Desempenho e fisiomecânica da corrida de 3000m

O desempenho na corrida de longa distância é determinado, dentre outros fatores, pela integração deparâmetros biomecânicos e fisiológicos. Sabe-se que os parâmetros do modelo massa-mola e as assimetrias contato e despregue se alteram com o envelhecimento e em outras formas de locomoção, contudo, não está claro o comportamento dessas variáveis mecânicas em relação ao custo metabólico(C) e desempenho de corrida. O objetivo desta tesefoi verificar se os parâmetros do modelo massa-mola, trabalho mecânico e o custo metabólico são alterados em corredores de diferentes níveis de desempenho. Foram selecionados atletas de corrida e divididos em dois grupos, determinados pela mediana do desempenho no teste de 3000m. Os participantes realizaram três testes em dias diferentes: i) teste de consumo máximo oxigênio realizado em uma esteira rolante; ii) teste das variáveis mecânicas da corrida realizado em esteira instrumentalizada com coleta das forças de reação do solo e cinemática nas velocidades (de 8 a 20 km.h-1); iii) teste de desempenho de 3000m com coleta do consumo de oxigênio realizado em pista de atletismo. O processamento dos dados foi realizado em ambiente LabVIEW e MATLAB para obtenção parâmetros do modelo massa mola, trabalho mecânico e custo metabólico. Para análise estatísticafoi utilizado o modelo de efeitos mistos lineares generalizados (GLMM) e o teste de post- hoc de Bonferroni para verificar as diferenças estatísticas. O nível de significância adotado foi de 5% (SPSS 25). Os corredores do grupo com desempenho superior apresentaram maior trabalho mecânico total (Wtot) e trabalho mecânico interno dos membros inferiores (Wint_leg) e menor trabalho de membros superiores (Wint_arms).Aliado a esses resultados, também apresentaram maior tempo aéreo efetivo (tae),rigidez (kvert), frequência do sistema massa-mola (fsist) e menores tempo de contato efetivo (tce) e frequência de passo (fstep) o que demonstrou adaptação específica que se refletiu nos resultados de custo metabólico e desempenho no teste de 3000m. Os parâmetros do sistema massa-mola demonstraram uma adaptabilidade dependente do nível de desempenho em corredores de longa distância. Com relação aos resultados do presente estudo conclui-se que os corredores de longa distância apresentam um sistema elástico otimizado e isso está relacionado ao desempenho de corrida pois apresentam melhor utilização do trabalho mecânico e menor custo metabólico.Performance in long distance running is determined, among other factors, by the integration of biomechanical and physiological parameters. It is known that the parameters of the mass-spring model and the contact and release asymmetries change with aging and in other forms of locomotion, however, it is not clear the behavior of these mechanical variables in relation to the metabolic cost (C) and running performance. The aim of this thesis was to verify if the parameters of the mass-spring model, mechanical work and metabolic cost are changed in runners with different performance levels. Running athletes were selected and divided into two groups determined by the median of the performance in the 3000m test. The subjects performed three tests on different days: i) maximal oxygen consumption test performed on a treadmill; (ii) test of the mechanical variables of the running performed in an instrumentalized treadmill with collection of ground reaction forces and kinematics at speeds (from 8 to 20 km.h-1); iii) 3000m performance test with collection of oxygen consumption performed in athletics track. Data processing was performed in LabVIEW and MATLAB environments to obtain parameters of the spring mass model, mechanical work and metabolic cost. For statistical analysis, the generalized linear mixed effects model (GLMM) and Bonferroni post-hoc test were used to verify statistical differences. The level of significance was 5% (SPSS 25). Higher performance group runners presented higher total mechanical work (Wtot) and internal mechanichal work of lower limbs (Wint_leg) and lower internal mechanical work of upper limbs (Wint_arms). In addition to these results, they also presented greater effective aerial time (tae), stiffness (kvert), spring mass frequency (fsist) and lower effective contact time (tce) and step frequency (fstep) which demonstrated a specific adaptation that was reflected in the results of metabolic cost and performance in the 3000m test. The parameters of the mass-spring system showed an adaptability depending on the level of performance in long distance runners. Regarding the results of the present study, it is concluded that long-distance runners have an optimized elastic system and this is related to running performance because they present better use of mechanical work and lower metabolic cost

