Mauro Heleno Chagas

Federal University of Minas Gerais | UFMG · Departamento de Esportes

RESUMO Durante a sticking region (SR) a velocidade do movimento diminui devido a uma desvantagem mecânica, ocorrendo com mais frequência quando resistências máximas ou próximas do máximo são vencidas durante o exercício (Elliott et al., 1989). Nessas condições, o início da SR é determinado pelo primeiro pico de velocidade durante a fase concêntrica...

Objective: This study analyzed the activation of pectoralis major and triceps brachii muscles in strength tests in bench press after 10 weeks of training. Methods: Thirty-three untrained individuals were divided into two experimental and one-control groups. Protocols were matched by intensity (50-55% of one repetition maximum - 1RM), frequency (3 t...

The objective of the present review was to analyze the effects of the number of touches on the ball, in the physical and physiological responses during small soccer games. Electronic searches were carried out in the databases: “Web of Science”, “Scopus” and “PubMed”, using the descriptors “Small-sided games”; “Intensity”; “Touches”; “Soccer”; “Socc...

Introduction Effects on strength performance and muscle activation in the contralateral limb have been observed after training with the ipsilateral limb (IL). Cross fatigue effects in the contralateral limb (CL) can occur at intervals of up to 48 h after a training session performed with the ipsilateral limb. The objective of this study was to ver...

Background: Magnetic resonance imaging (MRI) is a well-used technique to assess muscle size and can be acquired on different planes. Pectoralis major (PM) and triceps brachii (TB) muscles are often acquired and analyzed on the axial plane, however it is unknown if anatomical cross-sectional area (CSA) calculated from different planes will affect t...

International Journal of Exercise Science 16(2): 1025-1037, 2023. Ischemic preconditioning (IPC) has been an excellent strategy for enhancing sports performance recovery, although there is still no consensus on the ideal protocol. Thus, this study aimed to evaluate the effects of IPC with different cuff pressures (low pressure, medium pressure, and...

Ischemic preconditioning (IPC) has been an excellent strategy for enhancing sports performance recovery, although there is still no consensus on the ideal protocol. Thus, this study aimed to evaluate the effects of IPC with different cuff pressures (low pressure, medium pressure, and high pressure) on the attenuation of neuromuscular fatigue after...

Background CrossFit is characterized by a diverse range of exercises recruiting different muscles and requiring different muscle functions. A characterization of muscular performance parameters in this population is needed. Purpose To determine reference values for various aspects of muscular performance of muscles of the trunk, thigh, hip, and ma...

Contextualização: A diferença na força entre os membros superiores de escaladores esportivos no Campus Board (CB) é investigada por meio do pico de força. Menzel (1) e colaboradores não identificaram diferenças significativas entre o pico de força médio de escaladores avaliados no CB entre o membro esquerdo (501,3±54,0N) e membro direito (510,5±61,...

Objective: The effects of ROM manipulation on muscle strength and hypertrophy response remain understudied in long-term interventions. Thus, we compared the changes in strength and regional muscle hypertrophy after training in protocols with different ranges of motion (ROM) in the seated dumbbell preacher curl exercise using a within-participant e...

The first aim was to investigate the impact of different EMG parameters as a reference to normalize the EMG amplitude of the superficial quadriceps femoris muscles across different sets of a knee extension exercise. The second aim is to examine the reliability between days of the EMG parameters used as a reference. Eleven young males attended the l...

Os testes funcionais de levantar-se e se sentar da cadeira de 30s (TLS30s) e o teste Timed Up and Go (TUG) são utilizados com objetivo de fornecer informações sobre o desempenho da força muscular de membros inferiores e a agilidade funcional em idosos, respectivamente. Embora ambos os testes tenham como objetivo avaliar diferentes aspectos da aptid...

This study aimed to compare the physiological demand between three vs. three small-sided games (SSGs) with (3vs.3WITH) and without (3vs.3WITHOUT) the offside rule, as well as the within and between-session reliability of this demand. Twenty-four U-17 soccer athletes performed various three vs. three (plus goalkeepers) SSGs with and without the offs...

