Reliability and minimum detectable change of measures of gait in children during walking and running on an instrumented treadmill

BACKGROUND

Instrumented treadmills that incorporate pressure platforms are increasingly used to characterize gait in children. Although footprint size is known to influence the measurement performance of pressure platforms, published evidence on the reliability of such systems for children's gait is lacking.

RESEARCH QUESTION

This study evaluated the test-retest reliability of temporospatial gait parameters and vertical ground reaction forces measured in healthy children during barefoot walking and running on a capacitance-based treadmill system.

METHODS

Temporospatial gait parameters, including cadence, stride length, stride duration, stance and swing phase durations and the magnitude and timing of conventional vertical ground reaction force peaks were determined on two occasions in 17 healthy children (mean age, 11 ± 2 years; height, 148.4 ± 9.3 cm; and mass, 43.3 ± 10 kg) during walking and running at preferred speed on an instrumented treadmill. Reliability was assessed using Intra Class Correlation Coefficients (ICC) and the standard error of measurement (SEM). The minimum detectable change (MDC95%) was also calculated.

RESULTS

ICC values ranged from 0.91-0.99 for all variables. When expressed as a percentage of the mean, the SEM was <5% for all gait parameters assessed during walking and running. The MDC95% values for gait parameters were typically higher during running than walking, and were ±4% of the gait cycle for temporal parameters, ±55 cm for stride length and ±0.1 bodyweights for peak vertical ground reaction force.

SIGNIFICANCE

Children's gait parameters varied by <5% between test occasions and were more consistent during walking than running. These findings provide clinicians and researchers with an index of the reliability and sensitivity of the treadmill to detect changes in common spatiotemporal gait parameters and vertical ground reaction forces in children.

Factors associated with type of footwear worn inside the house: a cross-sectional study

Background

In specific populations, including those at risk of falls or foot ulcers, indoor footwear is an important aspect of preventative care. This study aims to describe the indoor footwear worn most over the previous year in a sample representative of the Australian inpatient population, and to explore the sociodemographic, medical, foot condition and foot treatment history factors associated with the indoor footwear worn.

Methods

This was a secondary analysis of data collected from inpatients admitted to five hospitals across Queensland, Australia. Sociodemographic information, medical history, foot conditions and foot treatment history were collected as explanatory variables. Outcomes included the self-reported type of indoor footwear (from 16 standard footwear types) worn most in the year prior to hospitalisation, and the category in which the self-reported footwear type was defined according to its features: 'protective', 'non-protective' and 'no footwear'. Multivariate analyses determined explanatory variables independently associated with each type and category.

Results

Protective footwear was worn by 11% of participants (including 4% walking shoes, 4% running shoes, 2% oxford shoes), and was independently associated with education above year 10 level (OR 1.78, p = 0.028) and having had foot treatment by a specialist physician (5.06, p = 0.003). Most participants (55%) wore non-protective footwear (including 21% slippers, 15% thongs/flip flops, 7% backless slippers), which was associated with older age (1.03, p < 0.001). No footwear was worn by 34% of participants (30% barefoot, 3% socks only). Those of older age (0.97, p < 0.001) and those in the most disadvantaged socioeconomic group (0.55, p = 0.019) were less likely to wear no footwear (socks or barefoot).

Conclusions

Only one in nine people in a large representative inpatient population wore a protective indoor footwear most of the time in the previous year. Whilst having education levels above year 10 and having received previous foot treatment by a specialist physician were associated with wearing protective footwear indoors, the presence of a range of other medical and foot conditions were not. These findings provide information to enable clinicians, researchers and policymakers to develop interventions aimed at improving indoor footwear habits that may help prevent significant health burdens such as falls and foot ulcers.

Factors associated with wearing inadequate outdoor footwear in populations at risk of foot ulceration: A cross-sectional study

BACKGROUND

Few studies have investigated if people at risk of foot ulceration actually wear the footwear recommended by best practice guidelines to prevent foot ulceration. This study aimed to investigate the prevalence of, and factors associated with, wearing inadequate outdoor footwear in those with diabetes or peripheral neuropathy in an inpatient population.

