Study of the association between gait variability and physical activity

Background: Gait variability can be considered an indirect measure of gait stability, in particular regarding temporal or spatial variability assessment. Physical activity, such as walking, is advised for the elderly and can be improved by gait stability. The aim of this study was to investigate the associations between gait stability and physical activity in women of different age ranges. Methods: Forty-two healthy women of different age ranges (18-40 yrs. and 65-75 yrs.) were recruited in the study. To assess physical activity, the subjects wore a multi-sensor activity monitor for a whole week, inferring the time spent in moderate to vigorous physical activity (MVPA). MVPA were analysed in bouts of at least 10 subsequent minutes (MVPAbouts) and in overall minutes (MVPAtot). A kinematic analysis was performed with an optoelectronic system to calculate gait variability - expressed as standard deviation (SD) and coefficient of variability (CV) of step width, stride length, stance and swing time (during treadmill walking at different speeds). Results: Elderly women, with high walking speed (5 km/h), and moderate step width variability (CV = 8â\u80\u9327%), met the recommended levels of physical activity (MVPAtotand MVPAbouts). Furthermore, gait variability, adjusted for age and number of falls, was significantly and negatively associated with MVPAtotonly at 3.5 km/h, and with MVPAboutsonly at 4 km/h. Conclusions: In a population of healthy elderly women, gait variability was significantly and negatively associated with the level of physical activity. Healthy elderly women, with moderate gait variability (step width variability), and high preferred walking speed, seem to be able to meet the recommended levels of physical activity

The face in Down’s syndrome: indices of overall size and harmony in Sudanese vs Italian subjects

The study aimed to provide quantitative information about the facial soft-tissues of Italian and Northern Sudanese subjects with Down’s syndrome (DS) by using summary anthropometric measurements representative of facial size and harmony. The 3D coordinates of soft-tissue facial landmarks were obtained by a computerized digitizer in 54 Italian subjects with DS (20 females, 34 males, aged 13-52 years), in 64 Northern Sudanese subjects with DS (18 females, 46 males, aged 5-34 years), in 578 healthy Italian, and 653 healthy Northern Sudanese reference subjects, matched for sex and age. From the landmarks, 16 facial dimensions were calculated. Data from subjects with DS were compared to those collected in reference individuals by computing z-scores. Two summary anthropometric measurements for quantifying craniofacial variations were obtained: the mean z-score (an index of overall facial size), and its standard deviation, or the craniofacial variability index (an index of facial harmony) [1]. In subjects with DS, facial size was significantly smaller, and craniofacial variability was significantly larger than in normal individuals; 93% of Italian and 81% of Northern Sudanese subjects with DS had one or both values outside the normal interval. Overall, Italian subjects with DS differed more from the norm than Northern Sudanese ones. In the Northern Sudanese subjects, the mean z-scores and the CVI decreased significantly with age. The facial soft-tissue structures of subjects with DS differed from those of normal controls of the same age, sex and ethnic group: a reduced facial size was coupled with a global anomalous relationship between individual measurements. The alterations in soft-tissue facial dimensions were different in the two ethnic groups and partially influenced by age

Three-dimensional analysis of balance control strategies in elite karateka

In karate, balance control represents a key performance determinant (1). Balance stability was reported to be related to a refined control of the center of mass (CoM) displacement (2). The aim of the current study was to quantitatively investigate the motor strategies adopted by elite and non-elite karateka to maintain balance control. We analyzed the execution of traditional karate techniques (kata) in two groups: elite Masters (n=6, 31±19 years) and non-elite Practitioners (n=4, 25±9 years). On each participant, the three-dimensional coordinates of 14 reflective markers (landmarks: right and left tragion, acromion, olecranum, radius styloid process, great trochanter, femur lateral epicondyle, lateral malleolus) were recorded by nine infrared cameras of an optoelectronic motion analyzer with a 120 Hz sampling rate. Kinematic parameters assessed were: CoM, step width, joints range of motions. CoM kinematics was computed according to the segmental centroid method (3). In the 11 steps of kata, CoM height was 8% lower (p<0.05, Mann-Whitney non parametric U-test), CoM average velocity and rms acceleration were approximately 35% higher (p<0.05) and step width was higher (p<0.05) in Masters. There was a significant difference between groups in CoM height and step width in seven and six out of the 11 steps, respectively. CoM vertical displacements resulted almost equal along the vertical direction, while in the horizontal direction it was significantly (p<0.05) higher in Masters than in Practitioners. Results suggest that elite karateka developed a refined body balance control, obtained through the increase of the base of support and different maneuvers of lower limbs. The proposed method could be used to objectively detect talented karateka, to measure proficiency level and to assess training effectiveness

