RELIABILITY OF THE ISOMETRIC DYNAMOMETER IN CONTROL, PARAPLEGIC, AND AMPUTEE INDIVIDUALS

Objective

To determine the Intraclass Correlation Coefficient (ICC), Standard Error of Measurement (SEM), Minimum Detectable Change (MDC), and the Minimum Clinically Important Difference (MCID) of the isometric measurements of muscle strength of trunk extension and of flexion and knee extension at maximum contraction in healthy, paraplegic, and amputee individuals, by using an isometric dynamometer with a belt for stabilization.

Methods

An observational cross-sectional study was carried out to assess the reliability of a portable isometric dynamometer in the trunk extension and flexion and knee extension movements of each group.

Results

In all measurements, ICC ranged from 0.66 to 0.99, SEM from 0.11 to 3.73 kgf, and MDC from 0.30 to 10.3 kgf. The MCID of the movements ranged from 3.1 to 4.9 kgf in the amputee group and from 2.2 to 3.66 kgf in the paraplegic group.

Conclusion

The manual dynamometer demonstrated good intra-examiner reliability, presenting moderate and excellent ICC results. Thus, this device is a reliable resource to measure muscle strength in amputees and paraplegics. Level of Evidence II, Cross-Sectional Study.

Reliability of Muscle Strength and Muscle Power Assessments Using Isokinetic Dynamometry in Neuromuscular Diseases: A Systematic Review

OBJECTIVE

The purpose of this study was to critically appraise and summarize the evidence for reliability of muscle strength and muscle power assessment in patients with neuromuscular diseases (NMDs) using isokinetic dynamometry.

METHODS

PubMed, CINAHL, and Embase electronic databases were searched from inception to March 8, 2022. Studies designed to evaluate reliability of muscle strength and power measurements using isokinetic dynamometry were included in this review. First, the methodological quality of the studies was assessed according to the Consensus-Based Standards for the Selection of Health Measurement Instruments guidelines. Next, the quality of measurement properties was determined. Finally, the methodological quality and quality of measurement properties of the studies were combined to obtain a best-evidence synthesis.

RESULTS

A best-evidence synthesis of reliability was performed in 11 studies including postpoliomyelitis syndrome (n = 5), hereditary motor and sensory neuropathy (n = 2), motor neuron diseases (n = 1), myotonic dystrophy (n = 1), and groups of pooled NMDs (n = 2). A best-evidence synthesis on measurement error could not be performed. Quality of evidence on reliability ranged from high in postpoliomyelitis syndrome to very low in hereditary motor and sensory neuropathy, motor neuron diseases, and groups of pooled NMDs. The most frequently used outcome measure was peak torque, which was reliable in all populations (intraclass correlation coefficient >0.7).

CONCLUSION

The quality of evidence for reliability of isokinetic dynamometry was found to vary substantially among different NMDs. High quality of evidence has been obtained only in patients with postpoliomyelitis syndrome. Further research is needed in the majority of known NMDs to determine reliability and validity of isokinetic dynamometry.

IMPACT

The ability of isokinetic dynamometers to capture clinically relevant changes in muscle strength and muscle power in NMDs remains unclear. Isokinetic dynamometry results in NMDs should be interpreted with caution.

Concurrent Validity and Reliability of a Low-Cost Dynamometer to Assess Maximal Isometric Strength in Neck Movements

OBJECTIVE

This study aimed to evaluate the concurrent validity and reliability of a low-cost digital dynamometer to assess maximal isometric strength in neck movements.

METHODS

Twelve recreationally active participants (6 women, 6 men; age: 24.1 ± 3.4 years; height: 1.71 ± 0.06 m; weight: 64.6 ± 11.7 kg) performed neck flexion, extension, and lateral flexion, and maximal isometric strength was simultaneously measured using an isokinetic dynamometer (gold standard) and a digital dynamometer to evaluate the concurrent validity of the latter. One week later, all the participants repeated 3 trials of each neck movement (3 minutes apart) registered only with the digital dynamometer. The first and second trial were guided by tester 1 and the third trial was guided by tester 2.

RESULTS

The concurrent validity of the digital dynamometer showed a nearly perfect correlation between both devices (r > 0.986, P < .001), with Bland-Altman plots showing absolute agreement. Intertester and intratester reliability were nearly perfect for all neck movements (intraclass correlation coefficient > 0.86).

CONCLUSION

The low-cost digital dynamometer showed valid and reliable measurements of maximal isometric strength in neck movements.

SHOULDER ISOKINETIC PERFORMANCE IN HEALTHY PROFESSIONAL JUDO ATHLETES: NORMATIVE DATA

Objective:

To evaluate normative data of shoulder isokinetic strength in healthy professional judo athletes.

