Frontiers in Physiology

Introduction Intrapleural injections of cholera toxin B conjugated to saporin (CTB-SAP) result in selective respiratory ( e.g. , phrenic) motor neuron death and mimics aspects of motor neuron disease [( e.g. , amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy (SMA)], such as breathing deficits. This rodent model allows us to study the impact motor neuron death has on the output of surviving phrenic motor neurons as well as the compensatory mechanisms that are recruited. Microglial density in the phrenic motor nucleus as well as cervical gene expression of markers associated with inflammation ( e.g ., tumor necrosis factor α; TNF-α) are increased following CTB-SAP-induced phrenic motor neuron death, and ketoprofen (nonsteroidal anti-inflammatory drug) delivery attenuated phrenic long-term facilitation (pLTF) in 7 day (d) CTB-SAP rats but enhanced pLTF in 28d CTB-SAP rats. Methods Here, we worked to determine the impact of TNF-α in the phrenic motor nucleus by: 1) quantifying TNFR1 (a high affinity transmembrane receptor for TNF-α) expression; 2) investigating astrocytes (glial cells known to release TNF-α) by performing a morphological analysis in the phrenic motor nucleus; and 3) determining whether acute TNFR1 inhibition differentially affects phrenic plasticity over the course of CTB-SAP-induced motor neuron loss by delivering an inhibitor for TNF-α receptor 1 (sTNFR1i) in 7d and 28d male CTB-SAP and control rats. Results Results revealed that TNFR1 expression was increased on phrenic motor neurons of 28d CTB-SAP rats ( p < 0.05), and that astrocytes were increased and exhibited reactive morphology (consistent with an activated phenotype; p < 0.05) in the phrenic motor nucleus of CTB-SAP rats. Additionally, we found that pLTF was attenuated in 7d CTB-SAP rats but enhanced in 28d CTB-SAP rats ( p < 0.05) following intrathecal sTNFR1i delivery. Conclusion This work suggests that we could harness TNFR1 as a potential therapeutic agent in CTB-SAP rats and patients with respiratory motor neuron disease by increasing compensatory plasticity in surviving neurons to improve phrenic motor neuron function and breathing as well as quality of life. Future studies will focus on microglial and astrocytic cytokine release, the role they play in the differential mechanisms of pLTF utilized by 7d and 28d CTB-SAP rats, and potential therapies that target them.

Introduction Research on the effects of training programs involving small-sided games (SSG) versus high-intensity interval training (HIIT) has been increasing in recent years. However, there is limited understanding of how an individual's initial physical fitness level might influence the extent of adaptations achieved through these programs. This study aimed to compare the impacts of SSG and HIIT on male soccer players, while also considering the players' athleticism, categorized into lower and higher total athleticism score (TSA). Methods A prospective cohort study was conducted over a 6-week pre-season training period, involving 43 male soccer players from regional-level teams (average age 16.5 ± 0.7 years). Players were evaluated at the start and after the 6-week period. One team incorporated SSG as a core component of their aerobic-based training, while the other team used HIIT. Evaluations included a countermovement jump (CMJ) test, a 30-meter linear sprint test, and the 30–15 intermittent fitness test (30–15 IFT). TSA was calculated to assess each player's overall athleticism level (classifying them as fit and non-fit). Results Results revealed that non-fit players showed significantly greater CMJ improvements (mean difference: 3.0 cm; p < 0.005) and VIFT improvements (mean difference: 0.682 km/h; p = 0.002) in SSG compared to fit players. In the HIIT group, non-fit players also revealed greater improvements than fit players in CMJ (mean difference: 2.5 cm; p < 0.005) and peak speed in sprint (mean difference: 0.706 km/h; p = 0.002). No significant differences were found between groups regarding the observed improvements. Discussion In conclusion, this study suggests that the initial level of physical fitness significantly influences the magnitude of adaptations. Specifically, players with lower fitness levels appear to benefit more from training interventions. Improvements in CMJ and aerobic capacity in SSG seem to depend on players’ fitness levels, and a similar trend is observed in HIIT for CMJ and peak speed. Individualizing training programs is recommended, with a focus on providing greater or different stimuli to more well-prepared players to ensure their continued development.