METHODS

This was a secondary analysis of a multi-site cross-sectional study investigating foot conditions in a large representative inpatient population admitted into hospital for any medical reason on one day. A range of explanatory variables were collected from all participants including sociodemographic, medical and foot condition factors. The outcome variable for this study was the self-reported outdoor footwear type worn most by participants outside the house in the year prior to hospitalisation. The self-reported footwear type was then categorised into adequate and inadequate according to footwear features recommended in guidelines for populations at risk of foot ulceration. Logistic regression identified factors independently associated with inadequate footwear in all inpatient participants, and diabetes and neuropathy subgroups.

RESULTS

Overall, 47% of a total of 726 inpatients wore inadequate outdoor footwear; 49% of the 171 in the diabetes subgroup and 43% of 159 in the neuropathy subgroup. Wearing inadequate outdoor footwear was independently associated (Odds Ratio (95% Confidence Interval)) with being female in the diabetes (2.7 (1.4-5.2)) and neuropathy subgroups (3.7 (1.8-7.9)) and being female (5.1 (3.7-7.1)), having critical peripheral arterial disease (2.5 (1.1-5.9)) and an amputation (0.3 (0.1-0.7)) in all inpatients (all, p<0.05).

CONCLUSIONS

Almost half of all inpatients at risk of foot ulceration reported wearing outdoor footwear most of the time that did not meet recommendations for prevention. We found women were much more likely to wear inadequate footwear. More work needs to be done to increase the uptake of footwear recommendations in these populations to prevent foot ulceration.

Independent factors associated with wearing different types of outdoor footwear in a representative inpatient population: a cross-sectional study

Background

Footwear can have both a positive and negative impact on lower limb health and mobility across the lifespan, influencing the risk of foot pain, ulceration, and falls in those at risk. Choice of footwear can be influenced by disease as well as sociocultural factors, yet few studies have investigated the types of footwear people wear and the profiles of those who wear them. The aim of this study was to investigate the prevalence and factors associated with outdoor footwear type worn most often in a representative inpatient population.

Methods

This study was a secondary data analysis of a cohort of 733 inpatients that is highly representative of developed nations’ hospitalised populations; 62 ± 19 years, 55.8% male, and 23.5% diabetes. Socio-demographic, medical history, peripheral arterial disease, peripheral neuropathy, foot deformity, foot ulcer history, amputation history and past foot treatment variables were collected. Participants selected the footwear type they mostly wore outside the house in the previous year from 16 types of footwear. Multivariate logistic regression identified independent factors associated with outdoor footwear types selected.

Results

The most common outdoor footwear types were: running shoes (20%), thongs/flip flops (14%), walking shoes (14%), sandals (13%) and boots (11%). Several socio-demographic, medical history and foot-related factors were independently associated (Odds Ratio; 95% Confidence Interval)) with different types of footwear. Running shoes were associated with male sex (2.7; 1.8–4.1); thongs with younger age (0.95 for each year; 0.94–0.97), being female (2.0; 1.2–3.1) and socio-economic status (3.1; 1.2–7.6); walking shoes with arthritis (1.9; 1.2–3.0); sandals with female sex (3.8; 2.3–6.2); boots with male sex (9.7; 4.3–21.6) and inner regional (2.6; 1.3–5.1) and remote (3.4; 1.2–9.5) residence (all, p < 0.05).

Conclusions

We profiled the types of outdoor footwear worn most in a large diverse inpatient population and the factors associated with wearing them. Sex was the most consistent factor associated with outdoor footwear type. Females were more likely to wear thongs and sandals and males boots and running shoes. Overall, this data gives insights into the socio-demographic, medical and other health factors that are related to footwear choice in a large diverse population primarily of older age.

Electronic supplementary material

The online version of this article (10.1186/s13047-018-0260-7) contains supplementary material, which is available to authorized users.

