Hand-held Dynamometry Research Articles

The association between muscle strength and activity limitations in patients with the hypermobility type of Ehlers–Danlos syndrome: the impact of proprioception

Purpose: The patients diagnosed with Ehlers–Danlos Syndrome Hypermobility Type (EDS-HT) are characterized by pain, proprioceptive inacuity, muscle weakness, potentially leading to activity limitations. In EDS-HT, a direct relationship between muscle strength, proprioception and activity limitations has never been studied. The objective of the study was to establish the association between muscle strength and activity limitations and the impact of proprioception on this association in EDS-HT patients.Methods: Twenty-four EDS-HT patients were compared with 24 controls. Activity limitations were quantified by Health Assessment Questionnaire (HAQ), Six-Minute Walk test (6MWT) and 30-s chair-rise test (30CRT). Muscle strength was quantified by handheld dynamometry. Proprioception was quantified by movement detection paradigm. In analyses, the association between muscle strength and activity limitations was controlled for proprioception and confounders.Results: Muscle strength was associated with 30CRT (r = 0.67, p = <0.001), 6MWT (r = 0.58, p = <0.001) and HAQ (r = 0.63, p= <0.001). Proprioception was associated with 30CRT (r = 0.55, p < 0.001), 6MWT (r = 0.40, p = <0.05) and HAQ (r = 0.46, p < 0.05). Muscle strength was found to be associated with activity limitations, however, proprioceptive inacuity confounded this association.Conclusions: Muscle strength is associated with activity limitations in EDS-HT patients. Joint proprioception is of influence on this association and should be considered in the development of new treatment strategies for patients with EDS-HT.Implications for rehabilitationReducing activity limitations by enhancing muscle strength is frequently applied in the treatment of EDS-HT patients. Although evidence regarding treatment efficacy is scarce, the current paper confirms the rationality that muscle strength is an important factor in the occurrence of activity limitations in EDS-HT patients.Although muscle strength is the most dominant factor that is associated with activity limitations, this association is confounded by proprioception. In contrast to common belief proprioception was not directly associated with activity limitations but confounded this association. Controlling muscle strength on the bases of proprioceptive input may be more important for reducing activity limitations than just enhancing sheer muscle strength.

The reliability of a maximal isometric hip strength and simultaneous surface EMG screening protocol in elite, junior rugby league athletes.

Firstly to describe the reliability of assessing maximal isometric strength of the hip abductor and adductor musculature using a hand held dynamometry (HHD) protocol with simultaneous wireless surface electromyographic (sEMG) evaluation of the gluteus medius (GM) and adductor longus (AL). Secondly, to describe the correlation between isometric strength recorded with the HHD protocol and a laboratory standard isokinetic device. Reliability and correlational study. A sample of 24 elite, male, junior, rugby league athletes, age 16-20 years participated in repeated HHD and isometric Kin-Com (KC) strength testing with simultaneous sEMG assessment, on average (range) 6 (5-7) days apart by a single assessor. Strength tests included; unilateral hip abduction (ABD) and adduction (ADD) and bilateral ADD assessed with squeeze (SQ) tests in 0 and 45° of hip flexion. HHD demonstrated good to excellent inter-session reliability for all outcome measures (ICC(2,1)=0.76-0.91) and good to excellent association with the laboratory reference KC (ICC(2,1)=0.80-0.88). Whilst intra-session, inter-trial reliability of EMG activation and co-activation outcome measures ranged from moderate to excellent (ICC(2,1)=0.70-0.94), inter-session reliability was poor (all ICC(2,1)<0.50). Isometric strength testing of the hip ABD and ADD musculature using HHD may be measured reliably in elite, junior rugby league athletes. Due to the poor inter-session reliability of sEMG measures, it is not recommended for athlete screening purposes if using the techniques implemented in this study.