Objective Extracting deep features from participants’ bioelectric signals and constructing models are key research directions in motor imagery (MI) classification tasks. In this study, we constructed a multimodal multitask hybrid brain-computer interface net (2M-hBCINet) based on deep features of electroencephalogram (EEG) and electromyography (EMG) to effectively accomplish motor imagery classification tasks. Methods The model first used a variational autoencoder (VAE) network for unsupervised learning of EEG and EMG signals to extract their deep features, and subsequently applied the channel attention mechanism (CAM) to select these deep features and highlight the advantageous features and minimize the disadvantageous ones. Moreover, in this study, multitask learning (MTL) was applied to train the 2M-hBCINet model, incorporating the primary task that is the MI classification task, and auxiliary tasks including EEG reconstruction task, EMG reconstruction task, and a feature metric learning task, each with distinct loss functions to enhance the performance of each task. Finally, we designed module ablation experiments, multitask learning comparison experiments, multi-frequency band comparison experiments, and muscle fatigue experiments. Using leave-one-out cross-validation(LOOCV), the accuracy and effectiveness of each module of the 2M-hBCINet model were validated using the self-made MI-EEMG dataset and the public datasets WAY-EEG-GAL and ESEMIT. Results The results indicated that compared to comparative models, the 2M-hBCINet model demonstrated good performance and achieved the best results across different frequency bands and under muscle fatigue conditions. Conclusion The 2M-hBCINet model constructed based on EMG and EEG data innovatively in this study demonstrated excellent performance and strong generalization in the MI classification task. As an excellent end-to-end model, 2M-hBCINet can be generalized to be used in EEG-related fields such as anomaly detection and emotion analysis.

Melatonin, a pleiotropic hormone plays a vital role in enhancing livestock performance not only by regulating circadian rhythms but also by exhibiting antioxidant, immunomodulatory, and metabolic regulatory effects that collectively improve resilience, fertility, and productivity. Melatonin’s synthesis is predominantly influenced by light exposure, with increased production in darkness; however, factors such as diet and health status further modulate its levels. By helping animals adapt to environmental stressors, melatonin boosts immune responses, mitigates chronic illnesses, and optimizes production efficiency. Its regulatory influence extends to the hypothalamic-pituitary-gonadal (HPG) axis, enhancing hormone secretion, synchronizing estrous cycles, and improving embryo viability. This results in improved reproductive outcomes through the protection of gametes, increased sperm motility, and enhanced oocyte quality, all of which benefit the fertilization process. Additionally, melatonin positively impacts productive performance, promoting muscle growth, development, and optimizing milk yield and composition through its interaction with metabolic and endocrine systems. As ongoing research continues to uncover its broader physiological effects, melatonin supplementation emerges as a promising approach to improving livestock welfare, productivity, and sustainability in modern animal husbandry.

Background This study aimed to determine the associations between different intensities of moderate to vigorous physical activity (MVPA) and the incidence of chronic diseases, and to assess the risk levels associated with these activities over time. Methods A prospective cohort study (UK Biobank Activity Project) with data collected between June 2013 and December 2015 included 59,896 adults (mean age = 59.68; male = 38.03%) free from chronic diseases. Participants were categorized into tertiles based on their weekly MVPA: lowest (<224 min for males, <143 min for females), medium (224–444 min for males, 143–308 min for females), and highest (≥444 min for males, ≥308 min for females), stratified by gender. The mean onset of chronic disease symptoms occurred at 3.57 years, with participants followed up during this period. Wearable accelerometry data were used to quantify MVPA levels. Findings Lowest tertile of MVPA were significantly correlated with increased risks of chronic disease (24%–110% increased risk) based on odds ratios (ORs), with dose-response relationship observed. In males with the lowest tertile of MVPA, significant associations were identified with type 2 diabetes mellitus (T2DM) (OR = 1.90; CI: 1.44–2.51), neurodegenerative disease (OR = 1.80; CI: 1.19–2.71), metabolic syndrome (OR = 1.34; CI: 1.18–1.53), hypertension (OR = 1.27; CI: 1.12–1.44), and atherosclerotic cardiovascular disease (ASCVD) (OR = 1.24; CI: 1.03–1.49). In females, the lowest tertile of MVPA levels were associated with increased risks of neurodegenerative disease (OR = 2.10; CI: 1.36–3.24), T2DM (OR = 1.88; CI: 1.37–2.58), cerebrovascular disease (OR = 1.61; CI: 1.12–2.29), ASCVD (OR = 1.58; CI: 1.23–2.03), metabolic syndrome (OR = 1.49; CI: 1.32–1.69), and hypertension (OR = 1.44; CI: 1.29–1.61). Longitudinally, the lowest tertile of MVPA in males showed elevated risks for neurodegenerative disease (HR = 2.13; CI: 1.24–3.66), T2DM (HR = 1.83; CI: 1.30–2.57), hypertension (HR = 1.33; CI: 1.15–1.53), metabolic syndrome (HR = 1.32; CI: 1.14–1.54), and ASCVD (HR = 1.29; CI: 1.03–1.61). In females, the lowest tertile of MVPA was associated with similar risks for ASCVD (HR = 1.59; CI: 1.16–2.20), T2DM (HR = 1.57; CI: 1.08–2.29), hypertension (HR = 1.53; CI: 1.34–1.74), and metabolic syndrome (HR = 1.50; CI: 1.29–1.73). Conclusion Using wearable accelerometry data, this study demonstrated the quantifiable risks of chronic diseases and their development, highlighting the importance of MVPA.

