Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 78
Filtrar
Más filtros

Tipo del documento
Intervalo de año de publicación
1.
Int J Biometeorol ; 2024 May 14.
Artículo en Inglés | MEDLINE | ID: mdl-38740646

RESUMEN

Crop growth simulation models relate the soil-water-plant-atmosphere components to estimate the development and yield of plants in different scenarios, enabling the identification of efficient irrigation strategies. The aim of this study was to calibrate crop coefficients for a common bean cultivar (IAPAR 57) and assess the AquaCrop model's efficacy in simulating crop growth under different irrigation regimes (T0 - non-irrigated, T1-fully irrigated, and T2-deficit irrigated) and sowing dates (S1-March 21, S2-April 24, and S3-August 23). Successful calibration was achieved for crop seasons with suitable temperatures to crop growth (S1 and S3). However, during periods with suboptimal temperatures (April 24 season), coupled with reduced irrigation supply (T0 and T2), the AquaCrop model did not appropriately account for the combined effects of thermal and water stresses. Despite adjustments to stress coefficients, this led to an overestimation of crop growth and yield. In long-term simulations, the model successfully replicated the variability of crop water availability over cropping seasons, reflecting the impact of precipitation variations. It recommended irrigation strategies for the study region (irrigate at depletion of 120 and 170% of readily available water for sowing on March 21 and August 24, respectively) to achieve high crop yield (> 2,769 kg ha-1) and water productivity (1,050 to 1,445 kg m-3) with minimal application depths (< 150 mm). While acknowledging the need for improvements in thermal stress calculations, the AquaCrop model demonstrates promising utility in studies and applications where water availability significantly influences crop production.

2.
An Acad Bras Cienc ; 96(1): e20200031, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38359287

RESUMEN

The potential of H. virginiana L. was evaluated against Candida spp. (C. albicans, C. dubliniensis, C. glabrata, C. guilliermondii, C. krusei, and C. tropicalis) and bacteria (Acinetobacter baumannii, Escherichia coli, Enterococcus faecalis, Klebsiella pneumoniae, Staphylococcus aureus, and Streptococcus mutans). Effect on murine macrophages (RAW 264.7) was also evaluated with respect to cytotoxicity and production of cytokines (IL-1ß and TNF-α) and nitric oxide (NO). The most effective concentrations of the extract were determined by microdilution broth. These concentrations were analyzed on biofilms, after 5 min or 24 h exposure. Cytotoxicity was performed by MTT assay and quantification of cytokines and NO by ELISA and Griess reagent, respectively. The extract acted against the planktonic forms and provided significant reductions of all the microbial biofilms; besides, showed no cytotoxic effect, except at 100 mg/mL, after 24 h exposure. There was cytokine production; however, a modulatory effect was observed in groups exposed to lipopolysaccharide (LPS) from E. coli. NO production was similar or higher than the control group. Thus, H. virginiana L. extract showed antimicrobial and antibiofilm effects; absence of cytotoxicity for RAW 264.7; anti-inflammatory action; and potential to fight infections through the NO production.


Asunto(s)
Antiinfecciosos , Candida , Óxido Nítrico , Animales , Ratones , Hamamelis , Candida albicans , Escherichia coli , Extractos Vegetales/farmacología , Antiinfecciosos/farmacología , Macrófagos , Antiinflamatorios/farmacología , Citocinas , Biopelículas
3.
Knee Surg Sports Traumatol Arthrosc ; 31(7): 2556-2562, 2023 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-36779987

RESUMEN

PURPOSE: To evaluate the incidence of anterior cruciate ligament (ACL) injuries in male athletes from professional soccer clubs over two consecutive seasons (2018-2019) with a sub-analysis based on age category: under-13 (U-13), under-15 (U-15), under-17 (U-17), and under-20 (U-20) years. METHODS: A total of 17,108 young male soccer players were retrospectively reviewed from sixty-three professional clubs in the four highest Brazilian soccer divisions. Data regarding the number of athletes and the number of ACL injuries confirmed by magnetic resonance imaging (MRI) exams in the 2018 and 2019 seasons were collected. Incidence of ACL injury were compared by season, age category (under-13; under-15; under 17; and under-20), demographic region, and club division. RESULTS: Clubs from all regions of Brazil participated in the study. A total of 336 primary ACL injuries were diagnosed over the two seasons (8,167 athletes during the 2018 season and 8,941 athletes during the 2019 season) among all athletes, which corresponds to 2% of the included athletes. There were 11 cases (0.3%) in the under-13, 53 cases (1.3%) in the under-15, 107 cases (2.5%) in the under-17, and 165 cases (3.8%) in the under-20 age category. There was a higher incidence of ACL injury in the older age groups (p < 0.001). CONCLUSION: A total of 336 ACL injuries were identified in 17,108 youth soccer players from 63 professional clubs with an overall incidence of 2% over 2 seasons of competition. ACL injury rate ranged from 0.3% to 3.8% and was higher in the older and more competitive club divisions. LEVEL OF EVIDENCE: IV.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Traumatismos en Atletas , Fútbol , Humanos , Masculino , Adolescente , Anciano , Lesiones del Ligamento Cruzado Anterior/epidemiología , Estaciones del Año , Estudios Retrospectivos , Fútbol/lesiones , Incidencia , Atletas , Traumatismos en Atletas/epidemiología
4.
Cytokine ; 151: 155787, 2022 03.
Artículo en Inglés | MEDLINE | ID: mdl-35065509

