2010), and Cochrane Central Register of Controlled Trials (The Cochrane Library Issue 3, 2009) electronic databases were searched. The literature search was conducted using the keywords muscle assessment, muscle strength, evaluation, isokinetic, neuromuscular diseases, muscle fatigue, functional test, rehabilitation, and literature search. Relevant references cited in the selected articles were also considered, regardless of the year of publication.

RESULTS

The search strategy yielded 13 articles involving a variety of patients with known NMDs. All studies demonstrated that isokinetic dynamometry is appropriate and safe for ambulatory patients with NMDs. Isokinetic testing has proven to be reliable (intratest/intertest correlation coefficient ranged from 0.65 to 0.98), with the proximal muscles having the highest reliability, and sensitive to disease progression and to the effects of various therapeutic interventions. However, isokinetic testing has never gained wide acceptance, partly because of concerns about stabilizing the dynamometer and the subject during the test and of the lack of standardized protocols for isokinetic strength measurement.

CONCLUSIONS

Isokinetic testing is an important part of the comprehensive evaluation and rehabilitation of patients with NMD. Research has demonstrated its efficacy in providing clinically relevant information. When integrated with a complete history, physical examination, and functional evaluation, isokinetic testing and exercise can be a valuable tool for the clinician in the assessment, rehabilitation, and performance enhancement of patients with NMD. Such equipment, however, has several disadvantages, rendering it usually impractical in the clinical setting.

Mood and Balance are Associated with Free-Living Physical Activity of People after Stroke Residing in the community

Purpose. To determine which characteristics are most associated with free-living physical activity in community-dwelling ambulatory people after stroke. Method. Factors (age, gender, side of stroke, time since stroke, BMI, and spouse), sensory-motor impairments (weakness, contracture, spasticity, coordination, proprioception, and balance), and non-sensory-motor impairments (cognition, language, perception, mood, and confidence) were collected on 42 people with chronic stroke. Free-living physical activity was measured using an activity monitor and reported as time on feet and activity counts. Results. Univariate analysis showed that balance and mood were correlated with time on feet (r = 0.42, 0.43, P < 0.01) and also with activity counts (r = 0.52, 0.54, P < 0.01). Stepwise multiple regression showed that mood and balance accounted for 25% of the variance in time on feet and 40% of the variance in activity counts. Conclusions. Mood and balance are associated with free-living physical activity in ambulatory people after stroke residing in the community.

The intra- and inter-rater reliability of manual muscle testing and a hand-held dynamometer for measuring wrist strength in symptomatic and asymptomatic subjects

Objective

The objective of this study was to assess the intra- and inter-rater reliability of manual muscle testing (MMT) and hand-held dynamometer (HHD) in the measurement of isometric wrist strength in asymptomatic and symptomatic (distal radius fractures [DRF] and non-specific wrist pain [NSWP]) populations.

Method

Thirty-nine adults participated in an intra session, repeat measure, crossover study design. MMT and HHD isometric wrist strength was tested in six standardized test positions by two raters.

Results

Poor-to-excellent intra- and inter-rater reliability with MMT was found in all patient populations (ICC = 0.04–1.00). Excellent intra-rater reliability with HHD in the DRF (ICC = 0.86–0.95) and NSWP (ICC = 0.92–0.97) populations and excellent inter-rater reliability in the asymptomatic (ICC = 0.77–0.93) and DRF (ICC = 0.82–0.95) populations. Fair to excellent intra-rater reliability with HHD was seen in the asymptomatic population (ICC = 0.71–0.94) and fair to excellent inter-rater reliability in the NSWP population (ICC = 0.59–0.90).

Conclusion

MMT is shown to have variable reliability when assessing isometric wrist strength and is insensitive to small strength changes. HHD has been shown to be an objective and reliable measure of isometric wrist strength in specific positions in asymptomatic, DRF and NSWP populations. Further studies are required to ensure adequate dynamometry stabilization and obtain an optimal testing procedure for these populations.

