Using plantar pressure for free-living posture recognition and sedentary behaviour monitoring

Health authorities in numerous countries and even the World Health Organization (WHO) are concerned with low levels of physical activity and increasing sedentary behaviour amongst the general population. In fact, emerging evidences identify sedentary behaviour as a ubiquitous characteristic of contemporary lifestyles. This has major implications for the general health of people worldwide particularly for the prevalence of non-communicable conditions (NCDs) such as cardiovascular disease, diabetes and cancer and their risk factors such as raised blood pressure, raised blood sugar and overweight. Moreover, sedentary time appears to be uniquely associated with health risks independent of physical activity intensity levels. However, habitual sedentary behaviour may prove complex to be accurately measured as it occurs across different domains, including work, transport, domestic duties and even lei¬sure. Since sedentary behaviour is mostly reflect as too much sitting, one of the main concerns is being able to distinguish among different activities, such as sitting and standing. Widely used devices such as accelerometer-based activity monitors have a limited ability to detect sedentary activities accurately. Thus, there is a need of a viable large-scale method to efficiently monitor sedentary behaviour. This thesis proposes and demonstrates how a plantar pressure based wearable device and machine learning classification techniques have significant capability to monitor daily life sedentary behaviour. Firstly, an in-depth review of research and market ready plantar pressure and force technologies is performed to assess their measurement capabilities and limitations to measure sedentary behaviour. Afterwards, a novel methodology for measuring daily life sedentary behaviour using plantar pressure data and a machine learning predictive model is developed. The proposed model and its algorithm are constructed using a dataset of 20 participants collected at both laboratory-based and free-living conditions. Sitting and standing variations are included in the analysis as well as the addition of a potential novel activities, such as leaning. Video footage is continuously collected using of a wearable camera as an equivalent of direct observation to allow the labelling of the training data for the machine learning model. The optimal parameters of the model such as feature set, epoch length, type of classifier is determined by experimenting with multiple iterations. Different number and location of plantar pressure sensors are explored to determine the optimal trade-off between low computational cost and accurate performance. The model s performance is calculated using both subject dependent and subject independent validation by performing 10-fold stratified cross-validation and leave-one-user-out validation respectively. Furthermore, the proposed model activity performance for daily life monitoring is validated against the current criterion (i.e. direct observation) and against the de facto standard, the activPAL. The results show that the proposed machine learning classification model exhibits excel-lent recall rates of 98.83% with subject dependent training and 95.93% with independent training. This work sets the groundwork for developing a future plantar pressure wearable device for daily life sedentary behaviour monitoring in free-living conditions that uses the proposed ma-chine leaning classification model. Moreover, this research also considers important design characteristics of wearable devices such as low computational cost and improved performance, addressing the current gap in the physical activity and sedentary behaviour wearable market

Towards understanding the functionality of foot orthosis based on foot structure and function

