Increasing Movement Amplitude in Speeded Hitting Enhances Contact Velocity Without Affecting Directional Accuracy or Movement Variability.

Performance of sport-related ballistic motor skills, like ball hitting in golf and baseball, requires wide movements to produce highly fast and spatially accurate movements. In this study, we assessed the effect of movement amplitude on directional accuracy in a ballistic hitting task. Participants performed the task of moving a manual handle over a flat surface to hit with high speed a moveable disc, aiming to propel it towards a frontal target. Five movement amplitudes were compared, ranging from 11.5 cm to 27.5 cm in steps of 4 cm. Kinematic analysis evaluated motions of the handle, disc, and arm joints. Results showed that greater movement amplitudes led to longer acceleration phases, with delayed peak velocities at the handle, shoulder and elbow, leading to higher contact and peak linear velocities of the handle, and higher angular velocities at the shoulder and elbow. Manipulation of movement amplitude led to no evidence for effects on either disc directional accuracy or variability. Results also revealed no evidence for differences in variability of contact velocity, peak velocity and time of peak velocity across movement amplitudes in the shoulder, elbow, and wrist. Our results indicated that greater movement amplitudes in hitting a spatial target lead to increased contact velocity while not affecting directional accuracy or movement variability.

Lesbian and Heterosexual Women's Implicit Responses to Gender Figures.

This study explored how heterosexual and lesbian women differ in their implicit sexual responses. Previous research indicates that heterosexual women have physiological and implicit responses to both genders, whereas lesbian women show stronger responses to their preferred gender. This study used two implicit measures: the Implicit Relational Assessment Procedure (IRAP) and the Function Acquisition Speed Test (FAST), both of which were novel in this context. We recruited 33 heterosexual and 25 lesbian women. Both IRAP and FAST were successful in differentiating the two sexual orientations as a group. The results confirmed that heterosexual women exhibit positive responses to both genders, while lesbian women show stronger, category-specific responses to their preferred gender. These findings align with previous research and provide further insight into the nuanced differences in sexual orientation responses among women.

Longitudinal association between dentition status and gait speed among older Brazilian adults: SABE cohort study.

BACKGROUND: Oral health has been associated with general health conditions, but few longitudinal studies evaluated the effect of dentition status on gait speed. OBJECTIVE: This study aimed to investigate the longitudinal association between different time-varying measures of dentition status (i.e., number of teeth, the presence of periodontal pockets and the functional impact of oral health) and gait speed (outcome) in older Brazilian adults. MATERIALS AND METHODS: This was a prospective study using data from the Health, Well-being and Aging cohort study (SABE) from 2006, 2010 and 2015. The gait speed was the dependent variable and the independent variables of interest were dentition status evaluated using the number of teeth, use of dental prostheses, presence of periodontal pocket, clinical attachment loss and self-perceived poor functional oral health. Dentition status measures were obtained through clinical oral examinations, performed by trained dentists using standardized criteria proposed by the World Health Organization. Self-perceived poor functional oral health was evaluated using the functional domain of the Geriatric Oral Health Assessment Index. The longitudinal effect of dentition status on gait speed was evaluated using mixed-effects linear models. The effect of the number of teeth/periodontal pocket/attachment loss on gait speed change over time was evaluated by including an interaction term between these variables. The effect of periodontal pocket was tested only among dentate individuals. RESULTS: Data for the complete sample included 3,306 observations from 1,964 individuals. The analyses for dentate individuals included 1,883 observations from 1,149 individuals. There was a positive association between the number of teeth and mean gait speed. Individuals using dental prostheses also had higher means of gait speed than those without dental prostheses. Gait speed was lower among individuals with periodontal pockets and with attachment loss. No interaction was found between any of the indicators of dentition status and time. CONCLUSION: Gait speed was associated with dentition status and this association was constant over time.

Evaluating Thermal Infrared Drone Flight Parameters on Spider Monkey Detection in Tropical Forests.

