Comparison of Common Methodologies for the Determination of Knee Flexor Muscle Strength

BackgroundKnee flexion strength may hold important clinical implications for the determination of injury risk and readiness to return to sport following injury and orthopedic surgery. A wide array of testing methodologies and positioning options are available that require validation prior to clinical integration. The purpose of this study was to 1) investigate the validity and test-retest reliability of isometric knee flexion strength measured by a fixed handheld dynamometer (HHD) apparatus compared to a Biodex Dynamometer (BD), 2) determine the impact of body position (seated versus supine) and foot position (plantar- vs dorsiflexed) on knee flexion peak torque and 3) establish the validity and test-retest reliability of the NordBord Hamstring Dynamometer.Study DesignValidity and reliability study, test-retest design.MethodsForty-four healthy participants (aged 27 ± 4.8 years) were assessed by two raters over two testing sessions separated by three to seven days. Maximal isometric knee flexion in the seated and supine position at 90^o knee flexion was measured with both a BD and an externally fixed HHD with the foot held in maximal dorsiflexion or in plantar flexion. The validity and test-retest reliability of eccentric knee flexor strength on the NordBord hamstring dynamometer was assessed and compared with isometric strength on the BD.ResultsLevel of agreement between HHD and BD torque demonstrated low bias (bias -0.33 Nm, SD of bias 13.5 Nm; 95% LOA 26.13 Nm, -26.79 Nm). Interrater reliability of the HHD was high, varying slightly with body position (ICC range 0.9-0.97, n=44). Isometric knee flexion torque was higher in the seated versus supine position and with the foot dorsiflexed versus plantarflexed. Eccentric knee flexion torque had a high degree of correlation with isometric knee flexion torque as measured via the BD (r=0.61-0.86). The NordBord had high test-retest reliability (0.993 (95%CI 0.983-0.997, n=19) for eccentric knee flexor strength, with an MDC₉₅ of 26.88 N and 28.76 N for the left and right limbs respectively.ConclusionCommon measures of maximal isometric knee flexion display high levels of correlation and test-retest reliability. However, values obtained by an externally fixed HHD are not interchangeable with values obtained via the BD. Foot and body position should be considered and controlled during testing.Level of Evidence2b     

The validity and reliability of the sphygmomanometer for hip strength assessment in Australian football players

Objectives: To investigate the intra-rater and inter-rater reliability of the sphygmomanometer for the assessment of the adductor squeeze test and isometric hip abduction strength and to investigate the concurrent validity of the sphygmomanometer for the assessment of hip muscular strength. Method: Thirty-two healthy adult male community Australian football players (age 23.9 ± 4.5 years) were assessed by two blinded raters that measured the strength of the adductor squeeze test and isometric hip abduction, using a commercially available sphygmomanometer. Concurrent validity was calculated using handheld dynamometry as the reference standard. Results: Moderate to high intra-rater reliability (ICC = 0.61 to 0.92) and high inter-rater reliability (ICC = 0.77 to 0.91) were found. High concurrent validity (Pearson’s r = 0.77 to 0.91) was established. Sixteen of the participants reached the maximal reading of the sphygmomanometer, demonstrating a ceiling effect. Conclusions: A sphygmomanometer is a cost-efficient device that appears to be both reliable and valid for the assessment of hip strength, offering clinicians an alternate and easily accessible option to obtain objective strength data. A ceiling effect may limit the application of the sphygmomanometer as a strength measurement device in stronger individuals.     

Differences in isometric neck muscle strength between healthy controls and women with chronic neck pain: the use of a reliable measurement

Cagnie B, Cools A, De Loose V, Cambier D, Danneels L. Differences in isometric neck muscle strength between healthy controls and women with chronic neck pain: the use of a reliable measurement.

Objectives

To determine the intra- and interrater reliability of the Biodex isokinetic dynamometer to measure the maximal isometric strength of the cervical flexors and extensors, to develop an age- and sex-based normative database in a healthy population, and to evaluate the differences in neck strength between women with chronic neck pain and healthy controls.

