Short Step Research Articles

Gait, physical function, and physical activity in three groups of home-dwelling older adults with different severity of cognitive impairment \u2013 a cross-sectional study

BackgroundThe research on associations between gait, physical function, physical activity (PA), and cognitive function is growing. Still, clinical assessments of cognitive function and motor function is often kept separate. In this study, we aimed to look at a broad range of measures of gait, physical function, and PA in three groups of home-dwelling older adults with no or questionable dementia, mild dementia, and moderate/severe dementia.MethodsThis cross-sectional study included 100 home-dwelling older adults, recruited from an outpatient geriatric memory clinic. Severity of dementia was categorised using the clinical dementia rating scale (CDR), with no or questionable dementia (CDR score 0 and 0.5), mild dementia (CDR score 1) and moderate/severe dementia (CDR score 2 and 3). We used thigh worn accelerometers to measure daily PA, the Short Physical Performance Battery (SPPB) to measure physical function, and an electronic gait mat to evaluate gait characteristics. Associations between severity of dementia and measures of PA, physical function, and gait characteristics were assessed by linear regression.ResultsParticipants’ (mean age 78.9 (SD 6.7) years, 57% women) average gait speed was 0.93 m/sec, and average upright time was 301 min/day. Statistically significant associations were found for the severity of dementia and gait speed (p=0.002), step time (p=0.001), physical function (SPPB, p=0.007), and PA (upright time, p=0.031), after adjusting for age. Overall, having no or questionable dementia was associated with faster gait speed (mean difference 0.163 (95% CI: 0.053 to 0.273)), shorter step time (-0.043 (-0.082 to -0.005)), better SPPB score (1.7 (0.5 to 2.8)), and longer upright time (78.9 (18.9 to 139.0)), compared to those with mild dementia. Furthermore, having no or questionable dementia was also associated with faster gait speed and better SPPB scores, as compared to those with moderate to severe dementia. No evidence of any differences was found between the participants with the mild dementia versus the moderate to severe dementia.ConclusionsAfter adjusting for age, we found that the no or questionable dementia group to be associated with better gait and physical function, and more PA, as compared with the two groups with mild or moderate/severe dementia. Evaluation of gait, physical function, and PA can add clinically important information of everyday functioning in memory clinics meeting geriatric patients, but investigations on how to use these results to guide interventions are still needed.

Corelation of gait parameters, cognitive impairment and brain atrophy in patients with Parkinson’s disease and the «normally aging population»

Objective — to identify the most significant markers of gait that indicate a decrease in cognitive function based on investigation of the corelation of cognitive impairment, gait parameters and atrophy of brain structures in groups of patients with Parkinson’s disease and the «normally aging population».
 Methods and subjects. 66 subjects were examined: 30 patients with Parkinson’s disease (mean age 54.9 ± 5.9, 50 % men) and 33 without neurological pathology (mean age 52.7 ± 7.6, 66 % men). All of them underwent neurological examination, assessment of temporal and spatial gait parameters using the GaitRite system, grading of brain atrophy using a comprehensive visual rating scale of MRI scans and assessment of cognitive status using the Montreal Cognitive Assessment Scale.
 Results. Cognitive performance was significantly lower in the subgroup of patients with Parkinson’s disease compared to the subgroup of «normally aging population». The gait profile of patients with Parkinson’s disease significantly differed from the gait profile of individuals from the «normal aging» subgroup by slower gait velocity, shorter step length and stride length for both limbs. The gait parameters, which showed a strong correlation with cognitive tests, differed in the subgroups, but gait velocity, stride length and step length for both extremities were common among them. These common gait parameters showed a strong direct correlation with brain atrophy in the subgroup of patients with Parkinson’s disease, but only velocity correlated with atrophy in the subgroup of «normal aging» among all of them. It was determined by the method of multiple regression analysis that it was precisely the atrophy of the brain that turned out to be the most influential factor in the decrease in cognitive function in the general group and subgroups.
 Conclusions. The gait profile in Parkinson’s disease subgroup is characterized by lower velocity, shorter step length, stride length for both limbs and significantly differs from the subgroup of «normal aging». These changes are a consequence of the influence of the disease on the motor sphere. Velocity showed a strong correlation in both subgroups not only with cognitive abilities, but also with cerebral atrophy. This confirms the hypothesis about the possibility of using gait velocity as a universal sensitive marker for current and longitudinal assessment of cognitive function, especially in clinical practice.