Dribbling skill determinants in youth soccer players

Dribbling and pass-kick are the most frequently performed techniques during match play. While an extensive knowledge is available about kicking biomechanics, little is known about dribbling kinematics. Given that dribbling performance can assist in the talent identification process [1], we aim at finding the biomechanics determinants of this technique. A motion analysis system recorded the 3-D coordinates of 21 reflective markers placed upon the body of 10 youth sub-elite soccer players (12.6±0.37 years, 42.9±6.15 kg, 1.54 ± 0.07 m). Each participant performed 5 slalom-dribbling tests consisting of a 180° turning and four changes of direction. Since dribbling speed is a separating performance factor, players were split into two groups of 5 according to the execution time (“fast” and “slow”). Center of Mass (CoM) trajectory, Range of Motion (RoM), velocity and acceleration were computed along the three directions [2]. Mann-Whitney’s non-parametric tests were used for comparisons. Fast and slow players did not differ in terms of age, weight, body height, BMI, playing position and number of foot-ball contacts (p>0.05). While CoM average velocity and root mean square acceleration were similar in the two groups, CoM mediolateral and craniocaudal RoM were significantly lower (p<0.05) in faster players. Skilled players took less time in completing the test because they were able to drive the ball while running through a shorter path. Their CoM vertical and lateral displacements were significantly lower, meaning that, at a higher skill level, dribbling technique is delivered in a more effective and economical way

Can experience in karate be estimated by Principal Component Analysis?

Karate is a Japanese martial art that involves repeated and technically demanding sequences of strikes and defences. In kata competition selected movements are organised in fixed sequences of varying duration and complexity. The evaluation of kata is usually made by subjective scoring from coaches and judges, who employ a qualitative, global assessment. Holistic quantitative evaluations of karate performance are still unavailable. Based on previous findings (1), we hypothesise that the multi-joint motion patterns that enable complex techniques are experience-dependent. If this were true, we would seek to find which motion pattern could be more sensible to the experience level. To test this hypothesis, a method based on the Principal Component Analysis (PCA) appears well-suited to detect the “synergies” or “coordinative structures” by which the motor system organises a movement (2). PCA can provide a quantitative global analysis of stylistic differences in technique. In this study we aimed at: describing the fundamental multi-joint synergies of a karate performance, under the hypothesis that the latter are skill-dependent; estimate karateka’s experience level, expressed as years of practice. A motion capture system recorded traditional karate techniques of ten professional and amateur karateka. At any time point, the 3D-coordinates of body markers gave posture vector that were normalised, concatenated from all karateka and submitted to a first PCA. Five principal movements described both gross movement synergies and individual difference, explaining 91% of the overall variance. A second PCA followed by linear regression estimated the years of practice using principal movements (eigenpostures and weighting curves) and centre-of-mass kinematics (error: 3.71 ys; R2=0.91,

Cabbage and fermented vegetables : From death rate heterogeneity in countries to candidates for mitigation strategies of severe COVID-19

Large differences in COVID-19 death rates exist between countries and between regions of the same country. Some very low death rate countries such as Eastern Asia, Central Europe, or the Balkans have a common feature of eating large quantities of fermented foods. Although biases exist when examining ecological studies, fermented vegetables or cabbage have been associated with low death rates in European countries. SARS-CoV-2 binds to its receptor, the angiotensin-converting enzyme 2 (ACE2). As a result of SARS-CoV-2 binding, ACE2 downregulation enhances the angiotensin II receptor type 1 (AT(1)R) axis associated with oxidative stress. This leads to insulin resistance as well as lung and endothelial damage, two severe outcomes of COVID-19. The nuclear factor (erythroid-derived 2)-like 2 (Nrf2) is the most potent antioxidant in humans and can block in particular the AT(1)R axis. Cabbage contains precursors of sulforaphane, the most active natural activator of Nrf2. Fermented vegetables contain many lactobacilli, which are also potent Nrf2 activators. Three examples are: kimchi in Korea, westernized foods, and the slum paradox. It is proposed that fermented cabbage is a proof-of-concept of dietary manipulations that may enhance Nrf2-associated antioxidant effects, helpful in mitigating COVID-19 severity.Peer reviewe

Nrf2-interacting nutrients and COVID-19 : time for research to develop adaptation strategies

There are large between- and within-country variations in COVID-19 death rates. Some very low death rate settings such as Eastern Asia, Central Europe, the Balkans and Africa have a common feature of eating large quantities of fermented foods whose intake is associated with the activation of the Nrf2 (Nuclear factor (erythroid-derived 2)-like 2) anti-oxidant transcription factor. There are many Nrf2-interacting nutrients (berberine, curcumin, epigallocatechin gallate, genistein, quercetin, resveratrol, sulforaphane) that all act similarly to reduce insulin resistance, endothelial damage, lung injury and cytokine storm. They also act on the same mechanisms (mTOR: Mammalian target of rapamycin, PPAR gamma:Peroxisome proliferator-activated receptor, NF kappa B: Nuclear factor kappa B, ERK: Extracellular signal-regulated kinases and eIF2 alpha:Elongation initiation factor 2 alpha). They may as a result be important in mitigating the severity of COVID-19, acting through the endoplasmic reticulum stress or ACE-Angiotensin-II-AT(1)R axis (AT(1)R) pathway. Many Nrf2-interacting nutrients are also interacting with TRPA1 and/or TRPV1. Interestingly, geographical areas with very low COVID-19 mortality are those with the lowest prevalence of obesity (Sub-Saharan Africa and Asia). It is tempting to propose that Nrf2-interacting foods and nutrients can re-balance insulin resistance and have a significant effect on COVID-19 severity. It is therefore possible that the intake of these foods may restore an optimal natural balance for the Nrf2 pathway and may be of interest in the mitigation of COVID-19 severity