Design

Cross-sectional.

Setting

Physical and rehabilitation medicine department.

Participants

Ninety-six healthy volunteers (4 age groups: 20-29, 30-39, 40-49, 50-59y; each consisting of 12 men and 12 women) and 30 women with chronic neck pain.

Interventions

Not applicable.

Main Outcome Measures

Peak isometric strength of the cervical muscles was tested for flexion and extension by using the Biodex isokinetic dynamometer. The intra- and interrater reliability of the protocol was evaluated in 12 volunteers.

Results

The reliability for strength was high for both flexion and extension (intraclass correlation coefficient, .92-.96). The mean peak torque for flexion and extension was significantly higher in men (24Nm, 36.4Nm, respectively) compared with women (16.6Nm, 26.5Nm, respectively) (P<.001). Peak torque production for extension was significantly lower in the patient group (22.3Nm) compared with the healthy female control group (26.5Nm) (P=.003). No significant differences in flexion strength between patient and female control group were found.

Conclusions

Results show a high degree of intra- and interrater reliability in measuring isometric neck muscle strength when using the Biodex isokinetic dynamometer. The use of normative data for neck strength when evaluating patients with neck disorders needs to take sex into account. The current study has shown that women with chronic neck pain have lower neck muscle strength in extension than the healthy female group.     

Intrarater Reliability of Neck Strength Measurement of Rugby Union Players Using a Handheld Dynamometer

Objective

The purpose of this study was to investigate the isometric neck strength profiles of rugby union players and to assess the intrarater reliability of isometric neck strength measurement using a handheld dynamometer.

Methods

Twenty-five male, academy-level, rugby union players (forwards [n = 16], backs [n = 9]) were tested on 2 occasions during a training week 2 days apart. Isometric strength of the neck musculature was tested using a handheld dynamometer, for flexion (F), extension (E), left side flexion (LSF), and right side flexion (RSF). The average of 3 trials for each test position was used for statistical analysis. The following isometric neck strength values were obtained: F, E, F:E, LSF, RSF, LSF:RSF, and total isometric strength.

Results

Intrarater reliability intraclass correlation coefficients ranged from 0.80 to 0.92 (intraclass correlation coefficient values: F, 0.85; E, 0.85; F:E, 0.85; LSF, 0.80; RSF, 0.85; LSF:RSF, 0.91; total isometric strength, 0.92), thus indicating excellent reliability in all instances. Forwards recorded significantly greater E scores compared with backs (637.10 ± 75.15 N vs 537.87 ± 82.25 N). Forwards also recoded significantly greater total isometric neck strength scores (2151.96 ± 231.11 N vs 1814.21 ± 211.26 N).

Conclusion

The results of this study provide isometric neck strength values for the forward and back units in the rugby union and indicate that a handheld dynamometer may be a reliable tool for assessing isometric neck strength in this population.     

Isometric knee extension force measured using a handheld dynamometer with and without belt-stabilization

Although evidence suggests that tester strength limits the magnitude of isometric force that can be measured using a handheld dynamometer (HHD), previous studies have not investigated the actual limits of force magnitude that can be measured by trained testers when a belt is or is not used to stabilize the dynamometer. Therefore, the primary aims of this study were to determine: 1) the magnitude of knee extension forces that could be measured with a HHD with and without belt-stabilization and 2) the relationship between tester characteristics and knee extension strength measured with and without belt-stabilization. The characteristics of 20 trained testers (10 men, 10 women) were determined. Thereafter, they measured isometric knee extension strength using the MicroFET HHD with and without belt-stabilization. Paired t-tests were used to compare maximal knee extension forces under two conditions. Pearson product–moment correlations were calculated to determine the relationship between tester characteristics and knee extension forces measured under the two conditions. Knee extension forces (Newtons) measured using the HHD without belt-stabilization (470.6?±?179.8) were significantly lower (t?=??7.968, p?<?0.001) than those measured with belt-stabilization (866.9?±?131.7). Pearson correlations between tester characteristics and knee extension forces measured with no belt-stabilization were all statistically significant (p?≤?0.002); however, the correlations were not statistically significant under the belt-stabilization condition. The forces that can be measured with a HHD are higher than those suggested by previous researchers. By rectifying limitations imposed by tester strength, use of a belt allows very high knee extension forces to be measured.     

