QUANTIFYING MECHANICAL LOADING DURING TRAINING IN TRACK ATHELTES

The present study investigated the potential of inertial sensors to objectively quantify mechanical load during training in track athletes. Three female sprinters wore a single inertial sensor attached to the distal tibia during identical training sessions on two separate occasions. Objective measures of the ‘relative’ mechanical loading (acceleration integral expressed per second) obtained from the inertial sensors were highly correlated with increases in running velocity and indicated excellent repeatability across the two sessions. Quantifying mechanical loading during training using this technology appears viable and may provide important insights into differences in training loading within and between individuals. Such training load measures may assist in identifying increased injury risk in high level track and field athletes

THE INFLUENCE OF HEEL HEIGHT ON ANKLE KINEMATICS DURING STANDING, WALKING, JOGGING AND SIDESTEPPING IN CHILDREN

The aim of this study was to quantify the effects of heel-forefoot height on ankle kinematics during locomotion in children. Measurements were taken by a motion capture system and a force plate on five children. They were asked to perform standing, walking, jogging and sidestepping in barefoot, low heel, standard heel and high heel shoe conditions. Results showed that rearfoot plantarflexion angle was different from shoe rake during standing. There was more ankle plantarflexion as heel height increased during walking, jogging and sidestepping. Ankle inversion velocity increased with shod condition but not significantly. High heel height will affect ankle kinematics during locomotion, which may increase the risk of foot problems. Children and their parents should choose footwear with caution

EFFECT OF FOOTWEAR ON LOWER LIMB KINEMATICS IN CHILDREN DURING SIDESTEP

Wearing shoes has been shown to affect children’s gait and neuromuscular development. This study aims to evaluate the effect of supportive shoes and flexible shoes on children’s lower limb kinematics during sidestep. Fourteen children aged 6 to 13 years, with no foot deformity were recruited. A motion analysis system and a force plate were used for motion capture. Compared to jogging, sidestep has increased sagittal plane motion and a different frontal plane movement pattern. The supportive shoes allowed smaller midfoot sagittal range of motion (ROM) and higher peak knee flexion whereas flexible shoes showed increased motion in the first metatarsophalangeal joint (MPJ), midfoot and hip with increased ankle eversion velocity and knee less internally rotated. Conventional supportive school shoes allowed less motion in healthy children’s feet, thus affecting negatively on long term lower limb functional development

CHANGES IN MOVEMENT REGULARITY DURING LEARNING OF A NOVEL DISCRETE TASK

Sample entropy and surrogate methods were employed to investigate changes in regularity of movement profiles during the learning of a novel discrete task under contextual interference conditions by two groups. The contextual interference effect was confirmed. Surrogate methods were used to show the presence of deterministic dynamics in observed data. Trends of decreased and increased movement regularity for groups 1 and 2 respectively were observed. The relative stage of learning and the ability to operate within an acceptable range of variability/complexity may explain these trends. Entropy estimates as a measure of regularity may provide important information about the learning of discrete tasks

A SURROGATE METHOD FOR DISCRETE MOVEMENT DATA

Sample entropy can be an effective tool for the investigation of human movement variability. However, before applying the method, it can be beneficial to employ an analysis to confirm that observed data is not solely the result of stochastic processes. This can be achieved using surrogate methods. Previous investigations have used surrogate methods within human gait data, yet no appropriate method has been applied to discrete human movement. This article proposes a surrogate method for discrete movement data. The technique reliably generated surrogates for discrete joint angle time series, effectively destroying fine-scale dynamics of the observed signal and maintaining macro structural characteristics (e.g., Mean, SD). Comparison of entropy estimates indicated that observed signals contained deterministic dynamics

Changes in Cardiopulmonary Reserve and Peripheral Arterial Function Concomitantly with Subclinical Inflammation and Oxidative Stress in Patients with Heart Failure with Preserved Ejection Fraction

Background. Changes in cardiopulmonary reserve and biomarkers related to wall stress, inflammation, and oxidative stress concomitantly with the evaluation of peripheral arterial blood flow have not been investigated in patients with heart failure with preserved ejection fraction (HFpEF) compared with healthy subjects (CTL). Methods and Results. Eighteen HFpEF patients and 14 CTL were recruited. Plasma levels of inflammatory and oxidative stress biomarkers were measured at rest. Brain natriuretic peptide (BNP) was measured at rest and peak exercise. Cardiopulmonary reserve was assessed using an exercise protocol with gas exchange analyses. Peripheral arterial blood flow was determined by strain gauge plethysmography. Peak VO2 (12.0±0.4 versus 19.1±1.1 mL/min/kg, P<0.001) and oxygen uptake efficiency slope (1.55±0.12 versus 2.06±0.14, P<0.05) were significantly decreased in HFpEF patients compared with CTL. BNP at rest and following stress, C-reactive-protein, interleukin-6, and TBARS were significantly elevated in HFpEF. Both basal and posthyperemic arterial blood flow were not significantly different between the HFpEF patients and CTL. Conclusions. HFpEF exhibits a severe reduction in cardiopulmonary reserve and oxygen uptake efficiency concomitantly with an elevation in a broad spectrum of biomarkers confirming an inflammatory and prooxidative status in patients with HFpEF

Toward Fast Determination of Protein Stability Maps: Experimental and Theoretical Analysis of Mutants of a <i>Nocardiopsis prasina</i> Serine Protease

The stability of serine proteases is of major importance for their application in industrial processes. Here we study the determinants of the stability of a <i>Nocardiopsis prasina</i> serine protease using fast residual activity assays, a feature classification algorithm, and structure-based energy calculation algorithms for 121 micropurified mutant enzyme clones containing multiple point mutations. Using a multivariate regression analysis, we deconvolute the data for the mutant clones and find that mutations of residues Asn47 and Pro124 are deleterious to the stability of the enzyme. Both of these residues are situated in loops that are known to be important for the stability of the highly homologous α-lytic protease. Structure-based energy calculations with PEATSA give a good general agreement with the trend of experimentally measured values but also identify a number of clones that the algorithm fails to predict correctly. We discuss the significance of the results in relation to the structure and function of closely related proteases, comment on the optimal experimental design when performing high-throughput experiments for characterizing the determinants of protein stability, and discuss the performance of structure-based energy calculations with complex data sets such as the one presented here