RESUMEN

This cross-sectional study examined the associations between serum interleukin-6 (IL-6) and muscle, bone, and fat parameters in recreationally active women. One-hundred forty-five women (48.7 ± 17.8 years; 164.4 ± 7.1 cm; 66.8 ± 10.7 kg; and 24.7 ± 3.9 kg/m2) underwent dual energy x-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT) assessments to determine total and regional muscle, bone, and fat parameters. Muscle performance of the knee extensors was examined via isometric, isotonic, and isokinetic dynamometry assessments, and serum IL-6 was measured via enzyme linked immunosorbent assay. Serum IL-6 was inversely associated with thigh muscle cross-sectional area (mCSA, r = -0.28, p < 0.01); isometric strength (r = -0.19, p < 0.05); hip areal bone mineral density [aBMD] (r = -0.18, p < 0.05); trochanter aBMD (r = -0.23, p < 0.01); total body aBMD (r = -0.20, p < 0.05); cortical volumetric bone density at 38 and 66% tibia (r = -0.18 and r = -0.19, respectively, both p < 0.05), and 66% cortical thickness (r = -0.17, p < 0.05). These associations were present after adjusting for age, BMI, and physical activity. Thigh mCSA was significantly lower in the tertile possessing the greatest IL-6 compared to the lowest tertile (p < 0.01); after adjusting for age, body mass index, and physical activity. Collectively, these observations indicate that IL-6 is inversely associated with skeletal muscle and bone parameters independent of relevant confounders. These observations bolster the prognostic value of serum IL-6.


Asunto(s)
Densidad Ósea , Interleucina-6 , Absorciometría de Fotón , Tejido Adiposo , Densidad Ósea/fisiología , Estudios Transversales , Femenino , Humanos , Músculo Esquelético
5.
J Therm Biol ; 103: 103151, 2022 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-35027201

RESUMEN

As global temperatures continue to rise due to global change, marine heatwaves are also becoming more frequent and intense, impacting marine biodiversity patterns worldwide. Organisms inhabiting shallow water environments, such as the commercially relevant ditch shrimp Palaemon varians, are expected to be the most affected by rising temperatures. Thus, addressing species' thermal ecology and climate extinction-risk is crucial to foster climate-smart conservation strategies for shallow water ecosystems. Here, we estimated sex-specific upper thermal tolerance limits for P. varians via the Critical Thermal Maximum method (CTmax), using loss of equilibrium as endpoint. We further calculated thermal safety margins for males and females and tested for correlations between upper thermal limits and shrimps' body size. To determine sex-biased variation in P. varians' traits (CTmax, weight and length), we compared trait variation between females and males through the coefficient of variation ratio (lnCVR). Females displayed an average CTmax value 1.8% lower than males (CTmaxfemales = 37.0 °C vs CTmaxmales = 37.7 °C). This finding may be related to the larger body size exhibited by females (156% heavier and 39% larger than males), as both length and weight had a significant effect on CTmax. The high energetic investment of females in offspring may also contribute to the differences recorded in thermal tolerance. Overall, organisms with a smaller body-size displayed a greater tolerance to elevated temperature, thus suggesting that smaller individuals may be positively selected in warmer environments. This selection may result in a reduction of size-at-maturity and shifts in sex ratio, given the sexual dimorphism in body size of shrimps. The thermal safety margin of P. varians was narrow (∼2.2 °C for males and ∼1.5 °C for females), revealing the vulnerability of this species to ocean warming and heatwaves.


Asunto(s)
Biodiversidad , Evolución Biológica , Tamaño Corporal , Palaemonidae/fisiología , Termotolerancia , Aclimatación , Animales , Cambio Climático , Femenino , Masculino , Océanos y Mares , Temperatura
6.
Arthroscopy ; 37(8): 2582-2588, 2021 08.
Artículo en Inglés | MEDLINE | ID: mdl-33771692

