Warm-up Phase Research Articles

Autonomic regulation in athletic horses repetitively participating in two novice jumping classes on consecutive days.

Animal welfare is of great concern in equestrian sports and has been evaluated in athletic horses competing at different levels. However, the impact of consecutive days of jumping competition and the extent of resultant stress responses remains unclear. To address this point, the present study compared the changes in stress response via heart rate variability (HRV) in horses participating in two national jumping events on consecutive days. The study involved six experienced horses equipped with heart rate monitoring devices. HRV variables were measured before, during, and after jumping at 10-min intervals for 60 min on each competition day. Multiple HRV variables decreased to varying degrees on both days from warm-up until 30 min post-jumping. Meanwhile, the mean heart rate increased during jumping and returned to normal levels at 50 min post-jumping on the first day (for all intervals, p < 0.05-0.001), while it remained elevated beyond 60 min post-jumping on the second day (for all intervals, p < 0.01-0.001). Additionally, maximum heart rate and respiratory rate were higher on the second day than in the first round during the warm-up phase (p < 0.05 for both variables). The proportion of the HRV low-frequency band was higher during riding on the second day (p < 0.05), while the proportion of the high-frequency band was reduced during warm-up on the first day (p < 0.05) and during course riding on the second (p < 0.01). Meanwhile, the sympathetic nervous system index took longer to return to baseline on the second day than on the first. These results suggest that autonomic regulation differed in horses between jumping rounds on two consecutive days, with horses experiencing higher sympathetic activity and potentially increased stress in the second round. This information is important for riders, highlighting the need to be mindful of potential stress that could, at least in part, impact the welfare of horses participating in the same jumping competition on consecutive days.

Outpatient exercise training for chronic lung disease - for whom, how and why?

There is a legal entitlement to participate in outpatient exercise groups in accordance with the German Social Code (Book IX) which regulates and facilitates prescriptions for patients with chronic respiratory diseases. A medical examination with specific inclusion and exclusion criteria prior to admission to an exercise group ensures safe participation.Traditional outpatient exercise groups are conducted in face-to-face groups for 60 to 90 minutes, once a week, with structured warm-up, main and cool-down phases. In addition, since the coronavirus pandemic, the introduction of online exercise groups via videoconferencing has enabled flexible participation (even without a prescription). To date, more than 11,000 German patients have participated in online exercise groups since 2021.Scientific evidence confirms the significant benefits of regular exercise, such as improved physical performance and reduced breathlessness. The psychosocial benefits and the promotion of self-efficacy are additionally supported by the supervision of a specialized trainer. Regular exercise (e.g. in outpatient exercise groups) is an inexpensive and very effective form of therapy to improve the quality of life of people with chronic respiratory diseases.

The impact of automobile warm-up noise characteristics on annoyance

In the automotive industry, the sound of a vehicle plays a crucial role in its perceived value, highlighting the importance of understanding the relationship between subjective auditory perceptions and objective physical measures. This study investigates the psychoacoustic properties of warm-up noise emitted by vehicles equipped with an accelerated warm-up system (AWS). Our main goal is to analyze the discomforting aspects of this noise and reveal that its cause is related to tonality. Through extensive auditory experiments, we aim to uncover the nuances of this relationship, finding that both tonality and roughness significantly contribute to annoyance perception, particularly at higher frequencies. This investigation provides crucial insights for acoustic optimization in automotive systems, focusing on improving the user experience and product quality during the AWS warm-up phase.

Cognitive reflection in experimental anchored guessing games

The cognitive reflection test or CRT (Frederick, 2005) has been found to be a reliable predictor of the degree of strategic sophistication of subjects in a variety of laboratory experiments. These studies have found that subjects who score higher in the CRT make choices that are closer to Nash equilibrium (i.e., Brañas-Garza et al., 2012). In an extended level-k model with free subjective beliefs, we theoretically decompose the closeness to equilibrium for the class of anchored guessing games introduced in Ballester et al. (2023) into two effects: subjects with a smaller distance to equilibrium must possess a higher reasoning level in the level-k hierarchy or their level-k iteration process must begin from a starting point (called “seed”) that is inherently more advantageously positioned, which translates into the concept of “seed distance” (or both). Our main experimental finding is that subjects with a higher CRT score play closer to equilibrium due to the fact that they iterate more often in their reasoning process (as in Brañas-Garza et al., 2012), yet we find no clear evidence that they have a smaller seed distance. We also find evidence of a learning or adaptation process, which can be characterized by a warm-up phase (in which subjects reduce their seed distance), followed by a learning phase (in which they increase their reasoning level, at a faster rate in subjects with higher CRT) and then a saturation phase in which no further improvements are made.