Foot Complications in a Representative Australian Inpatient Population

We investigated the prevalence and factors independently associated with foot complications in a representative inpatient population (adults admitted for any reason with and without diabetes). We analysed data from the Foot disease in inpatients study, a sample of 733 representative inpatients. Previous amputation, previous foot ulceration, peripheral arterial disease (PAD), peripheral neuropathy (PN), and foot deformity were the foot complications assessed. Sociodemographic, medical, and foot treatment history were collected. Overall, 46.0% had a foot complication with 23.9% having multiple; those with diabetes had higher prevalence of foot complications than those without diabetes (p < 0.01). Previous amputation (4.1%) was independently associated with previous foot ulceration, foot deformity, cerebrovascular accident, and past surgeon treatment (p < 0.01). Previous foot ulceration (9.8%) was associated with PN, PAD, past podiatry, and past nurse treatment (p < 0.02). PAD (21.0%) was associated with older age, males, indigenous people, cancer, PN, and past surgeon treatment (p < 0.02). PN (22.0%) was associated with older age, diabetes, mobility impairment, and PAD (p < 0.05). Foot deformity (22.4%) was associated with older age, mobility impairment, past podiatry treatment, and PN (p < 0.01). Nearly half of all inpatients had a foot complication. Those with foot complications were older, male, indigenous, had diabetes, cerebrovascular accident, mobility impairment, and other foot complications or past foot treatment.

The silent overall burden of foot disease in a representative hospitalised population

The aims of this study were to investigate the point prevalence, and associated independent factors, for foot disease (ulcers, infections and ischaemia) in a representative hospitalised population. We included 733 (83%) of 883 eligible adult inpatients across five representative Australian hospitals on one day. We collected an extensive range of self-reported characteristics from participants. We examined all participants to clinically diagnose foot disease (ulcers, infections and ischaemia) and amputation procedures. Overall, 72 participants (9·8%) [95% confidence interval (CI):7·2-11·3%] had foot disease. Foot ulcers, in 49 participants (6·7%), were independently associated with peripheral neuropathy, peripheral arterial disease, previous foot ulcers, trauma and past surgeon treatment (P < 0·05). Foot infections, in 24 (3·3%), were independently associated with previous foot ulcers, trauma and past surgeon treatment (P < 0·01). Ischaemia, in 33 (4·5%), was independently associated with older age, smokers and past surgeon treatment (P < 0·01). Amputation procedures, in 14 (1·9%), were independently associated with foot infections (P < 0·01). We found that one in every ten inpatients had foot disease, and less than half of those had diabetes. After adjusting for diabetes, factors linked with foot disease were similar to those identified in diabetes-related literature. The overall inpatient foot disease burden is similar in size to well-known medical conditions and should receive similar attention.

Prevalence of foot disease and risk factors in general inpatient populations: a systematic review and meta-analysis

OBJECTIVE

To systematically review studies reporting the prevalence in general adult inpatient populations of foot disease disorders (foot wounds, foot infections, collective 'foot disease') and risk factors (peripheral arterial disease (PAD), peripheral neuropathy (PN), foot deformity).

METHODS

A systematic review of studies published between 1980 and 2013 was undertaken using electronic databases (MEDLINE, EMBASE and CINAHL). Keywords and synonyms relating to prevalence, inpatients, foot disease disorders and risk factors were used. Studies reporting foot disease or risk factor prevalence data in general inpatient populations were included. Included study's reference lists and citations were searched and experts consulted to identify additional relevant studies. 2 authors, blinded to each other, assessed the methodological quality of included studies. Applicable data were extracted by 1 author and checked by a second author. Prevalence proportions and SEs were calculated for all included studies. Pooled prevalence estimates were calculated using random-effects models where 3 eligible studies were available.

RESULTS

Of the 4972 studies initially identified, 78 studies reporting 84 different cohorts (total 60 231 517 participants) were included. Foot disease prevalence included: foot wounds 0.01-13.5% (70 cohorts), foot infections 0.05-6.4% (7 cohorts), collective foot disease 0.2-11.9% (12 cohorts). Risk factor prevalence included: PAD 0.01-36.0% (10 cohorts), PN 0.003-2.8% (6 cohorts), foot deformity was not reported. Pooled prevalence estimates were only able to be calculated for pressure ulcer-related foot wounds 4.6% (95% CI 3.7% to 5.4%)), diabetes-related foot wounds 2.4% (1.5% to 3.4%), diabetes-related foot infections 3.4% (0.2% to 6.5%), diabetes-related foot disease 4.7% (0.3% to 9.2%). Heterogeneity was high in all pooled estimates (I(2)=94.2-97.8%, p<0.001).

CONCLUSIONS

This review found high heterogeneity, yet suggests foot disease was present in 1 in every 20 inpatients and a major risk factor in 1 in 3 inpatients. These findings are likely an underestimate and more robust studies are required to provide more precise estimates.