Understanding creep in TiAl alloys on the nanosecond scale by molecular dynamics simulations

Molecular dynamics (MD) simulations of creep generally face the problem that the creep most often evolves on time scales hard to capture with MD due to their typically short time step size. Consequently, MD studies of creep often use unrealistically high temperatures and stresses and simplified atomistic models to make creep-like processes happen on computationally accessible time scales. Apparently, this compromises the physical reliability of such studies. To alleviate this problem, we designed an MD model of titanium aluminide (TiAl) with a microstructure matching at least many of the key parameters of experimentally observed microstructures. We applied this MD model with stresses much lower than the ones used in most previous creep studies (well below yield stress) and in the temperature range 0.55TM-0.7TM, with melting temperature TM. Compared to typical previous MD studies, this much more realistic setup produces creep rates more than three orders of magnitude smaller and thus much closer to reality. We identified the driving mechanisms of primary creep on the nanosecond scale that agree very well with recent experimental observations, thus contributing towards the overarching goal of bridging the gap between atomistic creep simulations and continuum-scale creep simulations for engineering applications.

Validation of a Sensor-Based Gait Analysis System with a Gold-Standard Motion Capture System in Patients with Parkinson's Disease.

Digital technologies provide the opportunity to analyze gait patterns in patients with Parkinson’s Disease using wearable sensors in clinical settings and a home environment. Confirming the technical validity of inertial sensors with a 3D motion capture system is a necessary step for the clinical application of sensor-based gait analysis. Therefore, the objective of this study was to compare gait parameters measured by a mobile sensor-based gait analysis system and a motion capture system as the gold standard. Gait parameters of 37 patients were compared between both systems after performing a standardized 5 × 10 m walking test by reliability analysis using intra-class correlation and Bland–Altman plots. Additionally, gait parameters of an age-matched healthy control group (n = 14) were compared to the Parkinson cohort. Gait parameters representing bradykinesia and short steps showed excellent reliability (ICC > 0.96). Shuffling gait parameters reached ICC > 0.82. In a stridewise synchronization, no differences were observed for gait speed, stride length, stride time, relative stance and swing time (p > 0.05). In contrast, heel strike, toe off and toe clearance significantly differed between both systems (p < 0.01). Both gait analysis systems distinguish Parkinson patients from controls. Our results indicate that wearable sensors generate valid gait parameters compared to the motion capture system and can consequently be used for clinically relevant gait recordings in flexible environments.

Instrumented gait analysis defines the walking signature of CACNA1A disorders

BackgroundGait disturbances are a frequent symptom in CACNA1A disorders. Even though, data about their severity and progression are lacking and no CACNA1A-specific scale or assessment for gait is available.MethodsWe applied a gait assessment protocol in 20 ambulatory patients with genetically confirmed CACNA1A disorders and 39 matched healthy controls. An instrumented gait analysis (IGA) was performed by means of wearable sensors in basal condition and after a treadmill/cycloergometer challenge in selected cases.ResultsCACNA1A patients displayed lower gait speed, shorter steps with increased step length variability, a reduced landing acceleration as well as a reduced range of ankle motion compared to controls. Furthermore, gait-width in patients with episodic CACNA1A disorders was narrower as compared to controls. In one patient experiencing mild episodic symptoms after the treadmill challenge, the IGA was able to detect a deterioration over all gait parameters.ConclusionsIn CACNA1A patients, the IGA with wearable sensors unravels specific gait signatures which are not detectable at naked eye. These features (narrow-based gait, lower landing acceleration) distinguish these patients from other ataxic disorders and may be target of focused rehabilitative interventions. IGA can potentially be applied to monitor the neurological fluctuations associated with CACNA1A disorders.