Functional performance and muscle strength phenotypes in men and women with Danon disease

Danon disease is a rare X-linked myopathy that is characterized clinically by a triad of cardiomyopathy, skeletal myopathy, and cognitive impairment. The purpose of this investigation was to quantify functional performance, muscle weakness, and quadriceps activation in individuals with Danon disease as compared with healthy individuals. Four males (ages 10-34 years) and 4 females (ages 16-50 years), with the genetic markers of Danon disease, were compared with 8 healthy males (ages 22-34 years) and 8 healthy females (ages 23-41 years) and previously reported norms. Affected males and females had decreased functional performance, significant generalized muscle weakness, and decreased quadriceps strength and activation when compared with healthy individuals. Affected males had larger deficits in function, strength, and activation when compared with affected females. The results indicate that, although the presentation of Danon disease is variable and is typically only described in males, muscle weakness patterns exist in both affected males and females.

Hip abductor strengths after total hip arthroplasty via the lateral and posterolateral approaches

A retrospective control study was carried out to compare the postoperative hip abductor strengths after primary total hip arthroplasties via the lateral (lateral group; 38 hips) and posterolateral (posterior group; 40 hips) approaches. At a minimum of 2 years after total hip arthroplasty, abductor muscle strength was evaluated qualitatively by the Trendelenburg test and quantitatively using a dynamometer. The ratio of normalized strength of the reconstructed side to that of the nonoperated side was calculated (strength ratio). The Trendelenburg test was positive in 10 of 38 patients in the lateral group and in 11 of 40 patients in the posterior group. The average strength ratios of the lateral and posterior groups were 86.1% and 87.3%, respectively (P = .67). Strength ratio was positively correlated to femoral offset within both groups.

Effect of superior placement of the hip center on abductor muscle strength in total hip arthroplasty

We evaluated 100 limbs in 50 patients who had undergone unilateral primary total hip arthroplasty with a normal contralateral hip. The 50 patients were divided into 2 groups by postoperative acetabular cup position, specifically by inferior and superior placement (inferior and superior groups). Hip abductor muscle strength was evaluated qualitatively by the modified Trendelenburg test and quantitatively by handheld dynamometer. The ratio of normalized strength of the reconstruction side to that of the nonoperated side was calculated (strength ratio). The modified Trendelenburg test was positive in 5 of 23 patients in the inferior group and 11 of 27 in the superior group (P < .05). The strength ratio of the superior group was decreased by 7.7% in comparison with that of the inferior group (P < .01).

Use of hand-held dynamometry in the evaluation of lower limb muscle strength in people with Huntington's disease

PURPOSE

Sub-clinical muscle involvement, including myopathic changes and mitochondrial dysfunction of skeletal muscle, has been reported in people with Huntington's disease (HD). Muscle strength was evaluated using a hand-held dynamometer. Reliability and validity in people with HD were determined.

METHOD

Isometric muscle strength of 6 lower limb muscle groups was measured in 20 people with HD and matched healthy controls. People with HD were evaluated with the Unified Huntington's Disease Rating Scales (UHDRS). Within session reliability using intra-class correlation coefficients (ICC) was calculated. Discriminant and convergent validity was also evaluated.

RESULTS

UHDRS motor scores of people with HD ranged from 28 to 80. Reliability of strength testing was excellent (ICC 0.86 to 0.98). People with HD had on average about half the strength of healthy matched controls. UHDRS motor scores and strength scores were significantly correlated (convergent) providing a further indication of validity of strength testing.

CONCLUSIONS

The hand-held dynamometer is a reliable and valid measurement tool to detect strength differences between people with HD and a matched control group. There is significant reduction in lower limb muscle strength in HD which does not appear to have been described previously.

Total hip arthroplasty: the relationship between posterolateral reconstruction, abductor muscle strength, and femoral offset

PURPOSE

To evaluate the relationship between posterolateral reconstruction, abductor muscle strength, and femoral offset following total hip arthroplasty.

METHODS

Of 28 patients (56 limbs) we assessed, 12 underwent posterolateral reconstruction (reconstruction group) and 16 did not (non-reconstruction group). Isometric abductor muscle strength was measured with a handheld dynamometer. Each patient's muscle strength was converted into a force to body weight ratio, and this ratio was used in the comparisons.

