High-intensity exercises including tethered efforts are commonly used in training programs for athletes, active and even sedentary individuals. Despite this, the knowledge about the external and internal load during and after this effort is scarce. Our study aimed to characterize the kinetics of mechanical and physiological responses in all-out 30 seconds (AO30) tethered running and up to 18 minutes of passive recovery. Additionally, in an innovative way, we investigated the muscle oxygenation in more or less active muscles (vastus lateralis and biceps brachii, respectively) during and after high-intensity tethered running by near-infrared spectroscopy – NIRS. Twelve physically active young men were submitted to AO30 on a non-motorized treadmill to determine the running force, velocity and power. We used wearable technologies to monitor the muscle oxygenation and heart rate responses during rest, exercise and passive recovery. Blood lactate concentration and arterial oxygen saturation were also measured. In a synchronized analysis by high capture frequency of mechanical and physiological signals, we advance the understanding of AO30 tethered running. Muscle oxygenation responses showed rapid adjustments (both, during and after AO30) in a tissue-dependence manner, with very low tissue saturation index observed in biceps brachii during exercise when compared to vastus lateralis. Significant correlations between peak and mean blood lactate with biceps brachii oxygenation indicate an important participation of less active muscle during and after high-intensity AO30 tethered running.

Although several studies have focused on the adaptations provided by inspiratory muscle (IM) training on physical demands, the warm-up or pre-activation (PA) of these muscles alone appears to generate positive effects on physiological responses and performance. This study aimed to understand the effects of inspiratory muscle pre-activation (IM_PA) on high-intensity running and passive recovery, as applied to active subjects. In an original and innovative investigation of the impacts of IM_PA on high-intensity running, we proposed the identification of the interactions among physical characteristics, physiological responses and muscle oxygenation in more and less active muscle to a running exercise using a complex network model. For this, fifteen male subjects were submitted to all-out 30 s tethered running efforts preceded or not preceded by IM_PA, composed of 2 × 15 repetitions (1 min interval between them) at 40% of the maximum individual inspiratory pressure using a respiratory exercise device. During running and recovery, we monitored the physiological responses (heart rate, blood lactate, oxygen saturation) and muscle oxygenation (in vastus lateralis and biceps brachii) by wearable near-infrared spectroscopy (NIRS). Thus, we investigated four scenarios: two in the tethered running exercise (with or without IM_PA) and two built into the recovery process (after the all-out 30 s), under the same conditions. Undirected weighted graphs were constructed, and four centrality metrics were analyzed (Degree, Betweenness, Eigenvector, and Pagerank). The IM_PA (40% of the maximum inspiratory pressure) was effective in increasing the peak and mean relative running power, and the analysis of the complex networks advanced the interpretation of the effects of physiological adjustments related to the IM_PA on exercise and recovery. Centrality metrics highlighted the nodes related to muscle oxygenation responses (in more and less active muscles) as significant to all scenarios, and systemic physiological responses mediated this impact, especially after IM_PA application. Our results suggest that this respiratory strategy enhances exercise, recovery and the multidimensional approach to understanding the effects of physiological adjustments on these conditions.

The purpose of this study was to use traditional physical assessments combined with a metabolomic approach to compare the anthropometric, physical fitness level, and serum fasting metabolic profile among U22 soccer players at different competitive levels. In the experimental design, two teams of male U22 soccer were evaluated (non-elite = 20 athletes, competing in a regional division; elite = 16 athletes, competing in the first division of the national U22 youth league). Earlobe blood samples were collected, and metabolites were extracted after overnight fasting (12 h). Untargeted metabolomics through Liquid Chromatograph Mass Spectrometry (LC-MS) analysis and anthropometric evaluation were performed. Critical velocity was applied to determine aerobic (CV) and anaerobic (ARC) capacity. Height (non-elite = 174.4 ± 7.0 cm; elite = 176.5 ± 7.0 cm), body mass index (non-elite = 22.1 ± 2.4 kg/m²; elite = 21.9 ± 2.3 kg/m²), body mass (non-elite = 67.1 ± 8.8 kg; elite = 68.5 ± 10.1 kg), lean body mass (non-elite = 59.3 ± 7.1 kg; elite = 61.1 ± 7.9 kg), body fat (non-elite = 7.8 ± 2.4 kg; elite = 7.3 ± 2.4 kg), body fat percentage (non-elite = 11.4 ± 2.4%; elite = 10.5 ± 1.7%), hematocrit (non-elite = 50.2 ± 4.0%; elite = 51.0 ± 4.0%), CV (non-elite = 3.1 ± 0.4 m/s; elite = 3.0 ± 0.2 m/s), and ARC (non-elite = 129.6 ± 55.7 m; elite = 161.5 ± 61.0 m) showed no significant differences between the elite and non-elite teams, while the multivariate Partial Least Squares Discriminant Analysis (PLS-DA) model revealed a separation between the elite and non-elite athletes. Nineteen metabolites with importance for projection (VIP) >1.0 were annotated as belonging to the glycerolipid, sterol lipid, fatty acyl, flavonoid, and glycerophospholipid classes. Metabolites with a high relative abundance in the elite group were related in the literature to a better level of aerobic power, greater efficiency in the recovery process, and improvement of mood, immunity, decision making, and accuracy, in addition to acting in mitochondrial preservation and electron transport chain maintenance. In conclusion, although classical physical assessments were not able to distinguish the teams at different competitive levels, the metabolomics approach successfully indicated differences between the fasting metabolic profiles of elite and non-elite teams.