Prevalence and risk factors for foot and ankle musculoskeletal disorders experienced by nurses

Background

Nurses are at high risk of musculoskeletal disorders (MSDs). Although the prevalence of MSDs of the lower back, upper limbs, neck and shoulders have been reported previously in nursing, few studies have evaluated MSDs of the foot and ankle. This study evaluated the prevalence of foot and ankle MSDs in nurses and their relation to individual and workplace risk factors.

Methods

A self-administered survey incorporating the Nordic Musculoskeletal Questionnaire (NMQ) was distributed, over a nine-week period, to all eligible nurses (n = 416) working in a paediatric hospital in Brisbane, Australia. The prevalence of MSDs for each of the NMQ body regions was determined. Bivariate and multivariable logistic regression analyses were conducted to examine the relationships between activity-limiting foot/ankle MSDs and risk factors related to the individual (age, body mass index, number of existing foot conditions, smoking history, general physical health [SF36 Physical Component Scale], footwear features) or the workplace (level of nursing position, work location, average hours worked, hours worked in previous week, time since last break from work).

Results

A 73% response rate was achieved with 304 nurses completing surveys, of whom 276 were females (91%). Mean age of the nurses was 37 years (±10), younger than the state average of 43 years. Foot/ankle MSDs were the most prevalent conditions experienced by nurses during the preceding seven days (43.8%, 95% CI 38.2-49.4%), the second most prevalent MSDs to impair physical activity (16.7%, 95% CI 13.0-21.3%), and the third most prevalent MSD, after lower-back and neck problems, during the preceding 12 months (55.3%, 95% CI 49.6-60.7%). Of the nurse and work characteristics investigated, obesity, poor general physical health, existing foot conditions and working in the intensive care unit emerged as statistically significant (p < 0.05) independent risk factors for activity-limiting foot/ankle MSDs.

Conclusions

Foot/ankle MSDs are common in paediatric hospital nurses and resulted in physical activity limitations in one out of every six nurses. We recommend targeted education programs regarding the prevention, self-management and treatment strategies for foot/ankle MSDs. Further research is needed into the impact of work location and extended shift durations on foot/ankle MSDs.

The Queensland high risk foot form (QHRFF) - is it a reliable and valid clinical research tool for foot disease?

BACKGROUND

Foot disease complications, such as foot ulcers and infection, contribute to considerable morbidity and mortality. These complications are typically precipitated by "high-risk factors", such as peripheral neuropathy and peripheral arterial disease. High-risk factors are more prevalent in specific "at risk" populations such as diabetes, kidney disease and cardiovascular disease. To the best of the authors' knowledge a tool capturing multiple high-risk factors and foot disease complications in multiple at risk populations has yet to be tested. This study aimed to develop and test the validity and reliability of a Queensland High Risk Foot Form (QHRFF) tool.

METHODS

The study was conducted in two phases. Phase one developed a QHRFF using an existing diabetes foot disease tool, literature searches, stakeholder groups and expert panel. Phase two tested the QHRFF for validity and reliability. Four clinicians, representing different levels of expertise, were recruited to test validity and reliability. Three cohorts of patients were recruited; one tested criterion measure reliability (n = 32), another tested criterion validity and inter-rater reliability (n = 43), and another tested intra-rater reliability (n = 19). Validity was determined using sensitivity, specificity and positive predictive values (PPV). Reliability was determined using Kappa, weighted Kappa and intra-class correlation (ICC) statistics.

RESULTS

A QHRFF tool containing 46 items across seven domains was developed. Criterion measure reliability of at least moderate categories of agreement (Kappa > 0.4; ICC > 0.75) was seen in 91% (29 of 32) tested items. Criterion validity of at least moderate categories (PPV > 0.7) was seen in 83% (60 of 72) tested items. Inter- and intra-rater reliability of at least moderate categories (Kappa > 0.4; ICC > 0.75) was seen in 88% (84 of 96) and 87% (20 of 23) tested items respectively.

CONCLUSIONS

The QHRFF had acceptable validity and reliability across the majority of items; particularly items identifying relevant co-morbidities, high-risk factors and foot disease complications. Recommendations have been made to improve or remove identified weaker items for future QHRFF versions. Overall, the QHRFF possesses suitable practicality, validity and reliability to assess and capture relevant foot disease items across multiple at risk populations.