RESULTS

The reconstruction group showed a higher value in abductor muscle strength than the non-reconstruction group (p<0.05). Significant correlation between abductor muscle strength and femoral offset was found in the reconstruction group (p=0.016; r=0.674).

CONCLUSION

Posterolateral reconstruction and appropriate reconstruction of femoral offset following total hip arthroplasty are important to improve the abductor muscle strength.

Comparison of maximal voluntary isometric contraction and hand-held dynamometry in measuring muscle strength of patients with progressive lower motor neuron syndrome

Context. Maximal voluntary isometric contraction, a method quantitatively assessing muscle strength, has proven to be reliable, accurate and sensitive in amyotrophic lateral sclerosis. Hand-held dynamometry is less expensive and more quickly applicable than maximal voluntary isometric contraction. Objective. To investigate if hand-held dynamometry is as reliable and valid as maximal voluntary isometric contraction in measuring muscle strength in patients with an adult-onset, non-hereditary progressive lower motor neuron syndrome. Design. Two testers performed maximal voluntary isometric contraction and hand-held dynamometry measurements in six muscle groups bilaterally in patients with progressive lower motor neuron syndrome to assess reliability and validity of both the methods. Setting. Outpatient units of an academic medical center. Patients. A consecutive sample of 19 patients with non-hereditary progressive lower motor neuron syndrome (median disease duration 32.5 months, range 10-84) was tested. Outcome measures. Comparison between maximal voluntary strength contractions as measured by hand-held dynamometry and maximal voluntary isometric contraction. Results. Low intra- and interrater variation in all muscle groups were found, intraclass correlation coefficients vary between 0.86 and 0.99 for both methods. Both methods correlated well in all muscle groups with Pearson's correlation coefficients ranged between 0.78 and 0.98. Scatter plots indicated a trend to under-estimate muscle strength above 250 N by hand-held dynamometry as compared with maximal voluntary isometric contraction. Conclusions. For longitudinal evaluation of muscle strength in patients with progressive lower motor neuron syndrome (i.e. between 0 and 250 N), muscle strength can be accurate quantified with both hand-held dynamometry and maximal voluntary isometric contraction. Hand-held dynamometry has the advantage of being cheap and quickly applicable. However, our results indicate that hand-held dynamometry is less sensitive than maximal voluntary isometric contraction in detecting subnormal muscle strength in strong muscle groups (i.e. >250 N), due to limited strength of the tester.

The effect of posterolateral reconstruction on range of motion and muscle strength in total hip arthroplasty

Posterolateral reconstruction of the posterior capsule, piriformis tendon, and external rotators in total hip arthroplasty improves the stability of the hip joint. This study was performed to evaluate the effect of this reconstruction on range of motion (ROM) and circumferential muscle strength. We selected 58 limbs of 29 patients. Posterolateral reconstruction was performed in 13 patients (reconstruction group). Posterolateral reconstruction was not performed in 16 patients (nonreconstruction group). No significant differences were seen in preoperative and postoperative ROM between the 2 groups. The reconstruction group had significantly higher abduction muscle strength (P<.0001) and external rotation muscle strength (P<.01) than the nonreconstruction group. Posterolateral reconstruction may be effective in promoting the recovery of abduction and external rotator muscle strength, and it can improve joint stability without limiting ROM.

Reproducibility of neurophysiological and myometric measurement in the ulnar nerve-abductor digiti minimi system

Reliability in strength and neurophysiological measurements is important in evaluating progression of neuromuscular diseases. No data are available on the variability of neurophysiological parameters as compared with maximal voluntary isometric contraction (MVIC) in the same muscles, in healthy subjects. A control population of 26 healthy subjects was studied twice on different days. We evaluated the reliability of neurophysiological parameters obtained from bilateral ulnar nerve stimulation, recording the response over the abductor digiti minimi (ADM) muscle, including distal motor latency, compound muscle potential amplitude and area, F-wave frequency and mean F-wave latency, and the derived neurophysiological index that we have described previously. MVIC force was measured in each session in both ADM muscles. The variances between the grouped data obtained in the two recording sessions were identical, indicating a low intrinsic variability with this experimental methodology. Comparison of the mean values obtained in the two sessions revealed no statistically significant differences. The reliability of these neurophysiological and strength measurements in the same nerve/muscle system suggests they may be useful in comparing the dynamics of weakness and neurophysiological change in neuromuscular disease.