Comparison of portable handheld versus fixed isokinetic dynamometers in measuring strength of the wrist and forearm

Purpose: The purpose of this study was to test the concurrent validity of using hydraulic dynamometers in comparison to the gold standard isokinetic dynamometers in measuring wrist and forearm strength. Materials and methods: Healthy adults between the ages of 18–65 participated, including 24 participants, 8 men and 16 women. The examiner used a handheld dynamometer, forearm/wrist dynamometer, and an isokinetic dynamometer to measure force/torque production in forearm rotation and wrist flexion/extension using a standardized protocol of two handle types for each motion. Sequence of testing was randomized. The data were analyzed using Pearson correlation coefficients and paired t-tests. Results: When matched for handle type, three of the four correlations between the strength measurements taken with the different dynamometers were moderate to high with Pearson product moment coefficients ranging from 0.72 to 0.96; the screwdriver handle demonstrated less than acceptable correlation (r = 0.45, 0.67 for wrist flexion and extension, respectively). There were significant differences in most of the force/torque values obtained by different handle types for wrist and forearm motions. Discussion and conclusions: Overall, the dynamometers demonstrated acceptable correlations supporting concurrent validity for measuring forearm and wrist strength, except with the screwdriver handle. However, different tools, positions, and handle interfaces provided different absolute values, therefore the tools cannot be used interchangeably. It is recommended that repeated measurements to monitor patient progress are taken with the same tool and handle type.     

Concurrent Validation and Reference Values of Gluteus Medius Clinical Test

ContextThe hip abductor muscles, mainly the gluteus medius, are responsible for controlling hip adduction in a closed kinetic chain. Frontal plane knee alignment, assessed during functional activities such squatting, jumping and running, may overload joint structures, like the anterior cruciate ligament and patellofemoral joint. The hand-held dynamometer is reliable and effective for testing the muscular strength of the hip abductors.Objectives1. To assess the concurrent validity between the gluteus medius clinical test and a maximum isometric force test of the hip abductors using the hand-held dynamometer; (2) to determine the intra and inter-examiner reliability for the application of the gluteus medius clinical test; and (3) to describe reference values of gluteus medius clinical test on a population of youth athletes.DesignCross-sectional.MethodsThirty healthy individuals were recruited for validity and reliability testing. On the first day, participants performed the maximal isometric test of the hip abductors, measured via hand-held dynamometry. On the following week, the gluteus medius clinical test was performed. Intraclass correlation coefficients (ICC_2,2) were computed for the reliability analysis, with a 95% confidence interval. To generate reference values, the gluteus medius clinical test was performed on 273 athletes.ResultsThe results of this study indicated a weak positive correlation (r = 0.436, p = 0.001) between tests, which indicates that they examine different domains of gluteus medius muscle function, likely endurance and muscle strength. The magnitude of computed ICCs (>0.95) indicates excellent intra- and inter-examiner reliability.ConclusionThe findings of the current study indicate that the gluteus medius clinical test is reliable and examines a domain of muscular function not fully captured by HHD. The clinical test developed in this study is low-cost and can be included for gluteus medius assessment.Level of evidenceLevel 3.     