Geoffroy's spider monkeys, an endangered, fast-moving arboreal primate species with a large home range and a high degree of fission-fusion dynamics, are challenging to survey in their natural habitats. Our objective was to evaluate how different flight parameters affect the detectability of spider monkeys in videos recorded by a drone equipped with a thermal infrared camera and examine the level of agreement between coders. We used generalized linear mixed models to evaluate the impact of flight speed (2, 4, 6 m/s), flight height (40, 50 m above ground level), and camera angle (-45°, -90°) on spider monkey counts in a closed-canopy forest in the Yucatan Peninsula, Mexico. Our results indicate that none of the three flight parameters affected the number of detected spider monkeys. Agreement between coders was "substantial" (Fleiss' kappa coefficient = 0.61-0.80) in most cases for high thermal-contrast zones. Our study contributes to the development of standardized flight protocols, which are essential to obtain accurate data on the presence and abundance of wild populations. Based on our results, we recommend performing drone surveys for spider monkeys and other medium-sized arboreal mammals with a small commercial drone at a 4 m/s speed, 15 m above canopy height, and with a -90° camera angle. However, these recommendations may vary depending on the size and noise level produced by the drone model.

Whole-Body Vibration (WBV) as a Conditioning Activity for Roundhouse Kick (mawashi geri) Performance in Karate.

Karate athletes strategically use lower-limb techniques in combat, with the roundhouse kick (mawashi geri) being highly effective in kumite. To quickly improve the technical performance before training or competitions, conditioning activities (CAs) are often utilized. Recently, Whole-Body Vibration (WBV) has emerged as a potential conditioning activity (CA). This study aimed to analyze the acute effects of WBV as a CA on the performance of the mawashi geri. The sample included sixteen male karate athletes. The study had a familiarization and two experimental sessions: one with WBV and the other without (NWBV), conducted randomly and counterbalanced, each preceded and followed by a mawashi geri assessment on a force platform. During the CA intervention, the participants performed four sets of isometric half-squats on a vibration platform at a frequency of 26 Hz and an amplitude of 4 mm in the WBV condition, while the platform was off in the NWBV condition. A significant reduction in the mawashi geri attack phase time was observed under the WBV condition [pre: 0.31 ± 0.03 s; post: 0.30 ± 0.03 s] compared to the NWBV condition [pre: 0.31 ± 0.04 s; post: 0.32 ± 0.03 s] (p = 0.02). However, no differences were noted regarding the impact force or other kinetic variables between the conditions. Therefore, WBV did not increase the performance of the kinetic and kinematic variables of the mawashi geri in karate athletes, but it is possible that there is a positive effect on attack time, suggesting that further studies with different vibration protocol configurations would be beneficial.

Meal Duration and Obesity-Related Indicators among Adolescents: Insights from the EHDLA Study.

PURPOSE: This paper aims to examine the association between meal duration and obesity indicators among Spanish adolescents. METHODS: We conducted a cross-sectional analysis using data from the Eating Healthy and Daily Life Activities (EHDLA) project involving 755 adolescents aged 12 to 17 years (54.8% girls) from three secondary schools in the Valle de Ricote Region of Murcia, Spain. To evaluate overall meal duration, participants were asked how long (on average) breakfast, morning snacks, lunch, afternoon snacks, and dinner typically last. Subsequently, global meal duration was measured, and the participants were categorized into tertiles. Obesity-related indicators, including body mass index (BMI) z score, waist circumference (WC), and skinfold thickness, were assessed. The analyses were adjusted for potential confounders such as sex, age, socioeconomic status, physical activity, sedentary behavior, diet quality, and energy intake. RESULTS: Concerning meal duration status, adolescents with long meal durations had the lowest estimated marginal means of BMI z score, WC, and body fat percentage (using the sum of triceps and calf skinfolds). However, significant differences between adolescents with a long meal duration and those with a short meal duration were observed only for BMI z score (p = 0.008), and WC (p = 0.020). Furthermore, significant differences in BMI z score (p = 0.017) between adolescents with a long meal duration and those with a moderate meal duration were identified. CONCLUSIONS: These findings underscore the importance of promoting slower eating habits as part of obesity prevention strategies. Future studies should explore the causality of this association and its potential for behavioral interventions.

