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Limiar glicêmico durante teste muscular inspiratório incremental em indivíduos saudáveis e com doença pulmonar obstrutiva crônica

Wed, 29 Jul 2026 00:00:00 GMT

Título: Limiar glicêmico durante teste muscular inspiratório incremental em indivíduos saudáveis e com doença pulmonar obstrutiva crônica Autor(es): Silva, Wasly Santana Abstract: Introduction: The glycemic threshold (GT) during the incremental inspiratory muscle test (IIMT) has been proposed by our research group as a tool for inspiratory muscle functional assessment and individualized inspiratory muscle training (IMT) prescription. However, its agreement with the first lactate threshold (LT1) and its applicability in individuals with chronic obstructive pulmonary disease (COPD) have not yet been investigated. Objectives: To evaluate the agreement between GT and LT1 during the IIMT in healthy individuals and to investigate the determination of GT in individuals with COPD, as well as its associations with clinical and functional variables. Methods: Two studies were conducted using the IIMT. In the first study, healthy individuals performed the IIMT with simultaneous determination of GT, LT1, and the second lactate threshold (LT2). In the second study, individuals with COPD performed the IIMT for GT determination and analysis of its association with rating of perceived exertion, dyspnea, functional capacity, and cardiovascular autonomic balance. The incremental protocol started at 10% of the S-Index, with progressive workload increments until the point of exhaustion (PE). Results: In the first study, GT showed good agreement with LT1. LT1 and GT occurred at 22±8.3% and 26±13.2% of the S-Index, respectively, whereas LT2 and PE were identified at 44±10.1% and 60±14.1% of the S-Index. Bland–Altman analysis demonstrated low bias between methods for relative workload (−3.84±10.44% of the S-Index) and no proportional bias (p=0.06; R²=0.25). In the second study, GT was identified at 25±11.6% of the S-Index and showed a strong correlation with rating of perceived exertion during the IIMT (r=0.84; p<0.01). In addition, PE and ΔGT–PE were correlated with cardiovascular autonomic balance (LF/HF: r=−0.83 and r=−0.71; p<0.01), whereas ΔGT–PE was also correlated with dyspnea assessed by the modified Medical Research Council (mMRC) scale (r=−0.68; p=0.01) and Borg dyspnea at the end of the six-minute walk test (r=−0.83; p<0.01). Conclusion: GT is an identifiable physiological marker during the IIMT, showing agreement with LT1 in healthy individuals and association with important clinical and functional variables in individuals with COPD. These findings support its potential as a tool for inspiratory muscle functional assessment and individualized IMT prescription.

Avaliação dos perfis comportamentais e inflamatórios em modelos murinos de obesidade: influência do sexo e do tempo de exposição

Tue, 21 Jul 2026 00:00:00 GMT

Título: Avaliação dos perfis comportamentais e inflamatórios em modelos murinos de obesidade: influência do sexo e do tempo de exposição Autor(es): Freitas, Camila Evelyn Perete de Abstract: Advances in the study of the Developmental Origins of Health and Disease (DOHaD) suggest that insults occurring during early developmental stages can trigger significant physiological changes in adulthood, rendering the individual more susceptible to developing conditions such as obesity. In this context, "neonatal overnutrition" is a known factor associated with various metabolic and inflammatory alterations similar to those observed in obesity. It is also known that the persistence of obesity-related inflammatory changes negatively affects neural metabolism and synaptic transmission, leading to behavioral alterations. Thus, this study compared the effects of obesity induced by different murine models on metabolism and behavioral responses in both sexes. Male and female Swiss mice were assigned to control (CTRL) groups or to obesity-induction groups using either litter reduction (SL) or a high-fat diet (HFD). Body mass was monitored weekly after weaning. This monitoring lasted 10 weeks for both experimental groups, extending to 21 weeks for a subgroup of SL animals. Following an acclimatization period, a battery of three behavioral tests (defensive, social interaction, and cognitive) was conducted, followed by an analysis of locomotor activity in an open-field test. To evaluate the influence of time on the progression of the inflammatory response in LR animals, cytokine concentrations and the expression of genes associated with macrophage polarization were analyzed in various tissues at two different time points. Results showed a progressive increase in body mass and adiposity in both models at the 10-week and 21-week marks, with higher food intake observed only in male LR mice. Regarding behavior, female SL mice and both male and female HFD mice exhibited reduced active defense responses. Alterations in social affiliation and social memory were found, and age-dependent cognitive deficits were observed in SL animals of both sexes. Regarding inflammation, male RN mice exhibited an early inflammatory profile—characterized by increased TNF-α concentrations in adipose tissue and the liver, as well as the expression of genes associated with M1 macrophage polarization in the liver—as early as 10 weeks of age. In contrast, female SL mice displayed a delayed and limited inflammatory profile, with increased IL-1β levels observed only in the spleen. These results establish a significant sexual dimorphism by demonstrating that, in both models, obesity manifested as distinct metabolic and behavioral phenotypes in males and females. Furthermore, in SL animals, the progression over time played a significant role in the development of the metabolic and behavioral outcomes observed in both sexes.

