Test-retest reliabilities of hand-held dynamometer for lower-limb muscle strength in intellectual disabilities

Associations between motor competence and physical activity levels of children with intellectual disabilities and/or autism spectrum disorder: Movement matters

Motor competence is important for lifelong physical activity (PA). The current study aimed to examine associations between PA and motor competence. In total, 43 children aged 7-12 years with intellectual disabilities and/or autism spectrum disorder completed anthropometric measures, the Bruininks-Oseretsky Test of Motor Proficiency-2, and wore a wrist accelerometer to capture total PA, moderate-to-vigorous PA (MVPA), average acceleration, and intensity gradient. No significant associations were found between PA outcomes and motor competence. Motor competence performance was commonly 'below average' or 'average'. The weakest subtests were upper limb coordination and strength. The strongest subtest was running speed and agility. Total weekly MVPA was 336.1 ± 150.3 min, higher than UK recommendations of 120-180 per week for disabled children and young people. Larger scale studies are needed to better understand the relationship between PA and motor competence. Future research should also consider the influence of environmental factors on PA in this group.

Effects of Aquatic Exercise and Floor Curling on Balance Ability and Lower Limb Muscle Strength in Children with Intellectual Disabilities: A Pilot Study in China

Children with intellectual disabilities often face challenges in balance ability and lower limb muscle strength, which negatively impact their daily lives and motor function. Therefore, it is crucial to enhance the balance ability and lower limb muscle strength of children with intellectual disabilities. This study aimed to investigate the effects of a 12-week aquatic exercise and floor curling intervention on the balance ability and lower limb muscle strength of children with intellectual disabilities. Forty-two participants were randomly assigned to the aquatic exercise group, floor curling group, and control group. The aquatic exercise and floor curling groups received a 12-week intervention, while the control group engaged in supervised free activities. The participants' balance ability and lower limb muscle strength were assessed using the Berg Balance Scale and a muscle strength testing device before and after the intervention. The results showed significant improvements in balance ability and lower limb muscle strength for both the aquatic exercise group and the floor curling group after the intervention. The aquatic exercise group demonstrated an average improvement of 10.84% in balance ability and an overall average improvement of 16.28% in lower limb muscle strength. The floor curling group showed an average improvement of 9.04% in balance ability and an overall average improvement of 15.67% in lower limb muscle strength. These improvement results were statistically significant (p < 0.05) and ranged from medium to large effect sizes (d = 0.5~0.8). The findings of this study validate the positive effects of aquatic exercise and floor curling on the balance ability and lower limb muscle strength of children with intellectual disabilities. These interventions can be considered effective approaches for functional rehabilitation in children with intellectual disabilities.

Eight-week virtual reality training improves lower extremity muscle strength but not balance in adolescents with intellectual disability: A randomized controlled trial

Purpose: This study aims to assess the effects of 8-week virtual reality (VR) training on balance and lower extremity muscle strength in adolescents with intellectual disability (ID).

Methods: Thirty adolescents with intellectual disability were randomly divided into the virtual reality group and control group. The participants in the virtual reality group and the control group received the virtual reality training and the physical education (PE) course, respectively, for 8 weeks. The Berg Balance Scale (BBS), Timed Up and Go (TUG) test and lower extremity muscle strength were measured before and after the training.

Results: The between-group results showed that the participants in the virtual reality group increased the muscle strength of hip flexors (p &lt; 0.001), hip extensors (p = 0.002), hip abductors (p &lt; 0.001), knee flexors (p &lt; 0.001), knee extensors (p = 0.002) and ankle plantar flexors (p = 0.042) significantly after training, compared to the control group. However, no significant improvement was found in the berg balance scale and timed up and go scores between the virtual reality group and control group after training (p &gt; 0.05). The within-group results showed that the strength of all the muscle groups significantly increased after training in the virtual reality group (p &lt; 0.05) compared to the baseline. However, no significant difference was found in the muscle strength in the control group before and after training. The within-group berg balance scale and timed up and go scores showed no significant improvements in both groups.

Conclusion: Virtual reality training intervention might be effective in improving the lower extremity muscle strength, but no significant improvement was found on balance ability in adolescents with intellectual disability.

