CONCURRENT ASSESSMENT OF SYMMETRY, VARIABILITY, AND COMPLEXITY OF STRIDE DURING PROLONGED OUTDOOR RUNNING

The aim of this study was to analyse the influence of acute fatigue on the asymmetry, variability, and complexity of the running pattern. We equipped 11 half-marathon participants with an inertial measurement unit (IMU) on each foot and a global navigation satellite system (GNSS)-IMU sensor on chest. Every 10 minutes of the race, the participant pronounced their perceived rating-of-fatigue (ROF) on a scale of 1 to 10. We divided the race into 8 equal segments, with one ROF score per segment, and included only the flat running parts. Temporal gait parameters were extracted using validated algorithms, followed by the computation of their asymmetry, and the variability and complexity of the cycle time (CT). Gait asymmetry increased significantly toward the end of the race and at higher perceived fatigue; faster runners showed a greater increase in asymmetry. CT variability increased significantly at the beginning of the race and then remained stable for all participants, but faster runners showed up to 20% less variability. No significant change was observed in CT complexity. This study highlights the increase in asymmetry and variability due to acute fatigue, with differences between fast/slow runners, and the importance of simultaneously measuring perceived fatigue and gait parameters under real-world conditions

TRUNK MOTION DURING A HALF-MARATHON: THE IMPACT OF PERCEIVED FATIGUE ON MOTION STABILITY AND SMOOTHNESS

Our objective was to investigate the effects of acute fatigue on stability and smoothness of trunk motion during a half marathon. 13 recreational runners were fitted with a GNSS-IMU sensor on their chest. Every 10 minutes of the race, the participant pronounced their perceived fatigue, recorded by a smartphone attached to the arm. We divided the race into 8 equal segments, corresponding to one fatigue score per segment, and considered only level running. Based on mediolateral acceleration and running velocity (v), stability was characterized by spectral entropy, RMS of acceleration (RMSA), and autocorrelation between successive steps and strides; smoothness by jerk cost (JC), spectral arc length (SPARC), and inverse number of peaks (IPV) of v. Both RMSA and JC increased significantly shortly after race onset. RMSA increased significantly at a lower perceived fatigue level, while JC increased at a higher level. Whereas other measures did not change substantially, RMSA and JC showed a clear change with acute fatigue and also differentiated well between the five fastest and five slowest runners. With increasing perceived fatigue, both parameters showed a higher change for ‘slow’ group. This study highlights the loss of stability and smoothness in running due to acute fatigue and the importance of simultaneously measuring perceived fatigue and trunk biomechanics under real-world conditions

SWIMMING PHASE-BASED PERFOMANCE EVALUATION USING A SINGLE IMU IN FRONT CRAWL

The purpose of this study was to assess the potential of using a sacrum-worn inertial measurement unit (IMU) for performance evaluation in each swimming phase (wall push-off, glide, stroke preparation, and swimming) of national-level swimmers in front crawl technique. Nineteen swimmers were asked to wear a sacrum IMU and swim four one-way 25-m trials in front crawl, attached to a tethered speedometer and filmed by cameras in the whole lap for validation. Based on the literature, several goal metrics were defined over speedometer data, each one representing the performance of the swimmer either in one phase (maximum velocity of wall push-off phase) or several phases (time of 15 meters for wall push-off, glide, stroke preparation phases). Following a macro-micro approach, the IMU parameters of each swimming phase were used to predict the goal metrics. The selected IMU parameters were in line with the characteristics of movement within each phase and can estimate the corresponding goal metric with an R2 over 0.8 and relative RMSE lower than 10%

Short-term effects on heart rate variability of occipito-mastoid suture normalization in healthy subjects

Occipito-mastoid structure normalization (OMSN) is an osteopathic manipulative treatment aimed at reducing tension around the jugular foramen, where cranial nerves IX, X, and XI exit the skull. The purpose of this study was to observe how heart rate variability (HRV), a marker of autonomic cardiac regulation, was modulated after an OMSN vs. a sham technique (SHAM). Pre- and post-intervention HRV was analyzed in two randomly chosen groups of 15 participants (OMSN vs. SHAM group). HRV was collected in the supine position 5 min before and 5 min after a 10-min application of either OMSN or SHAM. The time and group effect was analyzed using a two-way ANOVA. Independently from group intervention, a significant time effect induced increased HRV. No group effect differences were observed. Multiple comparisons for time and group interaction showed that the root mean square of successive differences (RMSSD), a vagally mediated HRV variable, increased to a greater extent for the OMSN group (p = 0.03) than for the SHAM group. However, both OMSN and SHAM techniques had a significant effect on HRV. Compared to a SHAM technique, OMSN had a significant effect on HRV vagally related metric RMSSD in the short term. We conclude that 10 min of OMSN may be used to induce a short-term influence on parasympathetic autonomic nervous system modulations

La marche (un moyen standardisable de l'évaluation des capacités au cours des maladies cardiovasculaires ?)