RESUMEN

PURPOSE: To evaluate the relation between the femoral intercondylar index, tibial slope, and meniscal slope between 3 different groups of skeletally immature patients: primary anterior cruciate ligament (ACL) injury (group 1), ACL reconstruction failure (group 2), and control group, without an ACL injury history (group 3). METHODS: This retrospective study evaluated magnetic resonance imaging scans of the knees of 605 skeletally immature patients obtained between 2015 and 2020. The inclusion criteria were as follows: patients younger than 16 years who were skeletally immature and underwent knee magnetic resonance imaging for any reason. RESULTS: A total of 605 skeletally immature patients were included in the study. The ratio of patients with ACL injury (cases) to those without ACL injury (controls) was 1:2.5. Patients with ACL injury had significantly greater medial meniscal slope and lateral meniscal slope values than the control group without ACL injury (P < .001). There was no statistically significant difference between patients with primary ACL injury and those with ACL reconstruction failure for all measured variables. CONCLUSIONS: The medial and lateral meniscal slope values were significantly higher in skeletally immature patients with ACL injury than in the control group of patients without ACL injury. There was no statistically significant difference in measurements of the femoral intercondylar index, lateral meniscal slope, medial meniscal slope, lateral tibial slope, or medial tibial slope between patients with primary injury and those with ACL reconstruction failure. LEVEL OF EVIDENCE: Level III, retrospective comparative trial.


Asunto(s)
Lesiones del Ligamento Cruzado Anterior , Reconstrucción del Ligamento Cruzado Anterior , Lesiones del Ligamento Cruzado Anterior/diagnóstico por imagen , Lesiones del Ligamento Cruzado Anterior/cirugía , Humanos , Meniscos Tibiales/cirugía , Estudios Retrospectivos , Factores de Riesgo
7.
J Strength Cond Res ; 35(4): 1089-1094, 2021 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30272627

RESUMEN

ABSTRACT: Heishman, AD, Daub, BD, Miller, RM, Freitas, EDS, and Bemben, MG. Longitudinal hydration assessment in collegiate basketball players over various training phases. J Strength Cond Res 35(4): 1089-1094, 2021-To the best of our knowledge, previous literature has not longitudinally examined hydration status in collegiate basketball players. Therefore, the purpose of this investigation was to examine the prepractice hydration status of collegiate basketball players across various training phases for 2 consecutive years. Retrospective analyses examined prepractice urine-specific gravity (USG) assessments obtained from National Collegiate Athletic Association (NCAA) Division I male basketball players during the preseason and competitive season, for 2 consecutive years. The first year (year 1 = Y1) of analysis consisted of 15 athletes and the second year (year 2 = Y2) consisted of 16 athletes, with 8 athletes in both seasons. Hydration status was classified based on the National Athletic Trainers' criteria: (a) euhydrated, USG < 1.020; (b) hypohydrated, USG = 1.020-1.030; and (c) significantly hypohydrated, USG > 1.030. Additional comparisons examined the association of minutes played with hydration status and changes in hydration status for athletes returning from Y1 to Y2. The results indicated 55-65.7% of cases showed levels of significant hypohydration during the preseason and competitive seasons for both years. Preseason hydration status was significantly better than the competitive season (Y1, p = 0.008; Y2, p = 0.005). Despite significant differences in minutes played (p < 0.001), no differences in hydration status were observed. Returning athletes displayed no differences in hydration status between Y1 and Y2. Collegiate basketball players show levels of hypohydration when longitudinally examined across various training phases. Although hydration may be improved in the preseason, alternative factors such as average game minutes played and length in program may not influence hydration status.


Asunto(s)
Baloncesto , Atletas , Humanos , Masculino , Estudios Retrospectivos , Universidades , Urinálisis
8.
J Strength Cond Res ; 35(11): 3050-3055, 2021 Nov 01.
Artículo en Inglés | MEDLINE | ID: mdl-31567839

RESUMEN

ABSTRACT: Ferreira-Júnior, JB, Benine, RPC, Chaves, SFN, Borba, DA, Martins-Costa, HC, Freitas, EDS, Bemben, MG, Vieira, CA, and Bottaro, M. Effects of static and dynamic stretching performed before resistance training on muscle adaptations in untrained men. J Strength Cond Res 35(11): 3050-3055, 2021-This study evaluated the effects of dynamic and static stretching (SS) performed before resistance training on biceps femoris hypertrophy and knee flexor strength gains in untrained young men. Forty-five untrained young men (age, 21.2 ± 0.5 years; mass, 72.2 ± 5.6 kg; height, 178 ± 1 cm) were randomly assigned to 1 of the 3 groups: (a) 80 seconds of SS (n = 14); (b) 80 seconds of dynamic stretching (DS, n = 13); or (c) control group (CON, n = 18) in which subjects performed no stretching before exercise. Both SS and DS were performed before resistance exercise. Resistance training consisted of 4 sets of 8-12 repetition maximum of seated leg curl exercise 2 days per week for 8 weeks, with a period of at least 48 hours between sessions. Unilateral biceps femoris muscle thickness (MT) and maximal isometric strength (MIS) of the knee flexors were measured 1 week before training and 1 week after the last training session. There were significant increases in MIS (SS = 13.9 ± 10.3 kgf; DS = 10.2 ± 13.1 kgf; CON = 12.7 ± 7.6 kgf; p < 0.05) and MT (SS = 6.0 ± 3.5 mm; DS = 6.7 ± 4.1 mm; CON = 5.7 ± 3.0 mm; p < 0.05) with no significant differences across groups (p > 0.05). Additionally, all groups demonstrated moderate effect sizes for MIS (1.27-1.4), and DS was the only group that had a large effect size for MT increases (DS = 2.18; SS = 1.35; CON = 0.92). In conclusion, 80 seconds of SS and DS did not induce any additional muscular adaptations to resistance training in untrained young men.