The application of control limits analysis to the myometric assessment of motor performance in neuropathy patients

Measurement of muscle strength by myometry is used to monitor the natural course and treatment response of motor system diseases, both in individual patients and clinical trials. However, the practical usefulness of myometric data is reliant upon a statistical method for analysing serial strength measurements which distinguishes disease-related changes from random fluctuations in patient performance and operator/device dependent measurement errors. In this study we have applied control limits analysis to this problem. Using hand-held dynamometry, sets of baseline strength measurements were collected on two separate occasions during a period of clinical stability from up to four muscle groups in 22 patients with peripheral neuropathies. From these sets of data, 76 control limits were calculated and then used to describe the inter-measurement variation in muscle strength in individual muscles. The range of control limits was wide, varying from <10% of baseline (in 36% of muscles tested) to >50% (in 4% of muscles tested), with 88% of muscles falling within 30% of baseline. Follow-up data were also collected from all patients, including those undergoing treatment. Control limits analysis is a powerful and simple method for assessing the significance of motor performance changes in individual muscles in patients undergoing serial monitoring and can be easily applied to both single patients and clinical trials.

Muscle force measured using "break" testing with a hand-held myometer in normal subjects aged 20 to 69 years

OBJECTIVE

To measure the strength of 17 muscle groups in the upper and lower extremities in a large group of healthy subjects using "break" testing with a hand-held myometer, and to examine the intrasession and intersession reliability of the testing protocol. SUBJECTS AND INSTRUMENTATION: A convenience sample of 20 men and 20 women in each decade of age from 20 to 69 years (n = 200) was tested using a Penny & Giles hand-held myometer.

RESULTS

Reliability coefficients were >.85 for both intrasession and intersession reliability, except for the ankle dorsiflexors. Men exerted a significantly greater force than women for all muscle groups. Age, weight, and side of testing were significant predictors of force in the majority of muscle groups. The fifth percentile values, as the lower limit of normal, are reported separately for gender and side of testing for each decade of age.

CONCLUSION

Using the testing protocol specified in this study, data from patients with various neuromuscular diseases may be compared with the appropriate gender- and age-matched normal data to accurately identify the presence of weakness.

Measurement of isometric muscle strength: a reproducibility study of maximal voluntary contraction in normal subjects and amyotrophic lateral sclerosis patients

Amyotrophic lateral sclerosis (ALS) is a degenerative disease of unknown cause, resulting in the progressive loss of voluntary motor activity. Traditional methods of evaluating patients with ALS (neurologic assessment, manual muscle testing and rating scales) involve subjective elements and lack the sensitivity needed to detect small but meaningful changes in deterioration and therapeutic efficacy. This paper presents a recently developed strength measurement instrument, useful for the long-term monitoring of muscle strength deterioration in ALS. In addition, a reproducibility study to assess the intra- and interobserver reliability of maximal voluntary isometric contraction is reported. The strength measurement instrument consists of a strain gauge force transducer, a bridge amplifier and a mechanical structure to counteract movements. A personal computer acquires the strength signal during each voluntary contraction and automatically computes the maximal value. Reproducibility of measurement was assessed in 18 normal subjects tested twice, on successive days, with the same examiner and under the same conditions. The interexaminer reproducibility of measurement was assessed in a group of 13 normal subjects and 10 ALS patients. Each subject of the two groups was independently examined by three examiners. The two reproducibility studies showed a high intraclass correlation coefficient (0.91-0.97) and low SEM and measurement error (3-10%) in all muscle regions tested. The Bland and Altman plots confirmed these results.

Strength assessment in postpolio syndrome: validity of a hand-held dynamometer in detecting change

OBJECTIVES

To investigate the validity, the intraexaminer and interexaminer reproducibility, and the ability to detect change of a hand-held dynamometer (HHD) in strength measurements in former polio subjects.