Les maladies cardio et cérébro-vasculaires représentent la première cause de mortalité et de handicap dans le monde. Du fait des progrès thérapeutiques dans la prise en charge de ces pathologies à la phase aigüe, le nombre de patients porteurs de formes chroniques de ces affections limitant leurs capacités d effort est en augmentation constante. La problématique de ce travail de thèse s articule autour de l utilisation des tests de marche standardisés dans l évaluation des capacités d effort des patients porteurs de pathologies coronariennes. Nous avons dans un premier temps rappelé les notions de handicap et de qualité de vie appliqués aux maladies chroniques, et la nécessité d évaluations fonctionnelles spécifiques pour en apprécier le retentissement et l évolution. Puis nous avons fait le point sur les modalités actuelles de la réadaptation cardiaque, en développant plus particulièrement la place de l activité physique. Nous avons entrepris ensuite l étude des sollicitations physiologiques induites par un test de marche rapide de 200 mètres (TMR200) chez des sujets âgés sains, puis sur une population de patients coronariens. Ce test s est avéré bien toléré, et correspond à une intensité d exercice intermédiaire entre le premier seuil ventilatoire et les capacités maximales d exercice. Il apparaît ainsi particulièrement intéressant pour apprécier les capacités à effectuer des efforts fréquents de la vie quotidienne, plus intenses que ceux correspondant à la marche à vitesse spontanément adoptée au cours du classique tes de marche de 6 minutes (correspondant à un effort essentiellement aérobie). Par la suite nous avons cherché à définir la différence minimale cliniquement pertinente du test de marche (MCID) de 6 minutes (TM6) et du TMR200, afin de mieux interpréter les progrès fonctionnels des patients intégrés dans les programmes de réadaptation cardiaque après un syndrome coronarien aigu. Cette dernière a été estimée à 25 mètres pour le TM6. Enfin, nous avons étudié l intérêt de ces tests de marche dans l aide à l individualisation de la prescription de l intensité du réentraînement chez les patients coronariens. Ces modalités permettent aux patients d être plus souvent proches des intensités d entraînement conventionnellement préconisées, en aboutissant à des résultats comparables, sans la nécessité de pratiquer un test d effort maximal mobilisant des moyens significatifs en personnel et en matériel. Au total, ce travail apporte des arguments pour l utilisation en pratique clinique courante de ces tests de marche standardisés. Ils apparaissent complémentaires dans le cadre de l évaluation objective des capacités fonctionnelles et de la qualité de vie perçue des patients âgés et coronariens. Ces résultats ouvrent des perspectives pour poursuivre l étude de leurs propriétés métrologiques et de leurs applications cliniques au cours des affections chroniques incapacitantes.Cardiovascular and cerebrovascular diseases remain the first cause of mortality and handicap in the world. With the improvements in the management of the acute phase, the number of patients with limited exercise capacity due to chronic cardiovascular disease is increasing. The aim of this thesis was to conduct a thorough study of the use of standardized walk tests to assess exercise capacity in coronary artery disease patients. We first explain the concepts of handicap and quality of life in chronic diseases, and the need for functional evaluations in order to assess their impact and evolution. We then present the current modalities of cardiac rehabilitation, emphasizing the importance of physical activity. We studied the physiological demands of a 200-meter fast-walk test (200MFWT) in healthy elderly subjects, and in coronary artery disease patients. This test was well tolerated, and corresponds to an effort intensity lying between the ventilatory threshold and maximal exercise capacity. It therefore appears interesting to assess the capacities of an individual to perform activities encountered in daily life that are more intense than walking at a self-selected comfortable speed, as during the 6-minute walk test (6-MWT) (corresponding to a moderate submaximal intensity solicitation, mainly aerobic). We then investigated the minimal clinically important difference of the 6MWT and 200MFWT, in order to better appraise functional improvements in patients undergoing cardiac rehabilitation after an acute coronary syndrome. This difference has been estimated at 25 metres for the 6MWT. Finally, we studied the interest of using these walk tests to individualize training intensity prescription in these patients. These modalities bring patients closer to the recommended intensity, while leading to results comparable to those of more traditional training programs, without the need for repeated expensive tests. In conclusion, this work supports the use of these standardized walk tests in routine clinical setting. They bring complementary information in the assessment of functional capacity and perceived quality of life in elderly patients and those with coronary artery disease. These results are a basis for further investigations regarding their metrological properties and clinical applications in various chronic diseases that reduce exercise capacity.DIJON-BU Doc.électronique (212319901) / SudocSudocFranceF