Effects of Strain/Counter strain on Cervical Pain &amp; Disability: A Case Report

Background: The use of strain-counterstrain (S-CS) as a primary intervention has been controversial due to a lack of empirical evidence. The issue is further complicated when one adds in a generalized pathological condition, such as cervical pain. Research has demonstrated that S-CS decreases pain [1-5], improves strength [4], increases mobility [2-5], improves function [1,3], and decreases disability [3]; however, none of the studies have described the application of S-CS for musculoskeletal-related cervical pain. The purpose of this case report is to describe the effectiveness of S-CS on outcomes for a patient with cervical spine pain, weakness and disability. Methods: The patient was a 36-year-old male Marine referred for a cervical sprain with neck stiffness, weakness, and pain after injury due to an explosion. Treatment consisted of S-CS for the upper trapezius and superior oblique tender points, performed twice weekly for four weeks. RESULTS: He exhibited increased cervical flexion strength measured by hand-held dynamometry; a statistically significant reduction in pain scores measured by the Numeric Pain Rating Scale (NPRS) (Figure 1), and improved disability scores measured by the Neck Disability Index (NDI) (Figure 2). Conclusion: Although a causative effect may not be inferred by this case report, results suggest a potential benefit from the use of this gentle positional release intervention for reducing pain, improving strength and function. Future studies are recommended to investigate the effectiveness of S-CS in the treatment of neck pain and disability. Disclosures: The authors acknowledge they have no commercial interest conflicts associated with this manuscript.

Six-minute walk test is reliable and valid in spinal muscular atrophy.

The Six-Minute Walk Test (6MWT) was adopted as a clinical outcome measure for ambulatory spinal muscular atrophy (SMA). However, a systematic review of measurement properties reported significant variation among chronic pediatric conditions. Our purpose was to assess the reliability/validity of the 6MWT in SMA. Thirty participants performed assessments, including the 6MWT, strength, and function. Reproducibility was evaluated by intraclass correlation coefficients. Criterion/convergent validity were determined using Pearson correlation coefficients. Test-retest reliability was excellent. The 6MWT was associated positively with peak oxygen uptake, Hammersmith Functional Motor Scale Expanded (HFMSE), lower extremity manual muscle testing, knee flexion hand-held dynamometry, and inversely with 10-m walk/run. The 6MWT discriminates between disease severity, unlike the HFMSE. This study documents measurement properties of reproducibility, positive criterion validity, and convergent validity with established clinical assessments and reaffirms the value of the 6MWT as a pivotal outcome measure in SMA clinical trials. Muscle Nerve 54: 836-842, 2016.

Strength Measurements in Acute Hamstring Injuries: Intertester Reliability and Prognostic Value of Handheld Dynamometry.

Study Design Cohort study, repeated measures. Background Although hamstring strength measurements are used for assessing prognosis and monitoring recovery after hamstring injury, their actual clinical relevance has not been established. Handheld dynamometry (HHD) is a commonly used method of measuring muscle strength. The reliability of HHD has not been determined in athletes with acute hamstring injuries. Objectives To determine the intertester reliability and the prognostic value of hamstring HHD strength measurement in acute hamstring injuries. Methods We measured knee flexion strength with HHD in 75 athletes at 2 visits, at baseline (within 5 days of hamstring injury) and follow-up (5 to 7 days after the baseline measurement). We assessed isometric hamstring strength in 15° and 90° of knee flexion. Reliability analysis testing was performed by 2 testers independently at the follow-up visit. We recorded the time needed to return to play (RTP) up to 6 months following baseline. Results The intraclass correlation coefficients of the strength measurements in injured hamstrings were between 0.75 and 0.83. There was a statistically significant but weak correlation between the time to RTP and the strength deficit at 15° of knee flexion measured at baseline (Spearman r = 0.25, P = .045) and at the follow-up visit (Spearman r = 0.26, P = .034). Up to 7% of the variance in time to RTP is explained by this strength deficit. None of the other strength variables were significantly correlated with time to RTP. Conclusion Hamstring strength can be reliably measured with HHD in athletes with acute hamstring injuries. The prognostic value of strength measurements is limited, as there is only a weak association between the time to RTP and hamstring strength deficit after acute injury. Level of Evidence Prognosis, level 4. J Orthop Sports Phys Ther 2016;46(8):689-696. Epub 12 May 2016. doi:10.2519/jospt.2016.6363.