Asunto(s)
Músculos Isquiosurales , Ejercicios de Estiramiento Muscular , Entrenamiento de Fuerza , Adulto , Humanos , Masculino , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Adulto Joven
9.
J Strength Cond Res ; 35(9): 2479-2485, 2021 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-31136546

RESUMEN

ABSTRACT: Silva, JCG, Domingos-Gomes, JR, Freitas, EDS, Neto, GR, Aniceto, RR, Bemben, MG, Lima-dos-Santos, A, and Cirilo-Sousa, MS. Physiological and perceptual responses to aerobic exercise with and without blood flow restriction. J Strength Cond Res 35(9): 2479-2485, 2021-Although previous studies have demonstrated the potential benefits of aerobic exercise (AE) with blood flow restriction (BFR), these findings have been limited by the approaches used to determine the occlusive pressure. In addition, the physiological and perceptual responses of AE with BFR compared to high-intensity interval exercise (HIIE) remain unclear. Thus, we investigated the physiological and perceptual responses to AE with and without BFR, and HIIE. Twenty-two men were randomly assigned to 4 experimental conditions: AE (40% of maximal oxygen consumption [V˙o2peak]), AE with 50% of BFR (AE-BFR: 40% VV˙o2peak), HIIE (80% V˙o2peak), and a no exercise control condition (CON: 50% of BFR). Each exercise bout lasted 18 minutes, during which oxygen consumption (V˙o2), heart rate (HR), and ratings of perceived exertion (RPE) were measured at rest and at every 3 minutes during exercise. Ratings of discomfort before and after each trial. The HIIE condition induced the greatest increases in V˙o2 and HR (p < 0.05), whereas AE-BFR was significantly (p < 0.05) greater than AE and CON. HIIE and AE-BFR also elicited the greatest (p < 0.05), but similar (p > 0.05), increases in RPE during exercise, although AE-BFR was significantly greater than HIIE immediately after exercise (p < 0.05). AE-BFR and HIIE also induced similar levels of discomfort after exercise (p > 0.05). In conclusion, HIIE induced the greatest increases in V˙o2 and HR, although the perceptual responses were essentially the same compared with AE-BFR. However, albeit inferior to HIIE, V˙o2 was greater during AE-BFR compared with AE, indicating that this training method may be used to replace HIIE and still significantly elevate V˙o2.


Asunto(s)
Entrenamiento de Intervalos de Alta Intensidad , Ejercicio Físico , Frecuencia Cardíaca , Hemodinámica , Humanos , Masculino , Consumo de Oxígeno
10.
Clin Oral Investig ; 24(2): 727-734, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-31129878

RESUMEN

OBJECTIVES: To describe a new molar-incisor hypomineralization (MIH) severity scoring system (MIH-SSS) that focuses on the defects' severity and to assess the system's validity and reliability over 3 years. MATERIALS AND METHODS: One hundred eighty-one children diagnosed with MIH were examined by MIH-SSS. For reliability assessment, 15-20 children were examined twice, and analyses were performed at the tooth level at four different cutoff points. Follow-up examinations were performed over 36 months. Only teeth presenting MIH opacities at baseline were assessed. Odds ratios were calculated to evaluate the chance of post-eruptive breakdown (PEB) occurrence related to the colors of MIH defects. Survival curves were created for different types of teeth (molars and incisors) based on white and yellow opacities. The Kaplan-Meier method was used with PEB as the outcome. RESULTS: According to the MIH-SSS, kappa values ranged from 0.82 to 0.88. Regarding the longitudinal evaluation, for molars and incisors, yellow/brown opacities had a significantly higher chance to evolve to dentin breakdown compared with white/creamy opacities (OR = 2.54, OR = 10.58, respectively). Survival analysis showed that the occurrence of PEB was more frequent in the first evaluation period (12 months). CONCLUSION: MIH-SSS, which provides detailed information about MIH severity, is a valid instrument presenting high reliability. Yellow/brown opacities progressed more than did white/creamy opacities. CLINICAL RELEVANCE: It is of paramount importance to detect any surface breakdown as early as possible to be able to avoid pain and caries progression. Moreover, this is the first paper that shows survival curves for MIH enamel breakdown over time.


