Stroke Steadiness as a Determinant Factor of Performance in 100 m Freestyle in Young Swimmers.

The classical kinematic variables in swimming are based on the calculation of mean values. Stroke steadiness determines the relationship between the duration of all consecutive strokes throughout a test. The aims of the current investigation were to examine differences in stroke-to-stroke steadiness according to swimmers' performance level on both body sides (breathing and non-breathing) and to analyse the interrelationship with kinematics during a 100 m front-crawl test. Thirty-two young, experienced swimmers voluntarily participated in the present study and were divided into two groups, national level (n = 15) and local level (n = 17), according to their competitive status within the national age-rankings. All participants performed a 100 m maximal test in a 50 m pool where they were laterally recorded. Kinematic variables such as mean velocity, stroke rate, stroke length, and stroke index, as well as long-term steadiness and short-term steadiness, were calculated. The two 50 m sections were analysed independently. Significant differences were observed between the two groups in the classical kinematic variables and in stroke steadiness (p < 0.05). In addition, stroke steadiness showed moderately high correlations with velocity (r = [-0.61-(-0.749)]) and stroke index (r = [-0.356-(-0.582)]). Maintaining a more stable inter-stroke period appears to be a determinant of performance in young, high-level national swimmers.

Response to physical activity of females with multiple sclerosis throughout the menstrual cycle: a protocol for a randomised crossover trial (EMMA Project).

The relationship between multiple sclerosis (MS) and females is a crucial aspect in the development of the disease, with the ovarian hormonal cycle being a sensitive stage, especially in females with relapsing-remitting multiple sclerosis. The objectives of the study are to identify moderating variables that modify satisfaction with physical activity practice throughout the menstrual cycle (MC) in females in or out of their MC, during high-intensity interval training (HIIT) and strength training sessions and to compare the acute effects of different types of physical activity sessions in females with and without MS. This protocol is the methodology used in the EMMA Study, a randomised, single-blind crossover trial study conducted in females with MS who were matched 1:1, based on age, lifestyle factors and country of residence, with females without MS, to analyse the effect of physical activity practice on satisfaction, functionality, fatigue and inflammatory profile through their MC. Participants will visit the facilities approximately 10 times (4 preliminary familiarisation visits and 6 visits to carry out a physical activity session in each phase of the MC) for 3-4 months. A total sample of 30 females (15 females without MS and 15 with MS) is necessary for the study. The evaluation will comprise clinical, nutritional and psychological interviews, including different variables. It is hypothesised during the luteal phase, females with MS are expected to exhibit different acute responses to HIIT and strength training sessions as compared with females without the disease. Before starting the study, all participants will read and sign an informed consent form. Trial registration number: This research protocol is registered with ClinicalTrials.gov to ensure transparency and accessibility of study information (NCT06105463). The university's ethics committee number for this study is UALBIO2022/048.

Psychological, Physiological, and Physical Effects of Resistance Training and Personalized Diet in Celiac Women.

Background: Gluten intolerance is a systemic process of autoimmune nature; it develops in genetically predisposed subjects with gluten ingestion. The only treatment for celiac disease (CD) is a lifelong strict gluten-free diet (GFD). This study was designed to evaluate adherence to a GFD, risk of an eating disorder, and nutritional status in adult CD patients undergoing different interventions. Methods: A total of 28 Spanish women, aged 40 years or more, took part in a randomized controlled trial. Each group received a different intervention: group 1, gluten-free nutrition plan + exercise (GFD + E); group 2, gluten-free nutrition plan (GFD); group 3, celiac controls (NO-GFD); and group 4, non-celiac controls (CONTROL). The training was prescribed by a sport scientist. It was based on resistance training with elastic bands; beforehand a warm-up was performed and the resistance was increased progressively. The variables studied were adherence to the GFD, risk of eating disorders, blood values, and body composition. Results: Celiac women with personalized nutritional planning presented greater adherence to a gluten-free diet (p < 0.001). Regarding leukocytes, significant differences were observed between the GFD and control groups (p = 0.004). Perimeters and folds did not decrease significantly. Conclusion: Women with celiac disease who follow an adapted and personalized diet have a better adherence to a GFD compared to those who follow a non-professional diet, and therefore have a better immune system status (blood leukocytes).