Introduction Intracellular Ca ²⁺ signalling regulates membrane permeabilities, enzyme activity, and gene transcription amongst other functions. Large transmembrane Ca ²⁺ electrochemical gradients and low diffusibility between cell compartments potentially generate short-lived, localised, high-[Ca ²⁺ ] microdomains. The highest concentration domains likely form between closely apposed membranes, as at amphibian skeletal muscle transverse tubule–sarcoplasmic reticular (T-SR, triad) junctions. Materials and methods Finite element computational analysis characterised the formation and steady state and kinetic properties of the Ca ²⁺ microdomains using established empirical physiological and anatomical values. It progressively incorporated Fick diffusion and Nernst–Planck electrodiffusion gradients, K ⁺ , Cl ⁻ , and Donnan protein, and calmodulin (CaM)-mediated Ca ²⁺ buffering. It solved for temporal–spatial patterns of free and buffered Ca ²⁺ , Gaussian charge differences, and membrane potential changes, following Ca ²⁺ release into the T-SR junction. Results Computational runs using established low and high Ca ²⁺ diffusibility ( D Ca2+ ) limits both showed that voltages arising from intracytosolic total [Ca ²⁺ ] gradients and the counterions little affected microdomain formation, although elevated D Ca2+ reduced attained [Ca ²⁺ ] and facilitated its kinetics. Contrastingly, adopting known cytosolic CaM concentrations and CaM-Ca ²⁺ affinities markedly increased steady-state free ([Ca ²⁺ ] free ) and total ([Ca ²⁺ ]), albeit slowing microdomain formation, all to extents reduced by high D Ca2+ . However, both low and high D Ca2+ yielded predictions of similar, physiologically effective, [Ca ²⁺ -CaM]. This Ca ²⁺ trapping by the relatively immobile CaM particularly increased [Ca ²⁺ ] at the junction centre. [Ca ²⁺ ] free , [Ca ²⁺ -CaM], [Ca ²⁺ ], and microdomain kinetics all depended on both CaM-Ca ²⁺ affinity and D Ca2+. These changes accompanied only small Gaussian (∼6 mV) and surface charge (∼1 mV) effects on tubular transmembrane potential at either D Ca2+ . Conclusion These physical predictions of T-SR Ca ²⁺ microdomain formation and properties are compatible with the microdomain roles in Ca ²⁺ and Ca ²⁺ -CaM-mediated signalling but limited the effects on tubular transmembrane potentials. CaM emerges as a potential major regulator of both the kinetics and the extent of microdomain formation. These possible cellular Ca ²⁺ signalling roles are discussed in relation to possible feedback modulation processes sensitive to the μM domain but not nM bulk cytosolic, [Ca ²⁺ ] free , and [Ca ²⁺ -CaM], including ryanodine receptor-mediated SR Ca ²⁺ release; Na ⁺ , K ⁺ , and Cl ⁻ channel-mediated membrane excitation and stabilisation; and Na ⁺ /Ca ²⁺ exchange transport.

This study addresses the limitations of traditional sports rehabilitation, emphasizing the need for improved accuracy and response speed in real-time action detection and recognition in complex rehabilitation scenarios. We propose the STA-C3DL model, a deep learning framework that integrates 3D Convolutional Neural Networks (C3D), Long Short-Term Memory (LSTM) networks, and spatiotemporal attention mechanisms to capture nuanced action dynamics more precisely. Experimental results on multiple datasets, including NTU RGB + D, Smarthome Rehabilitation, UCF101, and HMDB51, show that the STA-C3DL model significantly outperforms existing methods, achieving up to 96.42% accuracy and an F1 score of 95.83% on UCF101, with robust performance across other datasets. The model demonstrates particular strength in handling real-time feedback requirements, highlighting its practical application in enhancing rehabilitation processes. This work provides a powerful, accurate tool for action recognition, advancing the application of deep learning in rehabilitation therapy and offering valuable support to therapists and researchers. Future research will focus on expanding the model’s adaptability to unconventional and extreme actions, as well as its integration into a wider range of rehabilitation settings to further support individualized patient recovery.