Asunto(s)
Hipoplasia del Esmalte Dental , Niño , Humanos , Incisivo , Diente Molar , Prevalencia , Reproducibilidad de los Resultados
11.
J Strength Cond Res ; 34(4): 1071-1077, 2020 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-32205835

RESUMEN

Miller, RM, Heishman, AD, Freitas, EDS, and Bemben, MG. Evaluating the effects of underloaded and overloaded warm-ups on subsequent swing velocity. J Strength Cond Res 34(4): 1071-1077, 2020-Several attempts to identify the optimal on-deck procedure to enhance swing velocity in baseball have been made. However, inconsistent findings continue to constitute much of the body of literature. In addition, the emergence of athlete monitoring in sport has led to the exploration of more sport-specific tasks to potentially identify athlete fatigue and readiness to perform. Therefore, the purpose of this investigation was to examine 3 different bat weight warm-up protocols on subsequent swing velocity and to examine the reliability of swing velocity measurements to allude to its potential a sport-specific athlete monitoring metric. Thirty-two recreational male baseball players 20.3 ± 2.0 years, 179.6 ± 7.1 cm and 89.6 ± 11.1 kg completed the study. Subjects completed 3 testing visits that included warming up with a control bat ([CB] 32 in., 29 oz), plastic bat ([PB] 31 in., 6.4 oz), or heavy bat ([HB] 32 in., 57 oz). Testing visits began with 3 CB swing trials followed by 3 intervention bat trials, then concluded with 3 additional CB swings. Swing velocity was assessed using visual 3D technology. Analyses of variance indicate that after the PB (26.6 ± 2.0 m·s) and CB interventions (26.2 ± 1.7 m·s) significantly faster (p < 0.001) swing velocities were generated when compared with the traditional HB intervention (24.1 ± 2.2 m·s). When assessed for reliability, the average ICC was 0.681 and Cronbach's alpha was 0.95, indicating exceptional reliability. Congruent to previous research, these data bolster the notion that warming up with a HB can hinder swing velocity. However, in contrast to previous research these data suggest that using a PB can increase swing velocity significantly. Furthermore, visual 3D can be designated as an exceptionally reliable device to measure swing velocity.


Asunto(s)
Béisbol/fisiología , Ejercicio de Calentamiento/fisiología , Atletas , Fatiga , Humanos , Masculino , Reproducibilidad de los Resultados , Proyectos de Investigación , Equipo Deportivo , Adulto Joven
12.
J Strength Cond Res ; 34(2): 546-558, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30138237

RESUMEN

Heishman, AD, Daub, BD, Miller, RM, Freitas, EDS, Frantz, BA, and Bemben, MG. Countermovement jump reliability performed with and without an arm swing in NCAA Division 1 intercollegiate basketball players. J Strength Cond Res 34(2): 546-558, 2020-The countermovement jump (CMJ) is routinely used in athlete performance to quantify adaptions to training, as well as monitor neuromuscular readiness and fatigue. However, controversy remains in whether to incorporate an arm swing during the CMJ (CMJ AS) or keep the hands placed on the hips (CMJ NAS). Incorporating the arms provides a higher degree of sport-specificity that may yield improved reliability, especially in skilled jumpers. By contrast, the hands-on-hips approach isolates lower extremity force production and eliminates potential arm-swing variation. Therefore, the purpose of this study was to establish the reliability of CMJ typical (CMJ-TYP), CMJ concentric alternative (CMJ-Conc-ALT), and CMJ eccentric alternative (CMJ-Ecc-ALT) variables obtained during the CMJ AS and CMJ NAS. Twenty-two (men = 14, women = 8) NCAA Division 1 collegiate basketball players performed 3 CMJ AS and 3 CMJ NAS on a force plate, in a randomized order. To assess the test-retest reliability, participants returned 1 week later to perform 3 additional CMJ AS and 3 CMJ NAS. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) were used to assess intersession and intrasession reliability for the various CMJ variables. A majority of CMJ-TYP and several CMJ-Conc-ALT and CMJ-Ecc-ALT variables exhibited adequate intersession and intrasession reliability (ICC > 0.700 and CV <10%) during both the CMJ AS and the CMJ NAS. Countermovement jump AS may provide more pertinent information about long-term changes in sport-specific performance, whereas the CMJ NAS may be more beneficial for detecting acute changes in neuromuscular fatigue and athlete readiness.