Біомеханічні особливості ходьби хворих на коксартроз за даними системи GAITRite Частина 1. Геометричні параметри ходьби

Мета роботи: оцінити динаміку та особливості геометричних параметрів ходьби пацієнтів до тотального протезування кульшового суглоба та після нього при збереженні та зменшенні довжини плеча дії абдукторів (ДПДА) стегна після протезування у віддаленому періоді спостереження. Матеріали та методи. Аналізували геометричні параметри ходьби: довжина кроку (Step Length) або короткий крок; довжина довгого кроку (Stride Length); ширина опори (H-H Base Support) та величини кута розвороту стопи (Toe In/Toe Out), що були отримані за допомогою системи GAITRite. Було проаналізовано параметри ходьби 46 хворих на коксартроз. До І групи увійшло 26 хворих, у яких рентгенометрично після протезування кульшового суглоба довжина плеча дії абдукторів стегна не змінилася або різниця не перевищувала 10 мм у бік зменшення. До ІІ групи потрапили хворі (20 пацієнтів), у яких після протезування рентгенометрично було виявлено зменшення ДПДА стегна більше ніж на 10 мм. Обстеження проводили до протезування та у віддалені періоди спостереження — через 1–1,5 та 5–7 років після протезування. Результати. До протезування групи за параметрами ходьби були однаковими. Протезування у більшості хворих приводило до відновлення параметрів ходьби, хоча у більшості випадків нормалізація параметрів і не досягала середньостатистичної референтної норми, але практично відновлювало симетричність ходьби. Через 5–7 років у хворих спостерігали погіршення параметрів ходьби, а у деяких хворих погіршення показників досягало значень до ендопротезування. Особливо це було помітно у хворих зі зменшеною довжиною дії плеча абдукторів стегна. У цих хворих відбувалося постійне перенапруження означених м’язів, що у віддаленому періоді призводить до розвитку чи прогресування дегенеративних змін в інших суглобах нижньої кінцівки — колінному суглобі, гомілково-ступневому суглобі та поперековому відділі хребта, що й обумовлює погіршення ходьби у віддаленому періоді спостереження. Висновки. Проведений аналіз показав, що у хворих зі зменшенням довжини плеча дії абдукторів стегна внаслідок тривалого однобічного перенапруження м’язів протезованої кінцівки у віддаленому періоді спостерігається втрата опорності та надбаних після протезування навичок ходьби.

Cortical activation during gait adaptability in people with Parkinson’s disease

BackgroundPeople with Parkinson’s disease (PD) have difficulties adapting their gait. While underlying neural mechanisms involving the prefrontal cortex (PFC) have been studied across various complex walking tasks, less is known about the premotor cortex (PMC) and supplementary motor area (SMA), key cortical regions for motor planning. This study compared frontal cortical regions activation patterns using functional near-infrared spectroscopy (fNIRS), between people with PD and healthy controls (HC) during gait adaptability tasks. MethodsForty-nine people with PD (mean (SD) age: 69.5 (7.9) years) and 21 HC (69.0 (5.9) years) completed a simple walk and three randomly presented gait adaptability tasks: (i) stepping on targets, (ii) avoiding obstacles and (iii) negotiating both targets and obstacles. Cortical activity in the dorsolateral PFC (DLPFC), SMA and PMC were recorded using fNIRS. Step length, velocity and accuracy and cortical activity were contrasted between the groups and walking conditions. ResultsCompared with the HC, the PD group exhibited greater PMC activation and walked significantly slower and took shorter steps in all conditions. A statistically significant group by condition interaction indicated an increase in DLPFC cortical activation in the HC participants when undertaking the obstacle avoidance task compared with the simple walk but no increase in cortical activation in the PD group when undergoing this more challenging gait task. ConclusionsOur findings suggest people with PD have little or no DLPFC, SMA and PMC capacity beyond what they need for simple walking and in consequence need to slow their gait velocity to meet the demands of target stepping and obstacle avoidance tasks. Such behavioral and neural patterns appear consistent with concepts of compensatory over-activation and capacity limitation.