Experimental Gas-Phase Removal of OH Radicals in the Presence of NH2C(O)H over the 11.7-353 K Range: Implications in the Chemistry of the Interstellar Medium and the Earth's Atmosphere.

Formamide (NH2C(O)H) has been observed both in the interstellar medium (ISM), being identified as a potential precursor of prebiotic molecules in space, and in the Earth's atmosphere. In these environments where temperature is very distinct, hydroxyl (OH) radicals may play an important role in the degradation of NH2C(O)H. Thus, in this work, we report for the first time the experimental study of the temperature dependence of the gas-phase removal of OH in the presence of NH2C(O)H over the 11.7-353 K range. In the lowest temperature range (11.7-177.5 K), of interest for the ISM chemistry, the kinetic study was performed using a pulsed CRESU (French acronym for Reaction Kinetics in a Uniform Supersonic Flow) apparatus, while a thermostatized slow-flow reactor was employed in the kinetic study of the OH + NH2C(O)H reaction over the 273-353 K range, of interest in the Earth's troposphere below room temperature. The pulsed laser photolysis at 248 nm of a suitable OH-precursor (hydrogen peroxide, tert-butyl hydroperoxide, or acetylacetone) was used to generate OH radicals in the reactor. The temporal evolution of OH was monitored by laser-induced fluorescence at 310 nm. An almost independent k(T) between 273 and 353 K (temperatures of the Earth's troposphere extended to T > 298 K) is reported, being the OH + NH2C(O)H reaction the major degradation route with an atmospheric lifetime of around 1 day. At lower temperatures of interest in the ISM (11.7-177.5 K), the potential formation of NH2C(O)H dimers was evaluated. Thermodynamically, under equilibrium conditions, formamide would be fully converted into the dimer in that T range. However, the qualitative agreement of the observed increase of k(T) with computational studies on the OH + NH2C(O)H reaction down to 200 K let us to report, between 177.5 and 106.0 K, the following parameters commonly used in astrochemical modeling: α = (3.76 ± 0.62) × 10-12 cm3 s-1, β = (3.07 ± 0.11), and γ = 0. At 11.7 K, a kinetic model reproducing the experimental data indicates that formamide dimerization could be important, but the OH-reaction with the monomer would be fast, 4 × 10-10 cm3 s-1, and the OH-reaction with the dimer, relatively slow [(0.1-1.0) × 10-11 cm3 s-1]. Despite that, the impact of the gas-phase OH + NH2C(O)H in the relative abundances of NH2C(O)H in a dense molecular cloud (T ∼ 10 K) and after the warm-up phase in the surroundings of hot cores/corinos (here, 10-400 K) appears to be negligible.

Establishing a novel model to assess exercise capacity in chronic heart failure based on stress echocardiography.

The aim of this study was to develop a simple, fast and efficient clinical diagnostic model, composed of exercise stress echocardiography (ESE) indicators, of the exercise capacity of patients with chronic heart failure (CHF) by comparing the effectiveness of different classifiers. Eighty patients with CHF (aged 60±11years; 78% male) were prospectively enrolled in this study. All patients underwent both cardiopulmonary exercise test (CPET) and ESE and were divided into two groups according to the VE/VCO2 slope: 30 patients with VE/VCO2 slope ventilation classification (VC)1 (i.e., VE/VCO2 slope<30) and 50 patients with VC2 (i.e., VE/VCO2 slope≥30). The analytical features of all patients in the four phases (rest, warm-up, peak and recovery phases) of ESE included the following parameters: left ventricular (LV) systolic function, LV systolic function reserve, LV diastolic function, LV diastolic function reserve and right ventricular function. Logistic regression (LR), extreme gradient boosting trees (XGBT), classification regression tree (CART) and random forest (RF) classifiers were implemented in a K-fold cross-validation model to distinguish VC1 from VC2 (LVEF in VC1 vs. VC2: 44±8% vs. 43±11%, P=0.617). Among the four models, the LR model had the largest area under the curve (AUC) (0.82; 95% confidence interval [CI]: 0.73 to 0.92). In the multiple-variable LR model, the differences between the peak-exercise-phase and resting-phase values of E (ΔE), s'peak and sex were strong independent predictors of a VE/VCO2 slope≥30 (P value: ΔE=0.002, s'peak=0.005, sex=0.020). E/e'peak, ΔLVEF, ΔLV global longitudinal strain and Δstroke volume were not predictors of VC in the multivariate LR model (P>0.05 for the above). Compared with the LR, XGBT, CART and RF models, the LR model performed best at predicting the VE/VCO2 slope category of CHF patients. A score chart was created to predict VE/VCO2 slopes≥30. ΔE, s'peak and sex are independent predictors of exercise capacity in CHF patients.