Factors affecting training and physical performance in recreational endurance runners

Abstract: Endurance running has become an immensely popular sporting activity, with millions of recreational runners around the world. Despite the great popularity of endurance running as a recreational activity during leisure time, there is no consensus on the best practice for recreational runners to effectively train to reach their individual objectives and improve physical performance in a healthy manner. Moreover, there are lots of anecdotal data without scientific support, while most scientific evidence on endurance running was developed from studies observing both recreational and professional athletes of different levels. Further, the transference of all this information to only recreational runners is difficult due to differences in the genetic predisposition for endurance running, the time available for training, and physical, psychological, and physiological characteristics. Therefore, the aim of this review is to present a selection of scientific evidence regarding endurance running to provide training guidelines to be used by recreational runners and their coaches. The review will focus on some key aspects of the training process, such as periodization, training methods and monitoring, performance prediction, running technique, and prevention and management of injuries associated with endurance running

Nordic walking training in elderly, a randomized clinical trial. Part II: Biomechanical and metabolic adaptations

BACKGROUND: Nordic walking is an attractive method of endurance training. Nevertheless, the biomechanic response due to the additional contribution of using poles in relation to free walking training has been less explored in the elderly. PURPOSE: This randomized parallel controlled trial aimed to assess the effects of 8 weeks of Nordic walking and free walking training on the walking economy, mechanical work, metabolically optimal speed, and electromyographic activation in elderly. METHODS: Thirty-three sedentary elderly were randomized into Nordic walking (n = 16) and free walking group (n = 17) with equalized loads. Submaximal walking tests were performed from 1 to 5 km h-1 on the treadmill. RESULTS: Walking economy was improved in both free and Nordic walking groups (x2 4.91, p = 0.014) and the metabolically optimal speed was increased by approximately 0.5 km h-1 changing the speed-cost profile. The electromyographic activation in lower and upper limbs, pendular recovery, and total, external, and internal mechanical work remained unchanged (p > 0.05). Interestingly, the internal mechanical work associated with arm movement was higher in the Nordic walking group than in the free walking group after training, while the co-contraction from upper limb muscles was reduced similarly to both groups. CONCLUSIONS: Eight weeks of Nordic walking training effectively improved the walking economy and functionality as well as maintained the gait mechanics, similar to free walking training in elderly people. This enhancement in the metabolic economy may have been mediated by a reduction in the co-contraction from upper limb muscles. TRIAL REGISTRATION: ClinicalTrails.gov NCT03096964

Modelling 5-km Running Performance on Level and Hilly Terrains in Recreational Runners

[EN] Incline and level running on treadmills have been extensively studied due to their different cardiorespiratory and biomechanical acute responses. However, there are no studies examining the performance determinants of outdoor running on hilly terrains. We aimed to investigate the influence of anthropometrics, muscle strength, and cardiorespiratory and gait spatiotemporal parameters during level (0%) and inclined (+7%) running on performance in level and hilly 5-km races. Twenty male recreational runners completed two 5-km outdoor running tests (0% vs. +7% and −7%), and two submaximal (10 km·h−1) and incremental treadmill tests at 0 and 7% slopes, after complete laboratory evaluations. The velocity at maximal oxygen consumption (VO2max) evaluated at 7% incline and level treadmill running were the best performance predictors under both hilly (R2 = 0.72; p < 0.05 ) and level (R2 = 0.85; p < 0.01) conditions, respectively. Inclusion of ventilatory and submaximal heart rate data improved the predictive models up to 100%. Conversely, none of the parameters evaluated in one condition contributed to the other condition. The spatiotemporal parameters and the runners’ strength levels were not associated to outdoor performances. These results indicate that the vVO2max evaluated at similar slopes in the lab can be used to predict 5-km running performances on both level and hilly terrains

Running stride length and rate are changed and mechanical efficiency is preserved after cycling in middle-level triathletes