Inter-stroke steadiness: a new kinematic variable related to 200m performance in young canoeists.

Traditionally, canoeing analyses have always been carried out by calculating mean values over a certain distance. However, a simple analysis of mean values in cyclic actions, such as canoe paddling, can lead to the loss of decisive data. Therefore, the objective of this study was to investigate whether the relationship between the periods of consecutive strokes can be an important aspect in all-out 200-m canoeing performance. A total of 22 young male canoeists aged 13.51 ± 0.43 years old voluntarily participated in the present study. Lateral recordings were taken from all participants when performing an all-out 200 m to subsequently analyse the kinematic variables of time, speed and cycle frequency, length and index. The time of each stroke was calculated by the frame differencesbetween two successive paddles. Likewise, short-term and long-term steadiness of consecutive strokes were analysed. Positive correlations were observed between all-out 200-m time and inter-stroke steadiness, identifying significant associations with long-term (r ≈ 0.8; p < 0.05) and short-term steadiness (r ≈ 0.7; p < 0.05). In conclusion, the present investigation defines and identifies inter-stroke steadiness as a new original kinematic variable that might be considered for performance analysis since it seems to be a key factor in all-out 200-m canoeing.

What Are the Physical Demands of Sexual Intercourse? A Systematic Review of the Literature.

The aim of this study was to systematically review the literature investigating the physical demands of sexual intercourse and to synthesize the evidence related to this research topic. Original studies published on PubMed, Scopus, and Web of Science up until April 2020 were examined. The Effective Public Health Practice Project scale was used to assess the methodological quality of each study. Eighteen studies analyzed physical demands during sexual intercourse through the physiological demands (n = 14) and kinematics (n = 4) of sexual intercourse. Sexual intercourse can elicit an energy expenditure of ~ 100 kcal (or ~ 6 metabolic equivalent units, METs) during the activity, mean heart rates between ~ 90 and ~ 130 beats per minute (bpm), and peak heart rates up to ~ 170 bpm. However, these physical demands may vary depending on health status, intercourse position, activity duration, intercourse phase, and sex differences. The movement pattern was cyclic in all positions and the greatest demands in lumbar spine flexion were found in the missionary positions for women. Missionary and side-lying positions elicited the greatest lumbar flexion movement in men. Regarding the movement of the hip joint during sexual intercourse, flexion, abduction, and external rotation mainly characterized the woman's movement while external rotation did so in the man. In conclusion, sexual intercourse may elicit moderate intensity physical demands, but these demands vary depending on contextual variables. In addition, not only studies combining physiological and kinematic analyses are necessary but also more high-quality studies need to be published in order to have a better understanding of the physical demands of sexual intercourse.

Personalised Nutritional Plan and Resistance Exercise Program to Improve Health Parameters in Celiac Women.

Celiac disease (CD) is a permanent immune reaction to gluten in those with a genetic predisposition. This study was designed to evaluate menopause-associated symptoms, mood, bone quality, and IgA antibody levels in women with CD, untreated and treated with a gluten-free diet (GFD), and with or without resistance exercise. The randomised controlled trial was conducted on 28 Spanish women (>40 years old). Participants were divided into the following intervention groups: personalised gluten-free nutrition plan + exercise (GFD + E); personalised gluten-free nutrition plan (GFD); celiac controls (NO-GFD); and non-celiac controls (CONTROL). The participants responded to the Menopause Rating Scale and the Profile of Mood States (POMS) questionnaires. Bone quality was measured with ultrasound and IgA with a blood test. After 12 weeks of intervention, the GFD + E group showed significant improvement in urogenital symptoms and scored higher on the 'vigour' subscale of the POMS. Negative associations were found between the total score on the Menopause Rating Scale and the 'vigour' subscale of the POMS questionnaire. Only those women who underwent a personalised GFD nutritional intervention combined with resistance exercise demonstrated significant changes after the intervention.

Validation of a global positioning system with accelerometer for canoe/kayak sprint kinematic analysis.

This study aimed to validate the use of a Global Positioning System with an accelerometer (GPS-Acc) unit to quantify canoeing kinematic variables. Eight canoe and kayak (200 and 500 m) sprint races were analysed. All the races were recorded sideways by a digital camera that followed the kayak or canoe bow and simultaneously using a GPS-Acc unit recorded the data concerning boat position, velocity, and acceleration. In 200 m races, 50 m splits were established over the entire race distance. In 500 m races, 100 m splits were used, excepting the race start and end, where the splits were divided into two sections of 50 m. The data of the GPS-Acc unit were analysed using a self-developed routine. The agreement between the video and the GPS-Acc analysis was measured regarding all the variables by a Bland-Altman analysis. No differences were found between both methodologies, except for time and velocity at the first 50 m, suggesting thus an agreement between the analysis methods. The GPS-Acc unit is valid for measuring quickly and accurately kinematic variables, mainly boat velocity and stroke rate. However, video analyses may be necessary when a more detailed analysis of the paddling technique is of interest.

Influence of maturity status on morphology, grip and throwing speed in young elite water polo players.

BACKGROUND: Water polo is a team sport that requires not only high levels of power and strength but a robust morphology with big body dimensions for an optimal performance. The aim of this study was to analyze the relationship between anthropometric variables, maturity, grip strength and throwing speed in young water polo competitors. METHODS: Body composition, biological age, grip strength and throwing speed were evaluated in 28 elite water polo players (15.74±0.83 years old) with competition experience (7.35±1.68 years). The participants were divided into two maturity groups based on the percentage of adult height attained at the moment of assessment (<98% and >98%). RESULTS: Significant differences and moderate effect sizes were observed across sitting height and upper body lengths and breadths in the more mature players of the >98% group compared with those observed in the <98% group (d>0.42; P<0.05). A large effect size in maturity status and percentage of adult height (d>0.82) was also identified in the >98% players. In addition, significant correlations (P<0.05) were determined between upper and lower body girths and not opposition throwing speed (NOT). Similarly, a linear regression analysis revealed that biacromial breadth, arm girth and medial calf skinfold significantly contributed in predicting NOT speed (r2=0.82; P<0.01). CONCLUSIONS: These findings suggest that body structure is positively related to throwing speed in young water polo players. Furthermore, the results of the present investigation might be useful for talent identification purposes.

The Importance of Biological Maturation and Years of Practice in Kayaking Performance.

Previous canoe sprint studies evaluated the best paddlers of their categories. This investigation aimed to identify the importance of biological maturation and athletes' experience in kayaking performance and observe possible differences regarding anthropometry, years of practice, and performance. Eighty under 14 years of age (U14) and fifty under 16 years of age (U16) kayakers aged 13.40 ± 0.54 and 15.25 ± 0.61 years were evaluated. Kayakers were assessed for anthropometry (body mass (kg); stretch stature (cm); and sitting height (cm)), performance (time at 3000 m for U14 and 5000 m for U16 kayakers), and somatic maturation (predicted adult height (PAH) and maturity offset). In the U14 kayakers, years of practice, sitting height, and maturity offset showed significant differences (p < 0.05) between the Top10 and Middle, and Middle and Bottom10 performance times. Significantly higher (p < 0.05) sitting heights were identified between the Top10 and Middle U16 kayakers. Significant differences (p < 0.05) were observed for maturity offset and PAH% between the Top10 and Middle groups compared to the Bottom10 group. In conclusion, this research shows differences in the maturity status of young U14 and U16 kayakers, identifying that the more biologically mature individuals, with more years of specific practice, achieved better performances.

Cardiac Parasympathetic Withdrawal and Sympathetic Activity: Effect of Heat Exposure on Heart Rate Variability.

(1) Background: Research on heart rate variability has increased in recent years and the temperature has not been controlled in some studies assessing repeated measurements. This study aimed to analyze how heart rate variability may change based on environmental temperature during measurement depending on parasympathetic and sympathetic activity variations. (2) Methods: A total of 22 volunteers participated in this study divided into an experimental (n = 12) and control group (n = 10). Each participant was assessed randomly under two different environmental conditions for the experimental group (19 °C and 35 °C) and two identical environmental conditions for the control group (19 °C). During the procedure, heart rate variability measurements were carried out for 10 min. (3) Results: Significantly changes were observed for time and frequency domains as well as Poincaré plot variables after heat exposure (p < 0.05). These findings were not observed in the control group, whose conditions between measurements did not change. (4) Conclusions: The reduction of heart rate variability due to exposure to hot conditions appears to be produced mostly by a parasympathetic withdrawal rather than a sympathetic activation. Therefore, if consecutive measurements have to be carried out, these should always be done under the same temperature conditions.

Development of alternatives to estimate resting metabolic rate from anthropometric variables in paralympic swimmers.

The resting metabolic rate (RMR) is one of the most representative components of total daily energy expenditure (TDEE). Multiple equations have been developed to estimate RMR, but none have been described for Para-Athletes. This study aimed to; i) develop and validate new RMR estimation models from anthropometric variables; and ii) explore the level of agreement between the RMR determined by indirect calorimetry (IC) and the developed models, as well as a selection of existent estimation models in Para-Athletes. Fifteen young Paralympic swimmers (age, 18.7±6.5 years) underwent assessments of RMR by IC and anthropometric batteries. Four RMR estimation models (M1-M4) were developed. The anthropometric variables which explained most of the variance were biacromial breadth (M3-37%), stature (M1-45%; M2-49%), and estimated stature from half arm span (M4-24%). However, the neck girth corrected by the submandibular skinfold entered in all four models. The 95% limits of agreement between IC and M3 equation (best performance model) ranged from -142.02 to 172.39 kcal×day-1 (bias 15.19 kcal×day-1). Concerning the commonly used equations, Harris & Benedict equation was the most consistent when compared to IC. The results of this study suggest four novel RMR equations that may assist in the estimation of energy requirements in elite Para-Athletes.

Evolución de la percepción y distorsión de la imagen corporal con la práctica de Pilates en suelo y con aparatos en mujeres adultas / Evolution of body image perception and distorsion with mat and apparatus Pilates practice in adult women

INTRODUCCIÓN: la práctica sistemática de ejercicio físico podría influir en la percepción y distorsión de la imagen corporal de mujeres adultas. OBJETIVO: analizar la evolución de la percepción y la distorsión de la imagen corporal en mujeres adultas que realizan una práctica sistemática de Pilates en suelo (PS) o Pilates con aparatos (PA). METODOLOGÍA: un total de 35 mujeres adultas participaron en un programa de PS (n = 19) o PA (n = 26) durante 16 semanas, dos días por semana. La imagen corporal se valoró antes y después de las intervenciones con el cuestionario "Inventario de la conducta alimentaria 3" (EDI-3), la escala de evaluación de la imagen corporal de Gardner y la escala de siluetas de Thompson y Gray. RESULTADOS: el grupo de PS mostró una reducción significativa de la insatisfacción con los glúteos, la insatisfacción con la imagen corporal, la imagen percibida, el índice de distorsión, el índice de insatisfacción, la imagen mental percibida, la imagen afectiva percibida, el índice de insatisfacción cognitiva y el índice de insatisfacción afectiva (p < 0,05; TE: 0,26-0,80). En relación con el grupo de PA se encontró una disminución significativa de la insatisfacción con los muslos, la insatisfacción con las caderas, la insatisfacción con la imagen corporal, el índice de insatisfacción, el índice de insatisfacción cognitiva y el índice de insatisfacción afectiva (p < 0,05; 0,22-0,79). CONCLUSIONES: la práctica sistemática de PS o PA mejora la imagen corporal en mujeres adultas, reduciéndose el grado de insatisfacción corporal de las mismas

INTRODUCTION: the systematic practice of physical exercise may influence the perception and distortion of body image in adult women. OBJECTIVE: to analyze the evolution of body image perception and distortion in adult women who performed a systematic practice of mat Pilates (PM) or Pilates with apparatus (PA). METHODS: a total of 35 adult women participated in a PM (n = 19) or PA (n = 26) program for 16 weeks, two days a week. Body image was assessed before and after the interventions using the Eating Behavior Inventory 3 (EBI-3), Gardner's body image assessment scale, and Thompson and Gray's silhouette scale questionnaires. RESULTS: the PM group showed a significant reduction in dissatisfaction with buttocks, dissatisfaction with body image, perceived image, distortion index, dissatisfaction index, perceived mental image, perceived affective image, cognitive dissatisfaction index, and affective dissatisfaction index (p < 0.05; ES: 0.26-0.80). As compared to the PA group, a significant reduction was shown in dissatisfaction with thighs, dissatisfaction with hips, dissatisfaction with body image, dissatisfaction index, cognitive dissatisfaction index, and affective dissatisfaction index (p < 0.05; 0.22-0.79). CONCLUSION: the systematic practice of PM or PA improves body image in adult women, reducing their body dissatisfaction

[Evolution of body image perception and distorsion with mat and apparatus Pilates practice in adult women]. / Evolución de la percepción y distorsión de la imagen corporal con la práctica de Pilates en suelo y con aparatos en mujeres adultas.

INTRODUCTION: Introduction: the systematic practice of physical exercise may influence the perception and distortion of body image in adult women. Objective: to analyze the evolution of body image perception and distortion in adult women who performed a systematic practice of mat Pilates (PM) or Pilates with apparatus (PA). Methods: a total of 35 adult women participated in a PM (n = 19) or PA (n = 26) program for 16 weeks, two days a week. Body image was assessed before and after the interventions using the Eating Behavior Inventory 3 (EBI-3), Gardner's body image assessment scale, and Thompson and Gray's silhouette scale questionnaires. Results: the PM group showed a significant reduction in dissatisfaction with buttocks, dissatisfaction with body image, perceived image, distortion index, dissatisfaction index, perceived mental image, perceived affective image, cognitive dissatisfaction index, and affective dissatisfaction index (p < 0.05; ES: 0.26-0.80). As compared to the PA group, a significant reduction was shown in dissatisfaction with thighs, dissatisfaction with hips, dissatisfaction with body image, dissatisfaction index, cognitive dissatisfaction index, and affective dissatisfaction index (p < 0.05; 0.22-0.79). Conclusion: the systematic practice of PM or PA improves body image in adult women, reducing their body dissatisfaction.

INTRODUCCIÓN: Introducción: la práctica sistemática de ejercicio físico podría influir en la percepción y distorsión de la imagen corporal de mujeres adultas. Objetivo: analizar la evolución de la percepción y la distorsión de la imagen corporal en mujeres adultas que realizan una práctica sistemática de Pilates en suelo (PS) o Pilates con aparatos (PA). Metodología: un total de 35 mujeres adultas participaron en un programa de PS (n = 19) o PA (n = 26) durante 16 semanas, dos días por semana. La imagen corporal se valoró antes y después de las intervenciones con el cuestionario "Inventario de la conducta alimentaria 3" (EDI-3), la escala de evaluación de la imagen corporal de Gardner y la escala de siluetas de Thompson y Gray. Resultados: el grupo de PS mostró una reducción significativa de la insatisfacción con los glúteos, la insatisfacción con la imagen corporal, la imagen percibida, el índice de distorsión, el índice de insatisfacción, la imagen mental percibida, la imagen afectiva percibida, el índice de insatisfacción cognitiva y el índice de insatisfacción afectiva (p < 0,05; TE: 0,26-0,80). En relación con el grupo de PA se encontró una disminución significativa de la insatisfacción con los muslos, la insatisfacción con las caderas, la insatisfacción con la imagen corporal, el índice de insatisfacción, el índice de insatisfacción cognitiva y el índice de insatisfacción afectiva (p < 0,05; 0,22-0,79). Conclusiones: la práctica sistemática de PS o PA mejora la imagen corporal en mujeres adultas, reduciéndose el grado de insatisfacción corporal de las mismas.

Predictive Performance Models in Long-Distance Runners: A Narrative Review.

Physiological variables such as maximal oxygen uptake (VO2max), velocity at maximal oxygen uptake (vVO2max), running economy (RE) and changes in lactate levels are considered the main factors determining performance in long-distance races. The aim of this review was to present the mathematical models available in the literature to estimate performance in the 5000 m, 10,000 m, half-marathon and marathon events. Eighty-eight articles were identified, selections were made based on the inclusion criteria and the full text of the articles were obtained. The articles were reviewed and categorized according to demographic, anthropometric, exercise physiology and field test variables were also included by athletic specialty. A total of 58 studies were included, from 1983 to the present, distributed in the following categories: 12 in the 5000 m, 13 in the 10,000 m, 12 in the half-marathon and 21 in the marathon. A total of 136 independent variables associated with performance in long-distance races were considered, 43.4% of which pertained to variables derived from the evaluation of aerobic metabolism, 26.5% to variables associated with training load and 20.6% to anthropometric variables, body composition and somatotype components. The most closely associated variables in the prediction models for the half and full marathon specialties were the variables obtained from the laboratory tests (VO2max, vVO2max), training variables (training pace, training load) and anthropometric variables (fat mass, skinfolds). A large gap exists in predicting time in long-distance races, based on field tests. Physiological effort assessments are almost exclusive to shorter specialties (5000 m and 10,000 m). The predictor variables of the half-marathon are mainly anthropometric, but with moderate coefficients of determination. The variables of note in the marathon category are fundamentally those associated with training and those derived from physiological evaluation and anthropometric parameters.

Morphological characteristics of visually impaired tennis practitioners / Características morfológicas de practicantes de tenis con discapacidad visual

OBJECTIVE: To evaluate somatotype and body composition of a population of sound-tennis players. METHOD: The research included a descriptive, cross-sectional design, with a quantitative focus. The sample consists of 13 male sound-tennis players: eight Spanish and five from other countries that were recruited in an international tournament in May 2017. The Spanish population started the practice of this discipline two years before the data collection, while the other group was more experienced with 4-6 years of sports practice. Anthropometric characteristics and body composition of both populations were determined by the protocols described by the International Society for the Advancement of Kinanthropometry. RESULTS: All the participants presented an endomorphic mesomorph somatotype. No significant differences were detected regarding fat and muscle masses when comparing Spanish vs others. Spanish players displayed significantly higher values of biceps and medial calf skinfolds, but also lower bone mass and height. CONCLUSIONS: All participants were slightly overweight. The Spanish para-athletes tend to accumulate fat in the upper and lower limbs that could affect their tennis performance. These indicators should be taken into account when planning diet, training and season goals

OBJETIVO: Caracterizar el somatotipo y la composición corporal de un grupo de tenistas con discapacidad visual. MÉTODO: La investigación contempló un diseño descriptivo, transversal, con un enfoque cuantitativo. La muestra estaba compuesta por 13 jugadores masculinos de tenis: ocho españoles y cinco extranjeros, reclutados en un campeonato internacional en mayo de 2017. La población española comenzó la práctica de esta disciplina dos años antes del momento de la toma de datos, mientras que el grupo de deportistas de otros países tenía un historial de práctica de 4-6 años. Las características antropométricas y la composición corporal de ambas poblaciones fueron determinadas siguiendo los protocolos de la Sociedad Internacional para el Avance de la Cineantropometría. RESULTADOS: Los deportistas presentaron un somatotipo mesomorfo endomórfico. No se observaron diferencias en las masas grasa y muscular al comparar españoles vs extranjeros. No obstante, los jugadores españoles presentaron valores significativamente mayores en los pliegues del bíceps y medial de la pierna, así como valores más bajos de masa ósea y altura. CONCLUSIONES: Todos los participantes del presente estudio presentaron un sobrepeso límite. Sin embargo, los deportistas españoles tendían a acumular más grasa en las extremidades superiores e inferiores, lo que podría condicionar su rendimiento. Estos indicadores deberían tenerse en cuenta a la hora de planificar la dieta, el entrenamiento y los objetivos de temporada

Tools Used to Measure the Physical State of Women with Celiac Disease: A Review with a Systematic Approach.

Celiac disease (CD) is an immunological disorder that mainly affects the small intestine, generating an inflammatory process in response to the presence of gluten (a protein). Autoimmune diseases are part of a group of diseases that are difficult to diagnose without a specific protocol or consensus to detect them due to the number of symptoms and diseases with which it has a relationship. Therefore, the aim of this review was to analyze the diagnostic tools of CD used in middle-aged women, to compare the use and effectiveness of the different tools, and to propose a strategy for the use of the tools based on the results found in the literature. The present research followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline. The search was conducted in the following databases: Scielo, PubMed, Web of Science, and Worldwide Science org. In the initial literature search, 2004 titles and relevant abstracts were found. Among them, 687 were duplicates, leaving 1130 articles. Based on the inclusion criteria, only 41 articles passed the selection process; 4 main types of analyses appear in the studies: blood tests, questionnaires, clinical history, and biopsy. It can be said that none of the analyses have a 100% reliability since most of them can present false negatives; therefore, the best way to diagnose celiac disease up to now is through a combination of different tests (Immunoglobulin A and small intestinal biopsy).

Cooper Test Provides Better Half-Marathon Performance Prediction in Recreational Runners Than Laboratory Tests.