The impact of neuromuscular warm-up on the level of dynamic stability of lower limbs in female football players in the context of injury prevention

Background: In female football, there’s a high incidence of injuries, with insufficient dynamic stability a significant risk for lower limb injuries. Consequently, diagnosing and compensating for dynamic stability in female footballers is crucial. Objective: The aim of the study was to verify the impact of neuromuscular warm-up on the level of dynamic stability as a method of preventing lower limb injuries in female football players. Methods: The research sample consisted of 36 players, who were divided into an experimental group (EG, n = 20) and a control group (CG, n = 16) based on their club affiliation. The average age of the EG was 17.45 ± 2.63 years, with a height of 168.31 ± 6.13 cm and a weight of 60.21 ± 8.87 kg. The CG consisted of players with an average age of 16.24 ± 1.09 years, a height of 163.84 ± 5.58 cm, and a weight of 55.91 ± 6.87 kg. The assessment of dynamic stability of the lower limbs was conducted using the Y Balance Test, which is considered a reliable test for assessing dynamic stability and identifying deficits in this area. The experimental factor of the research was neuromuscular warm-up, implemented during the warm-up phase of the players’ training sessions, with a frequency of 2-3 times per week for a duration of 12 weeks. Results: No statistically significant difference was found in the impact of neuromuscular warm-up in any tested direction or in the composite score of the female football players. Conclusion: We conclude that in our study, neuromuscular warm-up did not have an impact on the dynamic stability of female football players. More regular monitoring and higher frequency of neuromuscular warm-up may have beneficial effects on female football players.

Acute effects of different types of stretching exercises on explosive power: A pilot study

Athletes usually use warm-up and stretching exercises before starting a vigorous physical activity. The aim of this study was to investigate the positive and negative effects of different stretching and flexing exercises on kicking acceleration performance in taekwondo. A total of 12 elite taekwondo athletes (7 boys and 5 girls) with an average age of 20.75±1.48 years, an average height of 171±10.06 cm, an average body weight of 61.8±11 kg, and an average Body Mass Index (BMI) of 21.1±2.5 kg/m2 participated in this study. For the kick acceleration test (KAT), an accelerometer was used by attaching it to the ankle of the participants with the help of a smart phone and a smart watch. For KAT measurements, static stretching exercise (SSE), dynamic stretching exercise (DSE), proprioceptive neuromuscular facilitation exercise (PNFE) and ballistic stretching exercise (BSE) methods were applied on different days during the warm-up phase. In this study with elite level Taekwondo athletes, significant differences were found between palding chagi and dollyo-chagi kick acceleration values after SSE and PNFE applications (p

The Effects of Nordic Hamstring Exercise on Performance and Injury in the Lower Extremities: An Umbrella Review.

Due to their potential positive outcomes, hamstring eccentric exercises are becoming increasingly popular in training regimens. Among the various exercises, the Nordic Hamstring Exercise (NHE) is the most common. Despite its popularity, there are still some doubts about its benefits and risks. So, the aim of this umbrella review was to summarize the effects of NHE on performance and injury prevention. Following the PRISMA guidelines, a comprehensive literature search was conducted across multiple e-databases, according to the P (injured and non-injured athletes or recreationally active or healthy individuals) I (NHE) C (no intervention, placebo, or other interventions) O (performance or injury) S (systematic reviews) model. The quality of the studies was accessed with the AMSTAR-2. From the 916 systematic reviews found, only 10 could be included. They encompassed 125 studies, enrolling 17,260 subjects. The results from the studies indicate that NHE interventions demonstrated positive effects on sprint performance, muscle activation, eccentric strength, and muscle architecture (fascicle length, muscle thickness, and pennation angle). Furthermore, NHE is effective in preventing hamstring injuries (up to 51%). In conclusion, NHE should be integrated in training (especially, in the warm-up phase) for both enhancing athletic performance and preventing hamstring injuries. For achieving more positive results, it is recommended that high-volume is followed by low-volume maintenance, targeting 48 reps/week.