Are Children At Risk For Developmental Coordination Disorder Weak?

Muscle strength impairment in children has implications for long term health. For children at risk for developmental coordination disorder (rDCD), the literature has shown conflicting results regarding whether or not this group has strength impairment. The extent to which this lack of consensus is related to the specific muscle groups evaluated or to other factors affecting muscle strength is unknown. PURPOSE: To evaluate, in a wide variety of lower limb muscle groups, maximal isometric muscle strength differences between children identified as rDCD and typically developing children of the same sex and either the same age or body mass. METHODS: Maximal isometric muscle strength (torque) of the hip abductors, hip flexors, hip extensors, knee flexors, knee extensors and ankle dorsiflexors was evaluated in 34 children (13 girls, 6-12 years old) identified as rDCD according to standard and accepted procedures (scoring below the 16th percentile on the Movement Assessment Battery for Children-Second Edition and having no other diagnosis in the health record that could explain these test scores). Strength values for the comparison group came from a data base of 351 children with no known health conditions. The same valid and reliable hand-held dynamometry protocol was used for both groups. Children with rDCD were randomly matched with a child in the comparison group of the same sex and either the same age or body mass. A Wilcoxon signed-rank test was used to determine group differences. A p-value of <.05 was considered significant. RESULTS: For children of the same sex and age, the rDCD group showed significantly lower strength values (from 16,34% to 40,56%, p= 0.000 to 0.011) for all muscle groups evaluated except for the dorsiflexors. When children of the same sex and body mass were compared, the rDCD was significantly weaker only for the knee extensors (29,18 %, p=0.000) and the knee flexors (14,91 %, p=0.006). CONCLUSION: Children at risk for DCD have strength impairment, but the extent of the impairment depends on the muscle group being evaluated and the characteristics, in terms of age or body mass, of the comparison group. At least some of the strength impairment may be due to growth or body size factors. Longitudinal data are required to better understand the impact of sex, growth and maturation on strength development in this group.

Measurement of muscle strength with handheld dynamometer in Intensive Care Unit.

Background:Intensive Care Unit (ICU) acquired weakness is a common complication in critically ill patients affecting their prognosis. The handheld dynamometry is an objective method in detecting minimum muscle strength change, which has an impact on the physical function of ICU survivors. The minimal change in the force can be measured in units of weight such as pounds or kilograms.Aim of the Study:To detect the changes in peripheral muscle strength with handheld dynamometer in the early stage of ICU stay and to observe the progression of muscle weakness.Methodology:Three upper and three lower limb muscles force measured with handheld dynamometer during ICU stay. Data were analyzed using repeated measures ANOVA to detect changes in force generated by muscle on alternate days of ICU stay.Results:There was a reduction in peripheral muscle strength from day 3 to day 5 as well from day 5 to day 7 of ICU stay (P < 0.01). The average reduction in peripheral muscle strength was 11.8% during ICU stay.Conclusion:This study showed a progressive reduction in peripheral muscle strength as measured by handheld dynamometer during early period of ICU stay.