Although cycling impairs the subsequent metabolic cost and performance of running in some triathletes, the consequences on mechanical efficiency (Eff) and kinetic and potential energy fluctuations of the body center of mass are still unknown. The aim of this study was to investigate the effects of previous cycling on the cost-of-transport, Eff, mechanical energy fluctuations (Wtot), spring stiffness (Kleg and Kvert) and spatiotemporal parameters. Fourteen middle-level triathletes (mean\u2009\ub1\u2009SD: maximal oxygen uptake, [Formula: see text]O2max\u2009=\u200965.3\u2009\ub1\u20092.7\u2009ml.kg-1.min-1, age\u2009=\u200930\u2009\ub1\u20095 years, practice time\u2009=\u20096.8\u2009\ub1\u20093.0 years) performed four tests. Two maximal oxygen uptake tests on a cycle ergometer and treadmill, and two submaximal 20-minute running tests (14\u2009km.h-1) with (prior-cycling) and without (control) a previous submaximal 30-minute cycling test. No differences were observed between the control and post-cycling groups in Eff or Wtot. The Eff remains unchanged between conditions. On the other hand, the Kvert (20.2 vs 24.4 kN.m-1) and Kleg (7.1 vs 8.2 kN.m-1, p\u2009&lt;\u20090.05) were lower and the cost-of-transport was higher (p\u2009=\u20090.018, 3.71 vs 3.31\u2009J.kg-1.m-1) when running was preceded by cycling. Significantly higher stride frequency (p\u2009&lt;\u20090.05, 1.46 vs 1.43\u2009Hz) and lower stride length (p\u2009&lt;\u20090.05, 2.60 vs 2.65\u2009m) were observed in the running after cycling condition in comparison with control condition. Mechanical adjustments were needed to maintain the Eff, even resulting in an impaired metabolic cost after cycling performed at moderate intensity. These findings are compatible with the concept that specific adjustments in spatiotemporal parameters preserve the Eff when running is preceded by cycling in middle-level triathletes, though the cost-of-transport increased

Modelling 5-km running performance on level and hilly terrains in recreational runners

Incline and level running on treadmills have been extensively studied due to their different cardiorespiratory and biomechanical acute responses. However, there are no studies examining the performance determinants of outdoor running on hilly terrains. We aimed to investigate the influence of anthropometrics, muscle strength, and cardiorespiratory and gait spatiotemporal parameters during level (0%) and inclined (+7%) running on performance in level and hilly 5-km races. Twenty male recreational runners completed two 5-km outdoor running tests (0% vs. +7% and −7%), and two submaximal (10 km·h −1 ) and incremental treadmill tests at 0 and 7% slopes, after complete laboratory evaluations. The velocity at maximal oxygen consumption (VO2max) evaluated at 7% incline and level treadmill running were the best performance predictors under both hilly (R2 = 0.72; p < 0.05) and level (R2 = 0.85; p < 0.01) conditions, respectively. Inclusion of ventilatory and submaximal heart rate data improved the predictive models up to 100%. Conversely, none of the parameters evaluated in one condition contributed to the other condition. The spatiotemporal parameters and the runners’ strength levels were not associated to outdoor performances. These results indicate that the vVO2max evaluated at similar slopes in the lab can be used to predict 5-km running performances on both level and hilly terrains

Aspecto sociodemográfico, clínico e qualidade de vida em pacientes com artrite reumatoide

Objetivo: Caracterizar os aspectos sociodemográficos, clínicos e a qualidade de vida (QV) de pacientes com artrite reumatoide (AR). Métodos: Tratou-se de um estudo transversal e descritivo, com abordagem quantitativa. Avaliou-se 22 indivíduos com AR, independentemente do sexo, e com idade superior a 18 anos. Os participantes foram encaminhados para o Laboratório de Análise Multissetorial da Universidade Estadual de Santa Catarina por médicos reumatologistas vinculados ao Sistema Único de Saúde, no período de junho a setembro de 2010. Utilizou-se uma ficha de avaliação para levantamento dos aspectos sociodemográficos e clínicos, nível de atividade da doença (Disease Activity Score 28) e o Questionário de Qualidade de Vida (36 Item Short-Form Health Survey). Resultados: Houve predomínio do sexo feminino, com 81,8% (n=18); etnia branca, com 90,9% (n=20); e da sexta década de vida, com 60,0 (±12,90) anos no sexo masculino. Dentre os sintomas, 17 (77,3%) indivíduos referiram dor como a principal queixa. No nível de atividade da doença, verificou-se que os valores médios foram 4,4 (±1,56), com predomínio de 10 (45,5%)indivíduos em atividade moderada. Na QV, evidenciou-se diferença significativa no domínio dor e aspecto social em função do nível de atividade da doença (p<0,05). No domínio dor, houve diferença significativa quando comparado os grupos alta e baixa atividade da doença (p<0,01) e entre os grupos baixa e moderada (p<0,01). Conclusão: Pôde-se identificar, nos indivíduos com artrite reumatoide participantes do estudo, prejuízo no seu estado geral de saúde e, além disso, o elevado nível de atividade da doença interferiu na sintomatologia dolorosa e comprometeu o aspecto social