Safety and Feasibility of Neuromuscular Electrical Stimulation in Patients with Extracorporeal Membrane Oxygenation.

Background/Objectives: The aim of this study was to investigate the feasibility and safety of neuromuscular electrical stimulation (NMES) in patients on extracorporeal membrane oxygenation (ECMO) and thoroughly assess any potential adverse events. Methods: We conducted a prospective observational study assessing safety and feasibility, including 16 ICU patients on ECMO support who were admitted to the cardiac surgery ICU from January 2022 to December 2023. The majority of patients were females (63%) on veno-arterial (VA)-ECMO (81%), while the main cause was cardiogenic shock (81%) compared to respiratory failure. Patients underwent a 45 min NMES session while on ECMO support that included a warm-up phase of 5 min, a main phase of 35 min, and a recovery phase of 5 min. NMES was implemented on vastus lateralis, vastus medialis, gastrocnemius, and peroneus longus muscles of both lower extremities. Two stimulators delivered biphasic, symmetric impulses of 75 Hz, with a 400 μsec pulse duration, 5 sec on (1.6 sec ramp up and 0.8 sec ramp down) and 21 sec off. The intensity levels aimed to cause visible contractions and be well tolerated. Primary outcomes of this study were feasibility and safety, evaluated by whether NMES sessions were successfully achieved, and by any adverse events and complications. Secondary outcomes included indices of rhabdomyolysis from biochemical blood tests 24 h after the application of NMES. Results: All patients successfully completed their NMES session, with no adverse events or complications. The majority of patients achieved type 4 and 5 qualities of muscle contraction. Conclusions: NMES is a safe and feasible exercise methodology for patients supported with ECMO.

Effects of High-intensity Training and Electrical Stimulation on Pain, Disability, Knee Kinematic and Performance in Patellofemoral Pain: A Randomized Controlled Trial

Patellofemoral pain (PFP) is a widespread problem in athletes who participate in jumping, cutting, and pivoting sports. Forty-four players participated in this study. They were divided into two groups: exercise plus EMS (G1) and exercise without EMS (G2), both with 12 women and 10 men. The exercise performed was 8 weeks of a high-intensity strength program for 45-60 minutes, plus cooling and a warm-up phase. Visual analogue scale (VAS), disability (Kujala patellofemoral score), knee valgus angle (KVA) and single-leg hop (SLH) were tested before (pre-test) and after training (post-test at 8 weeks) using a within-between group analysis (ANOVA 2×2). At baseline, no differences between groups were found (p &gt; 0.05). After the intervention, both groups improved VAS, KVA, SLH (p &lt; 0.001), and disability (p = 0.042). G1 showed more improvements than G2 for VAS (- 63.4 vs - 51.5 %, p = 0.021, 𝜂p2 = 0.13), disability (+ 32.6 vs + 18.4 %, p = 0.001, 𝜂p2 = 0.52), KVA (+ 4.2 vs + 2.2 %, p = 0.016, 𝜂p2 = 0.214) and SLH (+ 12.3 vs + 6.0 %, p = 0.003, 𝜂p2 = 0.20) respectively. No differences were found between the sexes for each group. Despite both interventions being valid, high-intensity strength training combined with EMS improved pain, disability, knee kinematics, and lower extremity performance more than exercise alone in professional handball athletes with PFP. Keywords: Electrical muscle stimulation, Rehabilitation, Musculoskeletal, Knee, Handball players

Effects of a warm up integrated with core stability exercises on the motor abilities in young soccer players