Asunto(s)
Brazo/fisiología , Atletas , Baloncesto/fisiología , Prueba de Esfuerzo/métodos , Fuerza Muscular/fisiología , Adolescente , Rendimiento Atlético , Estudios Cruzados , Prueba de Esfuerzo/normas , Femenino , Humanos , Masculino , Reproducibilidad de los Resultados , Adulto Joven
13.
J Strength Cond Res ; 34(2): 440-444, 2020 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-30199448

RESUMEN

Miller, RM, Freitas, EDS, Heishman, AD, Koziol, KJ, Galletti, BAR, Kaur, J, and Bemben, MG. Test-retest reliability between free weight and machine-based movement velocities. J Strength Cond Res 34(2): 440-444, 2020-Several devices are available to measure muscular power through velocity measurement, including the Tendo FitroDyne. The ability for such devices to produce consistent results is still questioned, and the reproducibility of measurement between free weight and machine exercise has yet to be examined. Therefore, the aim of this investigation was to determine the test-retest reliability for barbell velocity during the bench press (BP) and weight velocity during the 2 leg press (2LP) for loads corresponding to 20-80% of 1 repetition maximum (1RM). Forty recreationally active individuals (22.6 ± 2.5 years; 175.9 ± 10.8 cm; and 76.2 ± 13.2 kg) with a 1RM BP and 2LP of 66.8 ± 32.4 kg and 189.5 ± 49 kg, respectively, volunteered for this study. Subjects completed 1 familiarization visit preceding 3 testing visits, which encompassed 1RM determination and 2 days of velocity testing. Forty-eight hours after 1RM testing, the subjects performed 1 repetition at 20, 30, 40, 50, 60, 70, and 80% of their 1RM for each exercise in randomized order. Subjects returned to the laboratory 1 week later to perform the velocity assessment again in randomized order. Intraclass correlation coefficient (ICC2,1) and relative SEM for the BP and 2LP ranged from 0.56 to 0.98 (3-18.1%) and 0.78 to 0.98 (2.8-7.2%), respectively, and no mean differences were observed between trials. The results suggest high reliability for BP velocity between 30 and 60% 1RM and moderate reliability at 20, 70, and 80% 1RM, while the 2LP displayed high to excellent reliability from 20 to 80% 1RM. Cumulatively, machine-based exercise displayed greater reproducibility; however, additional machine exercises need to be examined to bolster this conclusion.


Asunto(s)
Prueba de Esfuerzo/métodos , Entrenamiento de Fuerza/métodos , Adulto , Prueba de Esfuerzo/normas , Femenino , Humanos , Masculino , Fuerza Muscular/fisiología , Reproducibilidad de los Resultados , Levantamiento de Peso/fisiología , Adulto Joven
14.
J Sports Sci Med ; 19(1): 204-212, 2020 03.
Artículo en Inglés | MEDLINE | ID: mdl-32132844

RESUMEN

Limited research has paralleled concomitant changes in external training load (eTL) and countermovement jump (CMJ) performance. Therefore, this investigation characterized eTL and CMJ performance changes across preseason training in Division 1 male collegiate basketball athletes, while examining the influence of position (Guard vs. Forward/Center) and scholarship status (Scholarship = S vs. Walk-on = WO). During 22 practices, eTL was monitored in 14 male athletes, with weekly CMJs performed to quantify neuromuscular performance (Jump Height [JH], Flight Time:Contraction Time [FT:CT], Reactive Strength Index Modified [RSIMod ]). PlayerLoad per minute was significantly higher during W1 and W2 (5.4 ± 1.3au and 5.3 ± 1.2au, respectively; p < 0.05) compared to subsequent weeks, but no additional differences in eTL parameters across time were observed. Scholarship athletes displayed greater PlayerLoad (S = 777.1 ± 35.6, WO = 530.1 ± 56.20; Inertial Movement Analysis (IMA) IMA_High (S = 70.9 ± 15.2, WO = 41.3 ± 15.2); IMA_Medium (S = 159.9 ± 30.7, WO = 92.7 ± 30.6); and IMA_Low (S = 700.6 ± 105.1, WO = 405 ± 105.0;) (p < 0.05), with no observed differences in eTL by position. Moderate decreases in FT:CT and RSIMod paralleled increased eTL. Significant increases in practice intensity (W1 and W2) did not impact CMJ performance, suggesting athletes could cope with the prescribed training loads. However, moderate perturbations in FT:CT and RSIMod paralleled the weeks with intensified training. Cumulatively, scholarship status appears to influence eTL while player position does not.


Asunto(s)
Rendimiento Atlético/fisiología , Baloncesto/fisiología , Destreza Motora/fisiología , Acondicionamiento Físico Humano/fisiología , Becas , Humanos , Masculino , Fatiga Muscular/fisiología , Acondicionamiento Físico Humano/métodos , Estudios Prospectivos , Adulto Joven
15.
Biol Sport ; 36(1): 31-37, 2019 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-30899137

RESUMEN

Maximal muscular power is achieved at lower percentages of maximal strength (1RM); however, this notion has not been elucidated based on sex or training status. Therefore, the purpose of this investigation was to examine the influence of sex and training status on maximal power production. Sixty men and women (resistance trained or untrained) completed 1RM testing for the two-leg press (2LP) and bench press (BP). Participants then returned to perform single repetitions at 20, 30, 40, 50, 60, 70 and 80% of their 1RM to determine muscular power. Factorial analyses determined significant interactions (training status by sex by intensity) for the BP (F=35.6, p<0.001) and 2LP (F=8.2, p<0.001). Subsequent analyses indicated that during the BP trained men produce maximal power between 30-40% 1RM compared to untrained men at 60-70% 1RM. Trained women produced maximal power at 50% 1RM compared to untrained women at 60-70% 1RM. During the 2LP, trained men produced maximal power at 40% 1RM compared to untrained men at 60% 1RM. Trained women produced maximal power at 50% 1RM compared to 60-70% 1RM in untrained women. These data suggest that resistance trained individuals and men display maximal power at a lower relative intensity than untrained individuals and women.