Between-Days Reliability of Hop Performance and Lower Extremities Muscle Strength Tests

The purpose of this study is to examine the between-days reliability of single leg hop performance (horizontal hop and crossover hop for distance), and the reliability of muscle strength of hip extensors, knee flexors and extensors, and ankle plantar flexors during isometric and isokinetic (concentric and eccentric) testing, with a time interval of 7 days separating the 2 testing session. The study comprised of ten male recreationalathletes (age 32.9 ± 3.9 years; height 171.2 ± 6.1 cm; weight 84.4 ± 19.2 kg). Each participant performed 3 trails of single leg and crossover hop tests for both legs separately, 3 trails of isometric tests using hand-held dynamometry (HHD) for each muscle group, and 3 trials of isokinetic muscle tests throughout 5 maximal effort trials using a Biodex system (testing speed 60°/s). Interclass correlation coefficients (ICCs) ranged from 0.926 to 0.994 for the hop tests, the isometric tests ranged from 0.586 to -0.797, and from 0.619 to 0.958 for the isokinetic tests. The results indicate that the tests are reliable for the use with subjects in a sporting field or clinical environment.

Lower Extremity Handheld Dynamometry Strength Measurement in Children With Cerebral Palsy.

The purpose of this study was to evaluate the evidence on reliability of handheld dynamometry protocols to quantify maximal isometric strength of the muscles of the lower extremities of children with cerebral palsy. A systematic search of Cochrane, MEDLINE, CINAHL, and PubMed up to December 2013 and best-evidence synthesis were performed. Seven eligible studies were identified. Best-evidence synthesis revealed "unknown" to "moderate" evidence. Intraclass correlation coefficient values were "positive" for most muscle groups for intrarater reliability and showed mixed results for interrater reliability. Because of small sample sizes (10-25) in all included studies, the final level of evidence remains "unknown." Reliability data obtained in the included studies of handheld dynamometry in children with cerebral palsy are promising, despite low levels of evidence. When these protocols are applied very carefully, they may prove relevant to different clinical settings.

Isometric muscle strength and mobility capacity in children with cerebral palsy

Purpose: To determine the relationship between isometric leg muscle strength and mobility capacity in children with cerebral palsy (CP) compared to typically developing (TD) peers. Method: Participants were 62 children with CP (6–13 years), able to walk with (n = 10) or without (n = 52) walking aids, and 47 TD children. Isometric muscle strength of five muscle groups of the leg was measured using hand-held dynamometry. Mobility capacity was assessed with the 1-min walk, the 10-m walk, sit-to-stand, lateral-step-up and timed-stair tests. Results: Isometric strength of children with CP was reduced to 36–82% of TD. When adjusted for age and height, the percentage of variance in mobility capacity that was explained by isometric strength of the leg muscles was 21–24% (walking speed), 25% (sit-to-stand), 28% (lateral-step-up) and 35% (timed-stair) in children with CP. Hip abductors and knee flexors had the largest contribution to the explained variance, while knee extensors showed the weakest correlation. Weak or no associations were found between strength and mobility capacity in TD children. Conclusion: Isometric strength, especially hip abductor and knee flexor strength, is moderately related to mobility capacity in children with CP, but not in TD children. To what extent training of these muscle groups will lead to better mobility capacity needs further study.Implications for RehabilitationStrength training in children with cerebral palsy (CP) may be targeted more specifically at hip abductors and knee flexors.The moderate associations imply that large improvements in mobility capacity may not be expected when strength increases.

Lower Limb Strength Is Significantly Impaired in All Muscle Groups in Ambulatory People With Chronic Stroke: A Cross-Sectional Study