The Relationship of Ultrasound Measurements of Muscle Deformation With Torque and Electromyography During Isometric Contractions of the Cervical Extensor Muscles

ObjectivesSpeckle tracking analysis (STA) of ultrasound (US) images quantifies the longitudinal deformation of a region of muscle tissue to provide a mechanical measure of muscle activity. As the validity and reliability of this method has not yet been adequately assessed, the aim of this study was to determine the validity and reliability of STA in the dorsal neck muscles during isometric neck extension contractions.MethodsTwenty volunteers performed 3 repetitions of isometric neck extension in a dynamometer at 10%, 20%, 40%, 60%, and 80% of maximal voluntary torque while US and surface electromyography (EMG) data were recorded. Speckle tracking analysis was then used to calculate measurements of muscle deformation. The relationship among torque, muscle deformation (separate for each muscle and summed), and EMG was evaluated using linear regressions and Spearman's correlation coefficients. The reliability of EMG and muscle deformation was determined using intraclass correlation coefficients (ICCs).ResultsMuscle deformation in 4 of the 5 muscles when examined separately and collectively was significantly related to torque (P < .05); however, the relationship was weak (r² = 0.03-0.18). In contrast, a strong linear relationship was observed between torque and EMG (P < .001, r² = 0.83). Poor to moderate reliability of muscle deformation measures (ICC: 0.02-0.69) was found compared with EMG, which was highly reliable (ICC: 0.67-0.90).ConclusionThese results suggest that the validity of US STA measurements for isometric contractions of the dorsal neck muscles is questionable. Further investigation into this method is required before it can be used as a tool to measure muscle activity.     

Effects of an integrated neuromuscular inhibition technique program on neck muscle strength and endurance in individuals with chronic mechanical neck pain

BackgroundThe aim of this study was to investigate whether the application of the integrated neuromuscular inhibition technique (INIT) combined with therapeutic exercise (TE) can provide faster and greater improvement in maximum isometric strength and isometric endurance of the neck muscles in patients with chronic mechanical neck pain (CMNP).MethodsIn this 10-week, single-blind clinical trial, 40 participants (men and women) with CMNP were divided into two groups. The intervention group (IG) followed a TE program in combination with the INIT, while the control group (CG) followed the same TE program without the INIT technique. Changes in maximum isometric strength and isometric endurance of the neck muscles were evaluated before, during, and after the intervention, with follow-up measurements taken at 1, 3, and 6 months after the intervention. Analysis of variance with repeated measures was applied.ResultsBoth groups showed a significant improvement in all dependent measures after the intervention (p < .05). These changes were maintained for both groups 6 months after the intervention. However, the IG showed a greater improvement in the maximum isometric strength of neck flexion and an improved craniocervical flexion test score compared with the CG.ConclusionThe combination of TE and INIT had a positive effect on neck muscle strength and endurance in individuals suffering from CMNP as compared with TE alone.     

Influence of Neck Pain,Cervical Extensor Muscle Fatigue,and Manual Therapy on Wrist Proprioception

ObjectiveThe purpose of this study was to examine the effects of submaximal isometric neck muscle fatigue and manual therapy on wrist joint position sense (JPS) within healthy individuals and individuals with subclinical neck pain (SCNP).MethodsTwelve healthy participants and 12 participants with SCNP were recruited. Each group completed 2 sessions, with 48 hours between sessions. On day 1, both groups performed 2 wrist JPS tests using a robotic device. The tests were separated by a submaximal isometric fatigue protocol for the cervical extensor muscles (CEM). On day 2, both groups performed a wrist JPS test, followed by a cervical treatment consisting of manual therapy (SCNP) or neck rest (20 minutes, control group) and another wrist JPS test. Joint position sense was measured as the participant's ability to recreate a previously presented wrist angle. Each wrist JPS test included 12 targets, 6 into wrist flexion and 6 into wrist extension. Kinematic data from the robot established absolute, variability, and constant error.ResultsAbsolute error significantly decreased (P = .01) from baseline to post-fatigue in the SCNP group (baseline = 4.48 ± 1.58°; post-fatigue = 3.90 ± 1.45°) and increased in the control group (baseline = 3.12 ± 0.98°; post-fatigue = 3.81 ± 0.90°). The single session of manual cervical treatment significantly decreased absolute error in participants with SCNP (P = .004).ConclusionThis study demonstrated that neck pain or fatigue can lead to altered afferent input to the central nervous system and can affect wrist JPS. Our findings demonstrate that acute wrist proprioception may be improved in individuals with SCNP by a single cervical manual therapy session.     