16.
Sleep Breath ; 22(2): 431-437, 2018 05.
Artículo en Inglés | MEDLINE | ID: mdl-28840546

RESUMEN

BACKGROUND: Elderly people have a high prevalence to systemic arterial hypertension (SAH) and obstructive sleep apnea (OSA). Both comorbidities are closely associated and inflict damage on cardiorespiratory capacity. METHODS: In order to assess cardiorespiratory responses to the cardiopulmonary exercise test (CPET) among hypertensive elderly with OSA, we enrolled 28 subjects into two different groups: without OSA (No-OSA: apnea/hypopnea index (AHI) < 5 events/h; n = 15) and with OSA (OSA: AHI ≥ 15 events/h; n = 13). All subjects underwent CPET and polysomnographic assessments. After normality and homogeneity evaluations, independent t test and Pearson's correlation were performed. The significance level employed was p ≤ 0.05. RESULTS: Hypertensive elderly with OSA presented lower heart rate recovery (HRR) in the second minute (HRR2) in relation to the No-OSA group. A negative correlation between AHI and ventilation (VE) (r = -0.63, p = 0.02) was found in polysomnography and CPET data comparisons, and oxygen saturation (O2S) levels significantly correlated with VE/VCO2slope (r = 0.66, p = 0.01); in addition, OSA group presented a positive correlation between oxygen consumption and O2S (r = 0.60, p = 0.02), unlike the no-OSA group. CONCLUSIONS: OSA does not affect the CPET variables in hypertensive elderly, but it attenuates the HRR2. The association between O2S during sleep with ventilatory responses probably occurs due to the adaptations in the oxygen transport system unleashed via mechanical respiratory feedback; thus, it has been identified that OSA compromises the oxygen supply in hypertensive elderly.


Asunto(s)
Ejercicio Físico/fisiología , Fatiga/fisiopatología , Corazón/fisiología , Hipertensión/complicaciones , Hipertensión/fisiopatología , Respiración , Apnea Obstructiva del Sueño/complicaciones , Apnea Obstructiva del Sueño/fisiopatología , Anciano , Brasil , Femenino , Humanos , Masculino , Polisomnografía
17.
18.
J Strength Cond Res ; 32(7): 1869-1874, 2018 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-28682937

RESUMEN

Miller, RM, Keeter, VM, Freitas, EDS, Heishman, AD, Knehans, AW, Bemben, DA, and Bemben, MG. Effects of blood-flow restriction combined with postactivation potentiation stimuli on jump performance in recreationally active men. J Strength Cond Res 32(7): 1869-1874, 2018-Whole-body vibration (WBV) and maximum voluntary contractions (MVCs) combined with blood-flow restriction (BFR) to augment postactivation potentiation have yet to be examined. Therefore, the purpose of this investigation was to examine the augmented effects of postactivation potentiation when WBV and MVC are combined with BFR. Twenty men (21.8 ± 2.6 years, 180.5 ± 6.2 cm and 84.5 ± 12.1 kg) completed the study. Participants completed 3 testing sessions in a randomized design that included one of the following: (a) control (CON), (b) WBV and WBV combined with BFR (WBV + BFR), or (c) MVC and MVC combined with BFR (MVC + BFR). Jump height and power were recorded for 3 trials, PRE and POST jump height (cm) mean ± SD for each were as follows: CON 58.9 ± 8.6 and 57.9 ± 8.6, WBV 58.2 ± 8.1 and 59.9 ± 8.1, WBV + BFR 58.7 ± 7.6 and 60.2 ± 8.1, MVC 59.7 ± 7.4 and 60.2 ± 8.6, and MVC + BFR 57.7 ± 7.9 and 59.4 ± 8.1. PRE and POST jump power (W) mean ± SD for each were as follows: CON 1,224.3 ± 221.5 and 1,234.3 ± 189.2, WBV 1,251.1 ± 230.4 and 1,266.1 ± 215.7, WBV + BFR 1,265.8 ± 207.9 and 1,259 ± 223.3, MVC 1,264.7 ± 211.9 and 1,263.5 ± 236.5, and MVC + BFR 1,252.3 ± 222.0 and 1,294.6 ± 256.6. Significant differences were revealed in jump height between the 5 interventions (p < 0.01), WBV (p < 0.01), WBV + BFR (p < 0.01), and MVC + BFR (p < 0.01) revealed significant differences in time but no differences in jump power. In conclusion, the results of this study indicate that WBV, WBV + BFR, and MVC + BFR significantly improve jump height and time in air but not jump power.


