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1.
Neuron ; 109(6): 1029-1039.e8, 2021 03 17.
Artigo em Inglês | MEDLINE | ID: mdl-33567253

RESUMO

The theta rhythm organizes neural activity across hippocampus and entorhinal cortex. A role for theta oscillations in spatial navigation is supported by half a century of research reporting that theta frequency encodes running speed linearly so that displacement can be estimated through theta frequency integration. We show that this relationship is an artifact caused by the fact that the speed of freely moving animals could not be systematically disentangled from acceleration. Using an experimental procedure that clamps running speed at pre-set values, we find that the theta frequency of local field potentials and spike activity is linearly related to positive acceleration, but not negative acceleration or speed. The modulation by positive-only acceleration makes rhythmic activity at theta frequency unfit as a code to compute displacement or any other kinematic variable. Temporally precise variations in theta frequency may instead serve as a mechanism for speeding up entorhinal-hippocampal computations during accelerated movement.


Assuntos
Aceleração , Córtex Entorrinal/fisiologia , Hipocampo/fisiologia , Navegação Espacial/fisiologia , Ritmo Teta/fisiologia , Animais , Artefatos , Células de Grade/fisiologia , Masculino , Ratos , Ratos Long-Evans , Corrida/fisiologia
3.
Life Sci ; 270: 119002, 2021 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-33417954

RESUMO

AIMS: Apoptosis is a type of cell death that is vital for tissue homeostasis. Exercise can lead to initial stimulation of apoptotic regulator genes. We investigated their response to an acute exercise and their adaptations to chronic exercise training with an emphasis on eccentric and sprint interval exercises. MAIN METHODS: Male Sprague Dawley rats were randomly assigned to five groups (n = 8): acute eccentric exercise (AEE), acute sprint interval exercise (ASE), chronic eccentric exercise (CEE), chronic sprint interval exercise (CSE) and control (C). The AEE group underwent downhill running (at -16° slope) at 16 m/min 18 sets. The ASE group run for 7 sets and the speed increased gradually to 70-80 m/min. The chronic groups were implemented for 9 weeks. The CEE run 1 set for 15 min at -4° slope that increased gradually to 90 min at -16°. The CSE sprinted 1 min with 2-5 min rest. The mRNA in soleus (slow-twitch muscle) and super vastus lateralis (SVL) (fast-twitch muscle) muscles was analyzed by real-time RT-PCR. KEY FINDINGS: According to the gene expression level in soleus muscle, apoptotic responses to acute and chronic sprint interval exercise as well as towards chronic eccentric exercise were clearly evident. But in SVL muscle, the only acute eccentric exercise group showed significance increase in apoptotic factors. SIGNIFICANCE: these results revealed the apoptotic response to the exercise depends on the type and intensity of exercise and also on the sensitivity and susceptibility of the muscle.


Assuntos
Apoptose/fisiologia , Músculo Esquelético/metabolismo , Esforço Físico/fisiologia , Animais , Masculino , Músculo Esquelético/fisiologia , Condicionamento Físico Animal/fisiologia , Ratos , Ratos Sprague-Dawley , Corrida/fisiologia
4.
JMIR Mhealth Uhealth ; 9(1): e24806, 2021 01 12.
Artigo em Inglês | MEDLINE | ID: mdl-33433391

RESUMO

BACKGROUND: Physical activity is evidently a crucial part of the rehabilitation process for patients with chronic pain. Modern wrist-worn activity tracking devices seemingly have a great potential to provide objective feedback and assist in the adoption of healthy physical activity behavior by supplying data of energy expenditure expressed as metabolic equivalent of task units (MET). However, no studies of any wrist-worn activity tracking devices' have examined criterion validity in estimating energy expenditure, heart rate, or step count in patients with chronic pain. OBJECTIVE: The aim was to determine the criterion validity of wrist-worn activity tracking devices for estimations of energy expenditure, heart rate, and step count in a controlled laboratory setting and free-living settings for patients with chronic pain. METHODS: In this combined laboratory and field validation study, energy expenditure, heart rate, and step count were simultaneously estimated by a wrist-worn activity tracker (Fitbit Versa), indirect calorimetry (Jaeger Oxycon Pro), and a research-grade hip-worn accelerometer (ActiGraph GT3X) during treadmill walking at 3 speeds (3.0 km/h, 4.5 km/h, and 6.0 km/h) in the laboratory setting. Energy expenditure and step count were also estimated by the wrist-worn activity tracker in free-living settings for 72 hours. The criterion validity of each measure was determined using intraclass and Spearman correlation, Bland-Altman plots, and mean absolute percentage error. An analysis of variance was used to determine whether there were any significant systematic differences between estimations. RESULTS: A total of 42 patients (age: 25-66 years; male: 10/42, 24%; female: 32/42, 76%), living with chronic pain (duration, in years: mean 9, SD 6.72) were included. At baseline, their mean pain intensity was 3.5 (SD 1.1) out of 6 (Multidimensional Pain Inventory, Swedish version). Results showed that the wrist-worn activity tracking device (Fitbit Versa) systematically overestimated energy expenditure when compared to the criterion standard (Jaeger Oxycon Pro) and the relative criterion standard (ActiGraph GT3X). Poor agreement and poor correlation were shown between Fitbit Versa and both Jaeger Oxycon Pro and ActiGraph GT3X for estimated energy expenditure at all treadmill speeds. Estimations of heart rate demonstrated poor to fair agreement during laboratory-based treadmill walks. For step count, the wrist-worn devices showed fair agreement and fair correlation at most treadmill speeds. In free-living settings; however, the agreement for step count between the wrist-worn device and waist-worn accelerometer was good, and the correlation was excellent. CONCLUSIONS: The wrist-worn device systematically overestimated energy expenditure and showed poor agreement and correlation compared to the criterion standard (Jaeger Oxycon Pro) and the relative criterion standard (ActiGraph GT3X), which needs to be considered when used clinically. Step count measured with a wrist-worn device, however, seemed to be a valid estimation, suggesting that future guidelines could include such variables in this group with chronic pain.