Production capacity of maximal isometric grip strength in women with rheumatoid arthritis: a pilot study

O objetivo deste estudo foi verificar a capacidade de produção de força de preensão manual máxima (FPMmax) em mulheres com artrite reumatoide (AR) e sua relação com a atividade da doença. Foram selecionadas nove mulheres com AR e dez mulheres saudáveis. Foram registrados dados demográficos de ambos os grupos, além de características clínicas das mulheres com AR. A determinação do nível da atividade da doença foi conduzida pelo protocolo Disease Activity Score (DAS-28) por meio da Proteína C-Reativa (PCR). Para aquisição da FPMmax, foi utilizado o dinamômetro do tipo extensômetro. Os resultados demonstraram diferença significativa da FPMmax entre as participantes (Artrite e Controle: 129,41±52,10 e 192,46±38,98 N). Em relação à dominância, as mulheres com AR não apresentaram diferença significativa na FPMmax. Os resultados obtidos da FPMmax para a mão dominante evidenciaram uma forte relação linear com a PCR (r=0,751). Também se constatou uma moderada relação não linear da FPMmax para a mão dominante e não-dominante com o número de articulações dolorosas e edemaciadas. Assim, fica evidente que mulheres com AR apresentam redução na capacidade de produzir a FPMmax ndependente da dominância, além do que este estudo demonstrou a relação direta que existe entre a FPMmax e o nível de atividade da doença.Este artículo tuvo como objetivo verificar la capacidad de producción de fuerza de prensión manual máxima (FPMmax) en mujeres con artritis reumatoide (AR) y su relación con la actividad de la enfermedad. Han sido elegidas nueve mujeres con AR y diez saludables. Se han registrado datos demográficos de los dos grupos, además de las características clínicas de las mujeres con AR. La determinación del nivel de actividad de la enfermedad se realizó por el protocolo Disease Activity Score (DAS-28) a través de la Proteína C-Reactiva (PCR). Para la adquisición de la FPMmax se utilizó el dinamómetro de tipo extensómetro. Los resultados muestran una diferencia significativa de la FPMmax entre los participantes (Artritis y Control: 129,41±52,10 e 192,46±38,98 N). Con respeto a la dominación, las mujeres con AR no presentaron diferencias significativas en la FPMmax Se obtuvo resultados para la mano dominante en el cual mostró una fuerte relación lineal con la PCR (r=0,751). También se comprobó una moderada relación no lineal de la FPMmax para la mano dominante y la no dominante con el número de articulaciones dolorosas e inflamadas. De esta manera, resulta evidente que las mujeres con AR presentan reducción en la capacidad de producción de la FPMmax ndependiente de la dominancia, además de mostrar a través de esta investigación la relación directa entre la FPMmax y el nivel de actividad de la enfermedad.The aim of this study was to verify the capacity of maximum handgrip strength (HGSmax) in women with rheumatoid arthritis (RA) and its relationship with disease activity. Nine women with RA and ten healthy women were selected. The demographics data were recorded of both groups, and clinical characteristics of women with RA. The level of disease activity was evaluated by the protocol Disease Activity Score (DAS-28) using C-Reactive Protein (CRP). To measure the HGSmax was used an extensometer dynamometer. The results showed a statistically significant difference of HGSmax between the participants (Arthritis and Control: 129.41±52.10 e 192.46±38.98 N). In relation to dominance, women with RA showed no significant difference in HGSmax. The results of HGSmax for the dominant hand showed a strong linear relationship with the CRP (r=0.751). It also noted that was a moderate non-linear relation of HGSmax for the dominant hand and non-dominant with the number of tender and swollen joints. Thus, it is clear that women with RA have reduced ability to produce HGSmax independent of dominance, in addition, this study demonstrated the direct relationship that exists between HGSmax and the level of disease activity