Background and study aim. The warm-up phase in youth soccer can be used to introduce drills that do not find space within the training session. Core district exercises give stability to the trunk and hips, allowing for increased performance and reducing the risk of non-contact injuries. This study aims to test the effects of a warm up integrated with core stability exercises on the motor abilities in young soccer players. Material and methods. Young soccer players (n=32, 12.45±0.52 years, 1.49±0.05 m, 44±2.90 kg) were randomly divided into two groups: experimental (EG=17) and control group (CG=15). The EG performed an integrated warm-up with core stability tasks for 6 weeks (12 sessions). The CG followed the usual training schedule based on technical tactical and physical drills. Performance was assessed through broad jump, Hop test, Side Hop test, 10-meter sprint and 10x5-meter shuttle test. Results. Data analysis returns some statistically significant differences in intergroup comparison (T1): for broad jump (p = .008), for left limb Hop test (p = .02), for right limb Hop test (p = .02), for left limb Side Hop (p = .03), for right limb Side Hop (p = .04), for sprint 10-meters (p = .002), for shuttle run 10x5-meters (p = .03). Conclusions. The core stability exercises in the warm up seems to increase some performance correlated with the motor abilities stressed in the soccer. The warm up through appropriate modifications can represent, a useful and integrative moment to elicit more factors of performance and prevention.

Online Neural Path Guiding with Normalized Anisotropic Spherical Gaussians

Importance sampling techniques significantly reduce variance in physically based rendering. In this article, we propose a novel online framework to learn the spatial-varying distribution of the full product of the rendering equation, with a single small neural network using stochastic ray samples. The learned distributions can be used to efficiently sample the full product of incident light. To accomplish this, we introduce a novel closed-form density model, called the Normalized Anisotropic Spherical Gaussian mixture, that can model a complex light field with a small number of parameters and that can be directly sampled. Our framework progressively renders and learns the distribution, without requiring any warm-up phases. With the compact and expressive representation of our density model, our framework can be implemented entirely on the GPU, allowing it to produce high-quality images with limited computational resources. The results show that our framework outperforms existing neural path guiding approaches and achieves comparable or even better performance than state-of-the-art online statistical path guiding techniques.

Comprehensive laboratory constraints on thermal desorption of interstellar ice analogues

Gas accretion and sublimation in various astrophysical conditions are crucial aspects of our understanding of the chemical evolution of the interstellar medium. To explain grain growth and destruction in warm media, ice mantle formation and sublimation in cold media, and gas line emission spectroscopy, astrochemical models must mimic the gas--solid abundance ratio. Ice-sublimation mechanisms determine the position of snow lines and the nature of gas emitted by and locked inside planetary bodies in star-forming regions. To interpret observations from the interplanetary and extragalactic interstellar mediums, gas phase abundances must be modelled correctly. We provide a collection of thermal desorption data for interstellar ice analogues, aiming to put constraints on the trapping efficiency of water ice, as well as data that can be used to evaluate astrochemical models. We conduct experiments on compact, amorphous H$_2$O films, involving pure ices as well as binary and ternary mixtures. By manipulating parameters in a controlled way, we generate a set of benchmarks to evaluate both the kinetics and thermodynamics in astrochemical models. We conducted temperature-programmed desorption experiments with increasing order of complexity of ice analogues of various chemical compositions and surface coverages using molecular beams in ultrahigh vacuum conditions (1 times 10$^ $ hPa) and low temperatures (10 K). We provide TPD curves of pure ices made of Ar, CO, CO$_2$, NH$_3$, CH$_3$OH, H$_2$O, and NH$_4^+$HCOO$^-$, their binary ice mixtures with compact amorphous H$_2$O, ternary mixtures of H$_2$O : CH$_3$OH : CO, and a water ice made in situ to investigate its trapping mechanisms. Each experiment includes the experimental parameters, ice desorption kinetics for pure species, and the desorption yield (gas--solid ratio) for ice mixtures. From the desorption yields, we find common trends in the trapping of molecules when their abundance is compared to water: compact amorphous water ices are capable of trapping up to 20&lt;!PCT!&gt; of volatiles (Ar, CO, and CO$_2$), sim 3&lt;!PCT!&gt; of CH$_3$OH, and sim 5&lt;!PCT!&gt; NH$_3$ in relation to the water content within the ice matrix; ammonium formate is not trapped in the water ice films, and compact amorphous water ice formed in situ has similar trapping capabilities to a compact amorphous water ice deposited using molecular beams. Deposited or formed in a very compact structure, amorphous water ice of less than 100 layers cannot trap a large fraction of other gases, including CO and CO$_2$. These desorption yields offer insights into the availability of species that can react and form interstellar complex organic molecules during the warm-up phase of ice mantles. Furthermore, in order to be reliable, gas-grain astrochemical models should be able to reproduce the desorption kinetics and desorption yield presented in our benchmark laboratory experiments.