Assuntos
Acelerometria/instrumentação , Dor Crônica , Monitores de Aptidão Física , Acelerometria/métodos , Adulto , Idoso , Dor Crônica/diagnóstico , Dor Crônica/terapia , Metabolismo Energético/fisiologia , Feminino , Frequência Cardíaca/fisiologia , Humanos , Laboratórios , Masculino , Pessoa de Meia-Idade , Monitorização Ambulatorial/instrumentação , Monitorização Ambulatorial/métodos , Reprodutibilidade dos Testes , Corrida/fisiologia , Caminhada/fisiologia , Punho
5.
Sports Health ; 13(1): 71-77, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32813597

RESUMO

CONTENT: Distance running is one of the most popular physical activities, and running-related injuries (RRIs) are also common. Foot strike patterns have been suggested to affect biomechanical variables related to RRI risks. OBJECTIVE: To determine the effects of foot strike techniques on running biomechanics. DATA SOURCES: The databases of Web of Science, PubMed, EMBASE, and EBSCO were searched from database inception through November 2018. STUDY SELECTION: The initial electronic search found 723 studies. Of these, 26 studies with a total of 472 participants were eligible for inclusion in this meta-analysis. STUDY DESIGN: Systematic review and meta-analysis. LEVEL OF EVIDENCE: Level 4. DATA EXTRACTION: Means, standard deviations, and sample sizes were extracted from the eligible studies, and the standard mean differences (SMDs) were obtained for biomechanical variables between forefoot strike (FFS) and rearfoot strike (RFS) groups using a random-effects model. RESULTS: FFS showed significantly smaller magnitude (SMD, -1.84; 95% CI, -2.29 to -1.38; P < 0.001) and loading rate (mean: SMD, -2.1; 95% CI, -3.18 to -1.01; P < 0.001; peak: SMD, -1.77; 95% CI, -2.21 to -1.33; P < 0.001) of impact force, ankle stiffness (SMD, -1.69; 95% CI, -2.46 to -0.92; P < 0.001), knee extension moment (SMD, -0.64; 95% CI, -0.98 to -0.3; P < 0.001), knee eccentric power (SMD, -2.03; 95% CI, -2.51 to -1.54; P < 0.001), knee negative work (SMD, -1.56; 95% CI, -2.11 to -1.00; P < 0.001), and patellofemoral joint stress (peak: SMD, -0.71; 95% CI, -1.28 to -0.14; P = 0.01; integral: SMD, -0.63; 95% CI, -1.11 to -0.15; P = 0.01) compared with RFS. However, FFS significantly increased ankle plantarflexion moment (SMD, 1.31; 95% CI, 0.66 to 1.96; P < 0.001), eccentric power (SMD, 1.63; 95% CI, 1.18 to 2.08;P < 0.001), negative work (SMD, 2.60; 95% CI, 1.02 to 4.18; P = 0.001), and axial contact force (SMD, 1.26; 95% CI, 0.93 to 1.6; P < 0.001) compared with RFS. CONCLUSION: Running with RFS imposed higher biomechanical loads on overall ground impact and knee and patellofemoral joints, whereas FFS imposed higher biomechanical loads on the ankle joint and Achilles tendon. The modification of strike techniques may affect the specific biomechanical loads experienced on relevant structures or tissues during running.