Antimicrobial susceptibility testing of Neisseria gonorrhoeae using a phenotypic-molecular assay and lyophilized antimicrobials

Gonorrhea is an urgent global public health threat as Neisseria gonorrhoeae (Ng) has progressively developed resistance to all antibiotics commonly used for treatment. Surveillance of antimicrobial susceptibility trends is critical to monitor the emergence and spread of antimicrobial resistance. The gold standard methods for antimicrobial susceptibility testing (AST) of Ng are laborious and time-consuming. We evaluated a phenotypic molecular approach, involving a short cultivation step and quantitative PCR, with lyophilized antimicrobials to characterize antimicrobial susceptibility in Ng. There was excellent concordance between AST performed with liquid and lyophilized ciprofloxacin, penicillin, and tetracycline using the pheno-molecular assay, following a 4-hour incubation step. The categorical agreement between the pheno-molecular assay and the gold standard AST results was 92.4% for characterization of antimicrobial susceptibility. Essential agreement between the 2 methods was 91.9%. Characterization of ceftriaxone susceptibility in Ng using the pheno-molecular assay required a 6-hour incubation step.

Expansion of Emmental cheese and tofu using instant controlled pressure drop (DIC) process

Two foods, belonging to different protein sources (dairy vs plant), namely Emmental cheese and tofu, were treated by the instant pressure drop (DIC) process inserted between two drying stages to obtain expanded and crispy snacks. This process consisted of a short heating step (t = 38–52 s) using steam under pressure (p = 0.26–0.62 MPa) and instantaneous pressure drop toward a vacuum. This pressure drop provoked auto-vaporization of the superheated liquid, which resulted in volume expansion, and cooling of the food. The expansion was visualized using a rapid camera at a frequency of 1000 images/s. The pressure and temperature histories were registered simultaneously. Three expansion ratios were evaluated: (i) r the ratio of food volumes after and before DIC process measured using sand pycnometry, (ii) rC calculated from dimensions measured by a caliper, and (iii) rI calculated from dimension reading from images. The shrinkage s = (rI/rC) −1, and the deformation d = (rC/r) −1 of the samples were then evaluated. Using response surface methodology, the optimal processing conditions for maximum expansions r = 2.5 and rC = 4.5 were found for Emmental and tofu, respectively as p = 0.5 and 0.62 MPa, t = 40 and 38 s. The creation of mist, inherent to the pressure drop of steam, made the visual observation impossible at the beginning of pressure drop. The samples were already expanded when the mist disappeared. Taking the mist presence as the upper limit of expansion time, the expansion took dozens of milliseconds at a pressure drop rate of 1.25 MPa/s. The temperature in the reactor decreased at a rate of 750 °C/s.

An Arrow Against Profane and Promiscuous Dancing. Drawn out of the Quiver of the Scriptures.

When a dancing master arrived in Boston in 1685 and offered lessons and classes for both sexes during times normally reserved for church meetings, the Puritan ministers went to court to suppress the practice. Increase Mather (1639-1723) took the leading part, writing and publishing this tract, which compiles arguments and precedents for the prohibition of “Gynecandrical Dancing, [i.e.] Mixt or Promiscuous Dancing, viz. of Men and Women … together.” These justifications were certainly shared with the court, which found the dancing master guilty, fined him £100, and allowed him to skip town. Mather’s tract on dancing is an overwhelming compendium of sources and authorities: from the Bible, classical authors, Christian Church Fathers, medieval philosophers, and Reformed theologians both Continental and English. None of them, it appears, approved of mixed dancing—because it leads to adultery and worse. The vilest sins and the direst disasters lie only a short step from the dance floor. The Arrow is remarkable for two things (at least): for how much allusion and citation are packed into its brief 30 pages, and for how quickly it escalates the issue into life-or-death scenarios, all vividly painted to emphasize the mortal danger of men and women dancing together.