Impacto da cafeína sobre indicadores neuromusculares, estresse oxidativo e dano muscular no powerlifting paralímpico

Wed, 22 Jul 2026 00:00:00 GMT

Título: Impacto da cafeína sobre indicadores neuromusculares, estresse oxidativo e dano muscular no powerlifting paralímpico Autor(es): Menezes, Jainara Lima Abstract: Introduction: Resistance exercise improves performance but generates fatigue and muscle damage. Caffeine (CA) supplementation is used to mitigate these effects; however, neuromuscular parameters, muscle damage, and oxidative stress still need to be clarified, especially in paralympic powerlifting. Objective: To evaluate the effects of CA supplementation on strength performance (static and dynamic), oxidative stress, and muscle damage in paralympic powerlifting. Methods: This study investigated the acute effects of CA supplementation (9 mg/kg) on indicators of static strength (Rate of Force Development (RFD), Impulse, Peak torque, maximum isometric strength, peak strength at 1 second, and force variability) and dynamic strength (Mean Propulsive Velocity (MPV), Maximum Velocity (Vmax), and Power were evaluated at 45% of 1RM before, after, 24h, and 48h of a training session, and also at 80% of 1RM, performing 5x5). Markers of oxidative stress and enzymatic antioxidant activity (TBARS/MDA, total antioxidant capacity, sulfhydryl groups, and uric acid) and markers of muscle damage (thermography, CK (creatine kinase), LDH (lactate dehydrogenase), and creatinine) were assessed in 14 male Paralympic powerlifting athletes. The protocol included two conditions (CA and PLA (placebo)), 5x5 at 80% of 1RM in the bench press. Results: Regarding static strength, CA significantly increased RFD, impulse, peak torque, and maximum isometric strength, while improving peak strength at 1 second and reducing variability, suggesting enhanced motor unit recruitment. Regarding dynamic strength, no significant differences were observed at 45% of 1RM. However, at 80% of 1RM, the CA group demonstrated significant improvement compared to the PLA group during Set 1 and Set 5. Nonetheless, CA also led to an increase in oxidative stress, as evidenced by elevated TBARS levels, reduced antioxidant capacity, decreased sulfhydryl groups, and higher uric acid concentrations post-exercise. Thermography showed an increase in all evaluated muscles with CA compared to the PLA condition. For CK, LDH, and creatinine, there were no significant differences. Conclusion: CA demonstrates promising ergogenic properties, contributing to increased muscle strength and allowing athletes to maintain training intensity even with higher loads. Furthermore, it does not appear to increase muscle damage, suggesting a safe usage profile in this regard. However, while it acutely improves neuromuscular performance, CA does not reduce—and may even exacerbate—exercise-induced oxidative stress, indicating that its use in strength sports should be approached with caution.

A complexidade da tarefa como variável da dose do exercício físico na promoção da funcionalidade em mulheres idosas: Brain Functional Training

Thu, 09 Jul 2026 00:00:00 GMT

Título: A complexidade da tarefa como variável da dose do exercício físico na promoção da funcionalidade em mulheres idosas: Brain Functional Training Autor(es): Monteiro, Marcos Raphael Pereira Abstract: Physical exercise is one of the most widespread health practices worldwide, and its prescription has traditionally been guided by classical dose variables such as volume and intensity. However, task complexity has emerged as a relevant component for both movement analysis and physical training, although it still lacks greater theoretical and empirical density. In this context, a training model known as Brain Functional Training (BFT) arises from the premise of increasing task complexity to enhance the activation of brain areas related to movement planning. Accordingly, this thesis investigated the effects and possible mechanisms of manipulating task complexity on the functionality of physically independent older women. In Study I, a theoretical framework was developed, based on a literature review, to support complexity as a variable of exercise dose. The hypothesis was that increasing complexity expands planning demands, elevates acute cognitive load, and more intensely recruits prefrontal regions associated with executive functions, thereby promoting functional adaptations when applied repeatedly. In Study II, the acute effects of different levels of complexity in a squat task were examined on markers of cognitive effort, physical performance, and executive performance in older women. An increase in cognitive effort was observed under more complex conditions, particularly when the squat task was combined with mental calculation or involved unilateral predominance. Despite the higher cognitive cost, no immediate differences were identified between conditions for executive performance. In contrast, increased complexity resulted in longer execution time, reduced movement velocity, and, when complexity was predominantly motor, reduced range of motion. Perceived exertion did not differ between conditions. In Study III, the effects of a 16-week intervention with BFT, functional training, and mind–body interventions were investigated, as well as retention after 16 weeks of detraining, on functionality, executive function, and body composition. All three models promoted similar improvements in functional and executive performance, with partial maintenance after detraining. BFT showed specific advantages in movement under dual-task conditions and inhibitory control, suggesting potential superiority in cognitive demands integrated with movement. All groups also increased appendicular lean mass post-intervention, with a partial decline during the detraining period. It is concluded that task complexity constitutes a promising variable of exercise dose, with acute effects on cognitive effort and motor performance, as well as relevant repeated effects on functionality and cognition in older women.