Reliability of spatiotemporal and kinetic gait parameters determined by a new instrumented treadmill system

Background

Despite the emerging use of treadmills integrated with pressure platforms as outcome tools in both clinical and research settings, published evidence regarding the measurement properties of these new systems is limited. This study evaluated the within– and between–day repeatability of spatial, temporal and vertical ground reaction force parameters measured by a treadmill system instrumented with a capacitance–based pressure platform.

Methods

Thirty three healthy adults (mean age, 21.5 ± 2.8 years; height, 168.4 ± 9.9 cm; and mass, 67.8 ± 18.6 kg), walked barefoot on a treadmill system (FDM–THM–S, Zebris Medical GmbH) on three separate occasions. For each testing session, participants set their preferred pace but were blinded to treadmill speed. Spatial (foot rotation, step width, stride and step length), temporal (stride and step times, duration of stance, swing and single and double support) and peak vertical ground reaction force variables were collected over a 30–second capture period, equating to an average of 52 ± 5 steps of steady–state walking. Testing was repeated one week following the initial trial and again, for a third time, 20 minutes later. Repeated measures ANOVAs within a generalized linear modelling framework were used to assess between–session differences in gait parameters. Agreement between gait parameters measured within the same day (session 2 and 3) and between days (session 1 and 2; 1 and 3) were evaluated using the 95% repeatability coefficient.

Results

There were statistically significant differences in the majority (14/16) of temporal, spatial and kinetic gait parameters over the three test sessions (P < .01). The minimum change that could be detected with 95% confidence ranged between 3% and 17% for temporal parameters, 14% and 33% for spatial parameters, and 4% and 20% for kinetic parameters between days. Within–day repeatability was similar to that observed between days. Temporal and kinetic gait parameters were typically more consistent than spatial parameters. The 95% repeatability coefficient for vertical force peaks ranged between ± 53 and ± 63 N.

Conclusions

The limits of agreement in spatial parameters and ground reaction forces for the treadmill system encompass previously reported changes with neuromuscular pathology and footwear interventions. These findings provide clinicians and researchers with an indication of the repeatability and sensitivity of the Zebris treadmill system to detect changes in common spatiotemporal gait parameters and vertical ground reaction forces.

Agreement between temporal and spatial gait parameters from an instrumented walkway and treadmill system at matched walking speed

BACKGROUND

Commercially available instrumented treadmill systems that provide continuous measures of temporospatial gait parameters have recently become available for clinical gait analysis. This study evaluated the level of agreement between temporospatial gait parameters derived from a new instrumented treadmill, which incorporated a capacitance-based pressure array, with those measured by a conventional instrumented walkway (criterion standard).

METHODS

Temporospatial gait parameters were estimated from 39 healthy adults while walking over an instrumented walkway (GAITRite(®)) and instrumented treadmill system (Zebris) at matched speed. Differences in temporospatial parameters derived from the two systems were evaluated using repeated measures ANOVA models. Pearson-product-moment correlations were used to investigate relationships between variables measured by each system. Agreement was assessed by calculating the bias and 95% limits of agreement.

RESULTS

All temporospatial parameters measured via the instrumented walkway were significantly different from those obtained from the instrumented treadmill (P<.01). Temporospatial parameters derived from the two systems were highly correlated (r, 0.79-0.95). The 95% limits of agreement for temporal parameters were typically less than ±2% of gait cycle duration. However, 95% limits of agreement for spatial measures were as much as ±5cm.

CONCLUSIONS

Differences in temporospatial parameters between systems were small but statistically significant and of similar magnitude to changes reported between shod and unshod gait in healthy young adults. Temporospatial parameters derived from an instrumented treadmill, therefore, are not representative of those obtained from an instrumented walkway and should not be interpreted with reference to literature on overground walking.

An empirical analysis of consumers' attitudes toward optometrist advertising

The purposes of this study were to determine: (a) consumers' attitudes toward advertising by optometrists and (b) whether city of residence, occupation, age, sex, race, marital status, number of children in household, total family household income and education accounted for any significant differences in consumer attitudes toward optometrists that advertise. Information obtained from this study could be used by optometrists to plan and improve the quality of their advertising.