Explore the vast range of titles available.

The rat high-impact free weight drop model mimics the diffuse axonal injury caused by severe traumatic brain injury in humans, while severe controlled cortical impact can produce a severe traumatic brain injury model using precise strike parameters. In this study, we compare the pathological mechanisms and pathological changes between two rat severe brain injury models to identify the similarities and differences. The severe controlled cortical impact model was produced by an electronic controlled cortical impact device, while the severe free weight drop model was produced by dropping a 500 g free weight from a height of 1.8 m through a plastic tube. Body temperature and mortality were recorded, and neurological deficits were assessed with the modified neurological severity score. Brain edema and blood-brain barrier damage were evaluated by assessing brain water content and Evans blue extravasation. In addition, a cytokine array kit was used to detect inflammatory cytokines. Neuronal apoptosis in the brain and brainstem was quantified by immunofluorescence staining. Both the severe controlled cortical impact and severe free weight drop models exhibited significant neurological impairments and body temperature fluctuations. More severe motor dysfunction was observed in the severe controlled cortical impact model, while more severe cognitive dysfunction was observed in the severe free weight drop model. Brain edema, inflammatory cytokine changes and cortical neuronal apoptosis were more substantial and blood-brain barrier damage was more focal in the severe controlled cortical impact group compared with the severe free weight drop group. The severe free weight drop model presented with more significant apoptosis in the brainstem and diffused blood-brain barrier damage, with higher mortality and lower repeatability compared with the severe controlled cortical impact group. Severe brainstem damage was not found in the severe controlled cortical impact model. These results indicate that the severe controlled cortical impact model is relatively more stable, more reproducible, and shows obvious cerebral pathological changes at an earlier stage. Therefore, the severe controlled cortical impact model is likely more suitable for studies on severe focal traumatic brain injury, while the severe free weight drop model may be more apt for studies on diffuse axonal injury. All experimental procedures were approved by the Ethics Committee of Animal Experiments of Tianjin Medical University, China (approval No. IRB2012-028-02) in February 2012.

This study evaluated the impact of an 8-week training program on two groups of players, one performing free weights training and the other bodyweight training. The sample consisted of 14 athletes with a mean age of 22.6 years. Assessments of shooting strength were conducted before and after the program, measuring shot speed, acceleration, and strength. The free weights training included exercises with dumbbells and barbells, while the bodyweight training included squats, pushups, and planks. Sessions occurred twice a week, with gradual progress in the number of sets and repetitions. Statistical analyses were performed using GraphPad Prism software, with significance set at p<0.05. Data distribution was tested using the Shapiro-Wilk test, and comparisons between pre-and post-intervention assessments were made with paired ttests. Results showed significant improvements in shot speed, acceleration, and strength in the free weights training group, while the bodyweight training group showed no significant changes. It was concluded that free weights training is more effective for improving shooting strength in roller hockey players. Este estudio evaluó el impacto de un programa de entrenamiento de 8 semanas en dos grupos de jugadores, uno que realizó entrenamiento con pesas libres y el otro entrenamiento con peso corporal. La muestra consistió en 14 atletas con una edad media de 22,6 años. Se realizaron evaluaciones de la fuerza de tiro antes y después del programa, midiendo la velocidad, la aceleración y la fuerza del tiro. El entrenamiento con pesas libres incluyó ejercicios con mancuernas y barras, mientras que el entrenamiento con peso corporal incluyó sentadillas, flexiones y planchas. Las sesiones se realizaron dos veces por semana, con un progreso gradual en el número de series y repeticiones. Los análisis estadísticos se realizaron utilizando el software GraphPad Prism, con una significancia establecida en p < 0,05. La distribución de los datos se probó utilizando la prueba de Shapiro-Wilk, y las comparaciones entre las evaluaciones previas y posteriores a la intervención se realizaron con pruebas t pareadas. Los resultados mostraron mejoras significativas en la velocidad, la aceleración y la fuerza del tiro en el grupo de entrenamiento con pesas libres, mientras que el grupo de entrenamiento con peso corporal no mostró cambios significativos. Se concluyó que el entrenamiento con pesas libres es más eficaz para mejorar la fuerza de tiro en jugadores de hockey sobre patines.

In recent years, the EnodePro® device has been one of the most frequently used velocity sensors to track the bar velocity in resistance training, with the aim of providing load–velocity profiles. However, recent articles highlight a lack of reliability and validity in the estimated maximal strength, which can cause a serious health risk due to the overestimation of the bar velocity. With this study, we aimed to investigate whether imprecision in the measurement could explain the variance in this measurement error. Methods: The research question was evaluated by comparing the integrated velocities from the EnodePro® with the velocities from a high-resolution displacement sensor for the squat and bench press. The velocity was measured with loads corresponding to 30%, 50%, and 70% of the one-repetition maximum (1RM) in moderately trained participants (n = 53, f = 16, m = 37). Intraclass correlation coefficients (ICC) for agreement were supplemented by an exploration of the systematic bias and the random error (mean absolute error (MAE), mean absolute percentage error (MAPE)). Results: The results indicated movement specificity, with the ICC values for the squat ranging from 0.204 to 0.991 and with ICC = 0.678–0.991 for the bench press. Systematically higher velocities were reported by the EnodePro® sensor (p < 0.001–0.176), with an MAE = 0.036–0.198 m/s, which corresponds to an MAPE of 4.09–42.15%. Discussion: The EnodePro® seems to provide overly high velocities, which could result in the previously reported overestimation of the 1RM. Despite the validity problems of force/load–velocity profiles, we suggest evaluating the bar velocity with accurate measurement devices, which is, contrary to previous reports, not the case with the EnodePro®.