Assuntos
Pé/fisiologia , Corrida/fisiologia , Tendão do Calcâneo/fisiologia , Tornozelo/fisiologia , Fenômenos Biomecânicos , Análise da Marcha , Humanos , Joelho/fisiologia , Fatores de Risco , Corrida/lesões , Estresse Mecânico
6.
Sports Health ; 13(1): 37-44, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-32903164

RESUMO

CONTEXT: Plyometric training has been shown to be beneficial in adolescent overhead athletes. However, existing research on the effects of plyometrics on sport performance has been limited. OBJECTIVE: To systematically review the current literature to investigate whether plyometric training intervention improves upper- and lower-body sport performance. DATA SOURCES: Two electronic databases (MEDLINE and Web of Science) were searched using specific Medical Subject Headings (MeSH) terms up to February 2019, and hand-searching was performed by looking to relevant studies that were cited in other studies. STUDY SELECTION: A total of 932 items were identified and were further assessed for the eligibility in the systematic review. For a study to be eligible, each of the following inclusion criteria had to be met: (1) participants were aged 13 to 18 years and selected from a sports or athletic population and the study (2) involved the evaluation of a plyometric training intervention with an aim to improve sports performance; (3) must have included a control intervention and/or control group; (4) included a quantitative objective measure of sport performance variables concerning throwing, jumping, running, and sprinting; and (5) was published in English. STUDY DESIGN: Systematic review. LEVEL OF EVIDENCE: Level 3. DATA EXTRACTION: A first screening was conducted based on title and abstract of the articles. In the second screening, the full text of the remaining articles was evaluated for the fulfillment of the inclusion criteria. RESULTS: A total of 14 studies were included in this review. The methodological quality of the included studies ranged from low to moderate. There is moderate evidence that plyometric training intervention improves throwing and jumping performances. There is also preliminary evidence that plyometric training intervention improves sprint performance. CONCLUSION: The current evidence suggests that sport performance consisting of throwing capacity, jumping ability, and sprint performance significantly improved due to plyometric training interventions in adolescent overhead athletes.


Assuntos
Desempenho Atlético/fisiologia , Exercício Pliométrico , Esportes Juvenis/fisiologia , Adolescente , Humanos , Extremidade Inferior/fisiologia , Corrida/fisiologia , Extremidade Superior/fisiologia
7.
PLoS One ; 15(12): e0244105, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33373408

RESUMO

During racing, injury is more likely to occur on a bend than on a straight segment of track. This study aimed to quantify the effects of galloping at training speeds on large radius curves on stride parameters and limb lean angle in order to assess estimated consequences for limb loading. Seven Thoroughbred horses were equipped with a sacrum-mounted inertial measurement unit with an integrated GPS, two hoof-mounted accelerometers and retro-reflective markers on the forelimbs. Horses galloped 2-4 circuits anticlockwise around an oval track and were filmed at 120 frames per second using an array of ten cameras. Speed and curve radius were derived from GPS data and used to estimate the centripetal acceleration necessary to navigate the curve. Stride, stance and swing durations and duty factor (DF) were derived from accelerometer data. Limb markers were tracked and whole limb and third metacarpus (MCIII) angles were calculated. Data were analysed using mixed effects models with a significance level of p < 0.05. For horses galloping on the correct lead, DF was higher for the inside (lead) leg on the straight and on the curve. For horses galloping on the incorrect lead, there was no difference in DF between inside and outside legs on the straight or on the curve. DF decreased by 0.61% of DF with each 1 m s-2 increase in centripetal acceleration (p < 0.001). Whole limb inclination angle increased by 1.5° per 1 m s-1 increase in speed (p = 0.002). Limb lean angles increase as predicted, and lead limb function mirrors the functional requirements for curve running. A more comprehensive understanding of the effects of lean and torque on the distal limb is required to understand injury mechanisms.


Assuntos
Membro Anterior/fisiologia , Marcha/fisiologia , Cavalos/fisiologia , Corrida/fisiologia , Animais , Fenômenos Biomecânicos
8.
Rev. int. med. cienc. act. fis. deporte ; 20(80): 641-658, dic. 2020. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-198578

RESUMO

Este estudio analizó las exigencias de carga interna (Frecuencia cardíaca, FC) y externa (Velocidad; Player Load, PL; Power Metabolic, PM; Stiffness Vertical, KVERT; entropía aproximada, ApEn) producidas en función del desnivel del terreno en una carrera de montaña. Un atleta de nivel nacional (edad: 25.3 años; altura: 172 cm; peso: 67 kg; VO2MAX: 70.2 ml/kg/min) participó en una prueba oficial (Distancia: 27.6 km; Desnivel acumulado: 973 m), siendo analizado en 6 segmentos respecto al desnivel (sin desnivel, positivo y negativo). El registro de datos se realizó mediante un dispositivo inercial WIMU PROTM (RealTrack Systems, Almería, España). Los resultados muestran un aumento de PL/min y PM/min en desnivel negativo y de FCAVG en desnivel positivo. KVERT y ApEn fueron más bajos en desnivel positivo, mientras que la velocidad fue mayor sin desnivel. Se encuentra gran variabilidad en las exigencias en función de la orografía del terreno, siendo importante su análisis para el diseño específico del entrenamiento y la planificación del evento


This study analysed the internal (heart rate, HR) and external load demands (Speed; Player Load, PL; Power Metabolic, PM; Vertical stiffness, KVERT; approximated entropy, ApEn) during a trail running race in relation to the slope. A national-level athlete (age: 25.3 years; height: 172 cm; weight: 67 kg; VO2MAX: 70.2 ml/kg/min) participated in an official race (Distance: 27.6 km; Accumulated slope: 973 m), analysed in 6 segments related to the slope (without, positive and negative slope). Data was registered through an inertial device WIMU PROTM (RealTrack Systems, Almería, Spain). The results show an increase of PL/min and PM/min in negative slope and an increase of HRAVG in positive slope. KVERT and ApEn were lower in positive slope, while velocity was faster without slope. It is found a great variability in the trail runner demands related to terrain orography, being important its analysis to design specific training sessions and race planning


Assuntos
Humanos , Masculino , Adulto , Corrida/fisiologia , Montanhismo/fisiologia , Atletas , Exercício Físico/fisiologia , Treinamento de Resistência , Frequência Cardíaca , Fadiga/epidemiologia , Monitoração Neuromuscular , Altitude
9.
PLoS One ; 15(12): e0244361, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33370355

RESUMO

Field-based sports require athletes to run sub-maximally over significant distances, often while contending with dynamic perturbations to preferred coordination patterns. The ability to adapt movement to maintain performance under such perturbations appears to be trainable through exposure to task variability, which encourages movement variability. The aim of the present study was to investigate the extent to which various wearable resistance loading magnitudes alter coordination and induce movement variability during running. To investigate this, 14 participants (three female and 11 male) performed 10 sub-maximal velocity shuttle runs with either no weight, 1%, 3%, or 5% of body weight attached to the lower limbs. Sagittal plane lower limb joint kinematics from one complete stride cycle in each run were assessed using functional data analysis techniques, both across the participant group and within-individuals. At the group-level, decreases in ankle plantarflexion following toe-off were evident in the 3% and 5% conditions, while increased knee flexion occurred during weight acceptance in the 5% condition compared with unloaded running. At the individual-level, between-run joint angle profiles varied, with six participants exhibiting increased joint angle variability in one or more loading conditions compared with unloaded running. Loading of 5% decreased between-run ankle joint variability among two individuals, likely in accordance with the need to manage increased system load or the novelty of the task. In terms of joint coordination, the most considerable alterations to coordination occurred in the 5% loading condition at the hip-knee joint pair, however, only a minority of participants exhibited this tendency. Coaches should prescribe wearable resistance individually to perturb preferred coordination patterns and encourage movement variability without loading to the extent that movement options become limited.


Assuntos
Articulação do Joelho/fisiologia , Extremidade Inferior/fisiologia , Corrida/fisiologia , Adulto , Fenômenos Biomecânicos , Feminino , Humanos , Masculino , Dispositivos Eletrônicos Vestíveis , Suporte de Carga , Adulto Jovem
10.
Nutrients ; 13(1)2020 Dec 24.
Artigo em Inglês | MEDLINE | ID: mdl-33374147

RESUMO

BACKGROUND: To investigate the acute effects of a capsaicin analogue supplement on 10 km time-trial performance and physiological responses in amateur athletes. METHODS: Twenty-one participants (age = 29.3 ± 5.5 years, weight 74.2 ± 11.3 kg, height 176.0 ± 0.0 cm, fat mass 12.7 ± 3.8%, V˙O2max 62.7 ± 8.4 mL·k-1·min-1), completed two randomized, double-blind trials: capsaicin analogue condition (Capsiate (CAP) = 24 mg) or a placebo (PLA) condition. The participants consumed two doses of 12 mg of CAP or PLA capsule 45 min before and immediately at the start of each trial. The time required to complete 10 km, lactate concentration, maximum heart rate (HRpeak), and rating of perceived exertion (RPE) were recorded. RESULTS: The 10 km time-trial performance (CAP = 45.07 ± 6.41 min vs. PLA = 45.13 ± 6.73, p = 0.828) was not statistically significantly different between conditions. No statistically significant differences between conditions were detected for lactate concentration (p = 0.507), HRpeak (p = 0.897) and RPE (p = 0.517). CONCLUSION: Two doses of a 12 mg Capsaicin analogue supplement did not improve performance and physiological responses in a 10 km running time-trial in amateur athletes.


Assuntos
Atletas/estatística & dados numéricos , Desempenho Atlético/fisiologia , Capsaicina/análogos & derivados , Corrida/fisiologia , Adulto , Capsaicina/administração & dosagem , Estudos Cross-Over , Suplementos Nutricionais , Método Duplo-Cego , Frequência Cardíaca/efeitos dos fármacos , Humanos , Ácido Láctico/sangue , Masculino , Placebos , Fatores de Tempo
11.
PLoS One ; 15(12): e0243798, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33382751

RESUMO

Lizards run quickly and stably in a bipedal gait, with their bodies exhibiting a lateral S-shaped undulation. We investigate the relationship between a lizard's bipedal running and its body movement with the help of a dynamic simulation. In this study, a dynamic theoretical model of lizard is assumed as a three-link consisting of an anterior and posterior bodies, and a tail, with morphometrics based on Callisaurus draconoides. When a lizard runs straight in a stable bipedal gait, its pelvic rotation is periodically synchronized with its gait. This study shows that the S-shaped body undulation with the yaw motion is generated by minimizing the square of joint torque. Furthermore, we performed the biomechanical simulation to figure out the relationship between the lizard's lateral body undulation and the bipedal running locomotion. In the biomechanical simulation, all joint torques significantly vary by the waist and tail' motions at the same locomotion. Besides, when the waist and tail joint angles increase, the stride length and duration of the model also increase, and the stride frequency decreases at the same running speed. It means that the lizard's undulatory body movements increase its stride and help it run faster. In this study, we found the benefits of the lizard's undulatory body movement and figured out the relationship between the body movement and the locomotion by analyzing the dynamics. In the future works, we will analyze body movements under different environments with various simulators.


Assuntos
Lagartos/fisiologia , Fenômenos Mecânicos , Corrida/fisiologia , Animais , Fenômenos Biomecânicos , Modelos Biológicos
12.
PLoS One ; 15(12): e0243755, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33320868

RESUMO

There have been recent calls for strategies to improve oral health in athletes. High carbohydrate diets, exercise induced dehydration and transient perturbations to immune function combine to increase oral disease risk in this group. We tested whether a single dose of nitrate (NO3-) would offset the reduction in salivary pH following carbohydrate ingestion before and after an exercise bout designed to cause mild dehydration. Eleven trained male runners ([Formula: see text] 53 ± 9 ml∙kg-1∙min-1, age 30 ± 7 years) completed a randomised placebo-controlled study comprising four experimental trials. Participants ingested the following fluids one hour before each trial: (a) 140 ml of water (negative-control), (b) 140 ml of water (positive-control), (c) 140 ml of NO3- rich beetroot juice (~12.4 mmol NO3-) (NO3- trial) or (d) 140 ml NO3- depleted beetroot juice (placebo-trial). During the negative-control trial, participants ingested 795 ml of water in three equal aliquots: before, during, and after 90 min of submaximal running. In the other trials they received 795 ml of carbohydrate supplements in the same fashion. Venous blood was collected before and after the exercise bout and saliva was sampled before and repeatedly over the 20 min following carbohydrate or water ingestion. As expected, nitrite (NO2-) and NO3- were higher in plasma and saliva during the NO3- trial than all other trials (all P<0.001). Compared to the negative-control, salivary-pH was significantly reduced following the ingestion of carbohydrate in the positive-control and placebo trials (both P <0.05). Salivary-pH was similar between the negative-control and NO3- trials before and after exercise despite ingestion of carbohydrate in the NO3- trial (both P≥0.221). Ingesting NO3- attenuates the expected reduction in salivary-pH following carbohydrate supplements and exercise-induced dehydration. NO3- should be considered by athletes as a novel nutritional strategy to reduce the risk of developing acidity related oral health conditions.


Assuntos
Beta vulgaris/química , Carboidratos da Dieta/farmacologia , Sucos de Frutas e Vegetais/análise , Nitritos/análise , Resistência Física , Corrida/fisiologia , Saliva/efeitos dos fármacos , Adulto , Suplementos Nutricionais/análise , Voluntários Saudáveis , Humanos , Concentração de Íons de Hidrogênio , Masculino , Nitratos/sangue , Nitritos/sangue , Saliva/química
13.
Nat Commun ; 11(1): 4936, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33024098

RESUMO

Wearable exercise trackers provide data that encode information on individual running performance. These data hold great potential for enhancing our understanding of the complex interplay between training and performance. Here we demonstrate feasibility of this idea by applying a previously validated mathematical model to real-world running activities of  ≈ 14,000 individuals with ≈ 1.6 million exercise sessions containing duration and distance, with a total distance of ≈ 20 million km. Our model depends on two performance parameters: an aerobic power index and an endurance index. Inclusion of endurance, which describes the decline in sustainable power over duration, offers novel insights into performance: a highly accurate race time prediction and the identification of key parameters such as the lactate threshold, commonly used in exercise physiology. Correlations between performance indices and training volume and intensity are quantified, pointing to an optimal training. Our findings hint at new ways to quantify and predict athletic performance under real-world conditions.


Assuntos
Modelos Teóricos , Corrida/fisiologia , Atletas , Big Data , Exercício Físico/fisiologia , Humanos , Ácido Láctico/metabolismo , Consumo de Oxigênio , Resistência Física/fisiologia , Dispositivos Eletrônicos Vestíveis
14.
Arch. med. deporte ; 37(199): 310-317, sept.-oct. 2020. tab, graf
Artigo em Espanhol | IBECS | ID: ibc-199345

RESUMO

INTRODUCCIÓN: Los objetivos de este estudio fueron comparar las características antropométricas y cardiorrespiratorias de corredores de montaña masculinos y femeninos, y examinar la asociación entre las variables antropométricas y cardiorrespiratorias. MATERIAL Y MÉTODOS: Un total de 48 corredores de montaña, 16 mujeres y 32 hombres participaron en el estudio. Se midieron los parámetros antropométricos y se realizó un test incremental máximo en tapiz rodante con rampa para la valoración cardiorrespiratoria. RESULTADOS: Los resultados arrojaron diferencias significativas en las características antropométricas correspondientes a masa, talla, índice de masa corporal (IMC), perímetros, diámetros, % masa muscular, % masa residual y componente mesomórfico entre hombres y mujeres, siendo significativamente superiores en el grupo masculino (p < 0,05). El grupo femenino obtuvo en pliegues tricipital, muslo, pierna eilecorestal, así como en la suma Σ 8 pliegues, % de grasa, en la masa grasa, masa ósea y en el componente endomórfico valores significativamente mayores (p < 0,05). Con respecto a la capacidad cardiorrespiratoria, el grupo masculino obtuvo valores significativamente mayores en el volumen sistólico inicial (p < 0,01, TE = -1,45, alto), consumo de oxígeno en el segundo umbral ventilatorio (VO2VT2) (p < 0,01, TE = -1,66, alto) y consumo de oxígeno máximo (VO2máx) (p < 0,05, TE = -1,78, alto). Se obtuvo una correlación alta entre la suma de 8 pliegues y el VO2máx (r = -0,79, p < 0,01), entre el % de grasa y el VO2máx (r = -0,81, p < 0,01) y entre el % de grasa y el VO2VT2 (r = -0,79, p < 0,01). CONCLUSIONES: Los resultados parecen evidenciar diferencias entre corredores de montaña hombres y mujeres en las características antropométricas y en la capacidad cardiorrespiratoria y que las características antropométricas pueden influir en el rendimiento cardiorrespiratorio de los corredores de montaña


INTRODUCTION: The objectives of this study were to compare the anthropometric characteristics and the cardiorespiratory capacity of male and female mountain runners, and to examine the association between anthropometric and cardiorespiratory variables. MATERIAL AND METHOD: A total of 48 mountain runners, 16 women and 32 men take part in the study. Anthropometric parameters were measured and a maximum incremental test was performed on treadmill with ramp for cardiorespiratory assessment. RESULTS: The results showed significant differences in the anthropometric characteristics corresponding to mass, height, body mass index (BMI), perimeters, diameters, % muscle mass, % residual mass and mesomorphic component between men and women, being significantly higher in the male group (p < 0.05). The female group obtained significantly higher values (p < 0.05) in tricipital, thigh, leg and ilecorestal skinfolds, as well as in 8 folds sum, % fat, fat mass, bone mass and in the endomorphic component. With respect to cardiorespiratory capacity, the male group obtained significantly higher values in the initial systolic volume (p < 0.01, TE = -1.45, large), oxygen consumption at the second ventilatory threshold (VO2VT2) (p < 0.01, TE = -1.66, large) and maximum oxygen consumption (VO2max) (p < 0.05, TE = -1.78, large). A large correlation was obtained between the sum of 8 skinfolds and the VO2max (r = -0.79, p < 0.01), between the % fat and the VO2max (r = -0.81, p < 0.01) and between % fat and VO2VT2 (r = -0.79, p < 0.01). CONCLUSIONS: The results seem to show differences between male and female mountain runners in anthropometric characteristics and cardiorespiratory capacity and that anthropometric characteristics can influence the cardiorespiratory performance of mountain runners


Assuntos
Humanos , Masculino , Feminino , Adulto , Antropometria , Desempenho Atlético/fisiologia , Corrida/fisiologia , Aptidão Cardiorrespiratória/fisiologia , Fatores Sexuais , Valores de Referência , Consumo de Oxigênio , Oxigênio/metabolismo , Colômbia , Teste de Esforço
15.
Artigo em Inglês | MEDLINE | ID: mdl-32933124

RESUMO

Research has shown that cold air exercise causes significant respiratory dysfunction, especially in female athletes. However, how female and male athletes respond to cold air exercise is not known. Thus, we aimed to compare acute respiratory responses (function, recovery and symptoms) in males and females after high-intensity cold air exercise. Eighteen (nine female) athletes completed two environmental chamber running trials at 0 °C and -20 °C (humidity 34 ± 5%) on different days in a randomized starting order. Spirometry was performed pre, 3, 6, 10, 15 and 20 min post. Respiratory symptoms were measured posttrial and heart rate and rating of perceived exertion were assessed during each trial. No significant differences in delta change (pre to post) were found at either temperature between sexes for FEV1, FVC, FEF50% and FEF25-75%. At -20 °C, FEV1 decreased similarly in both sexes (males: 7.5%, females: 6.3%) but not at 0 °C, p = 0.003. Postexertion respiratory function recovery and reported symptoms were not different between sexes at either temperature. These results indicate no sex-based differences in acute respiratory responses (function, recovery and symptoms) to cold air exercise. However, intense exercise at -20 °C is challenging to the respiratory system in both sexes and may lead to altered respiratory responses compared to mild winter conditions like 0 °C.


Assuntos
Atletas , Temperatura Baixa , Exercício Físico/fisiologia , Corrida/fisiologia , Adulto , Feminino , Humanos , Masculino , Espirometria
16.
PLoS One ; 15(9): e0239162, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32956408

RESUMO

Our primary aim was to explore the development of player load throughout match time (i.e., the pattern) using moving 5-min windows in an elite soccer team and our secondary aim was to compare player load patterns between different positions within the same team. The dataset included domestic home matches (n = 34) over three seasons for a Norwegian Elite League team. Player movements (mean ± SD age 25.5 ± 4.2 years, height 183.6 ± 6.6 cm, body mass 78.9 ± 7.4 kg) were recorded at 20 Hz using body-worn sensors. Data for each variable (player load, player load per meter, total distance, accelerations, decelerations, sprint distance, high-intensity running distance) were averaged within positions in each match, converted to z-scores and averaged across all matches, yielding one time series for each variable for each position. Pattern similarity between positions was assessed with cross-correlations. Overall, we observed a distinct pattern in player load throughout match time, which also occurred in the majority of individual matches. The pattern shows peaks at regular intervals (~15 min), each followed by a period of lower load, declining until the next peak. The same pattern was evident in player load per meter. The cross-correlation analyses support the visual evidence, with correlations ranging 0.88-0.97 (p < .001) in all position pairs. In contrast, no specific patterns were discernible in total distance, accelerations, decelerations, sprint distance and high-intensity running distance, with cross-correlations ranging 0.65-0.89 (p < .001), 0.32-0.64 (p < .005), 0.18-0.65 (p < .005 in nine position pairs), 0.02-0.38 (p < .05 in three pairs) and 0.01-0.52 (p < .05 in three pairs), respectively. This study demonstrated similarity in player load patterns between both matches and positions in elite soccer competition, which could indicate a physical "pacing pattern" employed by the team.


Assuntos
Atletas/estatística & dados numéricos , Corrida/estatística & dados numéricos , Futebol/estatística & dados numéricos , Posição Ortostática , Caminhada/estatística & dados numéricos , Adulto , Desempenho Atlético/fisiologia , Desempenho Atlético/estatística & dados numéricos , Conjuntos de Dados como Assunto , Humanos , Masculino , Noruega , Corrida/fisiologia , Futebol/fisiologia , Caminhada/fisiologia , Adulto Jovem
17.
J Sports Med Phys Fitness ; 60(8): 1101-1109, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32955836

RESUMO

BACKGROUND: Minimizing the energy required for breathing muscles is based on the adaptation of the respiratory muscles which is reflected in the reduction of breathing frequency (BF) and tidal volume (VT) increase. This may be influenced through a targeted BE and the quality of breathing may be linked to endurance performance. Aim of this study was assess dynamic ventilation parameters at different load intensities and their changes due to the systematic breathing exercise (BE). METHODS: Study recruit 36 runners of both sexes with a mean age 16.8±1.6 years. A random distribution was performed. The intervention program consisted of a set of BE aimed at the activation of the diaphragm. We monitored the dynamics of ventilation parameters at intensities 2, 3, 4 W/kg during a stepped test on a bicycle ergometer. RESULTS: The BE was focused on the activation of the diaphragm for a 12.2±3.6 minutes per day, sixteen weeks. After eight weeks, there were significant changes in VT and BF (P<0.05). After sixteen weeks there was a significant increase in VT of 5.7-18.3% (P<0.01), depending on the load level, BF values decreased significantly by 5.4-14.4% (P<0.01). VE and VO2 values were without changes. There were no significant changes in the control group. CONCLUSIONS: It was confirmed that the two-month BE intervention focused on the activation of the diaphragm is sufficient and resulted in a significant change in the values of dynamic ventilation parameters. After four months of intervention, the changes are significantly greater compared with values found after a two-month intervention period.


Assuntos
Exercícios Respiratórios/métodos , Resistência Física/fisiologia , Respiração , Músculos Respiratórios/fisiologia , Adolescente , Diafragma/fisiologia , Teste de Esforço , Feminino , Humanos , Masculino , Corrida/fisiologia , Volume de Ventilação Pulmonar
18.
PLoS One ; 15(9): e0239158, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32966338