ObjectiveTo measure the strength of the major muscle groups of the affected and intact lower limbs in people with stroke compared with age-matched controls. DesignCross-sectional study. SettingUniversity laboratory. ParticipantsAmbulatory stroke survivors (n=60; mean age, 69±11y), who had had a stroke between 1 and 6 years previously, and age-matched controls (n=35; mean age, 65±9y) (N=95). InterventionsNot applicable. Main Outcome MeasuresThe maximum isometric strength of 12 muscle groups (hip flexors and extensors, hip adductors and abductors, hip internal rotators and external rotators, knee flexors and extensors, ankle dorsiflexors and plantarflexors, ankle invertors and evertors) of both lower limbs was measured using handheld dynamometry. All strength measurements were taken in standardized positions by 1 rater. ResultsThe affected lower limb of the participants with stroke was significantly weaker than that of the control participants for all muscle groups (P<.01). Strength (adjusted for age, sex, and body weight) was 48% (range, 34%–62%) of that of the control participants. The most severely affected muscle groups were hip extensors (34% of controls), ankle dorsiflexors (35%), and hip adductors (38%), and the least severely affected muscle groups were ankle invertors (62%), ankle plantarflexors (57%), and hip flexors (55%). The intact lower limb of the participants with stroke was significantly weaker than that of the control participants for all muscle groups (P<.05) except for ankle invertors (P=.25). Strength (adjusted for age, sex, and body weight) was 66% (range, 44%–91%) of that of the control participants. The most severely affected muscle groups were hip extensors (44% of controls), ankle dorsiflexors (52%), and knee flexors (54%). ConclusionsAmbulatory people with chronic stroke have a marked loss of strength in most of the major muscle groups of both lower limbs compared with age-matched controls.

Neuromuscular electrical stimulation-assisted gait increases muscle strength and volume in children with unilateral spastic cerebral palsy.

To determine if neuromuscular electrical stimulation (NMES) applied to the ankle dorsiflexors during gait improves muscle volume and strength in children with unilateral spastic cerebral palsy (CP). Thirty-two children (15 females, 17 males; mean age 10y 8mo, age range 5y 5mo-18y 1mo) with unilateral spastic CP and a Gross Motor Function Classification System of level I or level II were randomly assigned to either the 8-week daily NMES treatment group or control group (usual or conventional treatments). Outcomes at week 8 (post-NMES) and week 14 (carryover) included magnetic resonance imaging for muscle volumes (tibialis anterior, anterior compartment, and gastrocnemius), strength (hand-held dynamometry for isometric dorsiflexion strength and heel raises for functional strength), and clinical measures for lower limb selective motor control. At week 8, the treatment group demonstrated significantly (p<0.05) increased muscle volumes for tibialis anterior, anterior compartment, medial and lateral gastrocnemius, and dorsiflexion strength not only when compared to their baseline values but also when compared to the control group at week 8. At week 14, both tibialis anterior and lateral gastrocnemius volumes in the treatment group remained significantly increased when compared to their baseline values. However, only lateral gastrocnemius volumes had significantly greater values when compared to the control group at week 14. There were no between group differences in the clinical measures for lower limb selective motor control at week 8 and 14. Eight weeks of daily NMES-assisted gait increases muscle volume and strength of the stimulated ankle dorsiflexors in children with unilateral spastic CP. These changes are use-dependent and do not carry over after the 8-week treatment period. Gastrocnemius volume also increased post-treatment with carryover at week 14.

Assessment of Lower Limb Muscle Strength and Power Using Hand-Held and Fixed Dynamometry: A Reliability and Validity Study

IntroductionHand-held dynamometry (HHD) has never previously been used to examine isometric muscle power. Rate of force development (RFD) is often used for muscle power assessment, however no consensus currently exists on the most appropriate method of calculation. The aim of this study was to examine the reliability of different algorithms for RFD calculation and to examine the intra-rater, inter-rater, and inter-device reliability of HHD as well as the concurrent validity of HHD for the assessment of isometric lower limb muscle strength and power.Methods30 healthy young adults (age: 23±5yrs, male: 15) were assessed on two sessions. Isometric muscle strength and power were measured using peak force and RFD respectively using two HHDs (Lafayette Model-01165 and Hoggan microFET2) and a criterion-reference KinCom dynamometer. Statistical analysis of reliability and validity comprised intraclass correlation coefficients (ICC), Pearson correlations, concordance correlations, standard error of measurement, and minimal detectable change.ResultsComparison of RFD methods revealed that a peak 200ms moving window algorithm provided optimal reliability results. Intra-rater, inter-rater, and inter-device reliability analysis of peak force and RFD revealed mostly good to excellent reliability (coefficients ≥ 0.70) for all muscle groups. Concurrent validity analysis showed moderate to excellent relationships between HHD and fixed dynamometry for the hip and knee (ICCs ≥ 0.70) for both peak force and RFD, with mostly poor to good results shown for the ankle muscles (ICCs = 0.31–0.79).ConclusionsHand-held dynamometry has good to excellent reliability and validity for most measures of isometric lower limb strength and power in a healthy population, particularly for proximal muscle groups. To aid implementation we have created freely available software to extract these variables from data stored on the Lafayette device. Future research should examine the reliability and validity of these variables in clinical populations.