Background The relationship between conduction system pacing (CSP) and the incidence of atrial fibrillation (AF) in patients with heart failure and preserved ejection fraction (HFpEF) remains uncertain. This study aims to investigate the occurrence of atrial high-rate episodes (AHREs) following CSP in patients with HFpEF, in comparison to right ventricular pacing (RVP). Methods Patients with HFpEF who received dual-chamber pacemakers for atrioventricular block were retrospectively enrolled from January 2018 to January 2023. Both new-onset and progressive AHREs were recorded, along with other clinical data, including cardiac performance and lead outcomes. Results A total of 498 patients were enrolled, comprising 387 patients with RVP and 111 patients with CSP, with a follow-up duration of 44.42 ± 10.41 months. In patients without a prior history of AF, CSP was associated with a significantly lower incidence of new-onset AHREs when the percentage of ventricular pacing was ≥20% (9.52% vs. 29.70%, P = 0.001). After adjusting for confounding factors, CSP exhibited a lower hazard ratio for new-onset AHREs compared to RVP (HR 0.336; [95% CI: 0.142–0.795]; P = 0.013), alongside left atrial diameter (LAD) (HR 1.109; [95% CI: 1.048–1.173]; P < 0.001). In patients with a history of AF, the progression of AHREs in CSP and RVP did not differ significantly (32.35% vs. 34.75%, P = 0.791). Cardiac performance metrics, including left ventricular end-diastolic diameter (LVEDD) (49.09 ± 4.28 mm vs. 48.08 ± 4.72 mm; P = 0.015), LAD (40.68 ± 5.49 mm vs. 39.47 ± 5.24 mm; P = 0.001), and NYHA class (2.31 ± 0.46 vs. 1.59 ± 0.73; P < 0.001), improved obviously following CSP, while LVEDD (48.37 ± 4.57 mm vs. 49.30 ± 5.32 mm; P < 0.001), LAD (39.77 ± 4.58 mm vs. 40.83 ± 4.80 mm; P < 0.001), NYHA class (2.24 ± 0.43 vs. 2.35 ± 0.83; P = 0.018), and left ventricular ejection fraction (LVEF) (57.41 ± 2.42 vs. 54.24 ± 6.65; P < 0.001) deteriorated after RVP. Conclusion Our findings suggest that CSP may be associated with improvements in cardiac performance and a reduction in new-onset AHREs compared to RVP in patients with HFpEF. However, prospective randomized trials are anticipated to confirm these potential benefits.

Red blood cells (RBCs) play a role in the regulation of vascular tone via release of adenosine triphosphate (ATP) into the vasculature in response to various stimuli. Interestingly, ApoE/LDLR double-deficient (ApoE/LDLR −/− ) mice, a murine model of atherosclerosis, display a higher exercise capacity compared to the age-matched controls. However, it is not known whether increased exercise capacity in ApoE/LDLR −/− mice is linked to the altered ATP release from RBCs. In this work, we characterized the ATP release feature of RBCs from ApoE/LDLR −/− mice by exposing them to various stimuli in vitro . The results are linked to the previously reported mechanical and biochemical alterations in RBCs. 3V-induced ATP release from RBCs was at comparable levels for all groups, which indicated that the activity of adenylyl cyclase and the components of upstream signal-transduction pathway were intact. Moreover, hypoxia- and low pH-induced ATP release from RBCs was higher in ApoE/LDLR −/− mice compared to their age-matched controls, a potential contributing factor and a finding in line with the higher exercise capacity. Taken together, augmented hypoxia-induced ATP release from RBCs in ApoE/LDLR −/− mice indicates a possible deterioration in the ATP release pathway. This supports our previous reports on the role of the protein structure alterations of RBC cytosol in hypoxia-induced ATP release from RBCs in ApoE/LDLR −/− mice. Thus, we emphasize that the presented herein results are the first step to future pharmacological modification of pathologically impaired microcirculation.

Introduction This study aims to investigate the differences in functional movements and core muscle activities between experienced and novice practitioners during Pilates exercises. Methods Thirty-eight participants were recruited for the study, comprising 19 experienced and 19 novice Pilates practitioners. Participants performed functional movement screening (FMS) tests and six Pilates exercises at the basic, intermediate, and advanced levels. Surface electromyography (EMG) was utilized to measure muscle activity at four sites: right rectus abdominis (RA), external oblique (EO), multifidus (MU), and longissimus (LO). Mean EMG activity, co-contraction indices, and duration of core muscle activation were analyzed using independent t-tests to examine the differences between groups. Cohen’s d was used to calculate effect sizes based on the standard deviations of the groups. Statistical significance was set at p < 0.05. Results The experienced practitioners scored significantly higher in total FMS scores and in four sub-units of the FMS scores compared to the novice group (p ≤ 0.01). Mean EO EMG activity was also significantly greater in experienced practitioners during all Pilates exercises (p < 0.05). Additionally, the RA/EO co-contraction index was higher in experienced practitioners during the ‘double leg stretch’ exercise (p = 0.02). Conclusion The results suggest that experienced Pilates practitioners have superior functional movement abilities and greater core muscle activation, particularly in the EO muscle group, compared to novice practitioners. These findings may assist Pilates instructors in refining instructional strategies to cater to different skill levels and enhance training effectiveness.