DESIGN

HHD measurement of knee extensor strength was compared with the criterion standard of a chair dynamometer measurement in 49 subjects. The "break" method was used for HHD measurements. Reproducibility was studied for six lower extremity muscle groups in 28 subjects. The measurements were performed by one experienced and one inexperienced examiner on two separate occasions, with an interval of 1 week. The examiners were blinded to each other's and to previous results.

SETTING

University hospital.

SUBJECTS

Volunteer sample of former polio subjects.

RESULTS

For knee extension, the forces that could be measured with the HHD were limited to approximately 200N. Although the intraclass correlation coefficients were high (.75 to .98), the 95% limits of agreement between measurements showed large intervals for differences between two measurements (ratio intervals ranging from .76-1.52 to .52-2.77). The intraexaminer reproducibility for the experienced examiner was superior to that of the inexperienced examiner. The reproducibility of the inexperienced examiner showed systematic bias, with significantly higher strength values for the second session measurement of three muscle groups.

CONCLUSION

The device has good validity in the lower force range. However, because the agreement between measurements was poor, it has limited ability to detect a change in muscle strength. Therefore, this method is unable to detect small changes in lower extremity muscle strength in former polio patients.

Comparison of maximal voluntary isometric contraction and Drachman's hand-held dynamometry in evaluating patients with amyotrophic lateral sclerosis

Maximal voluntary isometric contraction (MVIC) is a standard tool for assessment of muscle strength in treatment trials for amyotrophic lateral sclerosis (ALS). There is need for more practical bedside techniques especially for severely disabled patients. Hand-held dynamometry (HH-Dyn) is an inexpensive and easy-to-handle device. MVIC was measured in five proximal muscle groups bilaterally and compared with HH-Dyn in 43 ALS patients. After a training period we found good intrarater correlation for HH-Dyn (r = 0.99), with a low coefficient of variation. Measurements tended to become more accurate after repeated testing due to practice effects in examiners and patients. Overall correlation between HH-Dyn and MVIC was good [r = 0.85 (P < 0.01)]. Strength-range-specific analysis showed a significant linear correlation up to 20 kg (44 lbs.) [r = 0.57 (P < 0.01)]. However, we found a tendency to underestimate muscle strength above 10 kg by HH-Dyn as compared with MVIC, but this became meaningful only above a force of 20 kg. HH-Dyn provides a strength estimate with a precision close to MVIC in weak muscle groups (MRC grade 4). With standardization and appropriate training, HH-Dyn is a useful bedside test, providing an alternative to MVIC for follow-up assessment in ALS.

The effects of aging on muscle strength and functional ability of healthy Saudi Arabian males

BACKGROUND

Loss of muscle strength as a result of normal aging is reported to impair functional ability in various communities. The purpose of this study was to determine the age at which loss of muscle strength and functional ability begins, and to establish a preliminary baseline for the pattern of changes in muscle strength and functional ability of aging in adult healthy Saudi Arabian males.

SUBJECTS AND METHODS

A sample of 160 healthy Saudi Arabian males aged 20-89 years participated in this study. The subjects were divided into seven age groups, each representing a decade. Maximum isometric A centAAmakeA centAA strength of bilateral quadriceps muscles were measured using a hand-held dynamometer. Functional ability tests that included stair walking, timed-up-and-go and balance tests were also performed and timed using a digital stopwatch.

RESULTS

Muscle strength and functional ability remained unchanged in the 20- and 30-year-old age groups. Around the age of 40, muscle strength and functional ability began to gradually decline. Muscle strength of males in their twenties was 380+/-62N and 330+/-60N in the right (RT) and left (LT) quadriceps, respectively. A decline with aging is represented by 190+/-40N and 110+/-30N in the RT and LT quadriceps muscles, respectively, by the eighth decade of life. Stair-walking, timed up-and-go and balance tests in the second decade were 4+/-1 sec, 8+/-2 sec and 130+/-20 sec, respectively, against 15+/-4 sec, 26+/-7 sec and 15+/-5 sec in the eighth decade. One-way ANOVA test showed that muscle strength and functional ability differed (P<0.01) among decades, except between the second and third decades (P<0.31). Age, muscle strength and functional ability displayed a significant relationship (P<0.001).

