1,036 research outputs found
Evaluation of WIMU Sensor Performance in Estimating Running Stride and Vertical Stiffness in Football Training Sessions: A Comparison with Smart Insoles
No full textTemporal parameters are crucial for understanding running performance, especially in elite sports environments. Traditional measurement methods are often labor-intensive and not suitable for field conditions. This study seeks to provide greater clarity in parameter estimation using a single device by comparing it to the gold standard. Specifically, this study aims to investigate how the temporal parameters and vertical stiffness (Kvert) of running stride exerted by IMU sensors are related to the parameters of the smart insole for outdoor acquisition. Ten healthy male subjects performed four 60-meter high-speed runs. Data were collected using the WIMU PRO™ device and smart insoles. Contact time (CT) and flight time (FT) were identified, and Kvert was calculated using Morin’s method. Statistical analyses assessed data normality, correlations, and reliability. WIMU measured longer CT, with differences ranging from 26.3% to 38.5%, and shorter FT, with differences ranging from 27.3% to 54.5%, compared to smart insoles, across different running speeds. Kvert values were lower with WIMU, with differences ranging from 23.96% to 45.01% depending on the running activity, indicating significant differences (p < 0.001). Using these results, a multiple linear regression model was developed for the correction of WIMU’s Kvert values, improving the accuracy. The improved accuracy of Kvert measurements has significant implications for athletic performance. It provides sports scientists with a more reliable metric to estimate player fatigue, potentially leading to more effective training regimens and injury prevention strategies. This advancement is particularly valuable in team sports settings, where easy-to-use and accurate biomechanical assessments of multiple athletes are essential
Exploring the Relationship Between the Acute:Chronic Workload Ratio and Running Parameters in Elite Football Athletes
No full textIn contemporary sports science, the integration of wearable inertial measurement units (IMUs) has revolutionized athlete performance monitoring, offering insights into training load management and injury risk mitigation. The acute:chronic workload ratio (ACWR) has emerged as a pivotal metric, indicating the balance between acute training stress and chronic adaptation. This study investigates the relationship between ACWR and running parameters, i.e., contact time (CT), flight time (FT), and vertical stiffness (Kvert). Data from thirty-five elite male soccer players were analyzed using the WIMU Pro system. Statistical analyses showed that CT increased with workload, with significant differences observed between athletes in the sweet spot and others in the danger zone (p vert values were consistently lower in athletes in the danger zone across all workload indicators (p < 0.001), with large effect sizes going up to 0.94. Conversely, FT showed no significant variation between ACWR groups. These findings suggest that elevated ACWRs may be linked to reductions in vertical stiffness, highlighting a potential increase in risk of injury. Coaches and practitioners can utilize these insights to tailor training programs, integrating load monitoring with tactical considerations to optimize athlete performance. Understanding the nuanced interplay between workload ratios and biomechanical parameters provides valuable insights for performance optimization for elite football athletes
Atrial natriuretic factor-like immunoreactive system in the brain of the frog, Rana esculenta, durin ontogenesis
No full textOrganization of atrial natriuretic factor-like immunoreactive system in the brain of the frog Rana esculenta during development
No full textImmunocytochemical distribution of the atrial natriuretic factor (ANF) has been studied in the brain and pituitary of the anuran Rana esculenta during development and in juvenile animals. Using human ANF and rat α-ANF antisera, immunoreactive cell bodies and nerve fibers were revealed in stage II-III tadpoles and in successive larval stages. Soon after hatching, stages II-III, the ANF-like-immunoreactive elements were confined to the preoptic area-median eminence complex. During successive stages of development, new groups of ANF-immunoreactive cell bodies appeared. In larval stage VI, immunoreactive perikarya were found in the rostral part of the anteroventral area of the thalamus and numerous ANF-like-immunoreactive cells appeared in the pars distalis of the pituitary. In larval stages XIV and XVIII, the distribution of ANF immunoreactivity was virtually similar. The ANF-immunoreactive cells in the preoptic nucleus and in the pituitary pars distalis were comparatively more abundant than in stage VI. During the metamorphic climax (stages XXI-XXII), a new group of ANF-immunoreactive cell bodies appeared in the rostral part of the ventrolateral area of the thalamus. During this stage, ANF-immunoreactive fiber projections were found in the pars intermedia for the first time. However, the pars distalis cells were very weakly immunofluorescent. The pattern of ANF immunoreactivity in the brain ofjuvenile animals was very similar to that described for stages XXI and XXII, whereas the pars distalis cells showed no immunoreactivity. It is conceivable that, early during development, ANF-related peptides may be involved in the regulation of pituitary secretion by means of autocrine mechanisms or may act as a classic pituitary hormone
Exploring the Relationship between Acute:Chronic Workload Ratio and Vertical Stiffness in Elite Football Athletes
No full textDistribution of vasoactive intestinal peptide-like immunoreactivity in the brain and pituitary of the frog (Rana esculenta) during development
No full textThe localization of vasoactive intestinal peptide (VIP)-like immunoreactive (ir) elements was investigated in the brain of the anuran amphibian, Rana esculenta, during development. Using an antiserum raised against the porcine VIP, ir cell bodies and fibers were observed in the forebrain of tadpoles a few days after hatching. During early premetamorphosis, ir perikarya were distributed in the ventral infundibular nucleus of the hypothalamus and in the posterocentral nucleus of the thalamus. Labeled fibers were detected in the olfactory bulbs and in the hypothalamus. In these larvae, furthermore, several VIP-ir cells were found in the pars distalis of the pituitary and there were ir fibers in the pars nervosa. In tadpoles at stages VIII-IX, a new group of VIP-labeled neurons was observed in the dorsal part of the infundibular nucleus. In other brain regions, the distribution of the immunoreactivity was similar to that described in the earliest stages, i.e., IV-VII. During mid-premetamorphosis, stages X-XII of development, an additional set of ir perikarya appeared in the ventrolateral area of the thalamus. During late premetamorphosis, stages XIII-XVIII, the organization of VIP-like immunoreactivity was more complex and its distribution more widespread. Two new groups of ir cell bodies appeared, one in the preoptic nucleus and another in the anteroventral area of the thalamus, and for the first time, VIP immunoreactivity was observed in the median eminence. This distribution pattern persisted through to the prometamorphic, four-limb stage. Strikingly, no VIP-ir elements were observed anywhere in the mid- and hindbrain. The present results indicate that a VIP-like ir peptide may be involved in the processing of olfactory information or may act as a neurohormone, hypophysiotropic factor, and neuromodulator in the brain of R. esculenta during development. Copyright (C) 1999 Elsevier Science B.V
Evaluation of WIMU sensor performance in estimating running stride time and vertical stiffness: a comparison with smart pressure insoles
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Analysis of Mathieu Equation Stable Solutions in the First Zone of Stability
No full textAbstractThe paper presents the results of a homogeneous Mathieu equation studies. Mathieu equation solutions are oscillations, modulated in amplitude and frequency. In the computational experiments we found dependences of the given oscillations on the ratio of the coefficients. These dependences are shown in graphs that can be used for an approximate estimation of the Mathieu equation solutions without integration
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