Assessing refrigerated preservation performance using Listeria predictive microbiology models and temperature data: Refrigerator performance indicator and time-temperature equivalent.

Time-temperature data for queso fresco (QF) cheese varieties stored in a residential refrigerator operating at 5°C and a predictive microbiology secondary model for Listeria monocytogenes in QF were used to estimate a refrigerator performance indicator (RPI) of microbial preservation. RPI values were used to assess how compressor technology (single [SS] and variable speed [VS]), ambient temperature (21.1°C [LT] and 32.2°C [HT]), and refrigerator load (22.5 kg regular load and 39 kg higher load) affected preservation performance. All deterministic and probabilistic RPI estimations slightly exceeded the desirable 1.0 value, i.e., the variable temperatures for the QF kept in the refrigerator were worse than keeping it constantly at the temperature recommended by food safety agencies for QF. Furthermore, the mean comparison of estimates of the time-temperature equivalent indicator previously developed by French researchers showed similar behavior to those observed for RPI. Finally, statistical analysis showed that Tambient was the factor with the highest impact on refrigerator performance because of its impact on the sample temperature increase during door openings and when exposed to ambient temperature during product use. This highlights the need to reduce the time for product temperature recovery by improving the compressor operation logic. Also important are consumer behavior changes such as a reduction in product exposure to ambient temperature and in the door opening duration and frequency. PRACTICAL APPLICATION: This study demonstrated how a quantitative tool (RPI) can assess refrigerator preservation performance. Although the findings presented can be applied to any cold chain segment, the data used was collected for its weakest link, the domestic refrigerator. Surveys show that 77% of them operate above the recommended 4°C. The RPI methodology is ready for use by refrigerator designers to assess performance improvements possible by modifications of the compressor operation logic. Moreover, it can be integrated into smart-hubs monitoring the frequency and duration of refrigerator door openings to inform consumers when their habits are compromising the preservation performance of the refrigerator.

Longitudinal association of sleep quality with physical performance measures: SABE cohort study, Brazil.

OBJECTIVES: The aim of this study was to investigate the longitudinal association of sleep with physical performance in a representative sample of non-institutionalised older adults residing in the municipality of São Paulo, Brazil. STUDY DESIGN: Prospective cohort study. METHODS: The current longitudinal study used data extracted from the Health, Well-being, and Aging Study (Estudo Saúde Bem-Estar e Envelhecimento [SABE]). The study population consisted of individuals aged ≥60 years who participated in the study in 2010 or 2015. Dependent variables included the Short Physical Performance Battery (SPPB) and gait speed. Independent variables of interest were self-reported sleep difficulty, daytime sleepiness and sleep quality. The longitudinal association between sleep variables and the outcomes was evaluated using Generalised Estimating Equations (GEE) Models adjusted for covariates. All the variables, except age, sex and schooling, were assessed at baseline and follow-up visits (2010 and 2015). RESULTS: The analyses included 2205 observations from 1559 individuals. The population mean age was 72 years in 2010 and 71 years in 2015, with a higher prevalence of women in both years. Between 2010 and 2015, there was a decline in the SPPB score and gait speed. Daytime sleepiness was negatively associated with the SPPB score [Coef.: -0.38 (95% confidence interval {CI}: -0.56, -0.21)] and gait speed [Coef.: -0.03 (95% CI: -0.05, -0.01)]. Poor sleep quality was negatively associated with the SPPB score [Coef.: -0.29 (95% CI: -0.57, -0.01)] and gait speed [Coef.: -0.03 (95% CI: -0.06, -0.00)]. CONCLUSIONS: Daytime sleepiness and poor sleep quality are associated with compromised physical performance in non-institutionalised older adults, and this association remained consistent over time.

Variations in strength-speed-power performance across the season: do true changes occur in elite rugby players?