Reliability of the hand held dynamometer in measuring muscle strength in people with interstitial lung disease

ObjectiveTo evaluate the inter-rater and intra-rater reliability of the hand held dynamometer in measuring muscle strength in people with interstitial lung disease (ILD). DesignTest retest reliability of hand-held dynamometry for elbow flexor and knee extensor strength between two independent raters and two testing sessions. SettingPhysiotherapy department within a tertiary hospital. ParticipantsThirty participants with ILD of varying aetiology were included. Twenty participants completed the inter-rater reliability protocol (10 idiopathic pulmonary fibrosis, mean (SD) age 73 (10) years, 11 male) and 21 participants completed the intra-rater reliability protocol (10 idiopathic pulmonary fibrosis, mean age 71 (10) years, 11 male). Main outcome measuresMean muscle strength (kg). Agreement between the two raters and testing sessions was analyzed using Bland–Altman plots and reliability was estimated using intraclass correlation coefficients (ICC). ResultsFor elbow flexor strength there was a mean difference between raters of −0.6kg (limits of agreement (LOA) −5.6 to 4.4kg) and within raters of −0.3kg (LOA −2.8 to 2.3kg). The ICCs were 0.95 and 0.98, respectively. For knee extensor strength there was a mean difference between raters of −1.5kg (LOA −6.9 to 3.9kg) and within raters of −0.7kg (LOA −3.9 to 2.4kg). The ICCs were 0.95 and 0.97, respectively. ConclusionsHand-held dynamometry is reliable in measuring elbow flexor and knee extensor strength in people with ILD.

Anthropometry, muscular strength and aerobic capacity up to 5 years after pediatric burns

ObjectivePhysical functioning is of major importance after burns in many areas of life, in both the short and the long term. This cross-sectional study aimed to describe anthropometry, muscular strength and aerobic capacity in children and adolescents between 0.5–5 years after burns over 10% TBSA. ProceduresAssessments took place in a mobile exercise lab. Demographics, burn characteristics and anthropometrics were recorded. Muscular strength in six muscle groups was measured using hand-held dynamometry and aerobic capacity was measured with a graded cardiopulmonary exercise test. Subjects’ scores were compared with Dutch age- and gender-matched norm values and converted to Z-scores. ResultsThe assessments were completed by 24 subjects with pediatric burns ranging from 10 to 41% TBSA and time after burn from 1 to 5 years (58.3% male; 6–18 years). On group level, no significant differences between the subjects’ scores and norm values were found. No trends were seen indicating an effect of extent of burn or time after burn. Individually, eight subjects (33.3%), mostly aged 6 or 7, showed significantly low performance on at least one variable: seven for strength, one for aerobic capacity and one for both. ConclusionAnthropometry, muscular strength and aerobic capacity are adequate in the majority of Dutch children and adolescents 1–5 years after 10–41% TBSA burns.

Strength and Pain Threshold Handheld Dynamometry Test Reliability in Patellofemoral Pain.