Correlation between handgrip and isokinetic strength of shoulder muscles in elite sitting volleyball players

The aim of this study was to examine the relationships between isometric handgrip (HG) strength and isokinetic strength data of the glenohumeral rotator muscles. Twelve (Female = 50%) Brazilian Sitting Volleyball (SV) national team players volunteered. Measures of maximal grip strength were obtained by a HG dynamometer Jamar® and isokinetic measures of peak torque (PT) and total work (TW) during shoulder rotations movements were obtained with a Biodex isokinetic dynamometer at speed of 60°/s and 180°/s. Pearson correlation coefficients between isometric HG and isokinetic strength data ranged between 0.23 and 0.72 for the PT and between 0.3 and 0.76 for the isokinetic TW. Results presented positive relationships between HG isometric strength and isokinetic strength of external rotators of the shoulder in SV players. We can suggest that in the absence of isokinetic dynamometers, HG isometric strength measurements could be used to measure strength levels of the external rotator muscles of elite SV players’ shoulder, particularly in the TW values.     

Ageing is not associated with a decline in neuromuscular innervation or reduced specific force in men aged 20 and 50 years

The exact mechanisms responsible for the decline in strength with age are yet to be completely elucidated. Three proposed mechanisms responsible for the detrimental effect of increasing age on strength include changes in muscle mass, specific force and/or neuromuscular innervation. Thus, the purpose of this investigation was to determine if the age‐related reduction in peak isometric strength was primarily associated with changes in muscle cross‐sectional area, neuromuscular innervation and/or specific force. The cross‐sectional area of the knee extensor muscles (QCSA) was estimated in 13 younger men (YM; 20·8 ± 1·6 years) and eight middle‐aged men (MM; 53·8 ± 4·2 years) prior to performing a series of four maximal voluntary isometric contractions on an isokinetic dynamometer at an angle of 60° knee flexion. Peak force was determined and surface electromyography was sampled from the rectus femoris muscle during each maximal voluntary contraction. The cross‐sectional area of the knee extensor muscles, peak force and integrated electromyography (IEMG) were significantly lower in the MM (P<0·01). However, when peak force and peak IEMG values were corrected for QCSA, there were no significant differences between age groups. These results suggest that the reduction in peak isometric force observed in the MM was primarily associated with quantitative changes in muscle mass, rather than reduced neuromuscular innervation or specific force. Therefore, preserving muscle mass through resistance training may significantly reduce the age‐associated differences in peak strength and assist in promoting quality of life and functional independence in older adults.     

Isometric osteopathic manipulation influences on cervical ranges of motion and correlation with osteopathic palpatory diagnosis: A randomized trial

IntroductionIsometric manipulation is a current practice in osteopathy and treatment benefits have been reported in the literature. Such benefits could be assessed using experimental non-invasive cervical mobility measurements. The main objective was to quantitatively measure the effects of isometric manipulation on principal and compensatory cervical motions.Methods101 healthy volunteers were included in this study. 51 healthy volunteers selected randomly underwent the experimental protocol before and after isometric treatment and were compared to 50 healthy volunteers who underwent a placebo treatment. Osteopathic diagnosis was performed on each healthy volunteer before and after the treatment. The experimental protocol included measurements by a motion capture system focusing on principal range of motion and compensatory motions.ResultsIn both the isometric and the placebo sample, respectively including 51 (age: 29.2 ± 8.1, BMI: 22.2 ± 3.5) and 50 healthy volunteers (age: 27.4 ± 6.8, BMI: 22.9 ± 2.8), a pre-treatment diagnosis revealed a light cervical dysfunction in all subjects, mainly in levels C3 and C4. Altered ranges of motion thresholds (C3/C4 alterations) were identified: 113.2° for flexion, 130.0° for rotation and 90.2° for lateral flexion.After manipulations, the volunteers who underwent the isometric treatment presented a slight increase in amplitude for lateral flexion (p < 0.04), which was not found in the volunteers who underwent the placebo treatment. Compensatory motions showed differences pre and post isometric treatment without reaching significant values.ConclusionPrincipal ranges of motion were found significantly higher after osteopathic treatment when compared to the placebo treatment. Osteopathic palpatory diagnosis showed significant correlation with range of motions before treatment.     