This study aimed to determine, through the use of a highly sensitive statistical tool, whether real changes in performance were present; and compare the rates of meaningful variations in strength, speed, and power parameters at different time-points during the competitive season in national team rugby players. Thirty-two players were assessed 5 times across the season using the following tests: squat jump and countermovement jump tests; 30-m sprint velocity; and one-repetition maximum (1RM) in the half-squat and bench-press exercises. A repeated-measures analysis of variance was conducted to test for differences between successive time-points. Individual coefficients of variation values were used to set target scores for post-measurements and examine whether changes in performance parameters were greater than the natural test variance, thus providing an indication of whether "true changes" occurred. No significant changes were detected in the vertical jump height, 1RM measures, and sprint velocity and momentum throughout the 11-month period (P > 0.05). True changes occurred much more frequently for strength-power measures than for sprint velocity and momentum. Elite rugby union players did not exhibit significant variations in neuromuscular performance across the competitive period, when a group-based analysis was conducted. However, at the individual level, "true changes" in strength-power-(but not in speed-) related qualities were consistently observed over the competitive season.

A deficit to reach the isokinetic velocity in youth wheelchair users with spina bifida.

INTRODUCTION: The self-paced adopted by wheelchair users in their postural transfers and locomotion may require sufficient levels of speed-strength in the upper limbs. In clinical practice, we observed limited functional independence and social participation. OBJECTIVES: This study aimed to investigate and compare the speed-strength relationship between wheelchair users with spina bifida (SB) and typically developing youth. In particular, to analyze if SB wheelchair users reached the preset velocities in the isokinetic evaluation of shoulder and elbow. DESIGN: Cross-sectional observational study. SETTING: Ribeirão Preto Medical School of the University of São Paulo. PARTICIPANTS AND PROCEDURES: SB (SB; n = 11) and controls (CT; n = 22) performed the isokinetic assessment of shoulder abductors (SAB), adductors (SAD), flexors (SFL), extensors (SEX), and elbow flexors (EFL) and extensors (EEX) at velocities of 60 and 120degree.s-1. The analysis of covariance was used to identify the intergroup differences in muscle performance. OUTCOME MEASURES: The values of peak torque (PT), power (Pow), time to peak torque (tPT) and the percentage to reach the isokinetic velocity. RESULTS: The percentage to reach 120degree.s-1 was moderate-to-low for both groups (26-75.9%). CT presented a significantly greater relative risk of reaching the preset velocities than SB. SB presented higher PT and Pow for SAB and SFL at 60degree.s-1, higher PT for SFL and EEX at 120degree.s-1, and lower tPT for SFL at 120degree.s-1 compared to CT. CONCLUSION: SB had difficulty reaching 120degree.s-1, probably related to neuromuscular differences. However, arm movements in their daily tasks seem to maintain the ability to produce PT and Pow.

Effects of Different Conditioning Activities on the Sprint Performance of Elite Sprinters: A Systematic Review With Meta-Analysis.

PURPOSE: Postactivation performance enhancement (PAPE), which refers to the phenomena associated with the attainment of enhanced performance in sport-specific tasks after a conditioning activity, is an important objective of warming-up practices in many sports. This is even more relevant for sprinters, as potential increases in sprinting speed will directly influence their competitive results. This systematic review with meta-analysis evaluated the effects of different PAPE protocols (ie, using plyometrics, strength-power exercises, and resisted/assisted sprints) on the sprinting performance (ie, sprint time or sprint speed) of competitive sprinters. METHODS: Initially, 1205 records published until last December 18 were identified, using the following databases: PubMed/MEDLINE, Scopus, and Clarivate Web of Science. After removing duplicates and screening titles and abstracts, 14 high-quality studies met the inclusion criteria for the meta-analysis. RESULTS: Overall, there were no significant changes in sprint performance after implementing various types of conditioning activities (standardized mean difference [SMD] = 0.16 [95% CI, -0.02 to 0.33]; Z = 1.78; P = .08; I2 = 0%). In addition, when comparing prechanges and postchanges between experimental, control, and other conditions, no significant differences were found in sprint speed or time across all studies (SMD = 0.09 [95% CI, -0.10 to 0.28]; Z = 0.92; P = .36; I = 0%). CONCLUSIONS: Results revealed that different types of conditioning activities may not be capable of acutely enhancing the sprint speed of competitive sprinters. This aligns with previous observations indicating that sprinting is a highly stable physical capacity, a phenomenon that is even more consistent among elite sprinters. Coaches and sport scientists should collaborate to develop more efficient PAPE protocols for these highly specialized athletes, with special attention to study design and individualization, while considering their effects on acceleration versus top speed.

