Evaluation of in-shoe plantar pressure and shear during walking for diabetic foot ulcer prevention.

OBJECTIVE: To investigate reliability and changes of in-shoe plantar pressure and shear during walking at three cadences with two insole designs. This was a precursor to the investigation of plantar loading in people with diabetes for potential foot ulcer prevention. METHOD: A sensorised insole system, capable of measuring plantar pressure and shear at the heel, fifth metatarsal head (5MH), first metatarsal head (1MH) and hallux, was tested with ten healthy participants during level walking. Reliability was evaluated, using intra-class correlation coefficient (ICC), while varying the cadences and insole types. Percentage changes in pressure and shear relative to values obtained at self-selected cadence with a flat insole design were investigated. RESULTS: Mean±standard deviation of maximum pressure, medial-lateral and anterior-posterior shear of up to 380±24kPa, 46±2kPa and -71±4kPa, respectively, were measured. The ICC in ranges of 0.762-0.973, 0.758-0.987 and 0.800-0.980 were obtained for pressure, anterior-posterior and medial-lateral shear, respectively. Opposite anterior-posterior shear directions between 5MH and 1MH (stretching), and between 1MH and hallux (pinching) were observed for some participants. Increasing cadence increased pressure and anterior-posterior shear (by up to +77%) but reduced medial-lateral shear at the heel and hallux (by up to -34%). Slower cadence increased anterior-posterior shear (+114%) but decreased medial-lateral shear (-46%) at the hallux. The use of a flexible contoured insole resulted in pressure reduction at the heel and 5MH but an increase in anterior-posterior shear at the heel (+69%) and hallux (+75%). CONCLUSION: The insole system demonstrated good reliability and is comparable to reported pressure-only systems. Pressure measurements were sensitive to changes in cadence and insole designs in ways that were consistent with the literature. However, our plantar shear showed localised shear changes with cadences and insoles for the first time, as well as stretching and pinching effects on plantar tissue. This opens new possibilities to investigate plantar tissue viability, loading characteristics and orthotic designs aimed towards foot ulcer prevention.

A Wearable Insole System to Measure Plantar Pressure and Shear for People with Diabetes.

Pressure coupled with shear stresses are the critical external factors for diabetic foot ulceration assessment and prevention. To date, a wearable system capable of measuring in-shoe multi-directional stresses for out-of-lab analysis has been elusive. The lack of an insole system capable of measuring plantar pressure and shear hinders the development of an effective foot ulcer prevention solution that could be potentially used in a daily living environment. This study reports the development of a first-of-its-kind sensorised insole system and its evaluation in laboratory settings and on human participants, indicating its potential as a wearable technology to be used in real-world applications. Laboratory evaluation revealed that the linearity error and accuracy error of the sensorised insole system were up to 3% and 5%, respectively. When evaluated on a healthy participant, change in footwear resulted in approximately 20%, 75% and 82% change in pressure, medial-lateral and anterior-posterior shear stress, respectively. When evaluated on diabetic participants, no notable difference in peak plantar pressure, as a result of wearing the sensorised insole, was measured. The preliminary results showed that the performance of the sensorised insole system is comparable to previously reported research devices. The system has adequate sensitivity to assist footwear assessment relevant to foot ulcer prevention and is safe to use for people with diabetes. The reported insole system presents the potential to help assess diabetic foot ulceration risk in a daily living environment underpinned by wearable pressure and shear sensing technologies.

A Systematic Review to Identify the Effects of Biologics in the Feet of Patients with Rheumatoid Arthritis.

Background and objective: Ninety percent of patients with rheumatoid arthritis (RA) feel foot pain during the disease process. Pharmacological treatment of RA has a systematic effect on the body and includes: Nonsteroidal anti-inflammatory drugs, disease-modifying antirheumatic drugs (DMARDs) and biologics. The objective of our review was to examine the impact of biologics on patients with RA 'foot. Methods and material: A systematic review of randomized control trials and observational studies that evaluated the efficacy of biologics against other pharmacological treatment, and included a foot outcome measure. The search covered MEDLINE Ovid, Pubmed, CINAHL, Cochrane Library, Evidence Search, and Web of Science. Risk of bias was evaluated using Cochrane guidance and the Newcastle Ottawa Scale adapted version. Results: A total of eight studies fully met the inclusion criteria: Three randomized control trials, and five observational studies were the basis of our review. A total sample of 1856 RA patients with RA treatment participated. The use of biologics was not associated as a risk factor for post-operative surgical site infection or delayed wound healing. The benefits of biologics, in terms of the disease evolution, were assessed using X-ray. Conclusion: Evidence suggests that the use of biologics is not a risk factor for post-operative surgical site infection or delayed wound healing. The use of biologics presents benefits in terms of the disease evolution assessed through X-ray.

Systematic review of the psychometric properties of patient-reported outcome measures for rheumatoid arthritis in the foot and ankle.

OBJECTIVE: To identify self-reported outcome measures specific to the foot and ankle in patients with rheumatoid arthritis and to investigate the methodological quality and psychometric properties of these measures. METHOD: A systematic review focusing on patients with rheumatoid arthritis. SETTING: The search was conducted in the PubMed, SCOPUS, CINAHL, PEDro and Google Scholar databases, based on the following inclusion criteria: population (with rheumatoid arthritis) > 18 years; psychometric or clinimetric validation studies of patient-reported outcomes specific to the foot and ankle, in different languages, with no time limit. Two of the present authors independently assessed the quality of the studies located and extracted the relevant data. Terwee's criteria and the COSMIN checklist were employed to ensure adequate methodological quality. RESULTS: Of the initial 431 studies considered, 14 met the inclusion criteria, representing 7,793 patients (56.8 years). These instruments were grouped into three dimensions (pain, perceived health status and quality of life and disability). The time to complete any of the PROMs varies around 15 minutes. PROMs criterias with the worst scores by COSMIN, 92.85% and 85.71% were criterion validity, measurement error, internal consistency and responsiveness. 28.57% of PROMs were compared with the measurement properties. CONCLUSION: the Self-Reported Foot and Ankle Score achieved the highest number of positive criteria (according to Terwee and COSMIN), and is currently the most appropriate for patients with Rheumatoid arthritis.

Ultrasound Characteristics of Foot and Ankle Structures in Healthy, Coper, and Chronically Unstable Ankles.

OBJECTIVE: Ankle sprains constitute approximately 85% of all ankle injuries, and up to 70% of people experience residual symptoms. While the injury to ligaments is well understood, the potential role of other foot and ankle structures has not been explored. The objective was to characterize and compare selected ankle structures in participants with and without a history of lateral ankle sprain. METHODS: A total of 71 participants were divided into 31 healthy, 20 coper, and 20 chronic ankle instability groups. Ultrasound images of the anterior talofibular and calcaneofibular ligaments, fibularis tendons and muscles, tibialis posterior, and Achilles tendon were obtained. Thickness, length, and cross-sectional areas were measured and compared among groups. RESULTS: When under tension, the anterior talofibular ligament (ATFL) was longer in copers and chronic ankle instability groups compared to healthy participants (P < .001 and P = .001, respectively). The chronic ankle instability group had the thickest ATFL and calcaneofibular ligament among the 3 groups (p < 0.001). No significant differences (P > .05) in tendons and muscles were observed among the 3 groups. CONCLUSIONS: The ultrasound protocol proved reliable and was used to evaluate the length, thickness, and cross-sectional areas of selected ankle structures. The length of the ATFL and the thickness of the ATFL and calcaneofibular ligament were longer and thicker in injured groups compared to healthy.

Exploring occupational standing activities using accelerometer-based activity monitoring.

Prolonged standing at work is required by an estimated 60% of the employed population and is associated with a high prevalence of musculoskeletal disorders. 'Standing' is expected to encompass a range of activities of varying intensity. This study aimed to define a range of 'standing' work-based activities; and objectively explore differences between 'standing' occupations. The following movements were defined using a triaxial accelerometer (ActivPAL) through recordings of known movements (n = 11): static standing, weight-shifting, shuffling, walking and sitting. Movements over a working day were defined for chefs (n = 10), veterinary surgeons (n = 7) and office workers (n = 9). Despite veterinary surgeons and chefs spending a similar time in an upright posture, veterinary surgeons spent 62% of this time standing statically whereas chefs split their time between all the movements. Overall, this study provides the first attempt to define 'standing' activities, allowing the differentiation of activities between occupations spending similar periods of time upright. Practitioner Summary: This study identified a range of work-based 'standing' activities of varying intensity. Differences in activity were recorded between two occupations spending a similar time in an upright posture (veterinary surgeons and chefs). A broader definition of standing activities could be important when considering factors related to musculoskeletal disorders at work.

The effect of topical anti blister products on the risk of friction blister formation on the foot.

INTRODUCTION: Foot blisters are a common injury, which can impact on activity and lead to infection. Increased skin surface hydration has been identified as a risk factor for blister formation, indicating that a reduction in hydration could reduce the risk of blister. METHOD: Thirty healthy adults were randomised into 3 groups, each receiving a preventative foot blister treatment (2Toms(®) Blister Shield(®); Flexitol(®) Blistop and Boots Anti-Perspirant Foot Spray). Cycles of compression and shear loads where applied to heel skin using a mechanism driven by compressed air. Temperature changes were measured during load application using a thermal imaging camera (FLIR Systems Inc. and Therm CAM™ Quick Report). Near surface hydration of the skin was measured using a Corneometer(®) (C & K, Germany). RESULTS: There was no significant difference in the rate of temperature change of the skin between the three groups compared to not using products (p = 0.767, p = 0.767, p = 0.515) or when comparing each product (p = 0.551). There was a significant decrease in near surface skin hydration, compared to baseline, after the application of powder (-8.53 AU, p = 0.01). There was no significant difference in hydration after the application of film former and antiperspirant (-1.47 AU, p = 0.26; -1.00 AU, p = 0.80, respectively). CONCLUSION: With the application of external load we found no significant difference in the effect of the three products on temperature change. The powder product demonstrated an effect on reducing the risk of blister. It is postulated that powder may have a barrier effect.

The effect of hydration on the risk of friction blister formation on the heel of the foot.

BACKGROUND: Friction blister research has focused on prevention and treatment approaches rather than exploring the pathophysiology of the friction blister. Increased skin hydration has been purported to be a key risk factor in friction blister development. This study aimed to test the effect of increased skin surface hydration on the risk of friction blister creation. METHODS: The skin on one foot was hydrated by soaking the foot in water. Intermittent loading was carried out until an observable change of 3°C was evident using infrared thermography. The contra lateral foot acted as a control. Skin hydration and elasticity was measured using electrical capacitance and negative pressure respectively. RESULTS: The rate of temperature change of the hydrated group was significantly greater than that of the non-hydrated foot group (P = 0.001) and showed a strong positive correlation (r = 0.520) with skin surface hydration. Weak negative correlations were seen between skin elasticity and rate of temperature change in response to load application (r = -0.166) and skin surface hydration and elasticity at baseline (r = -0.195). CONCLUSION: In controlled experimental conditions increased skin surface hydration increases the rate of temperature change of the skin in response to load application and consequently increases the risk of blister creation.

A scoping review of digital fabrication techniques applied to prosthetics and orthotics: Part 1 of 2-Prosthetics.

BACKGROUND: Traditionally, the manufacture of prostheses is time-consuming and labor-intensive. One possible route to improving access and quality of these devices is the digitalizing of the fabrication process, which may reduce the burden of manual labor and bring the potential for automation that could help unblock access to assistive technologies globally. OBJECTIVES: To identify where there are gaps in the literature that are creating barriers to decision-making on either appropriate uptake by clinical teams or on the needed next steps in research that mean these technologies can continue on a pathway to maturity. STUDY DESIGN: Scoping literature review. METHODS: A comprehensive search was completed in the following databases: Allied and Complementary Medicine Database, MEDLINE, Embase, Global Health Archive, CINAHL Plus, Cochrane Library, Web of Science, Association for Computing Machinery, Institute of Electrical and Electronics Engineers, and Engineering Village, resulting in 3487 articles to be screened. RESULTS: After screening, 130 lower limb prosthetic articles and 117 upper limb prosthetic articles were included in this review. Multiple limitations in the literature were identified, particularly a lack of long-term, larger-scale studies; research into the training requirements for these technologies and the necessary rectification processes; and a high range of variance of production workflows and materials which makes drawing conclusions difficult. CONCLUSIONS: These limitations create a barrier to adequate evidence-based decision-making for clinicians, technology developers, and wider policymakers. Increased collaboration between academia, industry, and clinical teams across more of the pathway to market for new technologies could be a route to addressing these gaps.

The formation of friction blisters on the foot: the development of a laboratory-based blister creation model.

BACKGROUND/PURPOSE: Friction blisters on the foot are a debilitating pathology that have an impact on activities of daily living and can severely impair function. The purpose of this study was to test the hypotheses that digital infrared thermographic imaging will reveal: 1) a correlation between load application to the skin and the creation of blisters, and 2) a correlation between thermographic readings and contact thermometric temperatures. METHODS: Apparatus was developed to cause the formation of heel blisters through controlled load application (70 kPa). One foot of each of the 30 healthy volunteers (21 men and 9 women), with an age range of 31 ± 8 years, was subjected to load until a blister formed, after which load application ceased and temperature measurements were taken at set times during the following 5.5 h. Temperature measurements were also taken using a contact thermometer. RESULTS: The majority of the participants (77%) blistered within 18 min of load application. All the blisters created showed significant increases in local temperature compared to baseline during blister creation (P < 0.001) and 30 min post-blister creation (P < 0.001). There was a strong correlation between contact thermometry and thermographic temperature data (r > 8). CONCLUSION: These results suggest that thermographic images may prove useful for the remote assessment of traumatically damaged foot skin.

The effects of transcutaneous electrical nerve stimulation on strength, proprioception, balance and mobility in people with stroke: a randomized controlled cross-over trial.

OBJECTIVE: To investigate the feasibility and potential efficacy of 'activeTENS' (that is transcutaneous electrical nerve stimulation (TENS) during everyday activities) by assessing the immediate effects on strength, proprioception, balance/falls risk and mobility after stroke. DESIGN: A paired-sample randomized cross-over trial. SUBJECTS: Twenty-nine mobile chronic stroke survivors with no pre-existing conditions limiting balance or mobility or contra-indications to TENS. SETTING: University clinical research facility. INTERVENTION: A single session of 'activeTENS' delivered via a 'sock electrode' (70-130 Hz, five second cycle) plus a session of control treatment (wearing the sock electrode with no stimulation), lasting approximately two hours in total. MAIN OUTCOMES: Dorsiflexor and plantarflexor strength and proprioception using an isokinetic dyanometer, balance and falls risk (Standing Forward Reach Test) and gait speed (10-m walk test). RESULTS: All participants tolerated 'active TENS'. Most parameters improved during stimulation with activeTENS; balance (p = 0.009), gait speed (p = 0.002), plantarflexor strength (p = 0.008) and proprioception of plantarflexion (p = 0.029), except dorsiflexor strength (p = 0.194) and dorsiflexion proprioception (p = 0.078). CONCLUSIONS: The results provide initial evidence of the potential of 'active TENS' to benefit physical function after stroke which warrants further phase II trials to develop the intervention. Concerns that stimulation could have a detrimental impact on balance and increase risk of falls were not supported.

Can a shoe-mounted IMU identify the effects of orthotics in ways comparable to gait laboratory measurements?

BACKGROUND: Footwear and orthotic research has traditionally been conducted within laboratories. With increasing prevalence of wearable sensors for foot and ankle biomechanics measurement, transitioning experiments into the real-world is realistic. However wearable systems must effectively detect the direction and magnitude of response to interventions to be considered for future usage. METHODS: RunScribe IMU was used simultaneously with motion capture, accelerometers, and force plates during straight-line walking. Three orthotics (A, B, C) were used to change lower limb biomechanics from a control (SHOE) including: Ground reaction force (GRF) loading rate (A), pronation excursion (A and B), maximum pronation velocity (A and B), and impact shock (C) to test whether RunScribe detected effects consistent with laboratory measurements. Sensitivity was evaluated by assessing: 1. Significant differences (t-test) and effect sizes (Cohen's d) between measurement systems for the same orthotic, 2. Statistical significance (t-test and ANOVA) and effect size (Cohen's d & f) for orthotic effect across measurement systems 3. Direction of orthotic effect across measurement systems. RESULTS: GRF loading rate (SHOE: p = 0.138 d = 0.403, A: p = 0.541 d = 0.165), impact shock (SHOE: p = 0.177 d = 0.405, C: p = 0.668 d = 0.132), pronation excursion (A: p = 0.623 d = 0.10, B: p = 0.986 d = 0.00) did not significantly differ between measurement systems with low effect size. Significant differences and high effect sizes existed between systems in the control condition for pronation excursion (p = 0.005 d = 0.68), and all conditions for pronation velocity (SHOE: p < 0.001 d = 1.24, A: p = 0.001 p = 1.21, B: p = 0.050 d = 0.64). RunScribe (RS) and Laboratory (LM) recorded the same significant effect of orthotic but inconsistent effect sizes for GRF loading rate (LM: p = 0.020 d = 0.54, RS: p = 0.042 d = 0.27), pronation excursion (LM: p < 0.001 f = 0.31, RS: p = 0.042 f = 0.15), and non-significant effect of orthotic for impact shock (LM: p = 0.182 d = 0.08, RS: p = 0.457 d = 0.24). Statistical significance was different between systems for effect of orthotic on pronation velocity (LM: p = 0.010 f = 0.18, RS: p = 0.093 f = 0.25). RunScribe and Laboratory agreed on the direction of change of the biomechanics variables for 69% (GRF loading rate), 40%-70% (pronation excursion), 47%-65% (pronation velocity), and 58% (impact shock) of participants. CONCLUSION: The RunScribe shows sensitivity to orthotic effect consistent with the laboratory at the group level for GRF loading rate, pronation excursion, and impact shock during walking. There were however large discrepancies between measurements in individuals. Application of the RunScribe for group analysis may be appropriate, however implementation of RunScribe for individual assessment and those including pronation may lead to erroneous interpretation.

Foot plantar pressure and centre of pressure trajectory differ between straight and turning steps in infants.

Plantar pressure has been used to understand loading on infant feet as gait develops. Previous literature focused on straight walking, despite turning accounting for 25% of infant self-directed steps. We aimed to compare centre of pressure and plantar pressure in walking steps in different directions in infants. Twenty-five infants who were walking confidently participated in the study (aged 449 ± 71 days, 96 ± 25 days after first steps). Plantar pressure and video were recorded whilst five steps per infant were combined for three step types: straight, turning inwards and outwards. Centre of pressure trajectory components were compared for path length and velocity. Pedobarographic Statistical Parametric Mapping explored differences in peak plantar pressure for the three step types. Significant differences were identified primarily in the forefoot with higher peak pressures in straight steps. Centre of pressure path was longer in the medial-lateral direction during turning (outward 4.6 ± 2.3, inward 6.8 ± 6.1, straight 3.5 ± 1.2 cm, p < .001). Anterior-posterior velocity was higher in straight steps and medial-lateral velocity highest turning inwards. Centre of pressure and plantar pressures differ between straight and turning steps with greatest differences between straight and turning. Findings may be attributed to walking speed or a function of turning experience and should influence future protocols.

Searching for online information on the fit of children's footwear during the COVID-19 pandemic: an analysis of Google Trends data.

BACKGROUND: Selecting footwear with appropriate fit in children is challenging due the changes with foot size and dimensions which occur throughout childhood. Access to appropriate footwear is important but recent challenges with the COVID-19 pandemic resulted in closure of retail stores for prolonged periods where parents/carers could not physically purchase footwear for their children and the footwear industry suffered disruption to their supply chain, and falls in retail sales. Simultaneously increased use of social media platforms for health information seeking throughout the pandemic have been documented. This likely would have included parents/carers seeking information online to support footwear purchases for their children. The primary aim of this work was to explore how searches for online fitting information for children changed throughout the COVID-19 pandemic lockdown periods. A secondary aim was to identify how searches were influenced by footwear style. METHODS:  We employed Google Trends to obtain search engine traffic related to footwear fitting information for children. We collected data spanning the three years pre, during and post the main national lockdown for three eight-week windows: (1) first eight weeks of the U.K. national lockdown; (2) the first eight weeks of the calendaryear; (3) the eight weeks leading up to children going back-to-school for the new academic year in the U.K. The search terms reflected parents/carers searching for footwear fit information relating to children and were grouped by style of footwear: children, infants, babies and toddlers as well as school shoes. RESULTS: We identified increased searching for footwear fit information for children during the pandemic, which reduced following post pandemic in all except the searches which related to school shoes. We saw reductions in searching related to fit of school shoes as schools closed indefinitely and an increase in online searches with the pandemic. This was also maintained post-pandemic despite shops reopening, suggesting that some of these changes in information reflect new consumer behaviours which may continue. CONCLUSIONS:  Increased searches for online resources regarding footwear fit highlights the importance of ensuring high quality accessible online information on footwear fit is available to support those buying footwear for their children.

Inter and intra-examiner reliability of musculoskeletal ultrasound scanning of Anterior Talofibular Ligament and ankle muscles.

PURPOSE: Although the function of subjects with chronic ankle instability (CAI) has been examined, structural analysis by ultrasound scanning of the structures surrounding the ankle is limited. Before such structural comparisons between injured and uninjured people can be made it is important to investigate a reliable measurement protocol of structures possibly related to CAI. The aim of this study was to investigate the inter-intra examiner reliability of ultrasonic characteristics of selected structures in healthy subjects. METHODS: Eleven healthy participants were assessed by an experienced sonographer and inexperienced certificated examiner. Ultrasound images were collected of the ATFL length and ankle muscles of gastrocnemius medialis (GM), tibialis anterior (TA) and peroneals. Thickness was measured for the muscles, whilst cross-sectional area (CSA) was measured for the peroneals. Inexperienced examiner repeated the measurements a week later. RESULTS: Inter-examiner reliability was excellent for all structures (ICC3,1 = 0.91-0.98). Intra-examiner reliability shows excellent agreement for all structures (ICC3,1 = 0.92-0.98) except GM (good agreement) (ICC3,1 = 0.82). LoA, relative to structure size, ranged from 1.38 to 6.88% for inter-reliability and from 0.07 to 5.79% for intra-reliability. CONCLUSION: This study shows a high level of inter-intra examiner reliability in measuring the structures possibly related to CAI. Future research has been planned to investigate the structural analysis in CAI by using applied MSUS protocol.

Where do you stand?: an exploration of perspectives toward feet, foot health, and footwear using innovative digital methods.

BACKGROUND: The cost of losing foot health is significant to the person, healthcare systems, and economy, with diabetes related foot health issues alone costing over £1 billion annually in the UK. Yet many foot health problems are preventable through alternative health behaviour. It is therefore important to understand how feet, foot health and footwear are conceptualised to gain understanding about how these might influence foot health behaviour and inform health messages that seek to protect or improve foot health through altered health behaviour. This research seeks to explore attitudes and beliefs and identify phenomena that may act as barriers or motivators to the proactive self-management of foot health. METHODS: Public conversations involving 2,699 expressions related to feet, footwear or foot health on Facebook, Twitter, and Instagram were extracted. Conversations on Facebook and Twitter were scraped with NVivo's NCapture plugin whereby data is extracted and downloaded to NVivo. Extracted files were uploaded to the Big Content Machine (software developed at the University of Salford) which facilitated the search for keywords 'foot', 'feet', 'footwear', 'shoe', and 'shoes'. Instagram was scraped by hand. Data was analysed using a Thematic Analysis approach. RESULTS: Three themes were identified; 1) connections and disconnections derived from social and cultural constructs, 2) phenomena beyond attitudes and beliefs that relate to symbolic representations and the impact when foot health is lost, and 3) phenomena relating to Social Media as a conduit for the exploration of attitudes and beliefs. CONCLUSIONS: This novel research exemplifies complex and sometimes incongruous perspectives about feet including their value for what they facilitate, contrasted with negative feelings about the negative impact that can have aesthetically when feet work hard. Sometimes feet were devalued, with expressions of disgust, disconnection, and ridicule. The importance of contextual, social, and cultural phenomena with implications for optimising foot health messages. Knowledge gaps including factors related to children's foot health and development, and how to treat foot health problems. The power of communities with shared experience to influence decisions, theories, and behaviour about foot health was also revealed. While people do talk about feet in some social contexts, it is not always in a way that promotes overt, positive foot health behaviour. Finally, this research demonstrates the benefit of exploring perspectives in uncontrived settings and illuminates the potential utility of social media (SoMe) platforms Facebook, Instagram, and Twitter as vehicles to promote foot health self-management behaviour that is responsive to the social and demographic variances of engagers who inhabit those spaces.

Validation of the RunScribe inertial measurement unit for walking gait measurement.

INTRODUCTION: The use of portable gait measurement systems in research is appealing to collect real-world data at low-cost, low participant burden, and without requirement for dedicated lab space. Most commercially available inertial measurement units (IMU's) designed for running only capture temporospatial data, the ability to capture biomechanics data such as shock and motion metrics with the RunScribe IMU makes it the closest to a lab alternative. The RunScribe system has been validated in running, however, is yet to be validated for walking. METHOD: Qualisys motion capture, AMTI force plates, and Delsys Trigno accelerometers were used as gold standard lab measures for comparison against the RunScribe IMU. Twenty participants completed 10 footsteps per foot (20 total) measured by both systems simultaneously. Variables for validation included: Vertical Ground reaction force (GRF), instantaneous GRF rate, pronation excursion, pronation velocity, total shock, impact force, braking force. Interclass correlation (ICC) was used to determine agreement between the measurement systems, mean differences were used to evaluate group level accuracy. RESULTS: ICC results showed moderate agreement between measurement systems when both limbs were averaged. The greatest agreement was seen for GRF rate, pronation excursion, and pronation velocity (ICC = 0.627, 0.616, 0.539), low agreement was seen for GRF, total shock, impact shock, braking shock (ICC = 0.269, 0.351, 0.244, 0.180). However mean differences show the greatest level of accuracy for GRF, GRF rate, and impact shock. DISCUSSION: Results show mixed agreement between the RunScribe and gold standard lab measures, and varied agreement across left and right limbs. Kinematic variables showed the greatest agreement, however GRF had the lowest relative mean difference for group results. The results show acceptable levels of agreement for most variables, however further work must be done to assess the repeatability and sensitivity of the RunScribe to be applied within areas such as footwear testing and gait retraining protocols.