Strength measurements in patients with Dravet Syndrome

BACKGROUND

Dravet Syndrome (DS) is a developmental and epileptic encephalopathy, characterized by drug resistant infantile onset seizures and cognitive and motor impairment. Walking problems progressively occur and crouch gait is frequently observed. Muscle weakness is hypothesized as contributing impairment. Yet, so far, no studies have performed strength measurements in patients with DS, most likely due to cognitive impairment.

AIMS

To determine the feasibility and validity of strength measurements in the framework of gait analysis and to outline strength problems in patients with DS.

METHODS

Manual muscle testing, dynamometry (hand grip strength and handheld dynamometry) and functional tests (underarm throwing, standing long jump, sit-to-stand, stair climbing) were performed in 46 patients with DS. Results were compared to age-related reference values from literature.

RESULTS

Forty one percent (19/46) of the patients (aged 5.2-24.8 years, median: 15.8 years) accomplished all measurements and scored generally below the fifth percentile of norm values. The remaining 59% (27/46) was not able to complete all strength assessment due to cognitive, behavioural and motor difficulties. Handheld dynamometry seemed most sensitive and specific to detect isolated muscle strength. Validity of the functional tests was controversial, as motor proficiency, balance and coordination may interfere.

CONCLUSION

Although measuring strength in patients with DS was challenging in the context of gait analysis, decreased muscle strength was observed in patients that could perform strength measurements. Handheld dynamometry is preferred over functional tests for future investigations of muscle strength and its interference with gait are required for better understanding of walking problems.

Knee strength measurement: Can we switch between isokinetic dynamometers?

BACKGROUND: Isokinetic evaluation is considered the gold standard in muscle strength measurement due to its sensitivity, intra-dynamometer reproducibility and usefulness in the injury prevention screening and follow up of subjects with musculoskeletal pathologies, neurological disease or after surgical operation. However, can one switch among different isokinetic dynamometers for the purpose of knee muscles evaluation? OBJECTIVES: To comprehensively evaluate the compatibility of the isokinetic short concentric and eccentric strength evaluation protocol and of the fatigability resistance evaluation between three different isokinetic devices. METHODS: Eighteen recreationally active men underwent three isokinetic knee testing sessions on three different isokinetic devices with 7–10 days of rest between each session. Relative (Pearson’s r product-moment correlation coefficient – PCC) and absolute (standard error of measurement – SEM, Cohen effect sizes (d) and probabilistic inferences – MBI) parameters of reproducibility were determined to assess the inter-dynamometer agreement. RESULTS: For the short concentric and eccentric strength evaluation protocol, the extensors in concentric mode and the flexors in eccentric mode can be compared (eventually with transposition formulas provided) between Biodex, Con-Trex and Cybex (almost all PCC ⩾ 0.80). The DCR could be compared between Con-Trex and Cybex and between Biodex and Cybex pairs (eventually with transposition formula provided). For the fatigability resistance evaluation protocol, the total sum can be compared for extensors (eventually with transposition formulas provided) for PM for all dynamometer pairs considered and, in the case of MW, only for Biodex and Con-Trex (PCC ⩾ 0.80). CONCLUSIONS: Only some of the parameters derived either from the short concentric and eccentric strength evaluation protocol or the fatigability resistance evaluation protocol may be interchangeable providing transposition formulas are applied. Otherwise, isokinetic findings are largely system-dependent save some specific instances.

Validating the Capability for Measuring Age-Related Changes in Grip-Force Strength Using a Digital Hand-Held Dynamometer in Healthy Young and Elderly Adults

Background

Grip-force performance can be affected by aging, and hand-grip weakness is associated with functional limitations of dasily living. However, using an appropriate digital hand-held dynamometer with continuous hand-grip force data collection shows age-related changes in the quality of hand-grip force control may provide more valuable information for clinical diagnoses rather than merely recording instantaneous maximal hand-grip force in frail elderly adults or people with a disability. Therefore, the purpose of this study was to indicate the construct validity of the digital MicroFET3 dynamometer with Jamar values for maximal grip-force assessments in elderly and young adults and confirmed age-related changes in the maximal and the quality of grip-force performance using the MicroFET3 dynamometer in elderly people.