FEATURES OF PHYSICAL THERAPY FOR FLAT FEET IN YOUNG ATHLETES TREATING FLAT FEET IN YOUNG ATHLETES: A PHYSICAL THERAPY APPROACH

The goal is to develop and substantiate a physical therapy program for correcting flat feet in young athletes of various sports specializations.&#x0D; Material and methods. The research was carried out at the City Specialized Children and Youth Sports School, Olympic Reserve, Kharkiv, focusing on the Figure Skating Department. A total of 10 participants were involved in the study.&#x0D; A hypothesis was formulated and subsequently validated regarding the adverse effects of specific loads in figure skating on athletes' feet. Following the acquisition of results, an affirming experiment was undertaken, involving young athletes from diverse specializations.&#x0D; Results. Engaging in sports carries inherent risks of diverse injuries. The prevalence of flat feet among athletes is extensively discussed in the literature, with statistics indicating that 50 to 92% of athletes across various specializations exhibit alterations in their foot arches. Addressing this issue becomes imperative, specifically through the development of an optimal rehabilitation program for children-athletes with flat feet in different specializations. An effective rehabilitation program for flat feet among young athletes of various specializations was formulated and experimentally evaluated. All athletes included in the study exhibited flat feet of the 1st or 2nd degree in their medical history. In a majority of cases, this condition was coupled with a valgus deformity. Notably, the degree of foot deformity varied between the right and left lower limbs in some instances. The rehabilitation program was seamlessly integrated into the warm-up phase of the training routine and implemented three times a week over a period of six weeks.&#x0D; Conclusions. The study findings conclusively highlight the efficacy of the program, as evidenced by the parameters derived from the experiment. There was a notable increase in the height of both the longitudinal and transverse arches, a reduction in the abduction angle of the 1st toe, and enhanced strength in the foot muscles. Rigorous statistical analysis of the collected data further substantiated their reliability, firmly establishing the effectiveness of the proposed rehabilitation program for athletes with flat feet. Additionally, it is noteworthy that this program can serve as a preventive measure against the development of flat feet.

Chemical differences among collapsing low-mass protostellar cores

Context. Organic features lead to two distinct types of Class 0/I low-mass protostars: hot corino sources exhibiting abundant saturated complex organic molecules (COMs) and warm carbon-chain chemistry (WCCC) sources exhibiting abundant unsaturated carbon-chain molecules. Some observations suggest that the chemical variations between WCCC sources and hot corino sources are associated with local environments and the luminosity of protostars. Aims. We aim to investigate the physical conditions that significantly affect WCCC and hot corino chemistry, as well as to reproduce the chemical characteristics of prototypical WCCC sources and hybrid sources, where both carbon-chain molecules and COMs are abundant. Methods. We conducted a gas-grain chemical simulation in collapsing protostellar cores, adopting a selection of typical physical parameters for the fiducial model. By adjusting the values of certain physical parameters, such as the visual extinction of ambient clouds (AVamb), cosmic-ray ionization rate (ζ), maximum temperature during the warm-up phase (Tmax), and contraction timescale of protostars (tcont), we studied the dependence of WCCC and hot corino chemistry on these physical parameters. Subsequently, we ran a model with different physical parameters to reproduce scarce COMs in prototypical WCCC sources. Results. The fiducial model predicts abundant carbon-chain molecules and COMs. It also reproduces WCCC and hot corino chemistry in the hybrid source L483. This suggests that WCCC and hot corino chemistry can coexist in some hybrid sources. Ultraviolet (UV) photons and cosmic rays can boost WCCC features by accelerating the dissociation of CO and CH4 molecules. On the other hand, UV photons can weaken the hot corino chemistry by photodissociation reactions, while the dependence of hot corino chemistry on cosmic rays is relatively complex. The value of Tmax does not affect any WCCC features, while it can influence hot corino chemistry by changing the effective duration of two-body surface reactions for most COMs. The long tcont can boost WCCC and hot corino chemistry by prolonging the effective duration of WCCC reactions in the gas phase and surface formation reactions for COMs, respectively. The scarcity of COMs in prototypical WCCC sources can be explained by insufficient dust temperatures in the inner envelopes that are typically required to activate hot corino chemistry. Meanwhile, the high ζ and the long tcont favors the explanation for scarce COMs in these sources. Conclusions. The chemical differences between WCCC sources and hot corino sources can be attributed to the variations in local environments, such as AVamb and ζ, as well as the protostellar property, tcont.