Fatigue in individuals with multiple sclerosis: Is there a relationship with walking speed and mobility?

BACKGROUND: Fatigue is a common symptom in patients with multiple sclerosis and it can lead to activity limitations. Thus, it is important to analyze the relationship between fatigue and activity outcomes, such as walking speed and mobility. OBJECTIVES: To investigate the relationship between fatigue and walking speed and mobility in individuals with multiple sclerosis. METHODS: A cross-sectional study was performed. Adults with multiple sclerosis, without cognitive impairments and who were able to walk were recruited. Fatigue was assessed with the Modified Fatigue Impact Scale (MFIS). Walking speed, usual and fast, was assessed with the 10-meter Walk Test (10MWT), and mobility with the Timed Up and Go Test (TUG). Pearson correlation analysis was performed. A significance level of 5 % was used. RESULTS: Thirty participants were included, most of the relapsing-remitting multiple sclerosis (n = 24, 80 %). A mean age of 41 (11) years and the median Expanded Disability Status Scale (EDSS) score was 2.65 (2.18) points. Mean MFIS score was 41.87 ± 19.42 points, mean usual walking speed was 1.02 ± 0.28 m/s, mean fast walking speed was 1.55 ± 0.48 m/s, and the mean total time in the TUG was 10.07 ± 3.05 s. A significant negative correlation of moderate magnitude was found between fatigue and usual walking speed (r=₋0.51, p < 0.05). A significant negative correlation of moderate magnitude was found between fatigue and fast walking speed (r=₋0.54, p < 0.05). A significant, positive correlation of moderate magnitude was found between fatigue and mobility (r = 0.54, p < 0.05). CONCLUSION: There was a correlation between fatigue and walking speed and mobility in individuals with multiple sclerosis. These results highlight the need to assess fatigue in individuals with multiple sclerosis, since the presence of fatigue is associated with reduced walking speed and mobility.

Does anaerobic speed reserve influence post-activation performance enhancement in endurance runners?

We investigated the influence of anaerobic speed reserve (ASR) on post-activation performance enhancement (PAPE). Twenty-two endurance runners and triathletes were evaluated for maximum sprinting speed (MSS) and countermovement jump (CMJ) before (non-fatigued) and after (fatigued) an incremental running test. They were allocated in LASR (low-ASR) and HASR (high-ASR) groups for comparisons between conditions. HASR showed greater CMJ and MSS (both p ≤ 0.005) performances, with enhanced CMJ in fatigued condition (p ≤ 0.008). Significant correlations were found between ASR, CMJ, and MSS in both conditions (p ≤ 0.01) for the entire sample, and between ∆CMJ and ∆MSS (p ≤ 0.001) in LASR. Our results show that ASR profile influences PAPE.

Association between Gait Speed and Balance Disorders in Older Adults from 12 High Andean Peruvian Communities, 2013-2019.