Methods:

Cross-sectional study with 20 professional male and female athletes (10 female), evaluated with an isokinetic dynamometer. The strength assessment was carried out in external and internal rotation, flexion, extension, adduction and abduction. All data collected on muscle torque were normalized with body mass index.

Results:

Athletes demonstrated higher peak torque and joint work in shoulder adduction, abduction, flexion, and extension for the dominant limb compared to the non-dominant limb (p <0.05), with most of these deficits below 10%. Shoulder internal/external rotation ratios for male and female athletes had no significant differences between dominant and non-dominant sides, demonstrating values at 60°/s of 49.4 ± 7.2 on the dominant side of males and 49.1 ± 4.9 for females.

Conclusion:

The normative data are described to assist during treatment, return to sport and injury prevention. Level of evidence IV, cross-sectional study.

Test-Retest Reliability of Handgrip Strength as an Outcome Measure in Patients With Symptoms of Shoulder Impingement Syndrome

OBJECTIVE

The purpose of this study was to investigate the degree of test-retest reliability of grip strength measurement using a hand dynamometer in patients with shoulder impingement syndrome.

METHODS

A total of 19 patients (10 women and 9 men; mean ± standard deviation age, 33.2 ± 12.9 years; range 18-59 years) with shoulder impingement syndrome were measured using a hand dynamometer by the same data collector in 2 different testing sessions with a 7-day interval. During each session, patients were encouraged to exert 3 maximal isometric contractions on the affected hand and the mean value of the 3 efforts (measured in kilogram-force [Kgf]) was used for data analysis. The intraclass correlation coefficient (ICC_2,1) as well as the standard error of measurement (SEM) and Bland-Altman plot were used to estimate the degree of test-retest reliability and the measurement error, respectively.

RESULTS

Grip strength data analysis revealed an ICC_2,1 score of 0.94, which, based on the Shrout classification, is considered as excellent test-retest reliability of grip strength measurement. The small values of SEMs reported in both sessions (SEM₁, 2.55 Kgf; SEM₂, 2.39 Kgf) and the small width of the 95% limits of agreement in the Bland-Altman plot (ranging from -7.39 Kgf to 7.03 Kgf) reflected the measurement precision and the narrow variation of the differences during the 2 testing sessions.

CONCLUSIONS

Results from this study identified excellent test-retest reliability of grip strength measurement in shoulder impingement syndrome, indicating its potential use as an outcome measure in clinical practice.

Relationship Between Headaches and Neck Pain Characteristics With Neck Muscle Strength

OBJECTIVE

The purpose of this study was to assess the correlations between neck muscle strength and pain features, such as neck-related disability, neck pain frequency and intensity, and headache frequency in women with headache.

METHODS

Seventy women with migraine between 18 and 55 years of age diagnosed according to International Headache Society criteria were assessed. Participants provided clinical information regarding neck pain and headache. The Neck Disability Index was used to assess neck-related disability, and neck muscle strength was assessed via maximum voluntary contraction during flexion, extension, and lateral flexion with a handheld dynamometer. The correlation was verified with Spearman's correlation coefficient (ρ). Multiple linear regression was performed to verify whether the clinical variables could predict the strength of neck muscles. All calculations were performed adopting a level of significance of 0.05.

RESULTS

Neck extensor strength was negatively correlated with all clinical variables (ρ_range = -.24 to -.32, p < .05); lateral flexor strength was negatively correlated with headache frequency, neck pain intensity, and neck-related disability (ρ_range = -.27 to -.39, p < .05); and flexor strength also correlated negatively with neck pain intensity and related disability (ρ_r = -.26 to -.29, p < .05). Headache frequency and neck pain intensity were identified as significant predictors of the strength variability in extension (R² = 0.16, p < .05) and in lateral flexion (R² = 0.18, p < .05).

CONCLUSIONS

For the women with migraine in this study, correlations of headache and neck pain with neck muscle strength features were weakly to moderately negative. Headache frequency and neck pain intensity may influence a small proportion of the strength variability in extension and lateral flexion.

Test-retest reliability of handgrip strength measurement using a hydraulic hand dynamometer in patients with cervical radiculopathy

OBJECTIVE

The purpose of this study was to evaluate the test-retest reliability of handgrip strength measurement using a hydraulic hand dynamometer in patients with cervical radiculopathy (CR).