This study compared the ability to predict performance in half-marathon races through physiological variables obtained in a laboratory test and performance variables obtained in the Cooper field test. Twenty-three participants (age: 41.6 ± 7.6 years, weight: 70.4 ± 8.1 kg, and height: 172.5 ± 6.3 cm) underwent body composition assessment and performed a maximum incremental graded exercise laboratory test to evaluate maximum aerobic power and associated cardiorespiratory and metabolic variables. Cooper's original protocol was performed on an athletic track and the variables recorded were covered distance, rating of perceived exertion, and maximum heart rate. The week following the Cooper test, all participants completed a half-marathon race at the maximum possible speed. The associations between the laboratory and field tests and the final time of the test were used to select the predictive variables included in a stepwise multiple regression analysis, which used the race time in the half marathon as the dependent variable and the laboratory variables or field tests as independent variables. Subsequently, a concordance analysis was carried out between the estimated and actual times through the Bland-Altman procedure. Significant correlations were found between the time in the half marathon and the distance in the Cooper test (r = -0.93; p < 0.001), body weight (r = 0.40; p < 0.04), velocity at ventilatory threshold 1, (r = -0.72; p < 0.0001), speed reached at maximum oxygen consumption (vVO2max), (r = -0.84; p < 0.0001), oxygen consumption at ventilatory threshold 2 (VO2VT2) (r = -0.79; p < 0.0001), and VO2max (r = -0.64; p < 0.05). The distance covered in the Cooper test was the best predictor of time in the half-marathon, and might predicted by the equation: Race time (min) = 201.26 - 0.03433 (Cooper test in m) (R 2 = 0.873, SEE: 3.78 min). In the laboratory model, vVO2max, and body weight presented an R 2 = 0.77, SEE 5.28 min. predicted by equation: Race time (min) = 156.7177 - 4.7194 (vVO2max) - 0.3435 (Weight). Concordance analysis showed no differences between the times predicted in the models the and actual times. The data indicated a high predictive power of half marathon race time both from the distance in the Cooper test and vVO2max in the laboratory. However, the variable associated with the Cooper test had better predictive ability than the treadmill test variables. Finally, it is important to note that these data may only be extrapolated to recreational male runners.

Recovery of Heart Rate Variability After Exercise Under Hot Conditions: The Effect of Relative Humidity.

INTRODUCTION: The aim of this study was to analyze changes in heart rate variability (HRV) during exercise in hot environments and recovery to baseline values depending on relative humidity. METHODS: Ten recreational runners participated in this study. Each participant performed 2 trials consisting of 30 min of continuous running under hot and dry (HD) (38°C and 28% relative humidity) and hot and humid (HH) conditions (38°C and 64% relative humidity) at their common 10 km race-running rhythm. HRV and body mass were assessed pre- and post-trial; the rating of perceived exertion and HRV were assessed during the trial; and HRV measurements were repeated 2, 4, 8, and 24 h postexercise. Primary HRV outcomes were root mean square of the successive differences, high frequency power, stress score, and sympathetic/parasympathetic ratio. One-way analysis of variance testing was used to analyze differences. RESULTS: No significant difference in body mass occurred across the different conditions or distances covered (P>0.05). Rating of perceived exertion presented the highest correlation values with stress score (r=0.729 for HD; r=0.568 for HH) and sympathetic/parasympathetic ratio (r=0.621 for HD; r=0.519 for HH) during exercise. HRV recovered to baseline values more quickly after exercising under dry conditions (4 h) than under humid conditions (between 8 and 24 h). CONCLUSIONS: Stress score and sympathetic/parasympathetic ratio seem to be the best HRV predictors of internal load. Although there are no differences in HRV during recovery at the same time points in both conditions, the recovery is slower after exercise in HH than in HD.