BACKGROUND: Gait speed is associated with a higher prevalence of balance disorders in older adults residing at high altitudes. This study investigated this association in older adults from 12 high-altitude Andean Peruvian communities. METHODS: We performed a secondary data analysis from an analytical cross-sectional study of adults >60 years of age, residing in 12 high-altitude Andean Peruvian communities, enrolled between 2013 and 2019. The exposure and outcome variables were gait speed (categorized in tertiles), and balance disorders (defined as a functional reach value of ≤20.32 cm), respectively. We built generalized linear models of the Poisson family with a logarithmic link function and robust variances, and estimated crude prevalence ratios (cPR) and adjusted prevalence ratios (aPR) with 95% confidence intervals (CIs). RESULTS: We analyzed 418 older adults; 38.8% (n=162) were male, and the mean age was 73.2±6.9 years. The mean gait speed and functional reach were 0.66±0.24 m/s and 19.9±6.48 cm, respectively. In the adjusted regression model, the intermediate (aPR=1.88; 95% CI, 1.39-2.55; p<0.001) and low (aPR=2.04; 95% CI, 1.51-2.76; p<0.001) tertiles of gait speed were associated with a higher prevalence of balance disorders. CONCLUSION: The intermediate and low tertiles of gait speed were associated with a higher prevalence of balance disorders among older adult residents of 12 high-altitude Andean communities. We recommend further research on the behavior of this association to propose interventions for these vulnerable groups and reduce the impact of geriatric conditions.

Association between Gross Motor Competence and Physical Fitness in Chilean Children Aged 4 to 6 Years.

The preschool period is considered critical for the development of motor competence, but as far as we know, no studies have investigated the association between motor competence and physical fitness in Chilean children. The aim of this study was to analyse the association between gross motor competence and physical fitness, controlling for possible confounding factors. A cross-sectional study was conducted with a sample of 144 preschool children (56.25% girls) with an average age of 5.3 years (4 to 6 years) from the Araucanía region, Chile. Motor competence was measured using the Children's Movement Assessment Battery, 2nd Edition (MABC-2). Regarding physical fitness, the components of cardiorespiratory fitness, lower body muscle strength and speed/agility were evaluated using the Battery to Assess FITness in PREschool (PREFIT). Partial correlation models and analysis of variance (ANCOVA) were used to assess differences in physical fitness between motor competence categories, controlling for age and body mass index. The mean fitness scores for cardiorespiratory fitness, lower body muscle strength and speed/agility components were significantly higher in children with higher gross motor competence. In terms of effect size, large values were found for the lower body strength component in model 1 for boys and in model 2 for the total samples of girls and boys. The results of this study suggest that good levels of gross motor competence are associated with better physical fitness levels.

The Association of Neighborhood Socioeconomic Status with Executive Function and Processing Speed in Cognitively Normal Mexican American Elders from the Health and Aging Brains Study: Health Disparities Cohort.

INTRODUCTION: Neighborhood socioeconomic status (NSES) has been linked with overall health, and this study will evaluate whether NSES is cross-sectionally associated with cognition in non-Hispanic whites (NHWs) and Mexican Americans (MAs) from the Health and Aging Brain: Health Disparities Study (HABS-HD). METHODS: The HABS-HD is a longitudinal study conducted at the University of North Texas Health Science Center. The final sample analyzed (n = 1,312) were 50 years or older, with unimpaired cognition, and underwent an interview, neuropsychological examination, imaging, and blood draw. NSES was measured using the national area deprivation index (ADI) percentile ranking, which considered socioeconomic variables. Executive function and processing speed were assessed by the trail making tests (A and B) and the digit-symbol substitution test, respectively. Linear regression was used to assess the association of ADI and cognitive measures. RESULTS: MAs were younger, more likely to be female, less educated, had higher ADI scores, performed worse on trails B (all p < 0.05), and had lower prevalence of APOE4 + when compared to NHWs (p < 0.0001). A higher percentage of MAs lived in the most deprived neighborhoods than NHWs. For NHWs, ADI did not predict trails B or DSS scores, after adjusting for demographic variables and APOE4. For MAs, ADI predicted trails A, trails B, and DSS after adjusting for demographic covariates and APOE4 status. CONCLUSION: Our study revealed that living in an area of higher deprivation was associated with lower cognitive function in MAs but not in NHWs, which is important to consider in future interventions to slow cognitive decline.

How Do Escape Distance Behavior of Broiler Chickens Change in Response to a Mobile Robot Moving at Two Different Speeds?

In poultry farming, robots are considered by birds as intruder elements to their environment, because animals escape due to their movement. Their escape is measured using the escape distance (ED) technique. This study analyzes the behavior of animals in relation to their ED through the use of a robot with two speeds: 12 rpm and 26 rpm. The objective is to understand whether the speeds cause variations in ED and their implications for animal stress. A broiler breeding cycle was analyzed (six weeks) through the introduction of the robot weekly. ED analyses were carried out on static images generated from footage of the robot running. The results indicate higher escape distance rates (p < 0.05) peaking midway through the production cycle, notably in the third week. Conversely, the final weeks saw the lowest ED, with the most significant reduction occurring in the last week. This pattern indicates a gradual escalation of ED up to the fourth week, followed by a subsequent decline. Despite RPM12 having shown low ED results, it did not show enough ED to move the animals away from their path of travel, causing bumps and collisions. RPM26 showed higher ED in all breeding phases, but showed ED with no bumps and collisions.

Relationship between appendicular muscular mass index and physical function in older people.

This study aimed to establish the relationship between the appendicular muscle mass index (AMMI), assessed from anthropometric variables, and the physical function of older people. Seventy-six older people participated in this study (72.03 ± 7.03 years). The participants underwent evaluations to determine their AMMI using anthropometry (weight, calf circumference, hip circumference, and knee height) and manual grip strength. Additionally, their physical function was evaluated using the 5-chair stand test, the 3-meter walk test, and the timed up and go test (TUG) to determine the strength of the lower limbs, the gait speed, and the dynamic balance, respectively. The results show that the AMMI did not present a significant relationship with the 5-chair stand test in both women (r = -0.135; p = 0.204) and men (r = -0.067; p = 0.349). The AMMI was moderately correlated with the gait speed in both women (r = 0.542; p < 0.001) and men (r = 0.556; p < 0.001). Finally, a statistical significance was observed in the relationship between the AMMI and the TUG test in women (r = -0.273; p = 0.047) and older men evaluated in this study (r = -0.284; p = 0.042). In conclusion, there is a relationship between the AMMI and both the dynamic balance and the gait speed. Therefore, the AMMI emerges as a potential public health assessment by enabling the clinical quantification of muscle mass and an estimation of physical function in the elderly population.

Metodología para incrementar la velocidad de reacción durante la defensa personal en cadetes

La preparación física, como parte del entrenamiento de los cadetes, busca poner en óptimo estado al practicante, perfecciona sus aptitudes naturales y desarrolla al máximo sus capacidades físicas por medio de ejercicios sistemáticos. En ese sentido, la velocidad de reacción durante la defensa personal constituye un importante aspecto a tratar; sin embargo, la observación y análisis de la realidad educativa en el Instituto de Enseñanza Superior del Ministerio del Interior, en Santiago de Cuba, reveló insuficiencias que limitan el logro de altos niveles en la velocidad de reacción. El objetivo del estudio consistió en elaborar una metodología para el desarrollo de la velocidad de reacción durante la defensa personal, en los cadetes de la carrera Ciencias de la Seguridad del Estado del Ministerio del Interior. En esa línea de pensamiento, se realizó una investigación con enfoque mixto y diseño cuasi experimental que empleó como métodos empíricos la revisión documental, la observación científica y la entrevista no estructurada; se utilizó la estadística inferencial por medio de la prueba de rangos de Wilcoxon para muestras relacionadas, lo que permitió conocer la eficiencia de los ejercicios especiales que se aplicaron. La calidad de la metodología quedó corroborada por los resultados obtenidos en la aplicación del criterio de expertos en la variante "Delphi" y del prexperimento, confirmados por diferentes técnicas estadísticas que resaltan la funcionalidad, sostenibilidad, pertinencia y factibilidad de la propuesta.