AdaMO: Adaptive Meta-Optimization for cold-start recommendation

Meta-learning has been proven effective in tackling the cold-start problem of recommendation systems. Most work in this line adopts the meta-optimization idea that learns global knowledge to initialize the base recommender and adapts it for unseen recommendation tasks. Typically, the process is non-adaptive in the sense that both the initialization and model fitting are not task-specific. Such non-adaptive approaches do not work well for the strict cold-start problem, where historical interaction data of the new users is scarce or not available at all. In this paper, we propose a novel adaptive meta-optimization approach, called Adaptive Meta-Optimization (AdaMO), to address the problem. AdaMO is fully adaptive, namely, it simultaneously customizes the initialization and model fitting according to task-specific information. During the cold-start phase, it aggregates task-specific information with transferred knowledge from all historical tasks to tune the initialization of the base model. In the subsequent warm-up phase, AdaMO mines the adaptive transition information from the behavior patterns and parameter status to effectively fit the model using transitional learning. By making a sophisticated balance between shared knowledge and task-specific information, AdaMO outperforms the state-of-the-art methods in various cold-start scenarios.

ASSESSMENT OF A SELF-PACED PROTOCOL FOR TESTING AEROBIC CAPACITY IN SCI INDIVIDUALS

https://youtu.be/u89x4ivgoIc BACKGROUND Underwater treadmill (UT) exercise is a recent and sparsely tested modality that may be beneficial for those with incomplete spinal cord injury (iSCI). Currently, VO2max and HRmax have not been assessed during UT exercise among those with iSCI. This study's purpose was to determine if a rating of perceived exertion (RPE) based max exertion protocol used with a motorized UT can elicit criterion-based max physiological responses among those with and without iSCI. METHODS Healthy adult males with iSCI (n=4; Age=49.8 +/- 3.9 yrs) and without iSCI (n=4; Age=50.0 +/- 7.2 yrs) participated. Borg OMNI RPE scale was used by participants to estimate intensity of exercise. Each participant reported to the lab on two occasions. On visit one, they completed informed consent papers and familiarization with the RPE scale and UT exercise. On visit two, they completed a speed-based, self-regulated incremental exercise test on the UT. Prior to all testing, the UT was filled and set to 92°F. Upon arrival, HR monitor and mask for gas collection were donned. Water height was modified to the xiphoid process. The test consisted of rest, warm-up, incremental exercise, and active recovery phases. For warm-up, treadmill speed was adjusted to 0.5 mph for 3 minutes. After walking 3 minutes, speed was increased to 0.75 mph for another 3 minutes. The incremental exercise phase consisted of four stages, 3 minutes in duration, totaling 12 minutes. For each stage, participants self-selected a speed perceived to correspond to RPE levels: 3, 5, 7, and 10. Treadmill speed was hidden from participants. At each stage's start, speed was only adjusted during the first minute until reaching the proper RPE. During the final stage, treadmill speed could be changed freely until volitional exhaustion. The test ended when volitional exhaustion was reached, at which point the speed was lowered for an active recovery. An independent samples t-test was used to compare time (minutes) until volitional exhaustion. Separate independent samples t-tests were used to compare the highest achieved HR and VO2 values. RESULTS All iSCI participants achieved a VO2peak. Only 1 participant without iSCI achieved a VO2max. Mean VO2 was significantly lower, t(6)=3.81, p=.027, for those with iSCI (13.88 +/- 10.57 mL/kg/min) than those without iSCI (34.50 +/- 2.38 mL/kg/min). CONCLUSION This study shows that the UT is a safe modality for graded exercise testing for those with and without iSCI. An RPE-regulated protocol may not be effective for eliciting criterion-based maximal aerobic results with the UT, but was well tolerated by those with iSCI. Those with iSCI may have lacked lower limb strength to achieve max workloads. Being able to use the UT to test peak aerobic fitness allows clinicians to track improvements in economy following UT training. More research of this modality is encouraged with larger samples to further evaluate potential testing protocols among this population.