RESUMO

Prolonged exercise is known to cause changes in common biomarkers. Occasionally, competition athletes need medical assistance and hospitalisation during prolonged exercise events. To aid clinicians treating patients and medical teams in such events we have studied common biomarkers after at The Norseman Xtreme Triathlon (Norseman), an Ironman distance triathlon with an accumulated climb of 5200 m, and an Olympic triathlon for comparison. Blood samples were collected before, immediately after, and the day following the Norseman Xtreme Triatlon (n = 98) and Oslo Olympic Triathlon (n = 15). Increased levels of clinical significance were seen at the finish line of the Norseman in white blood cells count (WBC) (14.2 [13.5-14.9] 109/L, p < 0.001), creatinine kinase (CK) (2450 [1620-3950] U/L, p < 0.001) and NT-proBNP (576 [331-856] ng/L, p < 0.001). The following day there were clinically significant changes in CRP (39 [27-56] mg/L, p < 0.001) and Aspartate Aminotransferase (AST) (142 [99-191] U/L, p < 0.001). In comparison, after the Olympic triathlon distance, there were statistically significant, but less clinically important, changes in WBC (7.8 [6.7-9.6] 109/L, p < 0.001), CK (303 [182-393] U/L, p < 0.001) and NT-proBNP (77 [49-88] ng/L, p < 0.01) immediately after the race, and in CRP (2 [1-3] mg/L, p < 0.001) and AST (31 [26-41] U/L, p < 0.01) the following day. Subclinical changes were also observed in Hemoglobin, Thrombocytes, K+, Ca2+, Mg2+, Creatinine, Alanine Aminotransferase and Thyroxine after the Norseman. In conclusion, there were significant changes in biomarkers used in a clinical setting after the Norseman. Of largest clinical importance were clinically significant increased WBC, CRP, AST, CK and NT-proBNP after the Norseman. This is important to be aware of when athletes engaging in prolonged exercise events receive medical assistance or are hospitalised.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Ciclismo/fisiologia , Corrida/fisiologia , Natação/fisiologia , Adulto , Biomarcadores/sangue , Feminino , Voluntários Saudáveis , Humanos , Masculino , Pessoa de Meia-Idade
19.
J Strength Cond Res ; 34(10): 2805-2814, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32986393

RESUMO

Hills, SP, Barrett, S, Busby, M, Kilduff, LP, Barwood, MJ, Radcliffe, JN, Cooke, CB, and Russell, M. Profiling the post-match top-up conditioning practices of professional soccer substitutes: An analysis of contextual influences. J Strength Cond Res 34(10): 2805-2814, 2020-Soccer practitioners implement "top-up" conditioning sessions to compensate for substitutes' limited match-play exposure. Although perceived to be valuable for reducing injury risk and augmenting positive physical adaptations, little research has considered the demands of post-match top-up training. To quantify post-match top-up responses, 31 professional soccer players wore 10 Hz microelectromechanical systems after 37 matches whereby they were selected in the match-day squad as substitutes (184 observations; 6 ± 5 observations·player). Linear mixed models and effect sizes (ES) assessed the influence of contextual factors on 23 physical performance variables. Top-ups lasted 17.13 ± 7.44 minutes, eliciting total and high-speed distances of 1.7 ± 6.2 km and 0.4 ± 1.7 km, respectively. Each contextual factor (i.e., position, substitution timing, match location, result, time of day, stage of the season, and fixture density) influenced at least 4 of the dependent variables profiled (p ≤ 0.05). Top-up duration; total, moderate-speed, and low-speed distance; and the number of repeated high-intensity efforts were greater for unused vs. used substitutes (ES: 0.38-0.73, small to moderate). Relative to away matches, home top-ups elicited heightened total, low-speed, and high-speed distances, alongside more moderate-speed accelerations and decelerations, and repeated high-intensity efforts (ES: 0.25-0.89, small to moderate). Although absolute and relative running distances were generally the highest when the fixture density was low, the greatest acceleration and deceleration demands were observed during the most congested fixture periods. Late-season top-ups typically elicited lower absolute physical responses than early and mid-season sessions. These data provide important information for practitioners when considering the aims and design of substitute top-up conditioning sessions, particularly with reference to contextual influences.


Assuntos
Atletas , Desempenho Atlético/fisiologia , Futebol/fisiologia , Aceleração , Adaptação Fisiológica , Humanos , Modelos Lineares , Sistemas Microeletromecânicos , Corrida/fisiologia
20.
J Sports Sci ; 38(19): 2200-2207, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32921248

RESUMO

The aims of this study were (a) to describe the kinematics underlying the phenomenon of the knee of the swing leg passing medially in front of the athlete during the single push (SP) phase of the block sprint start, and (b) to determine the relationships between block phase pelvis range of motion (RoM), 1st step width and block phase performance. Three-dimensional kinematic data (250 Hz) were collected from eleven competitive sprinters (100 m PB: 11.17 ± 0.41) performing maximal effort block starts. The joint angles of the rear hip with respect to the pelvis and the pelvis segment angles with respect to the laboratory coordinate system were calculated during the block start phase to the end of the 1st stance. A combination of pelvis list and rotation (not hip adduction) was coupled with the thigh of the swing leg moving medially during the SP phase. A very high positive correlation was found between pelvic list RoM and 1st step width (r = 0.799, p = 0.003). No other significant correlations were found. Attempting to reduce pelvic RoM or changing frontal and transverse plane hip joint angles to minimise medial thigh motion is unlikely to lead to an improvement to performance.


Assuntos
Articulação do Joelho/fisiologia , Pelve/fisiologia , Corrida/fisiologia , Aceleração , Fenômenos Biomecânicos , Feminino , Análise da Marcha , Articulação do Quadril/fisiologia , Humanos , Masculino , Postura/fisiologia , Amplitude de Movimento Articular , Coxa da Perna/fisiologia , Estudos de Tempo e Movimento , Adulto Jovem
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