Determining how energy flows through ecosystems reveals underlying ecological patterns that drive processes such as growth and food web dynamics. Models that assess the transfer of energy from producers to consumers require information on the energy content or energy density (ED) of prey species. ED is most accurately measured through bomb calorimetry, but this method suffers from limitations of cost, time, and sample requirements that often make it unrealistic for many studies. Percent dry weight (DW) is typically used as a proxy for ED, but this measure includes an indigestible portion (e.g., bones, shell, salt) that can vary widely among organisms. Further, several distinct models exist for various taxonomic groups, yet none can accurately estimate invertebrate, vertebrate and plant ED with a single equation. Here, we present a novel method to estimate the ED of organisms using percent ash‐free dry weight (AFDW). Using data obtained from 11 studies diverse in geographic, temporal and taxonomic scope, AFDW, DW as well as percent protein and percent lipid were compared as predictors of ED. Linear models were produced on a logarithmic scale, including dummy variables for broad taxonomic groups. AFDW was the superior predictor of ED compared to DW, percent protein content and percent lipid content. Model selection revealed that using correction factors (dummy variables) for aquatic animals (AA) and terrestrial invertebrates (TI) produced the best‐supported model—log10(ED) = 1.07*log10(AFDW) − 0.80 (R2 = 0.978, p < .00001)—with an intercept adjustment of 0.09 and 0.04 for AA and TI, respectively. All models including AFDW as a predictor had high predictive power (R2 > 0.97), suggesting that AFDW can be used with high degrees of certainty to predict the ED of taxonomically diverse organisms. Our AFDW model will allow ED to be determined with minimal cost and time requirements and excludes ash‐weight from estimates of digestible mass. Its ease of use will allow for ED to be more readily and accurately determined for diverse taxa across different ecosystems. Determining how energy flows through ecosystems reveals underlying ecological patterns that drive processes such as growth and food web dynamics. Models that assess the transfer of energy from producers to consumers require information on the energy density (ED) of prey species, however, measuring this value carries limitations of cost, time, and sample requirements. Here, we present a novel method to accurately estimate the ED of invertebrates, vertebrates, and plants using a single equation, with minimal cost and time requirements using percent ash‐free dry weight.

Background: This study compared the muscle activity and six repetition maximum (6-RM) loads in bench press with narrow, medium, and wide grip widths with sub-group comparisons of resistance-trained (RT) and novice-trained (NT) men. Methods: After two familiarization sessions, twenty-eight subjects lifted their 6-RM loads with the different grip widths with measurement of electromyographic activity. Results: Biceps brachii activity increased with increasing grip width, whereas wide grip displayed lower triceps brachii activation than medium and narrow. In the anterior deltoid, greater activity was observed using a medium compared to narrow grip. Similar muscle activities were observed between the grip widths for the other muscles. For the RT group, greater biceps brachii activity with increasing grip width was observed, but only greater activity was observed in the NT group between narrow and wide. Comparing wide and medium grip width, the RT group showed lower triceps activation using a wide grip, whereas the NT group showed lower anterior deltoid activation using a narrow compared to medium grip. Both groups demonstrated lower 6-RM loads using a narrow grip compared to the other grips. Conclusion: Grip widths affect both 6-RM loads and triceps brachii, biceps brachii, and anterior deltoid activity especially between wide and narrow grip widths.

The purpose of this study was to compare cardiac autonomic responses following bilateral and unilateral upper-body (UB) acute resistance exercise (ARE). In total, 14 individuals were assessed for markers of cardiac autonomic responses via heart rate variability (HRV) and baroreflex sensitivity (BRS) at rest and at 10- and 30-min following ARE. Logarithmically transformed (ln) HRV measures included: total power (ln TP), high-frequency power (ln HF power), low-frequency power (ln LF power), sympathovagal balance (ln LF: HF), and the square root of the mean squared differences of successive R-R intervals (ln RMSSD). BRS was assessed using the sequence method. Two-way repeated measures ANOVAs were used to analyze effects of UB ARE (bilateral, unilateral) across time (Rest, 10, and 30 min). There were no significant (p > 0.05) interactions. However, there were significant (p ≤ 0.05) main effects of time such that ln TP, ln HF power, ln RMSSD, and BRS decreased and did not recover within 30 min compared to Rest for both conditions. Collectively, this study suggests that bilateral and unilateral UB ARE yielded similar reductions, for at least 30 min, in respect to vagal measures of HRV and BRS.

The Fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith) invaded sub-Saharan Africa (SSA) in 2016 and has since become prevalent in many countries, causing significant maize grain yield losses and reduced grain quality. Breeding for host plant resistance to FAW requires improving multiple traits, complicating selection. This study evaluated the use of principal component (PC)-based multi-trait selection indices to identify FAW resistant maize genotypes. A total of 192 maize hybrids alongside four commercial hybrids, were evaluated over four seasons under artificial FAW infestation. Data on FAW leaf feeding damage (LD) at 7, 14, and 21 days after infestation, and ear damage (ED), ear rot (ER), and grain yield (GY) were recorded. The data were subjected to analysis of variance and PC analysis, and results used to construct two economic weight-free selection indices: PC1-based index (PC1BI) and PC2-based index (PC2BI). Broad-sense heritability estimates were 0.59 to 0.73 for LD, and 0.69 for GY. The two PCs explained 97.1% of the variation among the hybrids. PC1BI, with higher loadings for the leaf feeding damage traits, showed the larger desired gains for these traits (−2.92 to −3.84%) and GY (19.9%), making it a superior index to PC2BI. PC1BI identified six promising hybrids with GY above the cutoff of 7.0 t ha -1 for selection under FAW infestation. PC2BI exhibited larger gains for ED (−11.1%) and ER (−45.4%). The index-based selected hybrids consistently outperformed the commercial hybrid checks. The PC-based indices have the potential to serve as valuable tools for breeders to maximize selection gains; however, modifications are necessary to incorporate other desirable agronomic and adaptive traits.

Background While aerobic, resistance, and balance training are commonly used to counteract age-related declines in cognitive and physical functions, evidence for cognitive benefits of metabolic training (i.e., aerobic, resistance) remains inconsistent. In contrast, motor training (i.e., balance, coordination) involving higher task complexity may enhance cognition by engaging brain regions associated with cognitive control processes. Resistance training on unstable devices, also referred to as metastable resistance training (MRT), has been reported to increase metabolic, coordinative, and cognitive demands during exercise, as well as to improve cognitive performance in older adults. This study examined the effect of MRT on cognitive performance compared to traditionally recommended resistance training (T-RT) and balance training (BT). We hypothesized that MRT specifically improves cognitive task performance requiring perceptual processing and attention. Methods Eighty-three healthy older adults (mean age 70.5 ± 4.5 years) were matched into three groups which were randomly assigned to either MRT, BT or T-RT programs. Each group trained twice a week for 10 weeks. Cognitive functions were assessed using four tasks targeting working memory, inhibitory control, cognitive flexibility, and perceptual processing. Linear mixed-effects models were applied to examine the effect of MRT on cognitive performance in contrast to BT and T-RT. Results A significant time-by-group interaction was observed for inhibitory control when contrasting MRT with BT, t (80) = 3.56, p  < 0.001, β  = 0.42, 95% CI [0.19, 0.65], indicating improved response inhibition following MRT. Additionally, perceptual processing was significantly enhanced when comparing MRT with BT for both reaction time, t (79) = 2.35, p  = 0.020, β  = 0.19, 95% CI [0.03, 0.35], and accuracy, t (79) = -2.69, p  = 0.009, β = -0.26, 95% CI [-0.45, -0.07]. Conclusions In contrast to BT, MRT appears to selectively enhance cognitive functions requiring inhibitory control and perceptual processing in older adults. Consequently, metabolic demands associated with MRT may offer additional cognitive benefits beyond the coordinative demands offered by traditional balance training. Clinical trial number This trial, DRKS00030394, was registered in the German Clinical Trials Register on 16/08/2023.

Resistance exercise has been demonstrated to improve brain function. However, the optimal workout characteristics are a matter of debate. This randomized, controlled trial aimed to elucidate differences between free-weight (REfree) and machine-based (REmach) training with regard to their ability to acutely enhance cognitive performance (CP). A total of n = 46 healthy individuals (27 ± 4 years, 26 men) performed a 45-min bout of REfree (military press, barbell squat, bench press) or REmach (shoulder press, leg press, chest press). Pre- and post-intervention, CP was examined using the Stroop test, Trail Making Test and Digit Span test. Mann–Whitney U tests did not reveal between-group differences for performance in the Digit Span test, Trail Making test and the color and word conditions of the Stroop test (p > 0.05). However, REfree was superior to REmach in the Stroop color-word condition (+6.3%, p = 0.02, R = 0.35). Additionally, REfree elicited pre-post changes in all parameters except for the Digit Span test and the word condition of the Stroop test while REmach only improved cognitive performance in part A of the Trail Making test. Using free weights seems to be the more effective RE method to acutely improve cognitive function (i.e., inhibitory control). The mechanisms of this finding merit further investigation.