IMU PHASE-BASED PERFORMANCE EVALUATION SENSITIVITY TO THE PROGRESS OF YOUNG FRONT CRAWL SWIMMERS

The aim of this study was to evaluate the sensitivity of a phase-based performance assessment method obtained from a sacrum IMU to assess swimming progress. Five IMU-based goal metrics were extracted from the literature for the main swimming phases of wall push-off, glide, strokes preparation, swim, and total lap. Sixteen young competitive swimmers completed five one-way front crawl laps at maximum speed with an IMU attached to the sacrum while the coach recorded lap time as the main indicator of performance level. To monitor the swimmers\u27 performance improvement, the same test was repeated once a week for 10 weeks. The minimum 0.5s change in lap time was calculated as the minimum worthwhile enhancement. The results showed that the goal metric of whole lap and swim phase closely predict swimming progress (e.g., accuracy, precision, sensitivity, and specificity of 0.91, 0.89, 0.94, and 0.95 for the whole lap goal metric, respectively). Other goal metrics achieved high precision and specificity (≥ 0.79) for detecting the progress, indicating that they can be reliably used for further improvement of swimmers in the level of swimming phases. The results showed that coaches can use the goal metrics in training sessions to track the progress of the swimmers in each phase

Person identification using deep neural networks on physiological biomarkers during exercise

Much progress has been made in wearable sensors that provide real-time continuous physiological data from non- invasive measurements including heart rate and biofluids such as sweat. This information can potentially be used to identify the health condition of a person by applying machine learning algorithms on the physiological measurements. We present a person identification task that uses machine learning algorithms on a set of biomarkers collected from 30 subjects carrying out a cycling experiment. We compared an SVM and a gated recurrent neural network (RNN) for real-time accuracy using different window sizes of the measured data. Results show that using all biomarkers gave the best results from any of the models. With all biomarkers, the gated RNN model achieved ∼90% accuracy even in a 30 s time window; and ∼92.3% accuracy in a 150 s time window. Excluding any of the biomarkers leads to at least 7.4% absolute accuracy drop for the RNN model. The RNN implementation on the Jetson Nano incurs a low latency of ∼45 ms per inference

Predicting Hydration Status Using Machine Learning Models From Physiological and Sweat Biomarkers During Endurance Exercise: A Single Case Study

Improper hydration routines can reduce athletic performance. Recent studies show that data from noninvasive biomarker recordings can help to evaluate the hydration status of subjects during endurance exercise. These studies are usually carried out on multiple subjects. In this work, we present the first study on predicting hydration status using machine learning models from single-subject experiments, which involve 32 exercise sessions of constant moderate intensity performed with and without fluid intake. During exercise, we measured four noninvasive physiological and sweat biomarkers including heart rate, core temperature, sweat sodium concentration, and whole-body sweat rate. Sweat sodium concentration was measured from six body regions using absorbent patches. We used three machine learning models to determine the percentage of body weight loss as an indicator of dehydration with these biomarkers and compared the prediction accuracy. The results on this single subject show that these models gave similar mean absolute errors, while in general the nonlinear models slightly outperformed the linear model in most of the experiments. The prediction accuracy of using the whole-body sweat rate or heart rate was higher than using core temperature or sweat sodium concentration. In addition, the model trained on the sweat sodium concentration collected from the arms gave slightly better accuracy than from the other five body regions. This exploratory work paves the way for the use of these machine learning models to develop personalized health monitoring together with emerging, noninvasive wearable sensor devices