CONCLUSION

Loss of muscle strength and functional ability seem to begin in the fourth decade of life. The changes in muscle strength and functional ability have a significant relationship to aging. Clinically, these results may provide clinicians with a guide to the strength level of normal quadriceps and the functional ability of adult healthy Saudi Arabian males in relation to the normal aging process.

Reliability assessment of isometric knee extension measurements with a computer-assisted hand-held dynamometer

OBJECTIVE

To assess clinically relevant indexes of measurement error of hand-held dynamometer measurements using a computer-assisted hand-held dynamometer (CAHN-DY).

DESIGN

In separate sessions, different physical therapists performed repeated measurements of maximal isometric knee extension.

SETTING

Four physical therapy practices and outpatient departments.

PATIENTS

Consecutive samples of 30 male and 28 female patients aged 13 to 77 years, with isolated orthopedic knee disorders participated in this study.

MAIN OUTCOME MEASURES

For intrarater and interrater applications, the standard error of measurement (SEM) and related 95% confidence intervals and minimal detectable changes were assessed.

RESULTS

Sixty percent of the patients performed within the therapist's upper force limit. Variance between sessions performed by the same or different therapists accounted for a large percentage of the measurement error (70% to 81%). For single measurements, the standard error of measurement was assessed not to exceed 10N x m. Minimal detectable changes for different designs varied from 13.8 to 28.2N x m.

CONCLUSIONS

The CAHN-DY facilitated standardization of test performance in a satisfactory manner, resulting in less measurement error compared with simple hand-held dynamometry.

Hand-held dynamometry reliability in persons with neuropathic weakness

OBJECTIVE

To determine test-retest reliability of hand-held dynamometry (HHD) in measuring strength of persons with neuropathic weakness.

DESIGN

Intratester and intertester reliability of HHD-measured strength over a 7- to 10-day period. In addition, HHD knee strength was compared with criterion standard of fixed dynamometry (FD).

SETTING

Human performance laboratory of a university.

PARTICIPANTS

Convenience sample of ambulatory outpatients with Hereditary Motor and Sensory Neuropathy, Type I (HMSN) (n = 10) and able-bodied controls (CTL) (n = 11).

MAIN OUTCOME MEASURE

Maximal isometric torque.

RESULTS

Intratester intraclass correlation coefficients (ICCs) were high, generally ranging from .82 to .96 for HHD- and FD-measured strength for both HMSN and CTL groups. There were no significant differences between sessions for HHD-measured strength, while FD-measured strength was only significantly different for knee extension (p < .01). Intertester reliability was generally good for both HHD- and FD-measured strength, with ICCs ranging from .72 to .97 for HMSN and CTL groups. Exceptions were knee extensors and ankle dorsiflexors for the CTL group. Knee extensor strength was significantly lower measured by HHD compared with FD (p < .01), but knee flexor strength was similar for the two methods.

CONCLUSION

HHD appears to be a reliable method to measure maximal isometric strength in persons with neurogenic weakness, and may be useful to quickly and objectively evaluate strength in the clinical setting.

Guidelines for the use and performance of quantitative outcome measures in ALS clinical trials

ALS is a motor neuron disease defined as a progressive, neurological disorder, resulting from variable and combined degeneration of upper and lower motor neurons. The heterogeneity of clinical involvement early in the course of the disease makes it difficult to diagnose, as well as to identify one unique outcome measure to quantify neurological changes in the course of the disease. Since clinical evidence of upper and lower motor neuron degeneration must exist in four anatomical regions (bulbar, cervical, thoracic, and lumbosacral), outcome measures should assess these regions. The WFN Airline House recommendations specify the purpose, properties, and the preferred parameters which serve as outcome measures in ALS clinical trials. The purpose of this document is to serve as a review of these outcome measures in terms of their advantages, disadvantages, sensitivity, reliability, and other characteristics, as well as their proper performance in ALS clinical trials. Generally these outcome measures are allocated to four areas: respiratory function, muscle strength, general function, and bulbar function. Our review leads us to believe that respiratory function and strength provide the most useful information, both for research and clinical purposes, and are essential as outcome measures. Inclusion of bulbar and general function parameters in trial design may increase the possibility of identifying a beneficial effect of therapeutic intervention. It is essential to note that the guidelines and recommendations put forth are intended to provide initial evaluation and critique of the proper employment and performance of these outcome measures in ALS clinical trials, based on the available literature and our experience.