Methods

Sixty-five healthy young (23.3 ± 4.5 years) and 50 elderly (69.5 ± 5.8 years) adults were recruited and asked to perform a validity test of the grip-force maximum voluntary contraction (MVC) using both the dominant and nondominant hands with a Jamar dynamometer and a MicroFET3 dynamometer.

Results

A strong correlation of maximal grip-force measurements was found between the MicroFET3 dynamometer and Jamar standard dynamometer for both hands in all participants (p < 0.05). Although, the results showed that a lower grip force was measured in both hands by the MicroFET3 dynamometer than with the Jamar dynamometer by 49.9%~57% (p < 0.05), but confidently conversion formulae were also developed to convert MicroFET3 dynamometer values to equivalent Jamar values for both hands. Both dynamometers indicated age-related declines in the maximum grip-force performance by 36.7%~44.3% (p < 0.05). We also found that the maximal hand-grip force values generated in both hand by the elderly adults were slower and more inconsistent than those of the young adults when using the MicroFET3 dynamometer.

Conclusions

This study demonstrated that the digital MicroFET3 dynamometer has good validity when used to measure the maximal grip force of both hands, and conversion formulae were also developed to convert MicroFET3 dynamometer force values to Jamar values in both hands. Comparing with the Jamar dynamometer for measuring grip force, the MicroFET3 dynamometer not only indicated age-related declines in the maximum grip-force performance but also showed slower and more inconsistent maximal hand-grip strength generation by the elderly.

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

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

The validity and reliability of the Functional Strength Measurement (FSM) in children with intellectual disabilities

BACKGROUND

There is lack of valid and reliable field-based tests for assessing functional strength in young children with mild intellectual disabilities (IDs).

AIM

The aim of this study was to investigate the test-retest reliability and construct validity of the Functional Strength Measurement in children with ID (FSM-ID).

METHOD

Fifty-two children with mild ID (40 boys and 12 girls, mean age 8.48 years, SD = 1.48) were tested with the FSM. Test-retest reliability (n = 32) was examined by a two-way interclass correlation coefficient for agreement (ICC 2.1A). Standard error of measurement and smallest detectable change were calculated. Construct validity was determined by calculating correlations between the FSM-ID and handheld dynamometry (HHD) (convergent validity), FSM-ID, FSM-ID and subtest strength of the Bruininks-Oseretsky test of motor proficiency - second edition (BOT-2) (convergent validity) and the FSM-ID and balance subtest of the BOT-2 (discriminant validity).

RESULTS

Test-retest reliability ICC ranged 0.89-0.98. Correlation between the items of the FSM-ID and HHD ranged 0.39-0.79 and between FSM-ID and BOT-2 (strength items) 0.41-0.80. Correlation between items of the FSM-ID and BOT-2 (balance items) ranged 0.41-0.70.

CONCLUSION

The FSM-ID showed good test-retest reliability and good convergent validity with the HHD and BOT-2 subtest strength. The correlations assessing discriminant validity were higher than expected. Poor levels of postural control and core stability in children with mild IDs may be the underlying factor of those higher correlations.

Psychometric properties of field-based anaerobic capacity tests in children with Developmental Coordination Disorder

Background: Assessment of anaerobic capacity in children with Developmental Coordination Disorder (DCD) is essential for treatment planning. However, available field-based measures have no established validity and reliability in this population. Purpose: To examine the psychometric properties of selected field-based anaerobic capacity tests in children with and without DCD. Methods: School-aged children (6-16 years) with and without DCD participated in the study. The children completed the shuttle run sub-item of the Bruninks-Oseretsky test of motor proficiency-second edition, the 10 × 5 m sprint tests (straight and slalom) and the muscle power sprint test (MPST). Results: The shuttle run test item of the Bruninks-Oseretsky test of motor proficiency-second edition and 10 × 5 m sprint tests possess good construct validity and test-retest reliability in children with DCD. The 10 × 5 m sprint test-slalom was found to be the most responsive test among children with DCD. However, the MPST was less reliable in children with DCD compared to their typically developing peers, leading to a very large Smallest Detectable Difference. Conclusions: The findings suggest that the selected anaerobic capacity measures have sound psychometric properties among children with DCD with the exception of the MPST. Clinicians working on children with DCD could use these tests in their practice, especially in situations where logistical resources are limited. Implications for Rehabilitation Field-based anaerobic capacity tests are suitable measures for assessing anaerobic capacity in children with Developmental Coordination Disorder, particularly in situations where laboratory assessments are not feasible. The shuttle run test item of the Bruninks-Oseretsky test of motor proficiency-second edition and the 10 × 5 sprint tests (straight and slalom) have good construct validity in this population. The 10 × 5 sprint test (slalom) is the most sensitive anaerobic capacity test among children with Developmental Coordination Disorder.

