Test-retest reliability of lower extremity functional instability measures

Successful 10-second one-legged stance performance predicts survival in middle-aged and older individuals

OBJECTIVES

Balance quickly diminishes after the mid-50s increasing the risk for falls and other adverse health outcomes. Our aim was to assess whether the ability to complete a 10- s one-legged stance (10-second OLS) is associated with all-cause mortality and whether it adds relevant prognostic information beyond ordinary demographic, anthropometric and clinical data.

METHODS

Anthropometric, clinical and vital status and 10-s OLS data were assessed in 1702 individuals (68% men) aged 51-75 years between 2008 and 2020. Log-rank and Cox modelling were used to compare survival curves and risk of death according to ability (YES) or inability (NO) to complete the 10-s OLS test.

RESULTS

Overall, 20.4% of the individuals were classified as NO. During a median follow-up of 7 years, 7.2% died, with 4.6% (YES) and 17.5% (NO) on the 10-s OLS. Survival curves were worse for NO 10-s OLS (log-rank test=85.6; p<0.001). In an adjusted model incorporating age, sex, body mass index and comorbidities, the HR of all-cause mortality was higher (1.84 (95% CI: 1.23 to 2.78) (p<0.001)) for NO individuals. Adding 10-s OLS to a model containing established risk factors was associated with significantly improved mortality risk prediction as measured by differences in -2 log likelihood and integrated discrimination improvement.

CONCLUSIONS

Within the limitations of uncontrolled variables such as recent history of falls and physical activity, the ability to successfully complete the 10-s OLS is independently associated with all-cause mortality and adds relevant prognostic information beyond age, sex and several other anthropometric and clinical variables. There is potential benefit to including the 10-s OLS as part of routine physical examination in middle-aged and older adults.

Isometric Strength Database for Muscle Maximal Voluntary Endurance Field Tests: Normative Data

Background

Different field tests are used to evaluate muscle capacity, in particular maximal voluntary isometric endurance. However, although there are some normative values for a few muscle endurance tests, these do not consider the weight, height, gender, or age of individuals, which are well-known factors that influence muscle performance.

Hypothesis/Purpose

The purpose of this study was to investigate the test–retest reproducibility of eight field tests and establish muscle endurance norms, in a healthy population, based on their anthropometric characteristics, which could allow the optimal evaluation of the entire muscle function in a quick manner.

Design

Case series.

Methods

This study was conducted in two phases. The first phase was to check the reproducibility inter- and intra-assessor for eight isometric muscle field tests on 20 volunteer subjects aged 40.9 ± 11.6 years old (age range, 21–58 years). The second part was to establish muscle maximal voluntary isometric endurance norms according to these tests on a total of 400 healthy participants grouped by age (50 males and females in each of the age brackets, 20–29; 30–39; 40–49; 50–59 years old, for a total of 200 males and 200 females).

Results

The intra- and inter-assessor reproducibility tests are good for all muscle measurements (the intraclass correlation coefficients varied between 0.915 and 0.996 and the coefficient of variation between 3.6 and 11.8%). The area under the receiver operating characteristic curves demonstrates a good sensibility with values greater than 0.7 for each test. Each muscle belt presents same ratio regardless of the age and gender group. The simultaneous multiple regression analyses highlight that the anthropometric characteristics of subjects influence significantly the performance of isometric tests.

Conclusion

This study has permitted establishing prediction equations in a healthy population according to their anthropometric characteristics as well as agonist/antagonist ratios for eight muscle isometric field tests after demonstrating a good reproducibility of all tests.

Does kinesiotaping can improve static stability of the knee after anterior cruciate ligament rupture? A randomized single-blind, placebo-controlled trial

Background

The aim of the study was the assessment of the early impact of the selected kinesiotaping technique on the static stability of the knee joint in patients with ACL rupture on the basis of stabilographic parameters.

Methods

Sixty-two patients with a complete ACL rupture (32 patients in experimental group and 30 patients in placebo group) took part in the randomized single-blind, placebo-controlled trial. The ligament technique of KT was taken into consideration. Application of a KT tape only on the injured knee was to stabilize the knee joint. Experimental group had application of KT on the injured knee and the placebo group had a KT placebo application (with no tension on KT). Intervention and stabilographic test in both groups was the same.

Research tools included measurements of static stabilographic parameters on stabilometric platform CQStab2P®. Outcome measures were assessed before intervention and after KT application. The analysis included evaluation of outcome variables – total path length, (SP), statokinesiogram path length in the XY axes (SPML, SPAP), and mean velocities in the XY axes (MV, MVML, MVAP).

Results

The results show a statistically significant shortening of the SP, SPAP and SPML variables only in experimental group. In the placebo group the results were not significant. The analysis also showed a significant improvement in all analyzed variables in the experimental group compared to the healthy side. In the placebo group, the results did not improve significantly after KT application compared to the healthy side.

Conclusions

Application o

f KT in patients after ACL rupture shortened the total path length and improved the value of parameters in the frontal and sagittal planes in experimental group, which may suggest the potentially greater improvement in these parameters. By improving the values of the analyzed variables, the KT application is able to compensate for the loss of static stability of the knee.

Trial Registration

This study was registered retrospectively in the Australian New Zealand Clinical Trials Registry (ANZCTR). Registration number: ACTRN12616001407482.

Single leg hopping in children with fetal alcohol spectrum disorder: Dynamic postural stability and kinematics

BACKGROUND

This study compared dynamic postural stability (DPS) and lower limb kinematics during single leg hopping (SLH) performed by typically-developed children from urban and rural settings and children with Fetal Alcohol Spectrum Disorder (FASD) from a rural setting.

METHODS

Typically-developed nine-year-old children from an urban (n = 27) and rural setting (n = 14) (controls), and nine-year-old children with FASD from a rural setting (n = 14) (cases) performed SLH and landing on a pressure mat. Motion analysis systems described 1) Spatiotemporal and centre of pressure parameters (COP) and lower limb sagittal plane kinematics. Descriptive results are presented in median and ranges and differences between groups were determined by Kruskal-Wallis and Mann-Whitney U statistical tests. The level of significance was p < 0.05.