Patellofemoral pain syndrome (PFPS), characterized by peri- and retropatellar pain, is a common disorder in young, active people. The etiology is unclear; however, quadriceps strength seems to be a contributing factor, and sensitization might play a role. The study purpose is determining the inter-rater reliability of handheld dynamometry to test both quadriceps strength and pressure pain threshold (PPT), a measure for sensitization, in patients with PFPS. This cross-sectional case-control study comprises 3 quadriceps strength and one PPT measurements performed by 2 independent investigators in 22 PFPS patients and 16 matched controls. Inter-rater reliability was analyzed using intraclass correlation coefficients (ICC) and Bland-Altman plots. Inter-rater reliability of quadriceps strength testing was fair to good in PFPS patients (ICC=0.72) and controls (ICC=0.63). Bland-Altman plots showed an increased difference between assessors when average quadriceps strength values exceeded 250 N. Inter-rater reliability of PPT was excellent in patients (ICC=0.79) and fair to good in controls (ICC=0.52). Handheld dynamometry seems to be a reliable method to test both quadriceps strength and PPT in PFPS patients. Inter-rater reliability was higher in PFPS patients compared to control subjects. With regard to quadriceps testing, a higher variance between assessors occurs when quadriceps strength increases.

Intrarater reliability of goniometry and hand-held dynamometry for shoulder and elbow examinations in female team handball athletes and asymptomatic volunteers.

To evaluate the intrarater reliability for examining active range of motion (ROM) and isometric strength of the shoulder and elbow among asymptomatic female team handball athletes and a control group using a manual goniometer and hand-held dynamometry (HHD). 22 female team handball athletes (age: 21.0 ± 3.7 years) and 25 volunteers (13 female, 12 male, age: 21.9 ± 1.24 years) participated to determine bilateral ROM for shoulder rotation and elbow flexion/extension, as well as isometric shoulder rotation and elbow flexion/extension strength. Subjects were assessed on two separate test sessions with 7 days between sessions. Relative (intraclass correlation coefficients (ICC) and standard error of measurement (SEM) reliability were calculated. Reliability for ROM and strength were good to excellent for both shoulders and groups (athletes: ICC = 0.94-0.97, SEM 1.07°-4.76 N, controls: ICC = 0.96-1.00, SEM = 0.00 N-4.48 N). Elbow measurements for both groups also showed good-to-excellent reliability (athletes: ICC = 0.79-0.97, SEM = 0.98°-5.94 N, controls: ICC = 0.87-1.00, SEM = 0.00 N-5.43 N). It is important to be able to reliably reproduce active ROM and isometric strength evaluations. Using a standardized testing position, goniometry and HHD are reliable instruments in the assessment of shoulder and elbow joint performance testing. We showed good-to-excellent reproducible results for male and female control subjects and female handball athletes, although the single parameters in ROM and strength were different for each group and between the shoulders and elbows.

Comparative study on the assessment of the strength of the knee extensor and flexor muscles by hand-held dynamometer and isokinetic dynamometer

The strength of the knee extensor and flexor muscles is a relevant clinical indicator of the health status and functional capacities of an individual. For its evaluation, the practitioner must have simple and reliable measuring tools. Currently, the use of hand-held dynamometers is widespread both in the clinical practice and in research. However, their reliability for assessing the performance of strong muscles, such as the knee extensors and flexors, needs to be fully validated. The aim of this study is to compare the knee extensor and flexor muscle strength measurements using a hand-held dynamometer and the “gold standard” isokinetic dynamometer in a population of healthy individuals. The strength of the knee extensors and flexors was measured in 30 volunteers with a hand-held dynamometer (MicroFet 2, Hogan Health Industries, Inc 8020 South 1300 West, West Jordan, USA) and with an isokinetic dynamometer (Con-Trex MJ, CMV AG, Dübendorf, Switzerland). The correlations between the mean values of maximal isometric voluntary contraction measured with the hand-held dynamometer and the peak torque values in concentric, eccentric and isometric testing mode were then analyzed. Cross-sectional study. The reproducibility of the hand-held dynamometer was very good with coefficients of variation ranging from 3.2% (95%CI, 2.6–3.8%) to 4.2% (95% CI, 3.5–4.9%) depending on the muscle group. Strong positive correlations were found between hand-held and the isokinetic dynamometers. The correlation coefficients ( r ) ranged from 0.715 (95% CI, 0.478–0.855) to 0.872 (95% CI, 0.747–0.938) according to the muscle group and the isokinetic evaluation mode ( P < 0.01). The force values of the knee extensor and flexor muscles recorded with the hand-held dynamometer are reproducible and strongly and positively correlated with the values obtained with the three isokinetic evaluation modes, indicating that hand-held dynamometry represents a potential alternative tool for knee muscle strength assessment.