Muscular weakness assessment: use of normal isometric strength data. The National Isometric Muscle Strength (NIMS) Database Consortium

OBJECTIVE

Assessment of muscle strength is vital to the management of patients with muscular weakness. Clinical interpretation of isometric strength data for individual patients has been limited because of the lack of a reference population for comparison. The purpose of this study was to develop regression equations to predict maximal isometric strength based on gender, age, height, and weight. Patients' absolute strength values may then be expressed as a percentage of their predicted values, facilitating the determination of presence and extent of weakness.

DESIGN

Three separate neuromuscular research groups developed databases of normal maximal isometric strength values, using standardized testing procedures. The databases were combined into a single database, and multiple regression equations were formulated for strength prediction for the 20 muscle groups tested.

SETTING

Seven neuromuscular research units, each within the neurology department of a university-based teaching facility.

SUBJECTS

A convenience sample of 493 volunteers who had no medical conditions that would have prohibited them from performing a maximal isometric strength test.

MAIN OUTCOME MEASURE

Maximal isometric strength (kg) of ten muscle groups was measured bilaterally.

RESULTS

Regression equations and 95% prediction intervals are derived from the combined database. A case study demonstrates the use of the predictive equations in determining presence and extent of weakness.

CONCLUSION

Predictive strength equations facilitate assessment of muscular weakness.

Strength measurements of the lumbrical muscles

This study was designed to measure the strength of the lumbrical muscles in the index and long fingers in patients with ulnar nerve paralysis. A hand-held dynamometer was used. The results show that in ulnar nerve damage the index and long fingers have a mean metacarpophalangeal (MCP) joint flexion strength of 0.8 kg (range 0.3-1.5), compared with 6.4 kg (range 4.6-7.9) in the noninvolved hand. Thus, the damaged fingers have only about 12% of the strength of those of the noninvolved hand. In the hand with ulnar paralysis, the loss of intrinsic strength (dorsal and palmar interosseous muscles) is considerable (almost 90%). The contribution of the interosseous muscles in maintaining the intrinsic position is considerably greater than that of the lumbricals. Comparing the Medical Research Council (MRC) scale (0-5) with the dynamometry measurements shows that MRC grade 3 correlates with about 0.8 kg, while grade 5 correlates with about 6.5 kg of MCP joint flexion strength.

Computer-assisted hand-held dynamometer: low-cost instrument for muscle function assessment in rehabilitation medicine

In rehabilitation medicine, muscle function is assessed during the physical examination of the patient. Although a simple hand-held instrument improves the assessment of static strength, it is rarely used in clinical practice, where dynamic measurements are preferred. A computer-assisted hand-held dynamometer (CAHNDY) has been developed that enables the clinician to measure dynamic muscle function in a standardised manner, using simple (i.e. portable and low-cost) apparatus. The CAHNDY comprises a force transducer and a movement transducer interfaced to a personal computer. In the study dynamic measurement protocols are used, based on a biomechanical analysis of daily activities. In this way, iso-functional profiles can be established, describing the kinematics of muscle function in its functional context. Using the iso-functional profiles as a basis for standardisation, the double feedback algorithm of the CAHNDY assists the tester in meeting this standard, during maximal muscle function testing. In a multi-centre trial, the CAHNDY is evaluated by physical therapists for knee extensor and flexor function. The CAHNDY enables iso-functional dynamic muscle function testing, although application is limited by the maximal strength of the tester. It is concluded that the CAHNDY is suitable for use in rehabilitation medicine.