METHODS

A convenience sample of 19 participants (14 men and 5 women; mean ± SD age, 50.5 ± 12 years) with CR was measured using a Jamar hydraulic hand dynamometer by the same rater on 2 different testing sessions with an interval of 7 days between sessions. Data collection procedures followed standardized grip strength testing guidelines established by the American Society of Hand Therapists. During the repeated measures, patients were advised to rest their upper limb in the standardized arm position and encouraged to exert 3 maximum gripping efforts. The mean value of the 3 efforts (measured in kilogram force [Kgf]) was used for data analysis. The intraclass correlation coefficient, SEM, and the Bland-Altman plot were used to estimate test-retest reliability and measurement precision.

RESULTS

Grip strength measurement in CR demonstrated an intraclass correlation coefficient of 0.976, suggesting excellent test-retest reliability. The small SEM in both testing sessions (SEM1, 2.41 Kgf; SEM2, 2.51 Kgf) as well as the narrow width of the 95% limits of agreements (95% limits of agreement, -4.9 to 4.4 Kgf) in the Bland-Altman plot reflected precise measurements of grip strength in both occasions.

CONCLUSIONS

Excellent test-retest reliability for grip strength measurement was measured in patients with CR, demonstrating that a hydraulic hand dynamometer could be used as an outcome measure for these patients.

Association of postural balance and isometric muscle strength in early- and middle-school-age boys

OBJECTIVE

The purpose of this study was to evaluate the isometric muscle strength (IMS) and dynamic balance in early- and middle-school-age boys and to assess the strength of association between the dynamic balance scores and 6 different IMS indexes.

METHODS

This is a cross-sectional study of a convenience sample of 94 boys who were 6 to 10 years of age and classified into an early school age (6-8 years) group (n = 50) and a middle school age (8-10 years) group (n = 44). Balance was tested using a Biodex Balance System. Anteroposterior Stability Index, Mediolateral Stability Index, and Overall Stability Index were recorded. IMS of 11 muscle groups was measured with a handheld dynamometer and categorized into 6 different muscle strength indices.

RESULTS

The mean (SD) values of anteroposterior, mediolateral, and overall stability indexes observed for all study boys were 1.9 ± 1.0, 1.2 ± 0.7, and 2.5 ± 1.2 respectively. In the middle school age group, strong positive relationships were detected between the overall stability index and trunk, lower limb, anti-gravity, pro-gravity, and total strength indexes (r = -0.86/P < .001, r = -0.91/P < .001, r = -0.88/P < .001, r = -0.83/P < .001, and r = -0.84/P < .001 respectively), while no significant relationship was detected with the upper limb strength index (r = 0.159/P = .303). In the early school age group, moderate positive relationships were detected between the overall stability index and anti-gravity, lower limb, and total strength indexes (r = -0.404/P = .004, r = -0.356/P = .011, and r = -0.350/P = .013 respectively).

CONCLUSION

Dynamic balance did not appear to be mature by the age of 10 years. Better balance skills were recorded in the mediolateral direction than in the anteroposterior direction. In the middle school age group, the overall stability index had positive relationships with almost all examined muscle strength indexes excepting the upper limb strength index.

ARE THERE DIFFERENCES IN STRENGTH TESTS USING ISOKINETIC DYNAMOMETRY BETWEEN FIELD AND INDOOR PROFESSIONAL SOCCER PLAYERS?

OBJECTIVE

The objective of this study was to conduct a comparative analysis on isokinetic strength assessments between field and indoor male professional soccer players and correlate the findings with the higher levels of injury risk described in the literature.

METHODS

We analyzed 16 field soccer players and 15 indoor soccer players. All these professionals were male. Isokinetic muscle strength assessments were made on their knees.

RESULTS

The mean weight was 81.81 kg for field soccer and 80.33 kg for indoor soccer. The right and left peak extensor torque left and right for field soccer and indoor soccer were, respectively, 302.50 and 313.31 Nm and 265.20 and 279.80 Nm, and for flexors, 178 and 184.88 Nm and 158.27 and 154 Nm. The peak torque rates according to body weight for the left and right extensors for field soccer and indoor soccer were, respectively, 3.84 and 3.7 Nm/kg and 3.32 and 3.52 Nm/kg, and for flexors, 2.17 and 2.26 Nm/kg and 1.98 and 1.93 Nm/kg. The balance relationships between flexors and extensors on the right and left sides for field soccer and indoor soccer were, respectively, 59.81 and 59.44% and 60.47% and 54.80%. The relationships for extensors between the right and left sides for field soccer and indoor soccer were, respectively, 11.44 and 9.20%, and for the flexors, 7.31 and 8.80%.

CONCLUSIONS

In accordance with international parameters, comparative analysis on isokinetic strength assessments between field and indoor male professional soccer players before the season showed that there was muscle balance and low probability of injury. There were no statistically significant differences in the parameters analyzed between the players of the two types of soccer.