Introduction: Near-infrared spectroscopy (NIRS) offers valuable insights into exercise performance and enables the investigation of cerebral and muscular hemodynamic impairments associated with aging. This study aimed to examine cerebral and muscular hemodynamic adjustments during and after an aerobic exercise session in young adults and older adults. Methods: Twenty young adults and 20 older adults performed moderate-intensity aerobic exercise (60%–70% of maximum heart rate) on a treadmill for 10 min, followed by 15 min of passive recovery. NIRS devices continuously monitored oxyhemoglobin (O₂Hb) and deoxyhemoglobin (HHb) levels in the prefrontal cortex (PFC) and vastus lateralis (VL) and biceps brachii muscles (more and less active muscles, respectively). A 3-min seated baseline measurement was recorded before the exercise session. Changes in NIRS data were calculated by subtracting the values in each minute of exercise and recovery from baseline measurements. Results: In young adults, but not older adults, HHb in the VL muscle increased throughout the exercise. Additionally, after the first minute of exercise, young adults exhibited a continuous rise in PFC O₂Hb until the seventh minute, followed by stabilization; in contrast, older adults showed no significant change in PFC O₂Hb. During recovery, young adults demonstrated a decline in PFC O₂Hb after the second minute, persisting until the end of the recovery period. No significant adjustment was found in the muscular hemodynamics during the recovery period. Conclusion: Cerebral and muscular hemodynamic changes indicate that young adults exhibit greater adjustments to exercise demands than older adults. Aging appears to impair cortical and muscular oxygenation during aerobic exercise, which may negatively affect exercise performance. These findings enhance our understanding of age-related declines in muscle and cerebral oxygen delivery and utilization, potentially contributing to reduced exercise capacity in older adults.

O estudo investigou os efeitos da pré-ativação (PA) de músculos inspiratórios (MI) sobre as respostas perceptuais e afetivas, antes e após esforço all out (30s) de corrida atada em esteira não motorizada. Foram avaliados 10 homens ativos (22,3 ± 1,95 anos; %GC 7,24 ± 2,88), inicialmente submetidos à determinação da pressão inspiratória máxima (PImáx). Posteriormente, em quatro outras visitas ao laboratório, os participantes realizaram 30 segundos de corrida máxima em esteira não motorizada (AO30), em quatro diferentes condições aleatoriamente aplicadas: a) sem aquecimento de MI; b) com PA equivalente a 15% da PImáx, c) com PA de 40% da PImáx e d) com PA correspondente a 60% da PImáx. O protocolo de PA consistiu de 2 séries de 15 repetições, respirando com as restrições percentuais da PImáx em equipamento Powerbreathe K5, dois minutos antes da corrida. Antes, imediatamente após o teste e aos 20 minutos da recuperação passiva, os avaliados responderam às escalas de Percepção Subjetiva de Esforço, de Valência Afetiva e de Estados de Humor. As diferentes condições (com ou sem as PAs) não foram capazes de alterar a potência máxima de corrida no AO30, bem como as respostas perceptuais e de valência afetiva dos participantes, antes e após os esforços físicos de alta intensidade. Com relação ao estado de humor, observou-se respostas negativas apenas após as corridas, para as diferentes condições estudadas.

Repeated‐sprint ability is a key determinant of soccer performance. However, some mechanical and physiological responses underlying this task remain incompletely understood. This study characterized mechanical responses (force, velocity, and power) and regional muscle oxygen saturation (rSmO ₂ ) in the vastus lateralis (VL) and biceps brachii (BB) during field‐based tethered repeated‐sprint exercise (RSE). Associations between muscle oxygenation and mechanical performance, as well as post‐exercise rSmO ₂ , heart rate (HR), and blood lactate (LAC), were also examined. Ten professional soccer players performed a tethered Running Anaerobic Sprint Test (6 × 35‐m all‐out sprints separated by 10‐s intervals), while mechanical variables and rSmO ₂ were continuously recorded. Muscle oxygenation differed according to muscle function throughout exercise and recovery. The VL exhibited greater deoxygenation during sprints, whereas the BB showed a more preserved oxygenation profile. Associations between rSmO ₂ and mechanical performance were observed only during the fifth and sixth sprints. Furthermore, only VL integrated rSmO ₂ was positively correlated with the velocity fatigue index, whereas BB oxygenation provided complementary information on the physiological adjustments associated with RSE. Post‐exercise HR and LAC were not correlated with rSmO ₂ in both muscles. Simultaneous assessment of locomotor and non‐locomotor muscles provides complementary insights into fatigue development and post‐exercise recovery RSE.