Muscle strength characteristics of the hamstrings and quadriceps in players from a high-level youth football (soccer) Academy

The objective of this study was to investigate knee muscle strength characteristics in players from a high-level youth football Academy. In total, 110 players (aged 8-15 years) underwent muscle strength assessments carried out by a research physiotherapist using a computer-linked hand-held dynamometer. Results indicated that isometric hamstrings and quadriceps strength increased with age, whereas the isometric hamstring to quadriceps (H/Q) ratio decreased with age. A number of youth football players (n = 20; 18%; 95% CI: 11-27%) demonstrated isometric H/Q ratios of less than 0.60, as well as muscle strength asymmetries between limbs for the hamstrings (n = 40, 36%; 95% CI: 27-46%) and quadriceps (n = 51, 46%; 95% CI 37-56%), potentially increasing injury risk. This study provides new evidence that the isometric H/Q ratio reduces with advancing age during adolescence which may have important implications for junior athlete development and long-term injury prevention in football.

Systematic review of field-based physical fitness tests for children and adolescents with intellectual disabilities

BACKGROUND

Testing physical fitness in children and adolescents with intellectual disabilities (ID) can be challenging. This review provides an overview on psychometric properties of field-based physical fitness tests studied in children and adolescents with ID.

METHODS

A literature search was performed in March 2014. Studies were included if they evaluated feasibility, reliability and/or validity of a field-based physical fitness test in children and adolescents with ID.

RESULTS

Twenty-six papers met the inclusion criteria and described 18 tests on body composition (4), muscular strength (4), muscular endurance (6), and cardiorespiratory fitness (4). Best results on feasibility, reliability and/or validity were found for bioelectric impedance analysis, body mass index, grip strength, arm hang and distance run/walk tests. These results were mainly found in adolescents with mild to moderate ID.

CONCLUSION

Some tests were found feasible, reliable and/or valid in subgroups of children and adolescents with ID, but not in children and adolescents with all ages and levels of ID. Further assessment is needed before wider application in all children and adolescents with ID.

Test-retest reliability and minimal detectable change scores of twelve functional fitness tests in adults with Down syndrome

AIM

The purpose of the study was to explore the test-retest reliability and minimal detectable change of selected functional fitness test items in adults with Down syndrome.

METHODS

Forty-three adults with Down syndrome (24 men and 19 women) aged 18-50 years completed a battery of tests twice in a two-week period. The battery of tests consisted of two balance items, two flexibility items, five muscular strength and endurance items, two aerobic items, and one functional task. All items were considered valid and reliable tests in a general elderly or intellectually disabled population. The test-retest relative reliability for all repeated tests was assessed with intraclass correlation coefficient performing one-way analysis of variance. The test-retest absolute variability was measured by using the standard error of measurement (SEM) to calculate the minimal detectable change at the 90% confidence interval (MDC90). Reliability data was visualised with a Bland-Altman plot.

RESULTS

All tests showed excellent intraclass correlation coefficients (ICC's>0.9). All SEM values demonstrated acceptable measurement precision (SEM<SD/2). Values for MDC90 are provided for all 12 tests. The analyses indicated that there was no major systematic bias in the plots. The scatter around the Bland-Altman was distributed randomly.

CONCLUSION

All twelve functional fitness tests demonstrated adequate feasibility and relative and absolute test-retest reliability in adults with Down syndrome in South Africa. Information of this nature will help to monitor performance alterations over time and success of training interventions.