Objectives Inertial training, also called flywheel training is more and more popular among sportsmen. The available data concerning the effectiveness of inertial training compared to conventional resistance strength training are contradictory. The aim of this study was to compare the impact of inertial training (IT) vs. traditional gravity-dependent resistance training (TRT) on elbow flexor and knee extensor strength. Methods Twenty-six young, recreationally active males were randomized into IT group (n = 13) or TRT group (n = 13). Both groups performed strength training three times a week for 6 weeks. Before and after training, the maximum force of the trained muscles was evaluated under training conditions (one repetition maximum under gravity-dependent conditions and maximal force under inertial conditions) and isometric conditions. Countermovement jump, squat jump, pull-up test, and limb circumference were also evaluated. Results Elbow flexor muscle strength and arm circumference increased significantly in both IT and TRT over the course of training. There were no significant differences in relative muscle strength increases between groups. Knee extensor muscle strength also improved significantly in IT, regardless of the tested conditions, while TRT showed significant changes in one repetition maximum and isometric force but no significant changes in force obtained under inertial conditions. Thigh circumference increased in IT (P ≤ 0.05) but was unchanged in TRT. Jumping abilities improved significantly in both groups, without any differences between groups. Conclusion We cannot confirm the superiority of inertial training over traditional resistance training definitively. Nevertheless, inertial training had a slight advantage over traditional resistance training when knee extensor muscle training was considered.

Objective This study compared the effects of Flywheel Resistance Squat Training (FRST) vs. Traditional Resistance Squat Training (TRST) on lower body strength in female collegiate basketball players. Methods Nineteen participants were randomly assigned to either the FRST group (n = 9) or the TRST group (n = 10) through a random number draw. Both groups underwent a 6-week intervention with training sessions conducted twice a week. The FRST group utilized an inertia of 0.075 kg ·m², while another group trained at 80% of their one-repetition maximum (1RM). Each training session consisted of 4 sets of 8 repetitions with a 3-minute rest between sets. Both groups performed standardized warm-ups and stretches before and after each training session. The effectiveness of the training methods was assessed through the Countermovement Jump (CMJ), Reactive Strength Index (RSI), Eccentric Utilization Ratio, Running Vertical Jump, and 1RM squat. Results The FRST and TRST groups showed differences within groups in both CMJ and 1RM squat (p < 0.01), with the FRST group demonstrating moderate effect sizes in CMJ (Hedges’ g = 0.59) and 1RM (Hedges’ g = 1.01). However, there were no differences between groups (p > 0.05). The Eccentric Utilization Ratio showed a small effect size (p = 0.78; η p 2 = 0.01 ). Additionally, Reactive Strength Index and Running Vertical Jump exhibited low test-retest reliability. Conclusion The two groups did not exhibit a statistically significant difference. Nonetheless, both FRST and TRST demonstrated positive effects on 1RM squat and CMJ performance compared to baseline values for each method. Therefore, flywheel resistance training can be considered an effective alternative to traditional resistance training for enhancing strength levels in female basketball players.

Contrast-induced acute kidney injury (CI-AKI) has emerged as a global public health concern, ranking as the third most prevalent cause of hospital-acquired acute kidney injury, which is related to adverse outcomes. However, its precise pathogenesis remains elusive. Consequently, researchers are dedicated to uncovering CI-AKI’s pathophysiology and signaling pathways, including inflammation, oxidative stress, apoptosis, and ferroptosis, to improve prevention and treatment. This review thoroughly analyzes the signaling pathways and their interactions associated with CI-AKI, assesses the impact of various research models on pathway analysis, and explores more precise targeted treatment and prevention approaches. Aims to furnish a robust theoretical foundation for the molecular mechanisms underpinning clinical treatments.

Introduction Women with hypertensive disorders of pregnancy such as HELLP (hemolysis, elevated liver enzyme, low platelet) Syndrome are affected by acute kidney injury during pregnancy (PR-AKI) at higher rates than women without hypertension. Both hypertensive disorders of pregnancy and Acute Kidney Injury (AKI) outside the context of pregnancy have been associated with an increased risk of developing Chronic Kidney Disease (CKD) and cognitive impairment. In our current study, we set out to determine if PR-AKI led to the development of CKD and impaired cognition in the postpartum period and if HELLP syndrome exacerbates the impairments. Methods Using timed-pregnant Sprague Dawley rats, on gestational day (GD) 12, mini-osmotic pumps infusing anti-angiogenic factors were surgically placed in the intraperitoneal cavity to induce HELLP. On GD18, AKI was induced via bilateral renal reperfusion ischemia surgery. Mean arterial pressure and birth outcomes were used to assess the global effects of AKI, and liver enzymes were used to assess HELLP. CKD was assessed by measuring glomerular filtration rate (GFR), urinary output, and renal fibrosis. Anxiety-like behaviors, object recognition memory, spatial memory, and avoidance memory were assessed via behavioral experiments. Results HELLP + AKI rats demonstrated more evidence of renal injury, hypertension, and behavioral deficits compared to normal pregnant animals. In addition, AKI had a negative impact on birth outcomes and maternal survival. Conclusion HELLP + AKI together led to evidence of persistent hypertension, progressive renal dysfunction, and cognitive impairment, which were exacerbated compared to AKI or HELLP alone. These findings suggest that PR-AKI in the presence of a hypertensive disorder of pregnancy, such as HELLP, leads to the development of CKD, cognitive dysfunction, and hypertension.