平山病的动态磁共振成像研究

目的通过颈椎中立位及过屈位磁共振扫描观察平山病患者颈髓形态的变化,进一步分析平山病诊断的影像学依据,并初步探讨平山病的发病机制。方法选择正常人无颈椎病史30例,以及确诊平山病患者20例,进行颈椎中立位及过屈位磁共振扫描,选择C6水平分别在两种体位测量颈髓正中线前后径,另外测量过屈位相邻两个椎体后缘的角度。结果患者C6水平颈髓前后径中立位(Dn)及过屈位(Df)分别为(0.542±0.076)cm、(0.418±0.067)cm,正常对照Dn及Df分别为(0.670±0.049)cm、(0.595±0.047)cm,患者均较正常人小(P<0.01),且过屈位颈髓前后径患者较正常人变小更为明显,且以一侧变扁为著(P<0.01)。过屈位相邻椎体后缘成角依次为AC34(3.0±2.0)°、AC45(6.7±2.2)°、AC56(11.8±2.3)°、AC67(8.6±3.7)°,下颈段大于上颈段(AC56>AC67>AC45>AC34)。结论磁共振成像可以明确显示平山病形态学改变,是诊断平山病的重要依据之一,下颈段颈椎成角较大,可能是造成平山病集中在下颈段脊髓的原因之一。     

Validity of the modified sphygmomanometer test for the assessment of tip pinch strength in Parkinson's disease

BackgroundThe tip pinch is one of the most delicate and precise movement of the hand, and it is used to manipulate small objects, commonly observed in the activities of daily living of any individuals. Individuals with Parkinson Disease (PD) with impaired manual dexterity, manipulative skills, and hand weakness have an important barrier for activities of daily life. However, the dynamometer usually used for measuring the tip pinch have a high cost, so, validate a sphygmomanometer can make this assessment more accessible.ObjectiveTo investigate the validity of the modified sphygmomanometer test in the evaluation of tip pinch strength when compared to the gold standard.Methods50 individuals with idiopathic PD took part in the study. The muscle strength of tip pinch on the dominant and non-dominant side was measured by the modified sphygmomanometer test and the gold standard, the dynamometer. Concurrent validity was analyzed using Pearson's correlation coefficient.Results50 individuals diagnosed with idiopathic PD, mean age of 67 ± 8.0 years, 68% male, mean time of diagnosis in months of 84 ± 66 and Hoehn and Yahr mean of 2.5 ± 0.6. There was a significant correlation of moderate magnitude between the modified sphygmomanometer test and the dynamometer in dominant side (r = 0.44; p < 0.01) and non-dominant side (r = 0.48; p < 0.01).ConclusionThe modified sphygmomanometer test showed adequate validity for assessing the muscle strength of the tip pinch in individuals with PD.     

Isometric muscle strength in children and adolescents using Handheld dynamometry: reliability and normative data for the Brazilian population

Objective

Isometric muscle strength measured by Handheld dynamometer indicates physical ability. There is no normative data for the Brazilian population. This study aims (a) to describe the development of isometric muscle strength in healthy children and adolescents 5–15 years of age; (b) to evaluate Handheld dynamometer inter and intra-rater reliability.