Avaliação do equilíbrio corporal de pacientes com artrite reumatoide

Postural control, stability in voluntary movements in response to external disturbances and proprioception are basic elements for maintaining balance. People with Rheumatoid Arthritis (RA) have difficulty maintaining postural control, undermining the balance in the Activities of Daily Living (ADL's), making it an important risk factor for falls. The present study aimed to evaluate the body balance of individuals with RA, according to the level of disease activity. We evaluated 24 individuals with 54.66±9.52 years. All underwent a questionnaire identification and medical history, anthropometric measurements, blood sampling for analysis of C-Reactive Protein (CRP), determining the level of disease activity using the DAS-28 and equilibrium through tests: Berg Balance Scale (BBS) and TUG. Patients were divided into three groups: low, moderate and high disease activity. The results of equilibrium tests showed that, although the sample has presented low risk for falls, the group in high disease activity had higher frequency distribution (57.2%) in scores between 48-52 in the BBS compared to the moderate activity group, whose frequency distribution prevailed in the scores between 53 and 56 (92.3%-pControl postural, estabilidad en los movimientos voluntarios, reacción a las perturbaciones externas y propiocepción constituyen elementos básicos para la manutención del equilibrio. Personas con Artritis Reumatoidea (AR) tienen dificultad en mantener el control postural, perjudicando el equilibrio en las Actividades de Vida Diarias (AVD's), volviéndose un importante factor de riesgo de caídas. El presente estudio tuvo por objetivo evaluar el equilibrio corporal de individuos con AR, en función del nivel de actividad de la enfermedad. Fueron evaluados 24 individuos con 54,66±9,52 años. Todos fueron sometidos a la aplicación de cuestionario de identificación e historia clínica, evaluaciones antropométricas, colecta de muestra sanguínea para análisis de Proteína C-Reactiva (PCR), determinación del nivel de actividad de la enfermedad por medio del Disease Activity Score (DAS-28) y evaluación del equilibrio a través de los tests: Escala de Equilibrio de Berg (EEB) y Timed Up and Go (TUG). Los pacientes fueron divididos en tres grupos: baja, moderada y alta actividad de la enfermedad. Los resultados de los tests de equilibrio demostraron que, aunque la muestra haya presentado bajo riesgo de caídas, el grupo en alta actividad de la enfermedad presentó mayor distribución de frecuencia (57,2%) en los escores entre 48-52 en la EEB, en comparación con el grupo moderada actividad, cuya distribución de frecuencia predominó en los escores entre 53 y 56 (92,3%-pControle postural, estabilidade nos movimentos voluntários, reação às perturbações externas e propriocepção constituem elementos básicos para a manutenção do equilíbrio. Pessoas com Artrite Reumatoide (AR) têm dificuldade em manter o controle postural, prejudicando o equilíbrio nas Atividades de Vida Diárias (AVD's), tornando-se um importante fator de risco para quedas. O presente estudo teve por objetivo avaliar o equilíbrio corporal de indivíduos com AR, em função do nível de atividade da doença. Foram avaliados 24 indivíduos com 54,66±9,52 anos. Todos foram submetidos à aplicação de questionário de identificação e história clínica, avaliações antropométricas, coleta de amostra sanguínea para análise de Proteína C-Reativa (PCR), determinação do nível de atividade da doença por meio do Disease Activity Score (DAS-28) e avaliação do equilíbrio através dos testes: Escala de Equilíbrio de Berg (EEB) e Timed Up and Go (TUG). Os pacientes foram divididos em três grupos: baixa, moderada e alta atividade da doença. Os resultados dos testes de equilíbrio demonstraram que, embora a amostra tenha apresentado baixo risco para quedas, o grupo em alta atividade da doença apresentou maior distribuição de frequência (57,2%) nos escores entre 48-52 na EEB, em comparação ao grupo moderada atividade, cuja distribuição de frequência predominou nos escores entre 53 e 56 (92,3%-