Aim Assessment of blood pressure during exercise is routine in athletes, but normal values remain equivocal. This study examines the response of systolic blood pressure (SBP) to exercise in a large cohort of athletes and establishes normative values by sex and age. Methods Competitive athletes free of cardiovascular disease underwent pre-participation exercise testing on a bicycle ergometer. Resting (SBPrest) and peak blood pressure (SBPpeak), heart rate (HRrest and HRpeak), and power output (WR) were recorded. Workload indexed values were calculated. Results The cohort included 12,083 athletes (median age 15 years, 26.9% female). Median peak exercise SBP was similar between sexes, but WR-indexed measures including SBP/WR ratio and SBP/(WR/kg) slope were higher in females (0.9 vs. 0.7, p < 0.001; 10.94 vs. 9.52, p < 0.001). Univariate analyses revealed significant associations between SBPpeak and several predictors, including sex, age, weight, height, SBPrest, DBPrest, HRrest, HRpeak, and WR (all p < .001). Multivariate analysis showed that SBPrest (beta = 0.353, 95% CI [0.541, 0.609], p < 0.001), height (beta = 0.303, 95% CI [0.360, 0.447], p < 0.001), WR (beta = 0.171, 95% CI [0.029, 0.045], p < 0.001), and age (beta = 0.093, 95% CI [0.162, 0.241], p < 0.001) were the strongest predictors of SBPpeak. Conclusion This study provides reference values for the interpretation of SBP responses to exercise in athletes. Multivariate analyses highlight the complex interplay of factors influencing peak SBP, including SBPrest, height, WR, age, DBPrest, sex, endurance sport category, and weight. In future studies, these findings may inform the development of personalised training strategies and risk stratification models in athletic populations.

Purpose This study examined the physiological effects of 12 weeks of detraining and retraining in a highly trained master triathlete (age 53.8 years). Methods Variables associated with swimming, cycling, and running performance, including V ˙ O2max, peak power output (PPO), gross cycling efficiency (CE), running maximal aerobic velocity (MAV), running economy (RE), muscle strength, and body composition were assessed before the last race of the season (baseline), after 12 weeks of detraining, and after 12 weeks of retraining. Results Detraining resulted in a 9.1% and 10.9% decrease in relative V ˙ O2max for cycling and running, respectively. PPO and MAV declined by 12.7% and 8.6%, respectively. After detraining, CE decreased by 6.2%, and RE was 22% higher than the baseline. The maximal strength capacity of the knee extensor muscles decreased by an average of 8.2%. Body fat percentage increased from 10.5% to 13.8%, while lean mass decreased by 2.2 kg. After retraining, almost all variables returned to baseline or even slightly increased, except RE and lean mass, which did not return to baseline. Conclusion After 12 weeks of detraining, a lifelong master triathlete can regain his cardiorespiratory fitness (i.e., V ˙ O2max) with 12 weeks of progressive and structured retraining, but his running economy and lean mass remain slightly depressed.

Objective: The purpose of this study was to compare the impact of unilateral (U) and bilateral (B) contrast training on lower limb explosiveness, agility, and balance in college basketball athletes. Methods: Twenty male college basketball players were randomly assigned to either a unilateral group (U, n = 10) or a bilateral group (B, n = 10). Both groups underwent an 8week strength training program, with sessions held twice a week. The unilateral group performed six Bulgarian split squats and ten reverse lunge jump squats, while the bilateral group performed six barbell rear squats and ten double-leg vertical jumps. To comprehensively assess the training effects, the study utilized one-repetition maximum (1RM), countermovement jump (CMJ), 20m sprint, and single-leg hop tests to evaluate explosive power; the 505 and t-test to assess change-of-direction ability; and the Y-balance test (YBT) to evaluate dynamic balance. Paired sample t-tests were used to evaluate within-group changes, and a 2 (pre- and post-) × 2 (experimental and control groups) repeated measures analysis of variance (ANOVA) was used to assess between-group differences. Results: Within-group comparisons indicated that both unilateral and bilateral contrast training significantly improved all performance metrics. Between-group comparisons revealed that bilateral training was superior to unilateral training in improvements in 1RM and CMJ (p > 0.05) (growth rate of 1RM: B: 8.4%, U: 5.15%; growth rate of CMJ: B: 15.63%, U: 6.74%). Unilateral training showed greater improvements in the 20m sprint, dominant leg single-leg hop, YBT left, and YBT right (p > 0.05) (growth rate of 20m sprint: B: 5.43%, U: 10.41%; growth rate of advantage foot touch high: B: 4.56%, U: 9.35%; growth rate of YBT left: B: 3.77%, U: 8.53%; growth rate of YBT right: B: 4.72%, U: 13.8%). Unilateral training also significantly outperformed bilateral training in non-dominant leg single-leg hop, t-test, 505 left, and 505 right improvements (p < 0.05). Conclusion: Unilateral contrast training may offer advantages for enhancing change-of-direction ability and explosive power in the non-dominant leg, and it may also provide benefits for improving short-distance sprinting ability, explosive power in the dominant leg, and dynamic balance. In contrast, bilateral contrast training appears to be more effective for enhancing bilateral explosive power and may be more advantageous for increasing maximal strength.