Asunto(s)
Ejercicio Físico/fisiología , Contracción Muscular/fisiología , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Flujo Sanguíneo Regional/fisiología , Vibración/uso terapéutico , Rendimiento Atlético/fisiología , Estudios Cruzados , Prueba de Esfuerzo , Humanos , Masculino , Adulto Joven
19.
Int J Sports Med ; 38(13): 1009-1016, 2017 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-28965344

RESUMEN

This study determined the time course for changes in muscle swelling and plasma volume following high (HI) and low-intensity resistance exercise with blood-flow restriction (LI-BFR). Ten male participants (22.1±3.0 yrs) completed three experimental conditions: high-intensity exercise (HI - 80% of 1RM), low-intensity exercise with BFR (LI-BFR -20% of 1RM, and 160 mmHg of BFR), and control (CON - no exercise or BFR). Muscle cross-sectional area (mCSA), muscle thickness, thigh circumference, and percentage change in plasma volume (PV%∆) were measured. mCSA was significantly greater than rest values at 15 min post-exercise (p<0.01) for HI and LI-BFR, and at 75 min post-exercise (p<0.01) for HI. Muscle thickness was significantly greater than rest immediately post-exercise (p<0.01) and 30 min post-exercise (p<0.01) for HI and LI-BFR, and at 60 min post-exercise for HI (p=0.01). Muscle thickness was greater for BFR immediately post-exercise compared to HI (p=0.01) post-exercise. Thigh circumference was significantly greater from rest at 15 min post-exercise (p=0.01) and at 75 min post-exercise for both LI-BFR (p=0.03) and HI (p<0.01). PV%∆ significantly decreased from rest immediately post-exercise for both HI (p<0.01) and LI-BFR (p<0.01). In conclusion, BFR exercise induces changes in muscle swelling and plasma volume similar to those observed at high-intensities.


Asunto(s)
Músculo Esquelético/anatomía & histología , Músculo Esquelético/irrigación sanguínea , Volumen Plasmático , Entrenamiento de Fuerza/métodos , Adaptación Fisiológica , Estudios Cruzados , Ingestión de Energía , Prueba de Esfuerzo , Hematócrito , Humanos , Masculino , Fuerza Muscular/fisiología , Músculo Esquelético/fisiología , Flujo Sanguíneo Regional , Muslo/anatomía & histología , Adulto Joven
20.
Rheumatol Int ; 35(2): 243-53, 2015 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-24952418

RESUMEN

Neuromyelitis optica (NMO) is an inflammatory demyelinating autoimmune disease with severe, tremendously incapacitating, consequences in the patient's health and wellbeing. Until 2004, NMO was considered a restricted type of multiple sclerosis but in the same year an auto-antibody reacting against aquaporin-4 (NMO-IgG) was found to be related with NMO and it was considered the main etiologic agent of this disease. Its detection is very sensitive and specific allowing an early diagnosis and a better treatment and prognosis. With this tool, a spectrum of diseases including other autoimmune diseases was found to have NMO-IgG antibodies and a new classification named NMO spectrum disorders was created. In this review, we sum up the developments in this field associated with other autoimmune diseases. We approach the latest discoveries in the diagnosis like the new biomarkers that will possibly be used in the close future or the developments in the neuroimaging techniques. We reviewed the literature and synthesized case reports of NMO patients with concurrent autoimmune diseases and the information from useful larger studies. Finally, we summarize the commonly used treatments in NMO and we try to specify the best treatment for NMO with simultaneous autoimmune disease. This review updates the information about this issue and raises the awareness of rheumatologists for these severe diseases.


Asunto(s)
Acuaporina 4/inmunología , Autoanticuerpos/inmunología , Inmunoglobulina G/inmunología , Neuromielitis Óptica/inmunología , Enfermedades Autoinmunes/complicaciones , Enfermedades Autoinmunes/inmunología , Encéfalo/patología , Humanos , Lupus Eritematoso Sistémico/complicaciones , Lupus Eritematoso Sistémico/inmunología , Imagen por Resonancia Magnética , Miastenia Gravis/complicaciones , Miastenia Gravis/inmunología , Neuromielitis Óptica/complicaciones , Neuromielitis Óptica/diagnóstico , Sarcoidosis/complicaciones , Sarcoidosis/inmunología , Esclerodermia Sistémica/complicaciones , Esclerodermia Sistémica/inmunología , Síndrome de Sjögren/complicaciones , Síndrome de Sjögren/inmunología , Médula Espinal/patología
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA