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1.
Elife ; 102021 11 15.
Artigo em Inglês | MEDLINE | ID: mdl-34779766

RESUMO

Realistic mappings of genes to morphology are inherently multivariate on both sides of the equation. The importance of coordinated gene effects on morphological phenotypes is clear from the intertwining of gene actions in signaling pathways, gene regulatory networks, and developmental processes underlying the development of shape and size. Yet, current approaches tend to focus on identifying and localizing the effects of individual genes and rarely leverage the information content of high-dimensional phenotypes. Here, we explicitly model the joint effects of biologically coherent collections of genes on a multivariate trait - craniofacial shape - in a sample of n = 1145 mice from the Diversity Outbred (DO) experimental line. We use biological process Gene Ontology (GO) annotations to select skeletal and facial development gene sets and solve for the axis of shape variation that maximally covaries with gene set marker variation. We use our process-centered, multivariate genotype-phenotype (process MGP) approach to determine the overall contributions to craniofacial variation of genes involved in relevant processes and how variation in different processes corresponds to multivariate axes of shape variation. Further, we compare the directions of effect in phenotype space of mutations to the primary axis of shape variation associated with broader pathways within which they are thought to function. Finally, we leverage the relationship between mutational and pathway-level effects to predict phenotypic effects beyond craniofacial shape in specific mutants. We also introduce an online application that provides users the means to customize their own process-centered craniofacial shape analyses in the DO. The process-centered approach is generally applicable to any continuously varying phenotype and thus has wide-reaching implications for complex trait genetics.


Assuntos
Face/anatomia & histologia , Crânio/anatomia & histologia , Análise Multivariada , Fenótipo
2.
Respir Physiol Neurobiol ; 273: 103322, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31629879

RESUMO

Chronic obstructive pulmonary disease (COPD) is a heterogeneous disease, with pulmonary and extra-pulmonary factors contributing to exercise intolerance. The primary self-reported exercise-limiting symptom may reflect the primary pathophysiological factor contributing to exercise intolerance. We compared physiological and perceptual responses at the symptom-limited peak of incremental cardiopulmonary cycle exercise testing between people with COPD reporting breathlessness (B, n = 34), leg discomfort (LD, n = 16), or a combination of B and LD (BOTH, n = 42) as their main exercise-limiting symptom(s). Despite similarly impaired health status, symptomology and peak exercise capacity, the B group had greater restrictive constraints on tidal volume expansion at end-exercise and was more likely to report unpleasant qualities of exertional breathlessness than LD and BOTH groups. In conclusion, reporting breathlessness as the primary exercise-limiting symptom indicated the presence of distinct lung pathophysiology and symptom perception during exercise in people with COPD.


Assuntos
Dispneia/fisiopatologia , Exercício Físico/fisiologia , Exercício Físico/psicologia , Doença Pulmonar Obstrutiva Crônica/fisiopatologia , Idoso , Estudos Transversais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
3.
Circ Arrhythm Electrophysiol ; 12(7): e007233, 2019 07.
Artigo em Inglês | MEDLINE | ID: mdl-31242746

RESUMO

Background Identification and elimination of nonpulmonary vein targets may improve clinical outcomes in patients with persistent atrial fibrillation (AF). We report on the use of a novel, noncontact imaging and mapping system that uses ultrasound to reconstruct atrial chamber anatomy and measures timing and density of dipolar, ionic activation (ie, charge density) across the myocardium to guide ablation of atrial arrhythmias. Methods The prospective, nonrandomized UNCOVER AF trial (Utilizing Novel Dipole Density Capabilities to Objectively Visualize the Etiology of Rhythms in Atrial Fibrillation) was conducted at 13 centers across Europe and Canada. Patients with persistent AF (>7 days, <1 year) aged 18 to 80 years, scheduled for de novo catheter ablation, were eligible. Before pulmonary vein isolation, AF was mapped and then iteratively remapped to guide each subsequent ablation of charge density-identified targets. AF recurrence was evaluated at 3, 6, 9, and 12 months using continuous 24-hour ECG monitors. The primary effectiveness outcome was freedom from AF >30 seconds at 12 months for a single procedure with a secondary outcome being acute procedural efficacy. The primary safety outcome was freedom from device/procedure-related major adverse events. Results Between October 2016 and April 2017, 129 patients were enrolled, and 127 underwent mapping and catheter ablation. Acute procedural efficacy was demonstrated in 125 patients (98%). At 12 months, single procedure freedom from AF on or off antiarrhythmic drugs was 72.5% (95% CI, 63.9%-80.3%). After 1 or 2 procedures, freedom from AF was 93.2% (95% CI, 87.1%-97.0%). A total of 29 (23%) retreatments because of arrhythmia recurrence were performed with average time from index procedure to first retreatment being 7 months. The primary safety outcome was 98% with no device-related major adverse events reported. Conclusions This novel ultrasound imaging and charge density mapping system safely guided ablation of nonpulmonary vein targets in persistent AF patients with 73% single procedure and 93% second procedure freedom from AF at 12 months. Clinical Trial Registration URL: https://www.clinicaltrials.gov . Unique identifier: NCT02825992 EU/NCT02462980 CN.


Assuntos
Potenciais de Ação , Fibrilação Atrial/diagnóstico por imagem , Técnicas Eletrofisiológicas Cardíacas , Sistema de Condução Cardíaco/diagnóstico por imagem , Frequência Cardíaca , Ultrassonografia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Fibrilação Atrial/fisiopatologia , Fibrilação Atrial/cirurgia , Canadá , Ablação por Cateter , Eletrocardiografia Ambulatorial , Europa (Continente) , Feminino , Sistema de Condução Cardíaco/fisiopatologia , Sistema de Condução Cardíaco/cirurgia , Humanos , Masculino , Pessoa de Meia-Idade , Ensaios Clínicos Controlados não Aleatórios como Assunto , Valor Preditivo dos Testes , Intervalo Livre de Progressão , Estudos Prospectivos , Veias Pulmonares/fisiopatologia , Recidiva , Fatores de Tempo , Adulto Jovem
4.
Sports (Basel) ; 7(5)2019 May 07.
Artigo em Inglês | MEDLINE | ID: mdl-31067746

RESUMO

Athletes who merit the title 'elite' are rare and differ both quantitatively and qualitatively from athletes of lower qualifications. Serving and studying elite athletes may demand non-traditional approaches. Research involving elite athletes suffers because of the typical nomothetic requirements for large sample sizes and other statistical assumptions that do not apply to this population. Ideographic research uses single-athlete study designs, trend analyses, and statistical process control. Single-athlete designs seek to measure differences in repeated measurements under prescribed conditions, and trend analyses may permit systematic monitoring and prediction of future outcomes. Statistical process control uses control charting and other methods from management systems to assess and modify training processes in near real-time. These methods bring assessment and process control into the real world of elite athletics.

5.
Access Microbiol ; 1(7): e000025, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32974539

RESUMO

INTRODUCTION: Corynebacterium ulcerans can produce diphtheria toxin and although still rare, is now the predominant cause of toxigenic diphtheria infection in the UK, making this organism of great clinical and public health importance. Here we describe a cutaneous case, likely secondary to domestic animal contact. CASE PRESENTATION: A 60-year-old female presented with a slow-healing finger-burn wound. A skin swab cultured Corynebacterium ulcerans, which was confirmed to be toxin producing. She resided with her partner and two dogs, one of which had a chronic skin lesion. Her most recent diphtheria vaccine was in 2009. Four close contacts were identified, two of whom were healthcare professionals, and nose and throat swabs were obtained. The patient was treated with clarithromycin (14 day course), diphtheria vaccine and excluded from work until completion of antibiotics and negative clearance swabs. Contacts were given erythromycin (7 day course), vaccinated and healthcare worker contacts excluded from work until swab negative. A veterinary practitioner swabbed the throats and a skin lesion of their dogs. One contact (partner of patient) and all dog swabs were positive. Partial allelic profiles from MLST supported an epidemiological link. The dogs were treated with antibiotics and antimicrobial skin wash. Repeat swabs for the index case, contact and both dogs were negative following treatment. CONCLUSION: This was a rare case of cutaneous diphtheria secondary to Corynebacterium ulcerans with domestic animals the most likely source, although human-to-human contact could not be excluded, with important human and animal public health implications.

6.
PLoS One ; 13(6): e0199126, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29920527

RESUMO

There are numerous reasons to conduct scientific research within protected areas, but research activities may also negatively impact organisms and habitats, and thus conflict with a protected area's conservation goals. We developed a quantitative ecological decision-support framework that estimates these potential impacts so managers can weigh costs and benefits of proposed research projects and make informed permitting decisions. The framework generates quantitative estimates of the ecological impacts of the project and the cumulative impacts of the proposed project and all other projects in the protected area, and then compares the estimated cumulative impacts of all projects with policy-based acceptable impact thresholds. We use a series of simplified equations (models) to assess the impacts of proposed research to: a) the population of any targeted species, b) the major ecological assemblages that make up the community, and c) the physical habitat that supports protected area biota. These models consider both targeted and incidental impacts to the ecosystem and include consideration of the vulnerability of targeted species, assemblages, and habitats, based on their recovery time and ecological role. We parameterized the models for a wide variety of potential research activities that regularly occur in the study area using a combination of literature review and expert judgment with a precautionary approach to uncertainty. We also conducted sensitivity analyses to examine the relationships between model input parameters and estimated impacts to understand the dominant drivers of the ecological impact estimates. Although the decision-support framework was designed for and adopted by the California Department of Fish and Wildlife for permitting scientific studies in the state-wide network of marine protected areas (MPAs), the framework can readily be adapted for terrestrial and freshwater protected areas.


Assuntos
Conservação dos Recursos Naturais , Sistemas de Apoio a Decisões Administrativas , Técnicas de Apoio para a Decisão , Ecossistema , Meio Ambiente , Pesquisa , Animais , Organismos Aquáticos , Biodiversidade , California , Tomada de Decisões , Modelos Teóricos , Avaliação de Programas e Projetos de Saúde , Pesquisa/organização & administração
7.
PLoS One ; 13(3): e0192870, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-29558484

RESUMO

Disease outbreaks can have substantial impacts on wild populations, but the often patchy or anecdotal evidence of these impacts impedes our ability to understand outbreak dynamics. Recently however, a severe disease outbreak occurred in a group of very well-studied organisms-sea stars along the west coast of North America. We analyzed nearly two decades of data from a coordinated monitoring effort at 88 sites ranging from southern British Columbia to San Diego, California along with 2 sites near Sitka, Alaska to better understand the effects of sea star wasting disease (SSWD) on the keystone intertidal predator, Pisaster ochraceus. Quantitative surveys revealed unprecedented declines of P. ochraceus in 2014 and 2015 across nearly the entire geographic range of the species. The intensity of the impact of SSWD was not uniform across the affected area, with proportionally greater population declines in the southern regions relative to the north. The degree of population decline was unrelated to pre-outbreak P. ochraceus density, although these factors have been linked in other well-documented disease events. While elevated seawater temperatures were not broadly linked to the initial emergence of SSWD, anomalously high seawater temperatures in 2014 and 2015 might have exacerbated the disease's impact. Both before and after the onset of the SSWD outbreak, we documented higher recruitment of P. ochraceus in the north than in the south, and while some juveniles are surviving (as evidenced by transition of recruitment pulses to larger size classes), post-SSWD survivorship is lower than during pre-SSWD periods. In hindsight, our data suggest that the SSWD event defied prediction based on two factors found to be important in other marine disease events, sea water temperature and population density, and illustrate the importance of surveillance of natural populations as one element of an integrated approach to marine disease ecology. Low levels of SSWD-symptomatic sea stars are still present throughout the impacted range, thus the outlook for population recovery is uncertain.


Assuntos
Doenças dos Animais/epidemiologia , Estrelas-do-Mar , Alaska , Animais , Dinâmica Populacional
8.
Elife ; 62017 05 05.
Artigo em Inglês | MEDLINE | ID: mdl-28475038

RESUMO

Investigations into stem cell-fueled renewal of an organ benefit from an inventory of cell type-specific markers and a deep understanding of the cellular diversity within stem cell niches. Using the adult mouse incisor as a model for a continuously renewing organ, we performed an unbiased analysis of gene co-expression relationships to identify modules of co-expressed genes that represent differentiated cells, transit-amplifying cells, and residents of stem cell niches. Through in vivo lineage tracing, we demonstrated the power of this approach by showing that co-expression module members Lrig1 and Igfbp5 define populations of incisor epithelial and mesenchymal stem cells. We further discovered that two adjacent mesenchymal tissues, the periodontium and dental pulp, are maintained by distinct pools of stem cells. These findings reveal novel mechanisms of incisor renewal and illustrate how gene co-expression analysis of intact biological systems can provide insights into the transcriptional basis of cellular identity.


Assuntos
Perfilação da Expressão Gênica , Incisivo/citologia , Células-Tronco/fisiologia , Animais , Biomarcadores/análise , Proteínas de Transporte/análise , Linhagem da Célula , Glicoproteínas de Membrana/análise , Camundongos , Proteínas do Tecido Nervoso/análise
9.
Int J Sports Physiol Perform ; 12(Suppl 2): S263-S272, 2017 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27918664

RESUMO

Athlete preparation and performance continue to increase in complexity and costs. Modern coaches are shifting from reliance on personal memory, experience, and opinion to evidence from collected training-load data. Training-load monitoring may hold vital information for developing systems of monitoring that follow the training process with such precision that both performance prediction and day-to-day management of training become adjuncts to preparation and performance. Time-series data collection and analyses in sport are still in their infancy, with considerable efforts being applied in "big data" analytics, models of the appropriate variables to monitor, and methods for doing so. Training monitoring has already garnered important applications but lacks a theoretical framework from which to develop further. As such, we propose a framework involving the following: analyses of individuals, trend analyses, rules-based analysis, and statistical process control.


Assuntos
Desempenho Atlético/tendências , Coleta de Dados/métodos , Condicionamento Físico Humano , Atletas , Humanos
10.
Sports Med ; 46(3): 315-27, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26581832

RESUMO

Gymnastics is noted for involving highly specialized strength, power, agility and flexibility. Flexibility is perhaps the single greatest discriminator of gymnastics from other sports. The extreme ranges of motion achieved by gymnasts require long periods of training, often occupying more than a decade. Gymnasts also start training at an early age (particularly female gymnasts), and the effect of gymnastics training on these young athletes is poorly understood. One of the concerns of many gymnastics professionals is the training of the spine in hyperextension-the ubiquitous 'arch' seen in many gymnastics positions and movements. Training in spine hyperextension usually begins in early childhood through performance of a skill known as a back-bend. Does practising a back-bend and other hyperextension exercises harm young gymnasts? Current information on spine stretching among gymnasts indicates that, within reason, spine stretching does not appear to be an unusual threat to gymnasts' health. However, the paucity of information demands that further study be undertaken.


Assuntos
Ginástica , Exercícios de Alongamento Muscular , Amplitude de Movimento Articular , Coluna Vertebral/fisiologia , Atletas , Humanos , Instabilidade Articular/fisiopatologia , Exercícios de Alongamento Muscular/efeitos adversos , Coluna Vertebral/fisiopatologia
11.
Int J Sports Physiol Perform ; 11(2): 197-203, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26182439

RESUMO

PURPOSE: To investigate a new power-to-body-mass (BM) ratio 3-min all-out cycling test (3MT(%BM)) for determining critical power (CP) and finite work capacity above CP (W'). METHODS: The gas-exchange threshold (GET), maximal oxygen uptake (VO2max), and power output evoking VO2max (W(peak)) and GET (W(GET)) for cycle ergometry were determined in 12 participants. CP and W' were determined using the original "linear factor" 3MT (3MT(rpm^2)) and compared with CP and W' derived from a procedure, the 3MT(%BM), using the subject's body mass and self-reported physical activity rating (PA-R), with values derived from linear regression of the work-time model and power-inverse-time model (1/time) data from 3 separate exhaustive square-wave bouts. RESULTS: The VO2max, VO(2GET), W(peak), and W(GET) values estimated from PA-R and a non-exercise-regression equation did not differ (P > .05) from actual measurements. Estimates of CP derived from the 3MT(%BM) (235 ± 56 W), 3MT(rpm^2) (234 ± 62 W), work-time (231 ± 57 W), and 1/time models (230 ± 57 W) did not differ (F = 0.46, P = .72). Similarly, estimates of W' between all methods did not differ (F = 3.58, P = .07). There were strong comparisons of the 3MT(%BM) to 1/time and work-time models with the average correlation, standard error of the measurement, and CV% for critical power being .96, 8.74 W, and 4.64%, respectively. CONCLUSION: The 3MT(%BM) is a valid, single-visit protocol for determining CP and W'.


Assuntos
Ergometria/métodos , Teste de Esforço/métodos , Consumo de Oxigênio/fisiologia , Esforço Físico/fisiologia , Adulto , Ciclismo/fisiologia , Peso Corporal , Fadiga , Feminino , Humanos , Masculino , Adulto Jovem
12.
J Strength Cond Res ; 29(5): 1263-72, 2015 May.
Artigo em Inglês | MEDLINE | ID: mdl-24531439

RESUMO

Athlete recovery-adaptation is crucial to the progress and performance of highly trained athletes. The purpose of this study was to assess peristaltic pulse dynamic compression (PPDC) in reducing short-term pressure-to-pain threshold (PPT) among Olympic Training Center athletes after morning training. Muscular tenderness and stiffness are common symptoms of fatigue and exercise-induced muscle microtrauma and edema. Twenty-four highly trained athletes (men = 12 and women = 12) volunteered to participate in this study. The athletes were randomly assigned to experimental (n = 12) and control (n = 12) groups. Pressure-to-pain threshold measurements were conducted with a manual algometer on 3 lower extremity muscles. Experimental group athletes underwent PPDC on both legs through computer-controlled circumferential inflated leggings that used a peristaltic-like pressure pattern from feet to groin. Pressures in each cell were set to factory defaults. Treatment time was 15 minutes. The control group performed the same procedures except that the inflation pump to the leggings was off. The experimental timeline included a morning training session, followed by a PPT pretest, treatment application (PPDC or control), an immediate post-test (PPT), and a delayed post-test (PPT) after the afternoon practice session. Difference score results showed that the experimental group's PPT threshold improved after PPDC treatment immediately and persisted the remainder of the day after afternoon practice. The control group showed no statistical change. We conclude that PPDC is a promising means of accelerating and enhancing recovery after the normal aggressive training that occurs in Olympic and aspiring Olympic athletes.


Assuntos
Dispositivos de Compressão Pneumática Intermitente , Músculo Esquelético/fisiopatologia , Limiar da Dor/fisiologia , Esportes/fisiologia , Adolescente , Adulto , Feminino , Humanos , Extremidade Inferior , Masculino , Mialgia/fisiopatologia , Mialgia/terapia , Dor/etiologia , Medição da Dor , Pressão/efeitos adversos , Recuperação de Função Fisiológica , Adulto Jovem
13.
J Strength Cond Res ; 28(4): 1058-64, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24077383

RESUMO

This study investigated the effects of peristaltic pulse dynamic compression (PPDC) on range-of-motion (ROM) changes in forward splits. Serious stretching usually involves discomfort and large time investments. Tissue structural changes and stretch tolerance have heretofore been considered the primary mechanisms of enhanced ROM. The PPDC treatment was computer controlled. Circumferential and segmented inflation pressures were induced by feet to hip leggings. Nine subjects, experienced in stretching and a forward split position, volunteered. The subjects were familiarized with the protocol and randomly assigned to an initial condition: experimental (PPDC), or control (CONT). The study involved a crossover design. Second conditions were tested within 1-5 days. All tests were 2 trials of right and left forward splits. Split flexibility was assessed by measuring the height of the anterior superior iliac spine of the rear leg from the floor. Pelvic posture was controlled by rear leg position. The PPDC treatment was 15 minutes of seated PPDC. The control condition was the same except that leggings were not inflated. Pressures of 5 cells in the leggings were set at factory defaults, 70 mm Hg sequentially. Difference score results indicated statistically significant (p ≤ 0.05) differences by condition and the condition by leg interaction. The rapid acute changes in ROM (PPDC: right 25.3%, left 33.3%; CONT: right 12.2%, left 1.0%) support the premise that changes in ROM were dependent on mechanisms other than tissue structural changes and/or stretch tolerance. PPDC provides a means of rapidly enhancing acute ROM requiring less discomfort and time.


Assuntos
Perna (Membro)/fisiologia , Exercícios de Alongamento Muscular/métodos , Músculo Esquelético/fisiologia , Maleabilidade/fisiologia , Amplitude de Movimento Articular/fisiologia , Análise de Variância , Estudos Cross-Over , Tolerância ao Exercício/fisiologia , Feminino , Humanos , Contração Muscular/fisiologia , Pressão , Estatísticas não Paramétricas , Adulto Jovem
14.
J Strength Cond Res ; 27(12): 3335-41, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23478481

RESUMO

The critical velocity (CV) model offers an opportunity to prescribe and to test empirically different velocity-time (V-t) configurations of high-intensity interval training (HIIT); however, such experiments are lacking. We evaluated a group of competitive, female soccer players (age = 19 ± 1 years, height = 168 ± 6 cm, mass = 61 ± 6 kg) completing 1 of 2 different HIIT regimes: a short group (n = 6) completing higher V and shorter t configurations, and a long group (n = 10) completing lower V, longer t configurations. Both groups trained 2 d·wk for 4 weeks. For each workout, both groups ran at velocities exceeding CV and designed to deplete identical fractional percentages of the finite work capacity above CV (D'). The metrics of CV and D' were evaluated at pretraining and posttraining using the 3-minute all-out exercise test on an indoor track using video digitizing of displacement relative to time. Despite differences in the V-t configurations, both groups increased their CV (+0.22 m·s, +6%) and decreased their D' (-24 m, -13%; p < 0.05). We conclude that 2- to 5-minute HIIT bouts are suitable for increasing CV, in previously trained athletes, but they result in a decline of D'. To increase D', we suggest examining HIIT of intensities that are <2 minutes and >130% of maximum oxygen uptake.


Assuntos
Desempenho Atlético/fisiologia , Modelos Biológicos , Corrida/fisiologia , Futebol/fisiologia , Adolescente , Teste de Esforço , Feminino , Humanos , Modelos Lineares , Consumo de Oxigênio , Adulto Jovem
15.
J Strength Cond Res ; 27(7): 1994-9, 2013 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-23037611

RESUMO

Energy drinks (EDs) such as Red Bull (RB) are marketed to enhance metabolism. Secondary ingredients of EDs (e.g., taurine) have been purported to improve time trial performance; however, little research exists on how such secondary ingredients affect aerobic metabolism during heavy exercise. The purpose of this study was to investigate the effect of the secondary ingredients of RB on aerobic metabolism during and subsequent to heavy exercise. In double-blind, counterbalanced, and crossover fashion, 8 recreationally trained individuals completed a graded exercise test to determine the gas exchange threshold (GET). Subjects returned on 2 separate occasions and ingested either a 245 ml serving of RB or a control (CTRL) drink with the equivalent caffeine before engaging in two 10-minute constant-load cycling bouts, at an intensity equivalent to GET, with 3 minutes of rest between bouts. Accumulated liters of O2 (10 minutes) were higher for the first bout (17.1 ± 3.5 L) vs. the second bout (16.7 ± 3.5 L) but did not differ between drinks. Similarly, excess postexercise oxygen consumption was higher after the initial bout (RB mean, 2.6 ± 0.85 L; CTRL mean, 2.9 ± 0.90 L) vs. the second bout (RB mean, 1.5 ± 0.85 L; CTRL mean, 1.9 ± 0.87 L) but did not differ between drinks. No differences occurred between drinks for measures of heart rate or rating of perceived exertion. These results indicate that the secondary ingredients contained in a single serving of RB do not augment aerobic metabolism during or subsequent to heavy exercise.


Assuntos
Bebidas Energéticas , Metabolismo Energético/efeitos dos fármacos , Exercício Físico/fisiologia , Cafeína/farmacologia , Estudos Cross-Over , Método Duplo-Cego , Feminino , Frequência Cardíaca/efeitos dos fármacos , Humanos , Masculino , Consumo de Oxigênio/efeitos dos fármacos , Esforço Físico/efeitos dos fármacos , Placebos , Adulto Jovem
16.
J Strength Cond Res ; 27(8): 2104-12, 2013 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-23090321

RESUMO

The cycling 3-minute all-out exercise test (3 MT) provides the measures of critical power (CP) and the curvature constant (W') for the relationship between power and time limit to exhaustion in the severe exercise domain. The original procedures for the 3 MT required a preliminary graded exercise test (GXT) to establish the linear factor and the fixed load for the test. We evaluated a new procedure of establishing the load for the 3 MT using a percentage of body mass (% BM). Fifteen subjects of varied fitness levels completed a custom GXT-verification protocol to establish the gas exchange threshold and V[Combining Dot Above]O2max, a 3 MT using a load derived with the linear factor, and a 3 MT using a % BM. The subjects also completed a subsequent exhaustive bout at 10% above CP. The CP and W' estimated from either protocol did not differ. The CP estimates were consistent (α = 0.97, SEM = 7.1 W, coefficient of variation = 4%); however, W' was less reliable, a finding true of any method of measuring W'. The V[Combining Dot Above]O2 evoked during the 3 MT was lower than the values evoked by the exhaustive GXT-verification bouts and the 10% above CP bout after the 3 MT. All individual V[Combining Dot Above]O2 values in the 10% above CP bout were "≥" values measured in the 3 MT. Our findings indicate that several viable procedures for administering the 3 MT are plausible.


Assuntos
Limiar Anaeróbio/fisiologia , Teste de Esforço/métodos , Esforço Físico/fisiologia , Adolescente , Adulto , Peso Corporal , Feminino , Humanos , Masculino , Consumo de Oxigênio , Troca Gasosa Pulmonar , Fatores de Tempo , Adulto Jovem
17.
J Strength Cond Res ; 27(9): 2444-8, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23238098

RESUMO

Quantifying the maximal work capacity (W') above the aerobic critical power (CP) has emerged as a method for estimating anaerobic work capacity. Slower cadence, lower-load resistance training (RT), colloquially referred to as high-intensity training (HIT), is purported to be a better metabolic stressor than faster cadence higher-load RT, but to date, this belief has not been supported by research. We compared the acute effects of HIT and traditional RT bouts on average power within a 150-second time period (P(150 s)), CP, and W', as measured from a 3-minute all-out exercise test using cycling ergometry (3 MT). Eight recreationally active male subjects (mean ± SD: age 22 ± 2 years, body mass 85 ± 14 kg, and height 18 ± 9 cm) completed a baseline 3 MT 10 repetition maximum testing on leg press and leg extension machines, and post-bout 3 MTs after an HIT (4:2 second cadence) or a traditional RT bout (1:1 second cadence). Measurements of CP from the 3 MTs were similar between the baseline, post-HIT (α = 0.96), and post-traditional RT bouts (α = 0.98). Neither HIT (269.2 ± 51.3 W) nor traditional RT (275.1 ± 51.3 W) evoked depreciations (p > 0.05) in P(150 s) from the baseline (275.1 ± 45.4 W). Moreover, estimates of W' at the baseline (8.3 ± 3.2 kJ) were unaffected (p > 0.05) either by the HIT (7.6 ± 2.3 kJ) or by the traditional RT (8.3 ± 1.3 kJ) bouts. These data indicate that the 4:2 cadence is insufficient to exhaust a person's capacity for high-intensity work. Longer RT durations, either by slower cadences or by multiple sets, are necessary to evoke substantive declines on W' and should be investigated.


Assuntos
Limiar Anaeróbio/fisiologia , Resistência Física/fisiologia , Treinamento Resistido , Humanos , Masculino , Força Muscular/fisiologia , Treinamento Resistido/métodos , Adulto Jovem
18.
J Strength Cond Res ; 27(2): 549-55, 2013 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-22531615

RESUMO

Standardized graded exercise test (GXT) protocols are ineffective for testing endurance athletes. Scientists have called for the abandonment of traditional techniques for corroborating "true" maximum oxygen uptake (VO2max), as measured during a GXT. Instead, a new technique, the verification bout subsequent to the GXT, has emerged for establishing the "true" VO2max. The addition of the verification bout reframes how the GXT should be viewed. In this article, we summarize the methods for developing custom GXT protocols, identifying threshold and interpolating power or outdoor running velocity, and implicating the verification bout.


Assuntos
Teste de Esforço/métodos , Tolerância ao Exercício/fisiologia , Exercício Físico/fisiologia , Corrida/fisiologia , Humanos , Ácido Láctico/sangue , Consumo de Oxigênio , Troca Gasosa Pulmonar , Ventilação Pulmonar
19.
Int J Sports Physiol Perform ; 7(4): 350-6, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22645197

RESUMO

UNLABELLED: The lay press, scientists, and physicians appear to believe that gymnasts are continually getting smaller and that their "smallness" is a health risk. PURPOSE: To assess the historical changes in the size and age of the US women's Olympic gymnastics teams from 1956 to 2008. METHODS: The official records from the US Olympic Committee and USA Gymnastics of Olympic team members were assessed at 2 levels: individual height, mass, age, and body-mass index (BMI) and the team performance scores and rankings. Fourteen Olympic teams with a total of 106 team members, including the alternates, were included. Trend analyses were conducted using linear and polynomial models. RESULTS: Simple linear correlations indicated that since 1956, height, mass, age, BMI, and team Olympic rank have been declining. However, second-order polynomial curve fits indicated that in the last 4 Olympic Games the members of the US women's gymnastics teams have been getting larger. CONCLUSION: Women Olympic gymnasts were getting smaller through approximately the 1980s and early 1990s. Since then the size of these gymnasts has increased. The minimum-age rule modifications may have played a role in athlete size changes along with a shift from the near dominance of the former communist Eastern Bloc.


Assuntos
Atletas , Tamanho Corporal , Ginástica/tendências , Fatores Etários , Antropometria , Atletas/história , Desempenho Atlético , Estatura , Índice de Massa Corporal , Peso Corporal , Feminino , Ginástica/história , História do Século XX , História do Século XXI , Humanos , Modelos Lineares , Fatores Sexuais , Análise e Desempenho de Tarefas , Fatores de Tempo , Estados Unidos
20.
Environ Manage ; 50(1): 89-96, 2012 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-22525994

RESUMO

The invasion of the aquarium strain of the green alga Caulerpa taxifolia and subsequent alteration of community structure in the Mediterranean Sea raised awareness of the potential for non-native seaweeds to impact coastal communities. An introduction of C. taxifolia in southern California in 2000, presumably from the release of aquarium specimens, cost ~$7 million for eradication efforts. Besides C. taxifolia, other Caulerpa species being sold for aquarium use also may have the potential to invade southern Californian and U.S. waters. Surveys of the availability of Caulerpa species in southern California aquarium retail stores in 2000-2001 revealed that 26 of 50 stores sold at least one Caulerpa species (52 %) with seven stores selling C. taxifolia. In late 2001, California imposed a ban on the importation, sale, or possession of nine Caulerpa species; the City of San Diego expanded these regulations to include the entire genus. To determine the effectiveness of the California ban, we resurveyed Caulerpa availability at 43 of the 50 previously sampled retail stores in southern California in ~2006, ~4 years following the ban. Of the 43 stores, 23 sold Caulerpa (53 %) with four stores selling C. taxifolia. A χ(2) test of frequency of availability before and after the California ban suggests that the ban has not been effective and that the aquarium trade continues to represent a potential vector for distributing Caulerpa specimens, including C. taxifolia. This study underscores the need for increased enforcement and outreach programs to increase awareness among the aquarium industry and aquarium hobbyists.


Assuntos
Caulerpa/crescimento & desenvolvimento , Comércio , Política Ambiental/legislação & jurisprudência , Hidroponia/economia , Hidroponia/legislação & jurisprudência , California , Política Ambiental/economia , Regulamentação Governamental
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