RESULTS

During hopping, the urban controls had longer stance and swing times (p < 0.001) than the rural groups. The urban controls remained in greater hip flexion compared to the case group (p = 0.02). The urban controls landed in more plantarflexion at initial foot contact (IFC) than the cases (p < 0.001) and the rural controls (p = 0.03). The rural groups landed with greater knee extension at IFC than the urban controls (cases p = 0.04; rural controls p < 0.001). During the landing motion, the urban controls moved into more hip flexion compared to the cases (p = 0.015) and the rural controls (p = 0.026). The cases displayed greater COP anteroposterior values during landing compared to both control groups, but the case group displayed the fastest time to stability.

CONCLUSION

The different hopping strategies observed provides an indication of the movement capabilities of these groups.

Functional Status and Body Mass Index in Postmenopausal Women with Fibromyalgia: A Case-control Study

Reduced functional capacity is a common characteristic of fibromyalgia (FMS). We aimed to investigate the relationship between functional status and body mass index (BMI) in a population with and without FMS. A pilot case–control study was performed in 34 women with FMS and 22 healthy controls which were classified according to their BMI. The main outcome measures were: Balance (MiniBestest, One Leg Stance Test), functional mobility (Timed up and Go), physical disability (Health Assessment Questionnaire Disability Index), spinal range of motion (Spinal Mouse), level of physical activity at work (Leisure Time Physical Activity Instrument), and home and leisure time (Physical Activity at Home and Work). Statistical differences were observed between overweight/obese healthy controls and women with FMS for several indicators of functional capacity. FMS patients reported worse dynamic (p = 0.001) and static balance (right: p = 0.002, left: p = 0.001), poorer functional mobility (p = 0.008), and higher levels of physical disability (p = 0.001). Functional status is altered in FMS women compared to the healthy control group, independently of nutritional status; therefore, BMI is unlikely to play a main role in functional capacity indicators in postmenopausal FMS women. Only dynamic balance seems to reduce the obesity status in this population.

Medication and physical activity and physical fitness in severe mental illness

Anti-psychotic medication has emerged as the primary medical treatment for people with severe mental illness, despite the great risks involved in the use of this medication. In addition, this population suffers from problems of obesity, sedentary lifestyle and poor physical fitness, which is aggravated by the use of this type of medication. The objective of this study is to explore the influence of the most commonly used antipsychotics in this population (Olanzapine and Risperidone) on physical activity and the physical fitness of people with severe mental illness. Sixty-two people between 26 and 61 years of age with severe mental illness were assessed. All participants were evaluated with a battery of 11 physical tests to assess their physical fitness and with the IPAQ-short version questionnaire to determine their level of physical activity. The doses of Risperidone and Olanzapine were also evaluated in all participants. Significant differences were found for physical activity, with higher levels reported in those patients with severe mental illness who did not take any of these medications. Regarding physical fitness, significant differences were only found for the consumption of Risperidone, with better physical fitness levels seen in patients who did not consume this medication; on the other hand, for the consumption of Olanzapine, differences were found in muscular strength, balance and aerobic condition with better values in non-Olanzapine consumers compared with Olanzapine consumers.

Physical fitness and levels of physical activity in people with severe mental illness: a cross-sectional study

Background

Physical fitness is a crucial variable in people with severe mental illness as these people could be more independent and improve their job opportunities. The present study compared the physical fitness of physically active and inactive people with severe mental illness.

Methods

Physical fitness was evaluated in sixty-two people with severe mental illness using 11 physical tests that include strength, flexibility, balance and aerobic condition. Significant differences were found between both groups in muscle strength (handgrip test) and balance (single leg balance test and functional reach) with better performance in the group of physically active people.

Results

The results of the present study suggest that physical fitness (strength and balance) is higher in people with severe mental illness who practise regular physical activity that those who are inactive people.

Conclusions

Physical active people may have a reduced risk of falls and fractures due to their higher levels of physical fitness.

Could Slackline Training Complement the FIFA 11+ Programme Regarding Training of Neuromuscular Control?

The current study compared changes in neuromuscular control between slackline training and the stabilization training elements of the FIFA 11+ programme. Twenty-five students in 2 groups performed a 12-unit training programme. The slackline training group (n = 13) exclusively trained with a slackline. The stabilization training group (n = 12) practised exercises as described in the second part of the FIFA 11+ programme. Improvements in balance were assessed using three tests for dynamic, quasi-static, and perturbed postural control: the star excursion balance test (SEBT), the closed-eye single-leg stance, and the MFT S3-Check. Both groups significantly improved the stability and sensorimotor index of the MFT S3-Check (p < .001), their range on the SEBT (p < .001), and the duration of closed-eye single-leg stance (p < .001). The group × training interaction was significant for the MFT S3-Check (stability index: p = .042; sensorimotor index: p = .004) and the SEBT (dominant leg: p = .003; averaged both legs: p = .016), with the slackline training group showing a larger training effect than the stabilization training group. The results of the present study suggest that slackline training offers similar - or better - improvements in neuromuscular control as the FIFA 11+ warm-up programme. If compliance with the FIFA 11+ programme is declining, then slacklining might offer an alternative approach to reach the training goals of improved sensorimotor control.

A pilot study to evaluate multi-dimensional effects of dance for people with Parkinson's disease

Parkinson's disease (PD) is a progressive neurodegenerative disease associated with deficits in motor, cognitive, and emotion/quality of life (QOL) domains, yet most pharmacologic and behavioral interventions focus only on motor function. Our goal was to perform a pilot study of Dance for Parkinson's-a community-based program that is growing in popularity-in order to compare effect sizes across multiple outcomes and to inform selection of primary and secondary outcomes for a larger trial. Study participants were people with PD who self-enrolled in either Dance for Parkinson's classes (intervention group, N=8) or PD support groups (control group, N=7). Assessments of motor function (Timed-Up-and-Go, Gait Speed, Standing Balance Test), cognitive function (Test of Everyday Attention, Verbal Fluency, Alternate Uses, Digit Span Forward and Backward), and emotion/QOL (Geriatric Depression Scale, Falls Efficacy Scale-International, Parkinson's Disease Questionnaire-39 (total score and Activities of Daily Living subscale)) were performed in both groups at baseline and follow-up. Standardized effect sizes were calculated within each group and between groups for all 12 measures. Effect sizes were positive (suggesting improvement) for all 12 measures within the intervention group and 7 of 12 measures within the control group. The largest between-group differences were observed for the Test of Everyday Attention (a measure of cognitive switching), gait speed and falls efficacy. Our findings suggest that dance has potential to improve multiple outcomes in people with PD. Future trials should consider co-primary outcomes given potential benefits in motor, cognitive and emotion/QOL domains.

Direct and indirect measurement of neuromuscular fatigue in Canadian football players

This study assessed the effects of a fatiguing game simulation (G-Sim) on the balance of collegiate Canadian football players. The purpose of the study was to evaluate postural control as a potential tool for monitoring neuromuscular fatigue (NMF) in collision-based team sports. Fifteen male Canadian football players were recruited (mean ± SD: age 21.8 ± 1.6 years, weight 97.6 ± 14.7 kg). Indirect NMF measures (postural sway and countermovement jump (CMJ)) were performed 24 h before (TBase), immediately before (TPre) and after (TPost), and 24 h (T24) and 48 h after (T48) a Canadian football G-Sim. Peak isometric knee extensor torque of a maximal voluntary contraction (MVC) and electrically evoked tetani at 20 Hz (P20) and 80 Hz (P80) were also recorded as direct NMF measures at TBase, TPre, TPost, and T48. At TPost, we observed significant declines in MVC, P20, and the MVC/P80 ratio (–15.3%, –15.7%, and –12.1%, respectively; n = 12) along with reductions in CMJ takeoff velocity and peak power (–6.9% and –6.5%, respectively; n = 12) and larger area of the center of pressure trajectory (95.2%; n = 10) during a 60-s postural sway task. All variables were no longer different than baseline by T48. Acute neuromuscular impairment in this cohort is likely attributable to alterations in excitation–contraction coupling due to structural damage and central activation failure. Congruency between the direct and indirect measures of NMF suggests monitoring postural sway has the potential to identify both neuromuscular and somatosensory alterations induced by acute game-induced fatigue in collision-based team sports players.

H-index is important for postural control for people with impaired foot sole sensation

INTRODUCTION

People with Peripheral Neuropathy (PN), especially those with impaired sensory inputs through the small-afferent fiber (type II afferent fibers) reflex loop (SAF), might depend more on the large-afferent fiber (type I afferent fibers) reflex loop (LAF) for postural control.

PURPOSE

To examine whether the function of the LAF reflex loop, reflected by the H-reflex and ankle joint proprioception, influences postural control when the SAF reflex loop is impaired, as indicated by reduced foot sole cutaneous sensation.

METHODS

Thirteen participants (8 women, 5 men) diagnosed with PN and 12 age-matched controls (7 women, 5 men) completed the testing protocol. Measures of interest included the H-index, active (AAP) and passive (PAP) ankle proprioception, plantar pressure sensitivity (PPS), average sway velocity (VAVG) and area (A95) during 30 seconds eyes-closed standing, 6-minute walk distance (6MWD) and timed up-and-go duration (TUG).

RESULTS

Statistically significant group-dependent regression was observed between VAVG and H-index. Compared to the control group, the PN group demonstrated reduced PPS (2.0 ± 1.9 vs. 4.2 ± 1.2, P < .05) and H-index (63.6 ± 10.9 vs. 76.4 ± 16.0, P < .05), greater VAVG (3.5 ± 2.1 vs. 1.6 ± 0.6 cm/s, P < .05) and A95 (10.0 ± 10.1 vs. 2.5 ± 1.5 cm2, P < .05), shorter 6MWD (442.2 ± 93.0 vs. 525.3 ± 68.2 m, P < .05), and longer TUG (9.4 ± 1.6 vs. 6.5 ± 1.3 s, P < .05). Within the PN group, but not the control group, the H-index was correlated with VAVG (r = -.56, P < .05). Moreover, within the PN group only, PAP scores were correlated with 6MWD (r = -.68, P < .05) and TUG (r = -.59, P < .05) performance. No other statistically significant group difference, correlation or group-dependent regression was observed.

CONCLUSION

VAVG, 6MWD, and TUG correlated with LAF reflex loop function observed among those with impaired functioning of the SAF reflex loop. This observation suggests that the LAF reflex loop may be critical to the control of balance in those individuals suffering from small-fiber PN.

Clinical effect size of an educational intervention in the home and compliance with mobile phone-based reminders for people who suffer from stroke: protocol of a randomized controlled trial

Background

Stroke is the third-leading cause of death and the leading cause of long-term neurological disability in the world. Cognitive, communication, and physical weakness combined with environmental changes frequently cause changes in the roles, routines, and daily occupations of stroke sufferers. Educational intervention combines didactic and interactive intervention, which combines the best choices for teaching new behaviors since it involves the active participation of the patient in learning. Nowadays, there are many types of interventions or means to increase adherence to treatment.

Objective

The aim of this study is to enable patients who have suffered stroke and been discharged to their homes to improve the performance of the activities of daily living (ADL) in their home environment, based on advice given by the therapist. A secondary aim is that these patients continue the treatment through a reminder app installed on their mobile phones.

Methods

This study is a clinical randomized controlled trial. The total sample will consist of 80 adults who have suffered a stroke with moderate severity and who have been discharged to their homes in the 3 months prior to recruitment to the study. The following tests and scales will be used to measure the outcome variables: Barthel Index, the Functional Independence Measure, the Mini-Mental State Examination, the Canadian Neurological Scale, the Stroke Impact Scale-16, the Trunk Control Test, the Modified Rankin Scale, the Multidimensional Scale of Perceived Social Support, the Quality of Life Scale for Stroke, the Functional Reach Test, the Romberg Test, the Time Up and Go test, the Timed-Stands Test, a portable dynamometer, and a sociodemographic questionnaire. Descriptive analyses will include mean, standard deviation, and 95% confidence intervals of the values for each variable. The Kolmogov-Smirnov (KS) test and a 2x2 mixed-model analysis of variance (ANOVA) will be used. Intergroup effect sizes will be calculated (Cohen’s d).