Manual muscle strength testing: intraobserver and interobserver reliabilities for the intrinsic muscles of the hand

The reliability of manual muscle strength testing of the intrinsic muscles of the hand is reported. The muscle strengths of 28 patients who had neuropathies of the ulnar nerve or the ulnar and median nerves were graded by two physiotherapists to determine intraobserver and interobserver reliabilities. Muscle strength was graded using the numeric scale developed by the Medical Research Council (grades 0 to 5). Reliabilities were established for nine muscles or muscle groups. Intraobserver reliabilities ranged from 0.71 to 0.96 and interobserver reliabilities from 0.72 to 0.93. It is difficult to isolate, and hence grade, most of the intrinsic muscles of the hand. Therefore, it is suggested that specific movements be tested and graded when assessing and evaluating muscle or nerve function.

Replacement treatment with biosynthetic human growth hormone in growth hormone-deficient hypopituitary adults

OBJECTIVES

The physiological role of growth hormone in adult life has recently attracted increased interest. We have studied the clinical effects and the effects on body composition of prolonged replacement with biosynthetic human GH in a large number of hypopituitary adults.

DESIGN

A randomized double blind placebo controlled trial for 6 months followed by an open trial of GH treatment for 12 months. GH daily dose was 0.04 (0.02-0.05) IU/kg s.c.

PATIENTS

Forty GH deficient hypopituitary patients (19 M, 21 F; aged 19-67 years) on conventional replacement therapy were studied.

MEASUREMENTS

Serum insulin like growth factor I (IGF-I), skinfold thickness, total body potassium, total body water (TBW), exercise tolerance and muscle strength, and well-being.

RESULTS

During the 6-month double blind phase, two GH treated patients withdrew because of adverse events. Lean body mass (LBM) increased and percentage body fat (%BF) decreased on GH but not on placebo (P) (LBM: (GH: from 48.5 +/- 9.6 to 49.6 +/- 9.5 kg; P: from 50.9 +/- 9.2 to 50.1 +/- 9.0 kg, P < 0.05 GH vs P) and %BF (GH: from 34.7 +/- 11.4 to 34.2 +/- 10.7; P: from 37.4 +/- 7.6 to 38.7 +/- 8.1, P < 0.05 GH vs P)). TBW increased on GH (P < 0.01) but not on P. No change was observed in waist-to-hip ratio or in muscle strength. During longer-term follow-up combining the double blind and open phase components of the study, 34, 27 and 11 patients received GH for 6, 12 and 18 months respectively. Patients dropped out because of adverse events or lack of perceived benefit. Skinfold thicknesses decreased significantly at 6 and 12 months and the waist circumference at 6 months. Waist-to-hip ratio decreased significantly on GH at 12 months. LBM increased on GH treatment from 49.6 +/- 9.1 to 51.6 +/- 9.4 kg (P < 0.0006), 51.9 +/- 8.9 kg (P < 0.07) and 53.1 +/- 10.5 kg (P < 0.0001) at 6, 12 and 18 months respectively. Percentage body fat decreased on GH from 37.2 +/- 10.7 to 34.7 +/- 10.1 (P < 0.005), 35.1 +/- 12.8 (NS) and 34.5 +/- 8.6 (P < 0.04) at 6,12 and 18 months respectively. TBW also increased at 6 and 12 months of GH treatment. Exercise time increased significantly at 6, 12 and 18 months of GH treatment. Muscle strength in selected muscle groups increased significantly at 6, 12 or 18 months of GH treatment. Randomization resulted in the placebo group having a greater GHQ score (higher morbidity) than the GH group before therapy. Over the controlled phase, GHQ scores improved on placebo but not on GH and CPRS score was unchanged in either group. In the open phase, the GHQ score did not change on GH therapy but CPRS score improved at 6 and 12 months.

CONCLUSIONS

Growth hormone replacement therapy in adults for 6 months increased lean body mass, total body water and exercise tolerance, and decreased body fat. Growth hormone replacement for longer than 6 months maintains the advantageous effects seen in shorter-term studies and may have additional effects on body fat distribution, muscle strength and psychological well-being.