The raw data related to the second study of this thesis (Chapter 3) is available online in the section of supporting information at https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0232677. These files present the following data: S1 File. The pattern of foot orthosis depression/reformation for healthy subjects during walking with sport versus regular foot orthosis. S2 File. Raw data for the training session of sport foot orthosis. This Excel file consists three sheets in which the position of triad markers, the orientation of triad markers and the position of markers on plantar surface of foot orthosis are provided respectively. S3 File. Raw data for walking with sport foot orthosis. This Excel file consists two sheets in which the position of triad markers and the orientation of triad markers are provided respectively for subject 1. S4 File. The results of each participant during walking with sport foot orthosis. This .mat file includes “DispEachPoint” and “DispEachPointMean” which shows the displacement of each predicted marker on foot orthosis plantar surface during stance phase of walking relative to its corresponding position in static non weight-bearing for each trial and the average of trials respectively. In addition, “loc_stance” and “loc_meanstance” show the location of each predicted marker during stance phase of walking. “peaks” and “peaksMean” represent the minimum (depression) and maximum (reformation) value of displacement during walking S5 File. The results of each participant during walking with regular foot orthosis. This .mat file includes “DispEachPoint” and “DispEachPointMean” which shows the displacement of each predicted marker on foot orthosis plantar surface during stance phase of walking relative to its corresponding position in static non weight-bearing for each trial and the average of trials respectively. In addition, “loc_stance” and “loc_meanstance” show the location of each predicted marker during stance phase of walking. “peaks” and “peaksMean” represent the minimum (depression) and maximum (reformation) value of displacement during walkingLes orthèses plantaires (OP) sont des dispositifs médicaux fréquemment utilisés pour réduire les douleurs et blessures de surutilisation, notamment chez les personnes ayant les pieds plats. Le port d'OP permettrait de corriger les altérations biomécaniques attribuées à la déformation du pied plat, que sont la perte de l’arche longitudinale médiale et la pronation excessive du pied. Cependant, le manque de compréhension de la fonction des OP entraine une grande variabilité des OP prescrites en milieu clinique. L'objectif de cette thèse est d'approfondir les connaissances sur l’effet des OP sur la biomécanique, de quantifier les déformations des OP à la marche et de mettre en relation ces déformations avec la biomécanique du pied. La première étude a évalué la manière dont les différentes conceptions d'OP imposent des modifications dans le mouvement et le chargement appliqué sur le pied. Cet objectif a été atteint grâce à une revue systématique traitant des effets des OP sur la cinématique et la cinétique du membre inférieur pendant la marche chez des personnes ayant des pieds normaux. Les critères d'inclusion ont réduit les études à celles qui ont fait état des résultats pour les géométries les plus fréquentes des OP, à savoir les biseaux, les supports d’arche et les stabilisateurs de talon. La revue a mis en évidence que les orthèses avec un biseau médial peuvent réduire le moment d'éversion de la cheville. Aucune évidence significative n'a été trouvée dans notre méta-analyse sur l'efficacité des orthèses incluant des supports d’arche ou des stabilisateurs de talon. Les différents procédés et matériaux utilisés dans la conception des OP ainsi que les caractéristiques des pieds des participants pourraient expliquer la variabilité retrouvée au regard des effets des OP sur la biomécanique. La deuxième étude a apporté des informations précieuses et inédites sur le comportement dynamique des OP à la marche. La cinématique du contour des OP a été utilisée pour prédire la déformation de leur surface plantaire pendant la marche chez 13 individus ayant des pieds normaux en utilisant un réseau de neurones artificiels. Une erreur moyenne inférieure à 0,6 mm a été obtenue pour nos prédictions. En plus de la précision des prédictions, le modèle a été capable de différencier le patron de déformations pour deux OP de rigidités différentes et entre les participants inclus dans l’étude. Enfin, dans une troisième étude, nous avons identifié la relation entre la déformation des OP personnalisées et la biomécanique du pied à la marche chez 17 personnes avec des pieds plats. L'utilisation de modèles linéaires mixtes a permis d’exprimer les variations de la déformation des OP dans différentes régions en fonction des variables cinématiques du pied et de pressions plantaires. Cette étude a montré que l'interaction pied-OP varie selon les différentes régions de l’OP et les différentes phases du cycle de marche. Ainsi, des lignes directrices préliminaires ont été fournies afin de standardiser et optimiser la conception des OP. Dans l'ensemble, les résultats de cette thèse justifient l'importance d’'intégrer des caractéristiques dynamiques du pied de chaque individu dans la conception d'OP personnalisées. Des études futures pourraient étendre les modèles de prédiction de l'interaction pied-OP en incluant d'autres paramètres biomécaniques tels que les moments articulaires, les activations musculaires et la morphologie du pied. De tels modèles pourraient être utilisés pour développer des fonctions coût pour l'optimisation de la conception des OP par une approche itérative utilisant la simulation par les éléments finis.Foot orthoses (FOs) are frequently used medical devices to manage overuse injuries and pain in flatfoot individuals. Wearing FOs can result in improving the biomechanical alterations attributed to flatfoot deformity such as the loss of medial longitudinal arch and excessive foot pronation. However, a lack of a clear understanding of the function of FOs contributes to the highly variable FOs prescribed in clinical practice. The objective of this thesis was to deepen the knowledge about the biomechanical outcomes of FOs and to formulate the dynamic behaviour of FOs as a function of foot biomechanics during gait. The primary study investigated how different designs of FOs impose alterations in foot motion and loading. This objective was achieved through a systematic review of all literature reporting the kinematics and kinetics of the lower body during walking with FOs in healthy individuals. The inclusion criteria narrowed the studies to the ones which reported the outcomes for common designs of FOs, namely posting, arch support, and heel support. The review identified some evidence that FOs with medial posting can decrease ankle eversion moment. No significant evidence was found in our meta-analysis for the efficiency of arch supported and heel supported FOs. The findings of this study revealed that differences in FO design and material as well as foot characteristics of participants could explain the variations in biomechanical outcomes of FOs. The second study provided valuable information on the dynamic behaviour of customized FOs. The kinematics of FO contour was used to predict the deformation of FO plantar surface in 13 healthy individuals during walking using an artificial intelligence approach. An average error below 0.6 mm was achieved for our predictions. In addition to the prediction accuracy, the model was capable to differentiate between different rigidities of FOs and between included participants in terms of range and pattern of deformation. Finally, the third study identified the relationship between the deformation of customized FOs and foot biomechanics in 17 flatfoot individuals during walking. The use of linear mixed models made it possible to identify the variables of foot kinematics and region-dependent plantar pressure that could explain the variations in FO deformation. This study showed that the foot-FO interaction changes over different regions of FO and different phases of gait cycle. In addition, some preliminary guidelines were provided to standardize and optimize the design of FOs. Overall, the results of this thesis justify the importance of incorporating the dynamic characteristics of each individual’s foot into the design of customized FOs. Future studies can extend the predictive models for foot-FO interactions by including other determinants of foot biomechanics such as joint moments, muscle activation, and foot morphology. Based on such extended models, the cost functions could be devised for optimizing the designs of customized 3D printed FOs through an iterative approach using finite element modeling

Développement et étude de la validité d'une semelle instrumentée pour le comptage de pas

Les semelles instrumentées sont des dispositifs pouvant être utilisées pour la quantification de pas et la reconnaissance des activités. Il existe plusieurs modèles de semelles instrumentées, avec des niveaux de validité variables. Ce mémoire comprend trois objectifs : 1) faire une revue systématique de la littérature sur la validité de critère des semelles instrumentées existantes pour identifier les postures, les types d’activités et compter les pas, 2) développer une semelle instrumentée et 3) étudier sa validité pour le comptage de pas. Pour l’objectif 1, cinq bases de données ont permis de sélectionner 33 articles sur la validité de critère de seize modèles de semelles instrumentées pour la détection de posture, de type d’activités et de pas. Selon les indicateurs utilisés, les validités de critère varient de 65,8% à 100% pour la reconnaissance des activités et des postures et de 96% à 100% pour la détection de pas. En somme, peu d’études ont utilisé les semelles instrumentées pour le comptage de pas bien qu’elles démontrent une très bonne validité. Pour les objectifs 2 et 3, nous avons équipé une semelle commercialisée de cinq capteurs de pression et testé trois méthodes de traitement des signaux de pression pour la quantification de pas. Ces trois méthodes sont basées sur le signal de chaque capteur de pression, la moyenne ou la somme cumulée des cinq signaux de pression. Les résultats ont montré que notre semelle instrumentée détectait le pas avec un taux de succès de 94,8 ± 9,4% à 99,5 ± 0,4% à des vitesses de marche confortable et de 97,0 ± 6,2% à 99,6 ± 0,4% à des vitesses de marche rapide à l’intérieur et à l’extérieur d’un bâtiment avec les trois méthodes. Toutefois, la méthode basée sur la somme cumulée avait les niveaux de précision plus élevés pour le comptage de pasInstrumented insoles are devices which can be used for quantifying steps and recognizing activities. Validity of many instrumented insoles varies from medium to high. This thesis has three objectives: 1) to systematically review the literature on the validity of existing instrumented insoles for posture, type of activities recognition, and step counting, 2) to develop an instrumented insole and 3) to study its criterion validity for step counting. For objective 1, five databases were used to select 33 articles on criterion validity of sixteen insole models for posture and type of activities recognition, and step detection. According to indicators used, validity values vary from 65.8% to 100% for activities and postures recognition and from 96% to 100% for detection of steps. In summary, few studies have used instrumented insoles for steps counting even though they demonstrated a very good validity. For objectives 2 and 3, we equipped a commercialized insole with five pressure sensors and tested three pressure signal processing methods for step quantification. These three methods are based on signal of each pressure sensor, average or cumulative sum of five pressure signals. Results showed that our instrumented insole detected steps with a success rate varying from 94.8 ± 9.4% to 99.5 ± 0.4% at self-selected walking speeds and from 97.0 ± 6.2% to 99.6 ± 0.4% at maximal walking speeds in indoor and outdoor settings with all three processing methods. However, cumulative sum method had the highest levels of accuracy for step counting

Biomechanics beyond the lab: Remote technology for osteoarthritis patient data—A scoping review

The objective of this project is to produce a review of available and validated technologies suitable for gathering biomechanical and functional research data in patients with osteoarthritis (OA), outside of a traditionally fixed laboratory setting. A scoping review was conducted using defined search terms across three databases (Scopus, Ovid MEDLINE, and PEDro), and additional sources of information from grey literature were added. One author carried out an initial title and abstract review, and two authors independently completed full-text screenings. Out of the total 5,164 articles screened, 75 were included based on inclusion criteria covering a range of technologies in articles published from 2015. These were subsequently categorised by technology type, parameters measured, level of remoteness, and a separate table of commercially available systems. The results concluded that from the growing number of available and emerging technologies, there is a well-established range in use and further in development. Of particular note are the wide-ranging available inertial measurement unit systems and the breadth of technology available to record basic gait spatiotemporal measures with highly beneficial and informative functional outputs. With the majority of technologies categorised as suitable for part-remote use, the number of technologies that are usable and fully remote is rare and they usually employ smartphone software to enable this. With many systems being developed for camera-based technology, such technology is likely to increase in usability and availability as computational models are being developed with increased sensitivities to recognise patterns of movement, enabling data collection in the wider environment and reducing costs and creating a better understanding of OA patient biomechanical and functional movement data

Biomechanics beyond the lab: remote technology for osteoarthritis patient data-a scoping review

The objective of this project is to produce a review of available and validated technologies suitable for gathering biomechanical and functional research data in patients with osteoarthritis (OA), outside of a traditionally fixed laboratory setting. A scoping review was conducted using defined search terms across three databases (Scopus, Ovid MEDLINE, and PEDro), and additional sources of information from grey literature were added. One author carried out an initial title and abstract review, and two authors independently completed full-text screenings. Out of the total 5,164 articles screened, 75 were included based on inclusion criteria covering a range of technologies in articles published from 2015. These were subsequently categorised by technology type, parameters measured, level of remoteness, and a separate table of commercially available systems. The results concluded that from the growing number of available and emerging technologies, there is a well-established range in use and further in development. Of particular note are the wide-ranging available inertial measurement unit systems and the breadth of technology available to record basic gait spatiotemporal measures with highly beneficial and informative functional outputs. With the majority of technologies categorised as suitable for part-remote use, the number of technologies that are usable and fully remote is rare and they usually employ smartphone software to enable this. With many systems being developed for camera-based technology, such technology is likely to increase in usability and availability as computational models are being developed with increased sensitivities to recognise patterns of movement, enabling data collection in the wider environment and reducing costs and creating a better understanding of OA patient biomechanical and functional movement data

An Overview of Smart Shoes in the Internet of Health Things: Gait and Mobility Assessment in Health Promotion and Disease Monitoring

New smart technologies and the internet of things increasingly play a key role in healthcare and wellness, contributing to the development of novel healthcare concepts. These technologies enable a comprehensive view of an individual’s movement and mobility, potentially supporting healthy living as well as complementing medical diagnostics and the monitoring of therapeutic outcomes. This overview article specifically addresses smart shoes, which are becoming one such smart technology within the future internet of health things, since the ability to walk defines large aspects of quality of life in a wide range of health and disease conditions. Smart shoes offer the possibility to support prevention, diagnostic work-up, therapeutic decisions, and individual disease monitoring with a continuous assessment of gait and mobility. This overview article provides the technological as well as medical aspects of smart shoes within this rising area of digital health applications, and is designed especially for the novel reader in this specific field. It also stresses the need for closer interdisciplinary interactions between technological and medical experts to bridge the gap between research and practice. Smart shoes can be envisioned to serve as pervasive wearable computing systems that enable innovative solutions and services for the promotion of healthy living and the transformation of health care

Lower limb injury prevention in the New Zealand Army : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy (PhD) in Sport and Exercise at Massey University, Wellington, New Zealand

Background The mobility of the New Zealand Defence Force (NZDF) and its ability to deploy personnel at short notice is compromised by the high number of musculoskeletal injuries, particularly to the lower limbs. Literature searches indicated footwear may be the issue. The aim of this research is to examine the extent of the problem, which injuries and anatomical structures are most affected, the aetiology involved, and finally, the effects of a possible remedial intervention. Methodology Information from 11 years of NZDF injury records were examined. Chi square analysis was used to determine most affected joint(s), injury type and activities (sporting or military). The ankle joint appeared most vulnerable to injury, particularly during sporting or military activities involving running. Traumatic ankle sprains and strains were the most prolific injuries and this occurred when not wearing the military boot. This information was used to determine the subsequent investigations of the biomechanical and neurological aetiology underlying habitual boot-wear that might give rise to these injuries. Ankle range of motion (ROM), endurance strength, power and fatigue were measured using an isokinetic dynamometer (Biodex) in new recruits and repeated after one year of military boot-wear. Muscle activation of tibialis anterior and both the medial and lateral gastrocnemius were also measured during quiet standing on a force platform to measure postural sway. The same measures of aetiology were conducted on 65 habitual boot wearing regular force military male personnel pre and post-introduction of a low-cut flexible shoe. These 65 personnel all had served greater than two years in the NZDF. At 10 weeks, the effects of pre- and post- flexible shoe wear were measured to determine if the effects of habitual boot-wear could be reversed. Results After 12 months of habitual military boot-wear, ankle ROM was decreased in all planes of movement, endurance strength and power were significantly reduced and fatigue onset increased after one year of boot-wear. Muscle activation was increased in tibialis anterior and both the medial and lateral gastrocnemius, which coincided with significantly increased sway patterns indicating poor postural stability. After 10 weeks of transitioning from habitual military boot-wear to a flexible shoe, ankle ROM, and strength significantly increased, while fatigue, muscle activation and postural sway decreased. Conclusion Chronic military boot-wear causes mal-adaptations and is associated with the high number of ankle injuries in the NZDF, however the effects can be reversed. It was advised that when not on military manoeuvres that personnel wear a low-cut flexible garrison shoe