The lateral habenula (LHb) has been implicated in stress coping and autonomic control. The LHb regulates the midbrain system of monoamine neurotransmitters such as dopamine, serotonin, and noradrenaline. However, how the LHb regulates autonomic cardiovascular control in stressful situations is unclear. In this study, we examined the participation of the midbrain dopaminergic system in the cardiovascular response elicited by activation of the LHb. We used urethane-anesthetized Wistar male rats. We performed electrical stimulation of the LHb to observe changes in heart rate and blood pressure. Stimulation of the LHb caused bradycardia and a pressor response. Application of a nonselective dopamine receptor antagonist attenuated both the heart rate and the blood pressure changes induced by the LHb. We also tested the effects of blockade of dopamine receptor subtypes in the LHb-induced cardiovascular responses. Application of selective dopamine D1/D5, D2/D3, or D4 receptor antagonists attenuated the LHb-induced pressor response but did not change the HR response. Furthermore, we examined the effect of inactivation of the ventral tegmental area (VTA) on the cardiovascular response induced by LHb stimulation. Inactivation of the VTA turned bradycardia into tachycardia caused by the LHb stimulation and attenuated the pressor response. Our results indicated that regulation of the dopaminergic system by the LHb mediates the generation of the autonomic cardiovascular response. Dopamine D1-like and D2-like receptors mediate the sympathoexcitation resulting from the activation of the LHb. The VTA is one of the dopaminergic origins related to the cardiovascular response originating from LHb activation.

Background The Sensory Organization Test condition 5 (SOT5) assesses an astronaut’s vestibular function pre-/post-spaceflight but has a ceiling effect and mainly evaluates standing balance, neglecting the challenges of walking during space missions. A Locomotor Sensory Organization Test (LSOT) has been developed, mirroring the SOT concept but tailored to assess vestibular function during walking. This study aims to advance current knowledge by examining changes in ground reaction force (GRF) during normal walking (LSOT1) and walking in LSOT5 (vision blocked and treadmill speed varied), both with and without mastoid vibrations. Methods Sixty healthy adults were recruited and divided into two groups: one with mastoid vibration and one without. GRF peaks and respective variabilities were analyzed in the vertical (V), anterior-posterior (AP), and medial-lateral (ML) directions during stance cycles. The effects of LSOTs and mastoid vibration on each dependent variable were assessed using Friedman’s two-way analysis of variance by ranks. Results The findings revealed that:1) Walking in LSOT5 increased the variabilities of GRFs regardless of the administration of mastoid vibration; 2) the application of mastoid vibration reduced the amplitude of GRF peaks; and 3) walking in LSOT5 while receiving mastoid vibration was the most challenging task compared to all other tasks in this study. Conclusion The results indicated that analyzing GRF can detect changes in the strategy of balance control across different sensory-conflicted conditions. The findings could be beneficial for assessing the vestibular function pre- and post-space missions and planning for future sensorimotor training programs aimed at enhancing astronauts’ abilities to navigate unpredictable sensory-conflicted conditions.

Introduction The wound healing in diabetes is hindered and prolonged due to long-term inflammation, oxidative stress damage, and angiogenesis disorders induced by high glucose status. The management of such difficult-to-treat wounds continues to pose a significant challenge in clinical treatment. Dietary nitrate, commonly found in greens such as beets and spinach, acts as a nutritional supplement and is metabolized in the body through the salivary nitrate-nitrite-NO pathway. This pathway plays a crucial role in various physiological functions, including enhancing blood flow and attenuating inflammation. Methods In this study, we established a diabetic rat wound model. Forty-eight rats were randomly divided into six groups (n = 8): the Con group, the Con + Nitrate group, the STZ group, the STZ + NaCl group, the STZ + rhEGF group, and the STZ + Nitrate group. Skin wound healing was assessed on the day of surgery and on postoperative days 3, 7, 10, and 14. Specimens were taken on days 7 and 14 post-surgery for relevant tests. Results We found that dietary nitrate could accelerate skin wound healing by promoting angiogenesis and increasing blood perfusion. Significantly, dietary nitrate also regulated glucose and lipid metabolism and exhibited anti-inflammatory and antioxidant properties. Discussion These findings provide a novel theoretical basis for managing wounds in diabetic individuals, indicating the broad potential of dietary nitrate in future clinical applications.