Acute effects of heat on health variables during continuous exercise and their comparison with normal and cold conditions: A systematic review / Efectos agudos del calor sobre variables de salud durante el ejercicio continuo en comparación con condiciones normales y frías: una revisión sistemática

Background: There has been an increasing number of running practitioners in the last years. Although running activity involves several benefits for practitioners, it might also induce health problems when practicing under heat conditions. Purpose: The main aim of this systematic review was to evaluate how high temperatures affect runner's health during continuous exercise. Search strategy: The search for articles for this study was carried out in two different databases, Web of Science and Pubmed.Study selection: The inclusion criteria were a) Studies that investigated the effects of endurance exercise, at least at 27º, on health variables, determining exercise intensity, indicating total time for exercise and presenting pre- and post-test results or compare with normal or cold conditions. Results: 1336 articles were identified after the searching process. 333 runners were evaluated in fifteen articles that were included in the qualitative synthesis. High increases in heart rate, body and skin temperature, some urine and blood markers, blood pH, ventilation, rate of perceived exertion and sweat rate were identified during continuous activity under heat conditions, and also when comparing with normal or cold conditions. Lower values were found in body mass, eosinophil than those observed before the running activity. Lower values for oxygen consumption and plasma lactate may occur in hot conditions when comparing with normal conditions. Conclusions: Studies analyzed conclude that an uncontrolled long-term activity in hot conditions may induce health problems related to high body and skin temperatures. Cooling strategies should be assessed after continuous exercise under hot conditions. In addition exercise in hot conditions produces greater increases in immune functions, heart rate, breathing stress, metabolic responses and rate of perceived exertion, also compared with normal and cold conditions

Introducción: El número de corredores ha incrementado en los últimos años. Aunque la actividad de correr implica varios beneficios para los practicantes, también puede provocar problemas de salud cuando se practica en condiciones de calor. Propósito: El objetivo de esta revisión fue evaluar cómo las altas temperaturas afectan la salud del corredor. Estrategia de búsqueda: La búsqueda de artículos para este estudio se llevó a cabo en Web of Science y Pubmed. Selección de estudios: Los criterios de inclusión fueron estudios que investigaron los efectos del ejercicio de resistencia, al menos a 27º, sobre variables de salud, determinando la intensidad y duración del ejercicio y se presentaron resultados previos y posteriores a la prueba o compararon con condiciones normales o frías. Resultados: 1336 artículos fueron identificados después del proceso de búsqueda. 333 corredores fueron evaluados en quince artículos que fueron incluidos en la síntesis cualitativa. Durante la actividad en condiciones de calor, se identificaron incrementos elevados en la frecuencia cardíaca, la temperatura corporal y de la piel, algunos marcadores de orina y sangre, el pH sanguíneo, la ventilación, el esfuerzo percibido y la sudoración. Se encontraron valores más bajos de masa corporal y eosinófilos que los observados antes de la actividad de carrera. Valores más bajos de consumo de oxígeno y lactato aparecen en condiciones de calor cuando se comparan con las condiciones normales. Conclusiones: Los estudios analizados concluyen que una actividad no controlada a largo plazo en condiciones de calor puede inducir problemas de salud relacionados con altas temperaturas corporales y de la piel. Además, el ejercicio en condiciones de calor produce mayores incrementos en las funciones inmunitarias, la frecuencia cardíaca, el estrés respiratorio, las respuestas metabólicas y el esfuerzo percibido, también en comparación con las condiciones normales y frías

A longitudinal analysis of morphological characteristics and body proportionality in young elite sprint paddlers.

Introduction: There are certain anthropometric attributes common to most high-level paddlers and among the determinants for optimal performance consecution in senior categories.Objective: The present investigation aimed to determine the evolution of morphological characteristics of elite paddlers during adolescence and to compare them with the values exhibited by Olympic competitors.Methods: In a longitudinal study, thirteen young elite paddlers (seven boys and six girls) completed a battery of anthropometric tests (heights, weight, girths, lengths, and sum of skinfolds) and on-water performance assessments (200 and 500 m) during three consecutive years.Results: Body mass and upper body sizes significantly change over the years (p < .05), especially in boys. Both male and female paddlers presented significant differences and large effect sizes in muscle mass and skin mass values (η2p > .64) whereas bone mass and fat mass remained stable from the 1st to the 3rd year. Proportionality analysis revealed girths and breadths differences in arm and chest variables as well as large effect sizes in biacromial breadth among all years (η2p > .62; p < .05), particularly in boys. Similarly, significant improvements in 200-m performance times were observed for both sexes.Conclusions: The findings of the current investigation might suggest a tendency towards a leaner and more robust morphological profile of elite paddlers in the transition from young to senior categories. In addition, the presence of superior relative body dimensions from young categories seems to be paramount in the evolution to later successful paddling.