ASSESSMENT OF NERVOUS SYSTEM STRENGTH (BRAIN EFFICIENCY) IN YOUNG TAEKWONDO ATHLETES DURING TRAINING SESSIONS

Introduction. The article explores the dynamics of indicators of nervous system strength (brain efficiency) in young athletes during taekwondo training sessions, taking into account their age and gender characteristics. The relevance and prospects of the research are determined by the relationship between the psychophysiological properties of athletes and their performance in taekwondo competitions, as well as the necessity of considering this relationship in the training process. The research aims to assess the indicators of higher nervous activity (HNA), particularly the strength of nervous processes (brain efficiency), in young taekwondo athletes during training sessions, considering age and gender. Material and methods: general scientific (logical, inductive); analysis of scientific and methodological literature and internet sources; instrumental methods (study of nervous system strength as an indicator of brain efficiency), methods of mathematical data processing. The indicators of nervous system strength (brain efficiency) in young taekwondo athletes were assessed instrumentally using the PND method (M.Makarenko). Results. The dynamics of indicators of higher nervous activity, particularly the strength of nervous processes (brain efficiency), were studied in 34 young taekwondo athletes, taking into account their age and gender characteristics. Measurements were taken during training sessions: in the warm-up phase, the main phase, and the cool-down phase. The test results were systematized, and based on quantitative indicators, corresponding graphs were constructed, followed by analytical evaluation. Conclusions. The research on the dynamics of indicators of nervous system strength (brain efficiency) in young athletes during taekwondo training sessions, considering their age characteristics in two age groups of young taekwondo athletes, revealed that athletes in the older age group (boys aged 13–16 and girls aged 12–15) demonstrate better indicators of brain efficiency (fewer mistakes) compared to the younger group (boys aged 8–12 and girls aged 8–11), presumably due to developmental age characteristics and greater training experience. It was established that at the beginning of training sessions, the results of girls in the younger group outperform the results of boys, while in the older age group, boys' results are higher compared to girls. It was also found that young athletes in both groups demonstrate the best indicators of brain efficiency in the main part of the training session compared to the beginning and the cool-down phase.

Acute effects of a dynamic stretching and core stability exercise protocol on physical performance in U-16 volleyball players

Purpose: Stretching and core exercises are is often used in different sports to develop higher sport performance and reduce injury risks. In acute, dynamic stretching (DS) seems to produce more benefits than static for improving physical performance. Moreover, sports tasks characterized by explosive and multi joints movement, such as wall jumping or dunking and serving in volleyball, also require core stabilization. Therefore, the aim of present study was to evaluate a potential postactivation potentiation enhancement (PAPE) effect induced by a functional exercise protocol including dynamic stretching and stimulation of core stability (StretCor) on physical performance in a group of U-16 volleyball players. Methods: Eighteen young volleyball players (9 boys and 9 girls; age: 15.33± .68 y; BMI: 22.12±2.25 kg.m-2) participating in the regional championship were recruited by Italian Volleyball Federation (FIPAV) – Campania Committee. The StretCor protocol consisted in eight exercises, performed with ball, combining both DS and Core Stability (CS) exercises that stimulates the main muscles group. Before and after exercise protocol, Countermovement Jump (CMJ), modified Stars Excursion Balance Test (mSEBT) and agility T-test performances were assessed in all participants. Results: After StretCor protocol, there were improvements (P&lt; .05) in agility T-test (10.48±1.01 vs 10.70±1.09 s), jump height (31.81±5.36 vs 29.75±5.73 cm) and relative peak power (51.53±9.77 vs 46.04±6.21 W/kg). Moreover, in mSEBT, left normalized Anterior (left ANT) (71.29±7.59 vs 66.84±7.19 %), Posteromedial direction (left PM) (105.63±8.80 vs 98.28±12.82 %), Posterolateral (left PL) directions (106.15±9.95 vs 98.47±13.06 %) and in right normalized Posterolateral direction (right PL) (103.90±10.65 vs 98.14±12.95 %) were improved after StretCor protocol; in addition, improvement were also observed in left (94.36±6.61 vs 87.87±9.88 %) and right (92.85±7.03 vs 88.47±10.22 %) composite (COMP) score. Conclusions: The present study suggests that an acute session of StretCor protocol, improved lower limb muscle power, dynamic balance and agility in U-16 volleyball players. We suggest including these types of exercises as a CA to produce a PAPE effect in the warm-up phase of volleyball training for improve the physical performance.