Postural control during quiet standing and voluntary stepping response tasks in individuals post-stroke: a case-control study.

BACKGROUND: Postural control impairments following a stroke have an impact on mobility, reduce independence, and increase the risk of falls. Assessing these impairments during tasks representative of real-life situations, such as quiet standing (QS) and voluntary stepping response (VSR), will enhance our understanding of how the postural control system is impaired in individuals post-stroke (IPS). It will also inform the development of a more targeted and effective rehabilitation to prevent falls in IPS. OBJECTIVES: Identify the postural control impairments encountered by IPS during QS and VSR. METHODS: Twenty IPS and 16 healthy controls were recruited to perform QS and VSR tasks, while ground reaction forces and whole-body motion were measured. Displacement and speed variation of the COM, center of pressure (COP) displacement and spatiotemporal data were calculated and compared between groups. RESULTS: During QS, IPS exhibited greater maximal COP displacement in mediolateral direction, COM displacement in vertical direction and COM speed excursions compared to controls. During VSR, IPS exhibited smaller step length, braking force, posterior foot placement in relation to the pelvis and COM anteroposterior excursion compared to controls. IPS presented less static and dynamic postural stability compared to controls. CONCLUSIONS: Greater postural sway during QS, smaller anteroposterior COM displacement before losing balance and altered voluntary recovering steps during VSR could place IPS at more risk of falling when they face a postural challenge in the community. These novel results will improve the current knowledge base and should be considered in IPS rehabilitation.

Human ankle joint movements during walking are probably not determined by talar morphology.

Knowledge about the orientation of a representative ankle joint axis is limited to studies of tarsal morphology and of quasistatic movements. The aim of our study was therefore to determine the development of the axis orientation during walking. Intracortical bone pins were used to monitor the kinematics of the talus and tibia of five healthy volunteers. The finite helical axis was determined for moving windows of 10% stance phase and its orientation reported if the rotation about the axis was more than 2°. A representative axis for ankle dorsi- and plantarflexion was also estimated based on tarsal morphology. As reported by literature, the morphology-based axis was inclined more medially upwards for dorsiflexion than for plantarflexion. However, when a mean of the finite helical axis orientations was calculated for each walking trial for dorsiflexion (stance phase 15-25%) and for plantarflexion (stance phase 85-95%), the inclination was less medially upwards in dorsiflexion than in plantarflexion in four out of five participants. Thus, it appears that the inclination of a representative ankle joint axis for dynamic loading situations cannot be estimated from either morphology or quasi-static experiments. Future studies assessing muscle activity, ligament behaviour and articulating surfaces may help to identify the determining factors for the orientation of a representative ankle joint axis.

Foot posture after stroke: frequency, nature and clinical significance.

OBJECTIVES: Clinical convention suggests that foot posture and movements are adversely affected by stroke and cause walking difficulties but there is little objective data to support or refute these beliefs. This study explores static foot posture in people with stroke and their relationship to weakness and spasticity and walking limitations. DESIGN: Cross-sectional survey. SETTING: Stroke services and support groups of two acute hospitals. SUBJECTS: Seventy-two stroke survivors with mobility limitations. MAIN MEASURES: Foot Posture Index; Demographics; Motricity Index (weakness); modified Ashworth Scale (spasticity); Walking Handicap Scale (walking limitations). RESULTS: About one-third of participants had abnormal foot posture on the weak side, which was associated with walking limitations. Most (70%) had a symmetrical foot posture with similar frequencies of supination (13%) and pronation (16%) abnormalities. There was no relationship between foot posture and weakness and spasticity; age was the only independent predictor of foot posture abnormalities. CONCLUSIONS: A minority of people with stroke had abnormal or asymmetrical foot posture and equal numbers suffered pronation and supination abnormalities; these findings challenge the beliefs that underpin the clinical management of stroke-related foot problems.