Results

Currently, the study is in the recruitment phase and implementation of the intervention has begun. The authors anticipate that during 2015 the following processes should be completed: recruitment, intervention, and data collection. It is expected that the analysis of all data and the first results should be available in early-to-mid 2016.

Conclusions

An educational intervention based on therapeutic home advice and a reminder app has been developed by the authors with the intention that patients who have suffered stroke perform the ADL more easily and use their affected limbs more actively in the ADL. The use of reminders via mobile phone is proposed as an innovative tool to increase treatment adherence in this population.

Trial Registration

ClinicalTrials.gov NCT01980641; https://clinicaltrials.gov/ct2/show/NCT01980641 (Archived by WebCite at http://www.webcitation.org/6WRWFmY6U).

Reliability of Single-leg and Double-leg Balance Tests in Subjects with Anterior Cruciate Ligament Reconstruction and Controls

The purpose of this study was to assess the test-retest reliability of postural balance in patients with anterior cruciate ligament reconstruction (ACL) and controls. Ten healthy subjects and 15 individuals with ACL reconstruction performed single-leg and double-leg balance tests. The center of pressure (COP) was recorded using a pressure platform. For the total COP path, the intraclass correlation coefficient (ICC) ranged from 0.79 to 0.91. For the COP standard deviation, the ICCs ranged from 0.68 to 0.94. For the COP velocity, the ICCs ranged from 0.72 to 0.91. The sway area and ellipse scores displayed ICCs values of 0.67 to 0.95 and 0.53 to 0.92, respectively. The ICCs were higher for double leg tests compared with single-stance ones. These results indicate that 30 s balance tests in double and single-leg stance are reliable tools to assess static balance. The use of such tests to monitor rehabilitation programs following ACL reconstruction is recommended.

Relationship between Barthel index with physical tests in adults with intellectual disabilities

We usually find low levels of fitness condition affect other aspects of living for people with ID like dependency in carrying out activivities of daily living. Therefore we find high levels of dependency in activities of daily living due to poor fitness condition. The aim of the study is to explore the criterion validity of the Barthel index with a physical fitness test. An observational cross-sectional study was conducted. Data from the Barthel index and a physical fitness test were measured in 122 adults with intellectual disability. The data were analysed to find out the relationship between four categories of the physical fitness test and the Barthel index. It needs to be stressed that the correlations between the Barthel index and leg, abdominal and arm strength can confirm that these physical test are predictive of the Barthel index. The correlations between the balance variables as functional reach and single-leg stance with eyes open shown relationships with Barthel Index. We found important correlations between the physical fitness test and the Barthel index, so we can affirm that some physical fitness features are predictor variables of the Barthel index.

Parameterization and reliability of single-leg balance test assessed with inertial sensors in stroke survivors: a cross-sectional study

Background and purpose

There are no published studies on the parameterisation and reliability of the single-leg stance (SLS) test with inertial sensors in stroke patients. Purpose: to analyse the reliability (intra-observer/inter-observer) and sensitivity of inertial sensors used for the SLS test in stroke patients. Secondary objective: to compare the records of the two inertial sensors (trunk and lumbar) to detect any significant differences in the kinematic data obtained in the SLS test.

Methods

Design: cross-sectional study. While performing the SLS test, two inertial sensors were placed at lumbar (L₅-S₁) and trunk regions (T₇–T₈). Setting: Laboratory of Biomechanics (Health Science Faculty - University of Málaga). Participants: Four chronic stroke survivors (over 65 yrs old). Measurement: displacement and velocity, Rotation (X-axis), Flexion/Extension (Y-axis), Inclination (Z-axis); Resultant displacement and velocity (V):

Along with SLS kinematic variables, descriptive analyses, differences between sensors locations and intra-observer and inter-observer reliability were also calculated.

Results

Differences between the sensors were significant only for left inclination velocity (p = 0.036) and extension displacement in the non-affected leg with eyes open (p = 0.038). Intra-observer reliability of the trunk sensor ranged from 0.889-0.921 for the displacement and 0.849-0.892 for velocity. Intra-observer reliability of the lumbar sensor was between 0.896-0.949 for the displacement and 0.873-0.894 for velocity. Inter-observer reliability of the trunk sensor was between 0.878-0.917 for the displacement and 0.847-0.884 for velocity. Inter-observer reliability of the lumbar sensor ranged from 0.870-0.940 for the displacement and 0.863-0.884 for velocity.

Conclusion

There were no significant differences between the kinematic records made by an inertial sensor during the development of the SLS testing between two inertial sensors placed in the lumbar and thoracic regions. In addition, inertial sensors. Have the potential to be reliable, valid and sensitive instruments for kinematic measurements during SLS testing but further research is needed.

Reliability of nerve function assessments for people with peripheral neuropathy

Examining degenerative sensory and reflexive activity among people with peripheral neuropathy (PN) is important for clinical examinations and understanding relevant neural impairments. However, other than the test of presynaptic inhibition, the reliability of other related tests is largely unknown. The purpose of this project was to examine the test-retest reliability of lower extremity sensory and reflexive measures in people with PN. Twelve participants (8 women, 4 men, age = 72.5 ± 9.2 years) diagnosed with PN were assessed on two occasions at least 7 d apart. Plantar sensitivity, H-reflex and active and passive ankle proprioception (AAP and PAP) were tested. Paired student's t-test and Intraclass correlation coefficients (ICC) were used for statistical analysis. Significant difference was observed in AAP at 0º position (p = 0.04). No other significant differences were observed. Moderate to high reliability was observed at measures of Plantar sensitivity (0.92), peak to peak H (0.71) and M (0.84) waves, latency between H and M (0.78), H-Index (0.85), AAP (0.62) and PAP index (0.60). Low reliability was observed of other parameters. The measures of Hmax, Mmax, latency, H-Index, plantar sensitivity and AAP & PAP indices of proprioception tests can be measured reliably for further study in this population.