A preparação física, como parte do treinamento dos cadetes, busca colocar o praticante em ótimas condições, aperfeiçoar suas aptidões naturais e desenvolver ao máximo suas capacidades físicas por meio de exercícios sistemáticos. Nesse sentido, a velocidade de reação durante a defesa pessoal é um aspecto importante a ser abordado; no entanto, a observação e a análise da realidade educacional no Instituto de Ensino Superior do Ministério do Interior, em Santiago de Cuba, revelaram insuficiências que limitam a obtenção de altos níveis de velocidade de reação. O objetivo do estudo foi elaborar uma metodologia para o desenvolvimento da velocidade de reação durante a autodefesa, em cadetes do curso de Ciências de Segurança do Estado do Ministério do Interior. Nessa linha de pensamento, foi realizada uma pesquisa com abordagem mista e desenho quase experimental, utilizando como métodos empíricos a revisão documental, a observação científica e a entrevista não estruturada; foi utilizada a estatística inferencial por meio do teste de postos de Wilcoxon para amostras relacionadas, o que permitiu conhecer a eficiência dos exercícios especiais aplicados. A qualidade da metodologia foi corroborada pelos resultados obtidos na aplicação de critérios de especialistas na variante "Delphi" e no pré-experimento, confirmados por diferentes técnicas estatísticas que destacam a funcionalidade, a sustentabilidade, a relevância e a viabilidade da proposta.

Physical preparation, as part of training of the cadets, seeks to put the practitioner in optimal condition, perfects their natural aptitudes and develops their physical capabilities to the maximum through systematic exercises. In this sense, the speed of reaction during self-defense is an important aspect to address; however, the observation and analysis of the educational reality at the Institute of Higher Education of the Ministry of the Interior, in Santiago de Cuba, revealed insufficiencies that limit the achievement of high levels in reaction speed. The objective of the study was to develop a methodology for the development of reaction speed during self-defense, in the cadets of the State Security Sciences career of the Ministry of the Interior. In this line of thought, research was carried out with a mixed approach and quasi-experimental design that used documentary review, scientific observation and unstructured interviews as empirical methods; inferential statistics was used through the Wilcoxon rank test for related samples, which made it possible to know the efficiency of the special exercises that were applied. The quality of the methodology was corroborated by the results obtained in the application of expert criteria in the "Delphi" variant and of the pre-experiment, confirmed by different statistical techniques that highlight the functionality, sustainability, relevance and feasibility of the proposal.

Speed limits and their effect on air pollution in Mexico City: A quasi-experimental study.

Speed limits are an evidence-based intervention to prevent traffic collisions and deaths, yet their impact on air pollution in cities is understudied. The objective of this study was to investigate the association between lower speed limits and air pollution. We leverage the introduction of a new road safety policy in Mexico City in December 2015 which lowered speed limits, increased fines, and installed speed radars to enforce compliance. We tested whether the policy had an impact on particulate matter (PM2.5) and nitrogen dioxide (NO2) at the city level, and whether air-quality monitoring stations' proximity to speed radars moderated this effect due to more acceleration and deceleration around radars. NO2 and PM2.5 concentrations from January 2014 to December 2018 were obtained from the National System of Air Quality Information. Air-quality monitoring stations were classified as in close-proximity or far-from-speed radars. Interrupted time series analyses were conducted for each outcome separately, using linear mixed models and adjusting for seasonality and time-varying confounders: registered vehicles, temperature, wind-speed and relative humidity. The results suggest improvement in both contaminants after the speed limits policy. For NO2, the pre-policy trend was flat, while the post-policy trend showed a decline in concentrations of 0.04 ppb/week. For PM2.5, concentrations were increasing pre-policy by 0.08 µg/m3 per week, then this trend flattened in the post-policy period to a weekly, non-significant, increase of 0.03 µg/m3 (p = 0.08). Air-quality monitors' proximity to speed radars did not moderate the effect of the policy on either of the pollutants. In conclusion, the speed limits policy implemented in Mexico City in 2015 was associated with improvements in air pollution.