Flash-Lamp Enabled Atomic Layer Deposition of Titanium Oxide

Atomic layer deposition (ALD) processes are widely used in research and development as well as in various production environments. Nowadays, a variety of materials can be deposited using thermal and energy enhanced atomic layer deposition but there are limits that are mainly set by the properties of available precursors and the related processes. Besides the necessity of suitable precursors and chemical reactions to deposit a specific material, there are two major limitations: the thermal self-decomposition of precursor molecules which can be in conflict with the required process temperatures enabling desired film properties, and the typical temperature-related reactivity of precursors and co-reactants with substrate materials. These can affect the initial film growth and can lead to adhesion issues and unwanted interface layers, such as oxides formed by oxidizing agents used during the ALD process.The thermal stability of precursors can be improved by optimizing precursor molecules but this is often related to reduced volatility and reactivity. Additionally, increased process temperatures might be incompatible with the tolerable thermal budget. Hence, processes with precursors chemisorbing at sufficiently low temperatures to avoid self-decomposition in combination with a second,preferably short process step at elevated temperatures to enable the required film properties is desirable.We developed a novel flash lamp enabled atomic layer deposition (FLE-ALD) process to address these limitations of common ALD processes. The process combines the self-limiting chemisorption of precursor molecules in the first half-reaction with a millisecond flash lamp anneal (FLA) during the second half-reaction. The applied heat during the second process step can even enable single-source ALD processes by inducing a thermal decomposition of chemisorbed molecules that form the desired film material.This paper demonstrates the FLE-ALD approach for the deposition of titanium oxide in a single-source process combining titanium tetraisopropoxide (TTIP) precursor exposures with flashes of optical light with a duration in the millisecond range to heat a surface for a very short time and to decompose the chemisorbed TTIP molecules. The heat induced by the short FLA step is distributed into the substrate’s bulk and the process chamber during the subsequent purging step, resulting in a constant substrate temperature and maintaining the self-limiting behavior of the TTIP chemisorption.A process was developed to confirm the self-limiting film growth typical for ALD process as well as the constant growth per cycle by varying and characterizing process parameters like precursor dose, purge times, flash lamp energy, substrate temperature, and cycle numbers. The FLA energy variation confirmed the need for the induced heat to decompose the TTIP molecules. Below an applied voltage of 1 kV, the flash lamps weren’t ignited and no film growth could be observed. This behavior was even confirmed for temperatures up to 300 °C as shown in figure 1, which compares the film growth with and without an FLA step for a wide range of process temperatures. Spectroscopic ellipsometry was used to measure the thicknesses and to investigate the optical properties of the deposited films. The obtained data was successfully described by a model using the optical properties of titanium oxide from literature enabling reliable and reproducible film thickness measurements. This result matches the film composition measured by X-ray photoelectron spectroscopy, showing only titanium and oxygen without noteworthy carbon or hydrocarbon impurities with less than 1 at.%. Figure 1

Preterm Birth Affects Early Motor Development in Pigs.

Background: Preterm infants frequently show neuromotor dysfunctions, but it is not clear how reduced gestational age at birth may induce developmental coordination disorders. Advancing postnatal age, not only post-conceptional age, may determine neuromuscular development, and early interventions in preterm newborns may improve their later motor skills. An animal model of preterm birth that allows early postnatal detection of movement patterns may help to investigate this hypothesis.Methods: Using pigs as a model for moderately preterm infants, preterm (106-day gestation, equivalent to 90% of normal gestation time; n = 38) and term (115-day gestation, equivalent to 99% of normal gestation time; n = 20) individuals were delivered by cesarean section and artificially reared until postnatal day 19 (preweaning period). The neuromotor skills of piglets were documented using spatiotemporal gait analyses on video recordings of locomotion at self-selected speed at postnatal age 3, 4, 5, 8, and 18 days. Results were controlled for effects of body weight and sex.Results: Both preterm and term piglets reached mature neuromotor skills and performance between postnatal days 3–5. However, preterm pigs took shorter steps at a higher frequency, than term piglets, irrespective of their body size. Within preterm pigs, males and low birth weight individuals took the shortest steps, and with the highest frequency.Conclusion: Postnatal development of motor skills and gait characteristics in pigs delivered in late gestation may show similarity to the compromised development of gait pattern in preterm infants. Relative to term pigs, the postnatal delay in gait development in preterm pigs was only few days, that is, much shorter than the 10-day reduction in gestation length. This indicates rapid postnatal adaptation of gait pattern after reduced gestational age at birth. Early-life physical training and medical interventions may support both short- and long-term gait development after preterm birth in both pigs and infants.

Large Eddy simulation of the fluctuating wind environment at a bridge site in the mountainous area

To have a comprehensive understanding of the complex wind environment at a bridge site in the mountainous area, a numerical simulation study of the wind environment under the mean and the fluctuating wind flow conditions was carried out and the results were compared. First, according to the weighted amplitude wave superposition (WAWS) method, the fluctuating wind speed time history was compiled by UDF. And the wind speed time history was added to the inlet boundary of a numerical empty wind tunnel to verify the feasibility of the simulation method of the fluctuating wind. Then, with a bridge in the mountainous area in Yunnan as the engineering background, a numerical simulation study of the wind environment of the bridge site area under the mean wind flow and the fluctuating wind flow was carried out by using FLUENT. The study indicates that Large Eddy Simulation (LES) method more accurate than Reynold average method with a sufficient number of grids and a short enough time step. The average wind characteristics of the bridge site under the mean wind and the fluctuating wind are not much different. The fluctuating wind characteristics at the bridge site are mainly affected by the terrain and the pulsating component of the wind flow. There are different terrain pulsation effects at the bridge site under different incoming flow directions.

Biomechanical Mechanisms of Improved Balance Recovery to Repeated Backward Slips Simulated by Treadmill Belt Accelerations in Young and Older Adults.

Aim: Exposure to repeated gait perturbations improves the balance of older adults (OAs) and decreases their risks of falling, but little is known about the underpinning mechanical adjustments. We aimed to quantify the changing temporo-spatial and kinetic characteristics of balance recovery following repeated backward slips to better understand the mechanical adjustments responsible for improved balance.Methods: We exposed 17 young adults (YAs) (25.2 ± 3.7 years) and 17 OAs (62.4 ± 6.6 years) to 10 backward slips simulated on an instrumented treadmill by unilateral backward belt accelerations. We measured the balance of the participants (margin of stability: MoS), balance recovery (nsteps: number of steps necessary to return to a steady gait for at least three consecutive steps), temporo-spatial (step length), and kinetics [ground reaction force (GRF) angle, lower limb joint moments] for 15 steps following each slip. The results were compared with baseline.Results: Participants in both groups improved their MoS and nsteps with repeated exposure to the slips, but no significant effect of age was detected. During the perturbed step, the GRF vector was directed more posteriorly during mid-stance and more anteriorly during push-off than baseline, which resulted in a longer step. These adjustments were maintained from the first (Slip01) to the last (Slip10) slip, and by Slip10 were correlated with better balance (MoS) on the second recovery step. During the first recovery step following Slip01, participants developed lower plantarflexor and larger knee extensor moments whilst taking a shorter step, these adjustments were correlated with poorer balance and were not maintained with repeated slips. Joint moments and step length of the first recovery step returned to normal levels by Slip10.Conclusion: Young adults and OAs improved their balance with repeated slips. The adjustments that were positively correlated with balance (changes in step length, GRF angle) were maintained whilst those that were not (changes in joint moments) were discarded. All the responses observed in Slip10 were observed in Slip01. The observed balance improvements were achieved by refining the initial strategy rather than by developing a new one. The underlying mechanics were correlated with step length of the first recovery steps, which was associated with balance and should be monitored in fall prevention interventions.

Estimation and Error Analysis for Optomechanical Inertial Sensors.

A sensor model and methodology to estimate the forcing accelerations measured using a novel optomechanical inertial sensor with the inclusion of stochastic bias and measurement noise processes is presented. A Kalman filter for the estimation of instantaneous sensor bias is developed; the outputs from this calibration step are then employed in two different approaches for the estimation of external accelerations applied to the sensor. The performance of the system is demonstrated using simulated measurements and representative values corresponding to a bench-tested 3.76 Hz oscillator. It is shown that the developed methods produce accurate estimates of the bias over a short calibration step. This information enables precise estimates of acceleration over an extended operation period. These results establish the feasibility of reliably precise acceleration estimates using the presented methods in conjunction with state of the art optomechanical sensing technology.

One‐Pot Synthesis of C3‐Alkylated Imidazopyridines from α‐Bromocarbonyls under Photoredox Conditions

AbstractA convenient strategy is presented for the synthesis of C3‐alkylated imidazopyridines through one pot condensation and alkylation of α‐bromocarbonyl compounds with 2‐aminopyridines. A series of C3‐alkylated imidazopyridines were obtained in moderate to high yields. This strategy was also elaborated to enable the synthesis of zolpidem in short steps, which otherwise require multistep synthesis.

Humans ditched swivelling hips for shorter stride than chimps

As a short adult, I marvel at the long strides taken by tall people. Their lengthy legs devour metres relative to my stubby trotting limbs. But compared with the strides of our closest relatives, even the tallest amongst us take relatively short steps; ‘standardized by size, humans really don't have long strides’, says Nathan Thompson from the New York Institute of Technology, USA. However, until recently, most scientists believed that the human stride was relatively long for efficiency; ‘this is taught in almost every introductory class and textbook’, Thompson says, although the misconception only became truly apparent when he began delving into the literature. And when Thompson began investigating how far chimpanzees rotate their pelvises as they walk, he began wondering whether swivelling their hips could hold the key to the chimpanzee's longer strides. Intrigued by the possibility, he decided to compare chimps and humans walking over a range of different speeds to find out whether the pelvis rotation provides the chimp's longer stride.‘Working with people and animals always has its difficulties’, says Thompson, who spent several years with Brigitte Demes, Susan Larson (both at Stony Brook University, USA) and Matt O'Neill (Midwestern University, USA) familiarising the chimpanzees with walking upright on two feet while they filmed the animals in 3D. Even working with the human walkers wasn't without its challenges. Thompson remembers one volunteer who kept getting fits of the giggles because walking in bare feet on the treadmill felt weird; ‘they couldn't help but walk in a totally bizarre way’, Thompson recalls.Once Danielle Rubinstein, William Parrella-O'Donnell and Matt Brett reconstructed the human's stride pattern and hip motions in 3-D, the team scaled the humans down to the size of the chimpanzees and found that although the humans’ legs were proportionally 112% longer, their strides were 26.7% shorter. Meanwhile, the chimpanzees swivelled their hips between 28 and 61 deg in contrast to the humans, which barely twisted their pelvises at all, by only ∼8 deg. And when the team checked how much further the pelvic rotation got them in terms of stride length, the chimpanzees had a distinct advantage. Their swivelling hips extended their stride 5.4 times more, relative to their size, than the human's diminutive swivel.‘I think that chimpanzees use pelvic rotations to try to squeeze every bit of stride length out, otherwise their strides would be – absolutely – very small’, says Thompson, explaining that apes and monkeys tend to walk on crouched legs that naturally shorten their stride; ‘I don't think there are a lot of options other than rotating the pelvis, given their anatomical constraints’, he adds.But why have humans ditched swivelling their hips when it could extend their strides further? Thompson suggests that extreme rotations of the hips could throw out the natural swing of our arms and legs – which counterbalance each other – forcing our muscles to work harder and making walking less efficient; a price that simply might not be worth paying for an increased stride length. Thompson also explains that scientists had thought for decades that humans had evolved the longest possible stride for efficiency, but now that it turns out that our stride is considerably shorter than that of our nearest cousins, he suspects that other factors have had a larger impact on the way we walk. ‘Humans have had about 7 million years of selective pressure for economical bipedalism; this means that there has been a lot of time to experiment with the costs and benefits, so it might be worth it to walk with slightly shorter strides, because whatever energy we lose, we might make up elsewhere’, he suggests.

Patellofemoral Joint Loading In Forward Lunge Rehabilitation Exercises

PURPOSE: Exercises that strengthen hip and thigh musculature, such as the forward lunge, are important to enhance patellofemoral joint stability in rehabilitation and training. The objective was to assess how patellofemoral joint force and stress change while lunging with step length and step height variations. The hypothesis was that patellofemoral force and stress would be greater with a short step and a ground-level step. METHODS: Sixteen participants performed a bodyweight forward lunge using short and long steps both at ground level and up to a 10 cm platform. Electromyography, ground reaction force, and kinematic variables were collected and input into a biomechanical optimization model, and patellofemoral joint force and stress were calculated as a function of knee angle. A repeated measures 2-way ANOVA (p < 0.05) with Holm-Bonferroni sequential correction was employed. RESULTS: No interactions between step length and step height were found. Comparing forward lunge with long step to short step, patellofemoral force and stress in the lead knee were greater with long step at the beginning of landing (10° to 30° knee angle) and the end of push-off (10° to 40° knee angle) and greater with short step during the deep knee flexion portion of the lunge (50° to 100° knee angle). Comparing forward lunge at ground level to a 10 cm platform, patellofemoral joint force and stress were greater at ground level during lunge descent (50° to 100° knee angle) and lunge ascent (40° to 70° knee angle). Patellofemoral joint force and stress generally increased as knee flexion increased and decreased as knee flexion decreased. CONCLUSIONS: Patellofemoral joint loading in the forward lunge change as step length, step height, and knee angle change. To gradually increase patellofemoral joint force and stress, it may be prudent to progress forward lunges as follows: 1) initially, with minimal knee flexion (0° to 30°); 2) then, with moderate knee flexion (0° to 60°); 3) with long step and deep knee flexion (0° to 100°) up to a 10 cm platform 4) and finally, with long step and deep knee flexion (0° to 100°) at ground level.