Introduction Cardiorespiratory fitness (CRF), as assessed by VO2peak, along with metabolic and cardiovascular health indices, represents the strongest predictors of survival. However, it remains unclear whether concurrent high-intensity interval training (HIIT) and resistance training (RT) can similarly enhance these health markers in patients with type-1 diabetes (T1D) or type-2 diabetes (T2D) compared to healthy individuals. Methods Adults with uncomplicated T1D or T2D and healthy normoglycemic controls matched for sex and age (HC1 and HC2) performed 3 training sessions/week of concurrent HIIT and RT for 12 weeks. Pre- and post-intervention assessments included: lipids and glycemic profile, body composition (dual-energy x-ray absorptiometry) and a cyclo-ergometric cardio-pulmonary exercise test. Results Training improved VO2peak, the ventilatory threshold (VT1), maximal workload, ventilation and O2pulse, similarly in T1D in HC1 without changes in body composition or glycemic profile. In patients with T2D, training improved insulin sensitivity (HOMA-IR), lean mass, VE/VCO2 slope, VT1 and maximal O2pulse, workload and VO2peak with reduction in fat mass and visceral adipose tissue (VAT) (all, p < 0.05). However, improvements in VO2peak and O2pulse were lower than in healthy controls (respectively, T2D: +9%, HC2: +18% and T2D: +6%, HC2: +19%, p < 0.05). Conclusions Both patients with T1D and T2D benefit from combined HIIT and RT by improving CRF with specific adaptations influenced by the presence and type of diabetes. While identical magnitude of achievements were observed in T1D and HC1, T2D patients exhibited lower VO2peak and maximal O2pulse improvements but associated with notable additional health benefits regarding insulin sensitivity, body composition, visceral adipose tissue and ventilatory efficiency.

Critical illness myopathy (CIM) detrimentally affects muscle function in ICU patients, with a dramatic loss of muscle mass and function where the loss in specific force exceeds the loss in muscle mass (maximum force normalized to muscle cross-sectional area). The preferential loss of the molecular motor protein myosin, representing the hallmark of CIM, exhibiting a significant negative impact on the specific force generation by the muscle. Interestingly however, the preferential myosin loss is a relatively late event, and a specific loss in force generation capacity, is observed prior to the myosin loss. In the current study, employing an optimized cadmium telluride quantum dots (QD) mediated-thermometry approach to assess the efficiency of the myosin, we were able to determine the loss in specific force generated by the muscle, prior to the preferential loss of myosin. Reduction in QD fluorescent intensity correlates with greater heat loss, reflecting inefficient myosin function (less mechanical work performed and more heat loss on ATP hydrolysis by myosin). A significant decrease in myosin efficiency was observed in rats subjected to the ICU condition (immobilization and mechanical ventilation) for 5 days using an established experimental ICU model not limited by early mortality. Thus, qualitative myosin changes preceding quantitative myosin loss offer a mechanism underlying the early loss in specific force generation capacity associated with CIM and opens a venue for future CIM intervention strategies.

Insect cytochrome P450 monooxygenases (CYPs) play crucial roles in the metabolic detoxification of insecticides. Ethyl formate and benzothiazole have recently regained popularity as fumigants due to rising resistance to phosphine in the stored-product pests. However, the mechanisms underlying tolerance to these two fumigants in Lasioderma serricorne, a major global insect pest of stored products, remain poorly understood. In this study, two CYP genes, named CYP6SZ3 and CYP6AEL1, were identified from L. serricorne, belonging to the CYP6 family and containing five conserved domains characteristic of CYP proteins. Spatiotemporal expression analysis revealed that both genes were predominantly expressed in the larval stage and showed the highest expression in the foregut. Upon exposure to ethyl formate and benzothiazole, both genes were upregulated, with significantly increased transcription levels following treatment. RNA interference-mediated silencing of CYP6SZ3 and CYP6AEL1 led to increased susceptibility and significantly higher mortality of L. serricorne when exposed to these fumigants. Homology modeling and molecular docking analyses showed stable binding of these fumigants to CYP6SZ3 and CYP6AEL1 proteins, with binding free energies from −26.88 to −94.68 kcal mol⁻¹. These findings suggest that the induction of CYP6SZ3 and CYP6AEL1 is likely involved in the detoxification of ethyl formate and benzothiazole in L. serricorne.

Repetitive variations, such as oscillation, are ubiquitous in biology. In this mini review, we present a general summary of the ∼24 h circadian clock and provide a fundamental overview of another biological timekeeper that maintains ∼12 h oscillations. This ∼12 h oscillator is proposed to function independently of the circadian clock to regulate ultradian biological rhythms relevant to both protein homeostasis and liver health. Recent studies exploring these ∼12 h rhythms in humans are discussed, followed by our proposal that mammary gland physiology represents a promising area for further research. We conclude by highlighting potential translational applications in ∼12 h ultradian chronobiology.