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. Physical exercise performed at different intensities promotes distinct physiological responses during both activity and recovery process 1,2. High-intensity and short-volume efforts are widely used in the sports context and have also been extensively adopted in non-athlete training programs, such as high-intensity interval training (HIIT) and sprint interval training 3,4. In the same way, high-intensity tethered exercises (including resisted sled sprinting) performed maximally have been applied to improve physical and athletic performances 5,6. Despite that, there is a lack of knowledge about the mechanical and physiological kinetics during all-out tethered exercise and recovery. This gap can compromise the training load interpretation when this type of effort is adopted. Training load is described as external and internal, depending on which measurements of the athlete/participant are assessed 7. External load is defined as the amount and quality of work performed (e.g. distance covered, velocity and exercise power). On the other hand, the internal load indicates the physiological and psychophysiological responses of the organism to the effort imposed from the external load. However, internal-load indicators, especially during exercise, and the integration of external and internal loads need to be improved 7. Most exercise and recovery studies investigate systemic responses to the observed internal load, such as heart rate and blood lactat...

This study aimed to investigate and compare the effects of preferred music on anaerobic threshold determination in an incremental running test, as well the physiological responses and perceived exertion at this intensity, in physically active men and women. Additionally, by using area under the curve (AUC) analysis of the parameters of interest during the graded test, we studied the effects of music at two physiological moments—before and after anaerobic threshold intensity (iAT)—in men and women. Twenty (men = 10; women = 10) healthy and active participants completed four visits to the laboratory. The first and second sessions were used for sample characterization. In the third and fourth sessions, participants performed an incremental running test (started at 7 km.h -1 with increments of 1 km.h -1 at each 3-minute stage) under preferred music and non-music conditions. Blood lactate ([Lac]), heart rate (HR), and perceived exertion were measured by two scales (RPE Borg and the estimation of time limit ‒ ETL) during all tests, and the total time of effort (TT) was considered as performance. Individual curves of the “ intensity vs blood lactate ” analyzed by the bissegmentation method provide the iAT and the AUC of [Lac], HR, RPE Borg , and ETL before and after the iAT attainment were calculated. The iAT for men (non-music: 11.5±0.9km.h -1 vs music: 11.6±1.1km.h -1 ) and women (non-music: 9.8±0.7km.h -1 vs music: 9.7±0.7km.h -1 ) was not affected by music, and for both sexes, there was no difference between non-music and music conditions in all variables obtained at iAT. The AUC of all variables were not affected by music before the iAT attainment. However, [Lac], HR, and RPE Borg presented higher values of AUC after iAT for the female group with preferred music. This may be due to the fact that 70% of women have increased TT under music conditions. Overall, preferred music did not affect the iAT determination in an incremental running test. However, some physiological responses and perceived exertion after iAT of female subjects seems to be influenced by preferred music.

This study aimed to investigate the relationship between mechanical parameters from the Running-based Anaerobic Sprint Test (RAST2×17.5), agility performance from the Illinois Agility Test (IAT) and all-out 30-second tethered running (AO30) in college futsal athletes. It also investigates whether these protocols are capable of identifying differences between sexes. Twenty subjects were evaluated. The IAT was applied on a specific course and performance was considered as the total time (T.T). The RAST2×17.5 consisted of six maximum efforts in a shuttle exercise of 2x17.5 m per bout. The AO30 was conducted under maximal effort on a non-motorized treadmill. Maximum, mean and minimum power were determined for RAST2×17.5 and AO30. Mean power from RAST2×17.5 was inversely and significantly correlated to T.T regardless of sex (male: r=–0.76; p=0.010; female: r=–0.89; p=0.010). A similar association was noticed for maximum power for females (r=–0.94; p=0.001). The AO30 maximum and mean power were significantly correlated with T.T (male: r=–0.67; p=0.031 and r=–0.66; p=0.035, respectively; female: r=–0.64; p=0.046 and r=0.66; p=0.035, respectively). Maximum power from RAST2×17.5 and AO30 were significantly correlated (male: r=0.68; p=0.030; female: r=0.72; p=0.019). Our results reinforce the adoption of field-based tests like RAST2×17.5 and IAT for futsal, since significant relationships among these parameters and AO30 results were obtained. Moreover, these protocols differentiated male and female athletes by mechanical and agility parameters, proving their application under specific field evaluation.

No abstract

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.

The authoring of parameterized exercises has been a useful activity both for teachers, who could take advantage of databases of parameterized exercises for preparing study materials, but also for students that learn by producing new problems. This has been verified during the realization of MSc dissertations written by High School teachers that, as students again, have written about the positive aspects of their experience in the production of parameterized exercises. Parameterized exercises can also be used in online systems as a secondary study tool for STEM students (such as SIACUA system [2]). With these goals in mind, we have been developing a package named MEGUA to handle databases of parameterized exercises in the SageMath platform for mathematics. During the use of this system we gathered several requests from users claiming a better system. In this paper we present a redefined tool as well as some first opinions on the new facilities. Originally, this package had the old SageMath Notebook [4] as a front-end which has been presented in ICERI 2013 [3]. A new version of this package has been developed for the new platform named "Sage Math Cloud" (SMC) running in a secure and centralized web platform creating, for each new project, a virtual Linux machine with shell command access. In online systems (or cloud), a supervisor could follow student work and help to solve their problems (at distance) since it can see the student work in progress (no need to send emails with attachments).

O objetivo do presente projeto foi ampliar a especificidade do protocolo do Teste de Lactato Mínimo (TLM) ao futsal. Foram avaliados salonistas jovens (entre 17 e 25 anos) saudáveis, ativos, de nível universitário. Quatorze salonistas (Homens n=7; Mulheres n=7) foram submetidos a quatro sessões de avaliação. Na primeira, os participantes realizaram avaliações de caracterização (antropometria, hematócrito, somatotipo). De forma randomizada, o TLM foi conduzido em três subsequentes sessões (intervalo de 24-48 horas). A nova proposta (TLM NP) foi conduzida em duplicata, considerando três distintas fases: 1) aplicação do Illinois Agility Test (IAT) como indutor a hiperlactacidemia; 2) recuperação passiva de 8 minutos; 3) protocolo incremental em exercício vai-e-vem com distâncias comumente percorridas em esforços de alta intensidade por atletas (i.e. 13 metros). Para validação do TLM NP, comparamos a adequação do TLM ao futsal, sendo esse similar a nova proposta, a exceção da indução a hiperlactacidemia induzida pelo Running Anaerobic Sprint Test e as distâncias no protocolo incremental (i.e. 20 metros). Intensidade de lactato mínimo (iLacMin) foi considerada para comparação entre os protocolos e análise de reprodutibilidade. Baseado nos resultados apresentados, concluímos que a proposta original e TLM NP aqui proposto revertem distintas iLacMin. Contudo, esse parâmetro apresenta reprodutibilidade e ecologicamente respeita de maneira mais apropriada as demandas do futsal.

Due to a technical error in the typesetting, the authors' affiliations were not named correctly. This has now been changed with this erratum.This document was downloaded for personal use only. Unauthorized distribution is strictly prohibited.