Effects of auditory feedback on gait behavior, gaze patterns and outcome performance in long jumping.

In the current study, we conducted two experiments to investigate the impact of concurrent, action-induced auditory feedback on gait patterns, gaze behavior and outcome performance in long jumping. In Experiment 1, we examined the effects of present vs. absent auditory feedback on gait, gaze and performance outcome measures. Results revealed a significant interaction effect between condition (present vs. absent auditory feedback) and phase (acceleration vs. zeroing-in phase) on participants' step lengths indicating that the absence (rather than the presence) of auditory feedback led to facilitatory effects in terms of a more prototypical gait pattern (i.e., shorter steps in the acceleration phase and longer steps in the zeroing-in phase). Similarly, the absent auditory feedback led to a higher gaze stability in terms of less switches between areas of interest (AOIs). However, there was no effect on jumped distance. In Experiment 2, we scrutinized the influence of concurrent vs. delayed auditory feedback on all three performance parameters. In contrast to concurrent feedback, delayed auditory feedback negatively affected all three measures: participants showed (i) dysfunctional deviations from their prototypical gait pattern (i.e., shorter steps across both phases of the run-up), (ii) less stable, maladaptive gaze patterns (i.e., more switches between AOIs) and (iii) poorer jumping performance (i.e., shorter jumped distances). Together, the two experiments provide clear evidence for the impact of concurrent, action-induced auditory feedback on the coordination of complex, rhythmical motor tasks such as the long jump.

ИССЛЕДОВАНИЕ ВЛИЯНИЯ ИЗМЕНЕНИЯ ПАРАМЕТРОВ МОДЕЛИ ARIMA НА КАЧЕСТВО ПРОГНОЗА ДЛЯ КОРОТКИХ НАБОРОВ ДАННЫХ

Time series, i.e. data collected at various times. The data collection segments may differ de-pending on the task. Time series are used for decision making. Time series analysis allows you to get some result that will determine the format of the decision. Time series analysis was carried out in very ancient times, for example, various calendars became a consequence of the analysis. Later, time series analysis was applied to study and forecast economic, social and other systems. Time se-ries appeared a long time ago. Once upon a time, ancient Babylonian astronomers, studying the po-sition of the stars, discovered the frequency of eclipses, which allowed them to predict their appearance in the future. Later, the analysis of time series, in a similar way, led to the creation of various calen-dars, for example, harvest calendars. In the future, in addition to natural areas, social and economic ones were added. Aim. Search for classification patterns of time series, allowing to understand whether it is possible to apply the ARIMA model for their short-term (3 counts) forecast. Materials and methods. Special software with ARIMA implementation and all need services is made. We examined 59 data sets with a short length and step equal a year, less than 20 values in the paper. The data was processed using Python libraries: Statsmodels and Pandas. The Dickey – Fuller test was used to de-termine the stationarity of the series. The stationarity of the time series allows for better forecasting. The Akaike information criterion was used to select the best model. Recommendations for a rea-sonable selection of parameters for adjusting ARIMA models are obtained. The dependence of the settings on the category of annual data set is shown. Conclusion. After processing the data, four categories (patterns) of year data sets were identified. Depending on the category ranges of parame-ters were selected for tuning ARIMA models. The suggested ranges will allow to determine the starting parameters for exploring similar datasets. Recommendations for improving the quality of post-forecast and forecast using the ARIMA model by adjusting the settings are given.