A study of grip strength among 20–49-year-old British adults and comparison to existing norms

Introduction Hand grip strength is frequently assessed to evaluate interventions or guide treatment. When using calibrated equipment in a standardised method, hand-held dynamometry is a reliable measure for hand grip strength and can be compared to normative data. However, existing British grip strength normative data were published 20 years ago. Methods A non-experimental quantitative study was carried out to establish if existing UK hand grip norms and consolidated multinational norms were representative of today’s 20–49-year-old British adult population. The methodology used was modelled on a previous British study using the mean Jamar dynamometer maximal grip strengths and reported within age bands. Results A total of 135 healthy British citizens of various ethnicities between 20 and 49 years were recruited. Grip strength is decreased in comparison to the existing British normative data for both males and females in all age bands. A significant difference exists ( p &lt; 0.05) for male right hand aged 40–44 years and right and left hands for women 25–29 years and 45–49 years, respectively. Significant differences were also noted in 5 and 8 of the 12 multinational means for men and women respectively. Conclusions Due to small sample size, the ability of this study to demonstrate a significant difference in mean grip strength to the earlier British norms is low. However, a small increase in sample size may have resulted in further significant differences with both studies. A larger study, taking into consideration ethnicity, is recommended to ensure valid and reliable grip strength norms are used in practice.

Assessment of net knee moment-angle characteristics by instrumented hand-held dynamometry in children with spastic cerebral palsy and typically developing children.

BackgroundThe limited range of motion during walking in children with spastic cerebral palsy (SCP) may be the result of altered mechanical characteristics of muscles and connective tissues around the knee joint. Measurement of static net knee moment-angle relation will provide insights into these alterations, for which instrumented hand-held dynamometry may be applied.The aims of this study were: (1) to test the measurement error of the estimated net knee moment-angle characteristics, (2) to determine the correlation between knee extension angle measurement at a standardized knee moment and popliteal angle from common physical examination and (3) to compare net knee moment–angle characteristics in SCP versus typically developing children.MethodsWith the child lying in sideward position, the knee was extended by moving the lower leg by a hand-held force transducer on a low friction cart. Force data were collected for a range of knee angles. Data were excluded when activity (EMG) levels of knee extensor and flexor muscles exceeded the EMG level during rest by more than two standard deviations. The net knee flexion moments were calculated from recorded force data and measured moment arm. Reliability for knee angles corresponding with 0.5, 1, 2, 3, and 4 Nm knee net flexion moments was assessed by standard error of measurements (SEM) and smallest detectable difference (SDD).ResultsFor between day comparison, SEMs were about 5° and SDDs were below 14° for knee angles at 1-4 Nm net knee flexion moments. In SCP children, the knee angle measured at 4 Nm knee flexion moment was not related to the popliteal angle (r = 0.52). The slope at 4 Nm of the knee moment-angle curve in SCP children was significantly higher than that in typically developing children.ConclusionsThe presented knee hand-held dynamometry allows assessment of net knee flexion moment-knee angle characteristics in typically developing and SCP children and can be used to identify clinically relevant changes as a result of treatment. Overall stiffness of structures that contribute to the net knee flexion moment at the knee (i.e. muscles, tendons, ligaments) is elevated in SCP children.Electronic supplementary materialThe online version of this article (doi:10.1186/s12984-015-0056-y) contains supplementary material, which is available to authorized users.