Pituitary tumors contain a side population with tumor stem cell-associated characteristics

Pituitary adenomas cause significant endocrine and mass-related morbidity. Little is known about the mechanisms that underlie pituitary tumor pathogenesis. In the present study, we searched for a side population (SP) in pituitary tumors representing cells with high efflux capacity and potentially enriched for tumor stem cells (TSCs). Human pituitary adenomas contain a SP irrespective of hormonal phenotype. This adenoma SP, as well as the purified SP (pSP) that is depleted from endothelial and immune cells, is enriched for cells that express ‘tumor stemness’ markers and signaling pathways, including epithelial–mesenchymal transition (EMT)-linked factors. Pituitary adenomas were found to contain self-renewing sphere-forming cells, considered to be a property of TSCs. These sphere-initiating cells were recovered in the pSP. Because benign pituitary adenomas do not grow in vitro and have failed to expand in immunodeficient mice, the pituitary tumor cell line AtT20 was further used. We identified a SP in this cell line and found it to be more tumorigenic than the non-SP ‘main population’. Of the two EMT regulatory pathways tested, the inhibition of chemokine (C-X-C motif) receptor 4 (CXCR4) signaling reduced EMT-associated cell motility in vitro as well as xenograft tumor growth, whereas the activation of TGFβ had no effect. The human adenoma pSP also showed upregulated expression of the pituitary stem cell marker SOX2. Pituitaries from dopamine receptor D2 knockout (Drd2−/−) mice that bear prolactinomas contain more pSP, Sox2+, and colony-forming cells than WT glands. In conclusion, we detected a SP in pituitary tumors and identified TSC-associated characteristics. The present study adds new elements to the unraveling of pituitary tumor pathogenesis and may lead to the identification of new therapeutic targets.Fil: Mertens, Freya. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Gremeaux, Lies. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; Bélgica; BélgicaFil: Chen, Jianghai. Huazhong University of Science and Technology. Tongji Medical College Union Hospital; China. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Fu, Qiuli. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; Bélgica. Zhejiang Provincial Key Laboratory of Ophthalmology; China. Medical College of Zhejiang University. Eye Center of the 2nd Affiliated Hospital; ChinaFil: Willems, Christophe. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Roose, Heleen. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; BélgicaFil: Govaere, Olivier. KU Leuven. Department of Imaging and Pathology; BélgicaFil: Roskams, Tania. KU Leuven. Department of Imaging and Pathology; BélgicaFil: Cristina, Silvia Carolina. Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro de Investigaciones y Transferencia del Noroeste de la Provincia de Buenos Aires; ArgentinaFil: Becu Villalobos, Damasia. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Biología y Medicina Experimental (i); ArgentinaFil: Joriseen, Mark. University Hospitals Leuven. Unit Head and Neck Oncology; BélgicaFil: Vander Poorten, Vincent. University Hospitals Leuven. Research Group Experimental Oto-Rhino-Laryngology, ; BélgicaFil: Bex, Marie. University Hospitals Leuven. Unit Clinical and Experimental Endocrinology; BélgicaFil: Van Loon, Johannes. University Hospitals Leuven. Research Group Experimental Neurosurgery and Neuroanatomy; BélgicaFil: Vankelecom, Hugo. Ku Leuven University (University of Leuven). Research Unit of Stem Cell Research; Bélgic

Real-time smart multisensing wearable platform for monitoring sweat biomarkers during exercise

Sweat secreted by the human eccrine sweat glands can provide valuable biomarker information during exercise in hot and humid conditions. Real-time noninvasive biomarker recordings are therefore useful for evaluating the physiological conditions of an athlete such as their hydration status during endurance exercise. In this work, we describe a platform that in- cludes different sweat biomonitoring prototypes of cost-effective, smart wearable devices for continuous biomonitoring of sweat during exercise. One prototype is based on conformable and disposable soft sensing patches with an integrated multi-sensor array requiring the integration of different sensors and printed sensors with their corresponding functionalization protocols on the same substrate. The second is based on silicon based sensors and paper microfluidics. Both platforms integrate a multi-sensor array for measuring sodium, potassium, and pH in sweat. We show preliminary results obtained from the multi-sensor prototypes placed on two athletes during exercise. We also show that the machine learning algorithms can predict the percentage of body weight loss during exercise from biomarkers such as heart rate and sweat sodium concentration collected over multiple subjects