Development of a new index of balance in adults with intellectual and developmental disabilities

PURPOSES

The first objective was to propose a new model representing the balance level of adults with intellectual and developmental disabilities (IDD) using Principal Components Analysis (PCA); and the second objective was to use the results from the PCA recorded by regression method to construct and validate summative scales of the standardized values of the index, which may be useful to facilitate a balance assessment in adults with IDD.

METHODS

A total of 801 individuals with IDD (509 males) mean 33.1 ± 8.5 years old, were recruited from Special Olympic Games in Spain 2009 to 2012. The participants performed the following tests: the timed-stand test, the single leg stance test with open and closed eyes, the Functional Reach Test, the Expanded Timed-Get-up-and-Go Test. Data was analyzed using principal components analysis (PCA) with Oblimin rotation and Kaiser normalization. We examined the construct validity of our proposed two-factor model underlying balance for adults with IDD. The scores from PCA were recorded by regression method and were standardized.

RESULTS

The Component Plot and Rotated Space indicated that a two-factor solution (Dynamic and Static Balance components) was optimal. The PCA with direct Oblimin rotation revealed a satisfactory percentage of total variance explained by the two factors: 51.6 and 21.4%, respectively. The median score standardized for component dynamic and static of the balance index for adults with IDD is shown how references values.

CONCLUSIONS

Our study may lead to improvements in the understanding and assessment of balance in adults with IDD. First, it confirms that a two-factor model may underlie the balance construct, and second, it provides an index that may be useful for identifying the balance level for adults with IDD.

Physical fitness profile in adults with intellectual disabilities: differences between levels of sport practice

Neuromuscular and aerobic capacity can be reduced in people with intellectual disabilities (ID). Previous studies suggest these individuals might be particularly susceptible to losing basic functions because of poor physical fitness. The aim of this study is to describe the physical fitness profile of adult athletes with ID and identify whether there are differences in the physical performance between the most physically active individuals and less active individuals. A cross-sectional observational study was developed involving 266 athletes with mild ID (187 males and 79 females), recruited from the Spanish Special Olympics Games. A questionnaire was used to evaluate the health status of participants and their frequency of physical activity practice. A battery of 13 fitness tests was applied to assess flexibility, strength/endurance, balance and cardiovascular capabilities. Of the total participants, 44.3% were classified as sportspersons and the remainder as non sportspersons, taking in consideration the frequency of physical activity. Regarding the scores, a significant difference was found in degrees of flexibility between genders, higher for females for one test but higher for males in the other three. A significant difference was not encountered between other variables of physical fitness, although the men's scores were higher in strength/endurance and balance. When the scores of the sportspersons and non sportspersons groups were compared, no significant difference was found between the two, with the exception of one test for flexibility. Differences among groups and gender were not statistically significant in most of the tests. The findings in this study illustrate an unclear and inconclusive relation between the scores and the declared level of physical activity, maybe due to the context in which participants for the study were selected.

Muscle strength, gait, and balance in 20 patients with hip osteoarthritis followed for 2 years after THA

BACKGROUND

Patients with hip osteoarthritis (OA) have muscular weakness, impaired balance, and limp. Deficits in the different limb muscles and their recovery courses are largely unknown, however. We hypothesized that there is persisting muscular weakness in lower limb muscles and an impaired balance and gait 2 years after THA.

PATIENTS AND METHODS

20 elderly patients with unilateral OA were assessed before, and 6 and 24 months after surgery for maximal voluntary isometric strength of hip and knee muscles and by gait analysis, postural stability, and clinical scores (HHS, SF-36, EuroQoL).

RESULTS

Hip muscles showed a remaining 6% weakness compared to the contralateral healthy limb 2 years after THA. Preoperatively and 6 months postoperatively, that deficit was 18% and 12%, respectively. Knee extensors fully recovered a preoperative 27% deficit after 2 years. Gait analysis demonstrated a shorter single stance phase for the OA limb compared to healthy limb preoperatively, that had already recovered at the 6-month follow-up. Balance of two-foot standing showed improvement in both sagittal and lateral sway after operation. All clinical scores improved.

INTERPRETATION

Muscle strength data demonstrated a slow but full recovery of muscles acting about the knee, but there was still a deficit in hip muscle strength 2 years after THA. Gait and balance recovered after the operation. To accelerate improvement in muscular strength after THA, postoperative training should probably be more intense and target hip abductors.

Peripheral arterial disease, diabetes and postural balance among elderly Finns: a population-based study

BACKGROUND AND AIMS

Little is known about the role of peripheral arterial disease (PAD) in the development of balance impairment. The aim of this study was to assess postural balance among people having PAD or PAD combined with diabetes.

METHODS

As part of the comprehensive health examination of the Health 2000 survey (two-stage stratified cluster sampling), 1323 people aged 65 years or older took part in balance assessments using a force platform system. The presence of PAD was confirmed with data from the National Hospital Discharge Registry. Individuals with hospitalization due to PAD were regarded as having severe disease, whereas those with solely self-reported diagnosis were considered possible cases. Diabetes was ascertained on the basis of self-reported physicians' diagnoses subsequently confirmed in a clinical examination.

RESULTS

Forty-five (3.4%) individuals had previously been hospitalized due to PAD, and 32 (2.4%) reported that they had been diagnosed with the disease. 413 (31%) participants had diabetes. Compared with people without PAD, those with confirmed diagnoses exhibited significantly increased movement of the center of pressure while standing, indicating deteriorated balance. Those with possible PAD formed an intermediate group. Diabetes exacerbated the deterioration in balance, but the interaction term between PAD and diabetes did not reach statistical significance. The risk of failing tandem stance tests was over three-fold (OR 3.20, 95% CI 1.09-9.37) among those with confirmed PAD and almost one and a half-fold (OR 1.44, 95% CI 1.07-1.93) among those with diabetes, in comparison to those without these diseases.

CONCLUSIONS

Individuals over 65 years of age with severe PAD showed increased balance impairment, a known risk factor for falls and disability in aged people. Diabetes affected balance somewhat less than PAD, but there was no formal evidence of the synergetic effect of the two diseases. Additional studies are indicated to reveal the possible effect of proper treatment of PAD and diabetes, combined with suitable training interventions on slowing down the progression of balance impairment.

Twelve-week biomechanical ankle platform system training on postural stability and ankle proprioception in subjects with unilateral functional ankle instability

BACKGROUND

Functional ankle instability is defined as the subjective sensation of giving way or feeling joint instability after repeated episodes of ankle sprain. The purpose of this study was to examine the effects of 12-week biomechanical ankle platform system training on static postural stability and ankle reposition sense in subjects with unilateral functional ankle instability.

METHODS

Twelve university students (4 females and 8 males) with unilateral functional ankle instability volunteered as subjects. The active and passive reposition senses were assessed using an isokinetic dynamometer. The mean radius of the center of pressure excursion was recorded during single-leg standing with a force platform. A 12-week training program and a progression test for controlling the platform in certain directions and advancing to next training level was given to each subject. Repeated-measures 2-way analyses of variance were conducted to determine differences in postural stability and ankle proprioception between each limb before and after the training period.

FINDINGS

The mean radius of center of pressure on unilateral standing and the absolute error from pre-selected ankle angle in the functional ankle instability limb were significantly reduced after 12 weeks of training.

INTERPRETATION

These improvements in postural stability appear to reflect improved neuromuscular ability along with enhanced functional joint stability, as ankle proprioception also demonstrated the same positive improvements after training.

Process stationarity and reliability of trunk postural stability

BACKGROUND

Empirical assessments of torso stability can be estimated from postural variability and nonlinear analyses of seated balance tasks. However, processing methods require sufficient signal duration and test-retest experiments require the assessment must be reliable. Our goal was to characterize the reliability and establish the trial duration for torso stability assessment.

METHODS

Kinetic and kinematic data were recorded while subjects maintained a seated posture on a wobbly seat pan. Stability was evaluated from dynamic variability and nonlinear stability analyses. Process stationarity of the measured signals characterized the minimum necessary trial duration. Intra-class correlations measured within-session and between-session reliability.

FINDINGS

Trial duration necessary to achieve process stationarity was 30.2 s. Shorter time to stationarity was observed with measures that included multi-dimensional movement behavior. Summary statistics of movement variability demonstrated moderate intra-session reliability, intra-class correlation=0.64 (range 0.38-0.87). Inter-session reliability for movement variance was moderate, intra-class correlation=0.42 (range 0.22-0.64). Nonlinear stability measures typically performed better than estimates of variability with inter-session reliability as high as intra-class correlation=0.83. Process stationarity and reliability were improved in more difficult balance conditions.

INTERPRETATION

To adequately capture torso dynamics during the stability assessment the trial duration should be at least 30 s. Moderate to excellent test-retest reliability can be achieved in intra-session analyses, but more repeated measurements are required for inter-session comparisons. Stability diffusion exponents, H(S), and the Lyapunov exponents provide excellent measures for intra-session analyses, while H(S) provides excellent inter-session comparisons of torso stability.

Ankle eversion to inversion strength ratio and static balance control in the dominant and non-dominant limbs of young adults

The purpose of this study was to: (1) compare unilateral ankle eversion to inversion strength ratio (E/I R) and static balance control in the dominant and non-dominant limbs and (2) determine the relationship between ankle E/I R and static balance control in the dominant and non-dominant limbs. Twenty-eight young, healthy adults without any physical training experience participated in this study. Ankle E/I R was measured by an isokinetic dynamometer at speeds of 30 degrees s(-1) and 120 degrees s(-1). Static balance control was determined by the center of pressure excursion parameters on a force platform during the single-leg upright standing balance test. No significant differences in ankle E/I R and static balance control existed between the dominant and non-dominant limbs. Ankle E/I R was greater at a speed of 30 degrees s(-1) than that at a speed of 120 degrees s(-1) in the dominant and non-dominant limbs. In addition, no significant correlation was identified between the unilateral ankle E/I R and static balance control. The data indicated that both unilateral ankle E/I R and static balance control in the dominant and non-dominant limbs were symmetric in young, healthy adults. In addition, the absence of a correlation between ankle E/I R and static balance control is consistent with the independence of these parameters under the testing conditions used herein. It is suggested that any asymmetry in ankle E/I R at these angular velocities and single-leg standing balance in young, healthy adults is due to factors other than limb dominance.

The Influence of Gender and Somatotype on Single-Leg Upright Standing Postural Stability in Children

The purpose of this study was to investigate the influence of gender and somatotypes on single-leg upright standing postural stability in children. A total of 709 healthy children from different schools were recruited to measure the anthropometric somatotypes and the mean radius of center of pressure (COP) on a force platform with their eyes open and eyes closed. The results were that (a) girls revealed significantly smaller mean radius of COP distribution than boys, both in the eyes open and eyes closed conditions, and (b) the mesomorphic, muscular children had significantly smaller mean radius of COP distribution than the endomorphic, fatty children and the ectomorphic, linear children during the eyes closed condition. The explanation for gender differences might be due to the larger body weight in boys. The explanation for somatotype differences might be due to the significantly lower body height and higher portion of muscular profile in the mesomorphic children.

Static and dynamic standing balance: test-retest reliability and reference values in 9 to 10 year old children

INTRODUCTION

Based on the literature, reliability reports and normative data for bilateral stance assessments in elementary schoolchildren are limited. The present study was designed to report test-retest reliability and reference values for postural stability in 9 to 10 years old schoolchildren using the Balance Master system.

MATERIALS AND METHODS

Twenty children participated in the reproducibility study (mean age 10.1+/-0.7) including test and retest measurement with a one-week interval. The modified clinical test of sensory interaction on balance (mCTSIB) quantified children's static standing balance. The test for the limits of stability (LOS) measured dynamic standing balance. The study sample to determine reference values consisted of 99 children (mean age 9.8+/0.5).

RESULTS

The ICCs for inter-item reliability of the four sensory conditions of the mCTSIB showed fair to excellent reliability (ICCs between 0.62 and 0.80). The reproducibility between test and retest was non-significant for the condition 'firm surface with eyes closed' (ICC of 0.37), fair to good for the three other sensory conditions (ICCs between 0.59 and 0.68), and excellent for the composite sway velocity (ICC of 0.77). For all LOS parameters, the significant ICCs showed fair to good reproducibility (ICCs between 0.44 and 0.62), with the exception of the non-significant ICC for the composite reaction time. The ICCs for the separate LOS parameters showed fair to good and excellent reliability for nine parameters (ICCs between 0.46 and 0.81), while 11 separate LOS scores did not demonstrate significant ICCs.

DISCUSSION

Analysing reference values, girls performed better on all the composite balance parameters compared to boys, with the exception of reaction time and movement velocity. No differences were found on standing balance scores between 9 and 10 year olds.

CONCLUSION

In conclusion, the Balance Master showed fair to good reliability for most postural parameters in 9 to 10 year olds. The current data on postural control in children aged 9 to 10 years are relevant for research in other domains within the clinical field, like obesitas and developmental coordination disorder or in relation to back pain prevalence at early age.

Absent pedal pulse and impaired balance in older people: a cross-sectional and longitudinal study

BACKGROUND AND AIMS

The purpose of this study was to determine the relationship between abnormal pedal pulse status and postural balance in older people.

METHODS

Prospective, population-based cohort study of older residents in the city of Jyväskylä, Finland. A total of 419 individuals aged 75 or 80 at baseline, with known lower extremity pulse status and balance tests performed on a force platform, were eligible for analysis.

RESULTS

Cross-sectionally, persons with both dorsal pedal artery pulses absent were found to sway more (p=0.047 anteroposterior velocity, normal standing eyes-open position). The risk of being unable to do the full tandem stance was twofold (OR=2.20, 95% CI 1.29-3.78) for persons without palpable dorsal pedal arteries compared with those with normal pulse status. Balance deterioration was observed at five years (p<0.001 for time) but without group-by-time interaction. At ten years, however, the interaction term became significant for the normal standing eyes-closed position (p=0.025 for anteroposterior velocity and p=0.026 for mediolateral velocity), indicating greater balance deterioration among those with both dorsal pedal artery pulses absent.

CONCLUSIONS

According to our study, the absence of both dorsal pedal artery pulses is associated with impaired balance in older people. The association was observed both cross-sectionally and longitudinally. In addition, as diminished pedal pulses are frequently associated with impaired lower extremity circulation, our results have also produced information on the possible pathophysiological mechanisms of balance deterioration in older people, which warrant further study.

Time-to-boundary measures of postural control during single leg quiet standing

A novel approach to quantifying postural stability in single leg stance is assessment of time-to-boundary (TTB) of center of pressure (COP) excursions. TTB measures estimate the time required for the COP to reach the boundary of the base of support if it were to continue on its instantaneous trajectory and velocity, thus quantifying the spatiotemporal characteristics of postural control. Our purposes were to examine: (a) the intrasession reliability of TTB and traditional COP-based measures of postural control, and (b) the correlations between these measures. Twenty-four young women completed three 10-second trials of single-limb quiet standing on each limb. Traditional measures included mean velocity, standard deviation, and range of mediolateral (ML) and anterior-posterior (AP) COP excursions. TTB variables were the absolute minimum, mean of minimum samples, and standard deviation of minimum samples in the ML and AP directions. The intrasession reliability of TTB measures was comparable to traditional COP based measures. Correlations between TTB and traditional COP based measures were weaker than those within each category of measures, indicating that TTB measures capture different aspects of postural control than traditional measures. TTB measures provide a unique method of assessing spatiotemporal characteristics of postural control during single limb stance.

Measurement and Evaluation of Dynamic Joint Stability of the Knee and Ankle After Injury

Injuries to the lower extremity, specifically the knee and ankle joints of the human body can occur in any athletic event and are most prevalent in sports requiring cutting and jumping manoeuvres. These joints are forced to rely on the dynamic restraints to maintain joint stability, due to the lack of bony congruence and the inability of the static restraints to handle the forces generated during functional tasks. Numerous variables (proprioception, postural control, electromyography, kinetics/kinematics, dynamic stability protocols) have been measured to better understand how the body maintains joint stability during a wide range of activities from static standing to dynamic cutting or landing from a jump. While the importance of dynamic restraints is not questioned, a recent impetus to conduct more functional or sport-specific testing has emerged and placed a great deal of emphasis on dynamic joint stability and how it is affected by lower extremity injuries. Evidence suggests that surgery and aggressive rehabilitation will not necessarily restore the deficits in dynamic joint stability caused by injury to the anterior cruciate ligament or lateral ankle ligaments. In today's athletic society, there is a major push to return athletes to play as quickly as possible. However, the ramifications of those decisions have not been fully grasped. If an athlete is not fully recovered, a quick return to play could start a vicious cycle of chronic injuries or permanent disability.

Bilateral total knee arthroplasty increases the propensity to trip on an obstacle

Tripping over an obstacle is the most frequent cause of falls. We examined the effects of total knee arthroplasty on obstacle avoidance success rates in older adults. Obstacle avoidance success rates, body mass index, visual acuity, contrast sensitivity, depth perception, and single-leg stance duration were evaluated in 29 subjects who had bilateral total knee arthroplasties (age range, 72.6 +/- 5.4 years) and 27 age-matched healthy control subjects (age range, 70.6 +/- 5.5 years). The patients who had total knee arthroplasties had a lower obstacle avoidance success rate, lower single-leg stance duration, and greater body mass index than control subjects. Age, contrast sensitivity, and depth perception were not different between patients who had total knee arthroplasties and control subjects. Obstacle avoidance success rates decreased linearly as single-leg stance duration decreased in the control group and across all groups, but not in the group that had total knee arthroplasties. Linear relationships between obstacle avoidance success rates and body mass index existed for all subjects but not for the group that had total knee arthroplasties or the control group individually. Total knee arthroplasty reduces obstacle avoidance success rate, suggesting that persons who have total knee arthroplasties have an increased propensity to trip on an obstacle and fall. Increased body mass index and decreased single-leg stance duration in patients who have total knee arthroplasties are associated with a decreased obstacle avoidance success rate.

Detection of Dynamic Stability Deficits in Subjects with Functional Ankle Instability

PURPOSE

To determine which combination of landing protocol and analysis technique would be the most effective at detecting differences in dynamic stability between healthy subjects and subjects with functional ankle instability (FAI).

METHODS

Fifty-eight subjects participated in this investigation: 29 healthy individuals and 29 individuals with FAI. Subjects were assessed during a single test session for time to stabilization (TTS) in the anterior/posterior, medial/lateral, and vertical directions from two protocols: a step down and jump protocol. The step down protocol started with each subject atop a 20-cm-high platform, and the jump protocol started with subjects in a standing position 70 cm from the center of a force plate and required each subject to jump off both legs and touch a designated marker placed at a position equivalent to 50% of the subject's maximum vertical leap. TTS scores in the anterior/posterior, medial/lateral, and vertical direction were compared between group, protocol, and type of analysis.

RESULTS

A significant protocol by analysis by group interaction (F(1,56) = 6.9, P = 0.011) was observed for anterior/posterior TTS. Likewise, protocol by group (F(1,56) = 4.4, P = 0.042) and protocol by analysis (F(1,56) = 14.1, P < 0.001) interactions were also noted in anterior/posterior TTS. The jump protocol (2381.7 +/- 36.5 ms) produced significantly greater TTS scores in the vertical direction than the step protocol (1533.5 +/- 71.8 ms), whereas the unbounded third order polynomial (UTOP) method (2554.4 +/- 68.7 ms) produced significant greater TTS scores as compared with the sequential estimation (SE) method (1360.8 +/- 52.1 ms).

CONCLUSIONS

The jump protocol and UTOP method of analysis are the most effective TTS combination in detecting differences between healthy and FAI groups.

Effect of training on postural control in figure skaters: a randomized controlled trial of neuromuscular versus basic off-ice training programs

OBJECTIVES

To compare the effect of a neuromuscular training program and a basic exercise program on postural control in figure skaters.

DESIGN

Two groups; parallel design; prospective, randomized controlled trial.

SETTING

Postural control laboratory, arenas, September 2001 to December 2002.

PARTICIPANTS

Forty-four young, healthy figure skaters (18 years +/- 3 years).

INTERVENTIONS

Participants were randomly assigned to receive a neuromuscular training program (n = 22) or a basic exercise training program (n = 22). Both programs were completed 3 times per week for 4 weeks, and each session was supervised.

MAIN OUTCOME MEASUREMENTS

Participants completed baseline and postintervention measures of postural control on a force plate. Postural control was quantified as the center of pressure (CoP) path length during tests of single-limb standing balance that mimicked figure skating skills and challenged the postural control system to varying degrees. The primary outcome measure was the CoP path length observed during a landing jump test completed with eyes closed.

RESULTS

The post intervention CoP path lengths during the more challenging tests were significantly (P < 0.05) lower (indicating better postural control) for the neuromuscular trained group than for the basic exercise-trained group. For the landing jump test completed with eyes closed, the percent improvement in the neuromuscular trained group was significantly greater (mean = 21.0 +/- 22.0%) than the basic exercise trained group (mean = -4.9 +/- 24.9%; P < 0.05). The magnitude of improvement in the neuromuscular-trained group ranged from approximately 1% to 21%, depending on the specific postural control test used.

CONCLUSIONS

The results suggest that off-ice neuromuscular training can significantly improve postural control in figure skaters, whereas basic exercise training does not.

Balance in single-limb stance in healthy subjects--reliability of testing procedure and the effect of short-duration sub-maximal cycling

BACKGROUND

To assess balance in single-limb stance, center of pressure movements can be registered by stabilometry with force platforms. This can be used for evaluation of injuries to the lower extremities. It is important to ensure that the assessment tools we use in the clinical setting and in research have minimal measurement error. Previous studies have shown that the ability to maintain standing balance is decreased by fatiguing exercise. There is, however, a need for further studies regarding possible effects of general exercise on balance in single-limb stance. The aims of this study were: 1) to assess the test-retest reliability of balance variables measured in single-limb stance on a force platform, and 2) to study the effect of exercise on balance in single-limb stance, in healthy subjects.

METHODS

Forty-two individuals were examined for test-retest reliability, and 24 individuals were tested before (pre-exercise) and after (post-exercise) short-duration, sub-maximal cycling. Amplitude and average speed of center of pressure movements were registered in the frontal and sagittal planes. Mean difference between test and retest with 95% confidence interval, the intraclass correlation coefficient, and the Bland and Altman graphs with limits of agreement, were used as statistical methods for assessing test-retest reliability. The paired t-test was used for comparisons between pre- and post-exercise measurements.

RESULTS

No difference was found between test and retest. The intraclass correlation coefficients ranged from 0.79 to 0.95 in all stabilometric variables except one. The limits of agreement revealed that small changes in an individual's performance cannot be detected. Higher values were found after cycling in three of the eight stabilometric variables.

CONCLUSIONS

The absence of systematic variation and the high ICC values, indicate that the test is reliable for distinguishing among groups of subjects. However, relatively large differences in an individual's balance performance would be required to confidently state that a change is real. The higher values found after cycling, indicate compensatory mechanisms intended to maintain balance, or a decreased ability to maintain balance. It is recommended that average speed and DEV 10; the variables showing the best reliability and effects of exercise, be used in future studies.