This study followed a cross-sectional design and aimed to compare the offensive and defensive tactical-technical actions and the physical and physiological responses between four 3vs.3 basketball small-sided games (SSGs) played on the half-court: with regular rules (3vs.3REGULAR), with defensive pressure (3vs.3DEFPRESS), with the close-shot rule (3...

This study is aimed at evaluating the profile of inflammatory markers and components of redox regulation in untrained women after 10 weeks of resistance training using equalized protocols but different muscle action duration (MAD). Twenty-two women underwent progressive resistance training exercising the knee extensor muscles for 10 weeks—3x/week,...

Esta revisão de escopo objetivou verificar as respostas tático-técnica, física e fisiológica de atletas a pequenos jogos (PJ) de basquetebol. Utilizou-se o método Preferred Reporting Items for Systematic Reviews and Meta-Analyses – Extension for Scoping Reviews. Dois pesquisadores realizaram a busca eletrônica em seis bases de dados, em inglês, por...

The aim of the study was to compare the levels and relative responses of C-Reactive Protein (CRP) and Skin Temperature (Tsk) of the lower limbs (LLs) of professional soccer athletes following three consecutive games with short intervals (<4 days). Eleven male professional athletes (age, 29.26 ± 4.52 years) from an Brazil elite team were evaluated,...

This study aimed to systematically review the influence of the relative area on athletes' physical and physiological responses (outcomes) during small-sided games of soccer which were not matched to the relative area. It also presents a meta-analysis comparing standard small-sided games protocols with different relative areas. We searched the Web o...

Muscle volume (MV) and anatomical cross-sectional area (CSA) are used as measures of muscle-size, but determining these from magnetic resonance imaging (MRI) is a very time-consuming process. Additionally, it is unclear if the use of different muscle size assessments (all vs. reduced number of slices images) would impact the muscle size-strength re...

Purpose The present study aimed to compare the strength performance in the one-repetition maximum (1RM) test with a knee extension machine among different ranges of motion (ROMs), and to compare the force reduction after the performance of a dynamic exercise configured with different ROMs. Methods Nine women (mean ± standard deviation: age: 24.2 ±...

Small-sided games are used to improve tactical-technical and physical performances in team sports. This study compared the physical, physiological, and tactical-technical responses during 3 versus 3 basketball small-sided games performed in full and half-court: numerical equality (3 vs. 3), numerical superiority (4 vs. 3), and with a non-scorer flo...

The aim of this study was to determine whether the first sensation of stretching (ROMFSS) may predict the maximum range of motion (ROMMAX) in male (N = 37) and female (N = 32) volunteer subjects, and to assess the reliability of the ROM perceived by subjects in relation to a pre-determined ROM (ROM50%). Subjects attempted three experimental session...

The present study investigated the effect of 10-week matched (range of motion, volume, intensity, rest, and repetition duration) training protocols with varying muscle action duration (MAD) on maximal voluntary isometric contraction (MVIC) test at eight different knee angles and one-repetition maximum (1RM) test after in seated knee extensor machin...

The study compared changes in strength and regional muscle hypertrophy between different ranges of motion (ROM) in the knee extension exercise. Forty-five untrained women were randomized to either a control group or to perform the exercise in one of the following 4 groups (0°=extended knee): Full ROM (FULLROM: 100°-30° of knee flexion); Initial Par...

The aim of this study was to investigate the effects of 2 training protocols equalized by tension (TUT) on maximal strength (1 repetition maximum [RM]), regional cross-sectional areas (proximal, middle, and distal), and total cross-sectional areas (sum of the regional cross-sectional areas) of the pectoralis major and triceps brachii muscles. Thirt...

This study investigated the impact of 10 weeks performing two equalized resistance training (RT) protocols that differ only by repetition duration and number in the force-position and EMG-position relationship. Participants performed an equalized (36 s of time under tension; 3-4 sets; 3 min between sets; 50-55% of one-repetition maximum; 3x week) R...

Background. This study investigated the effects of two 14-week resistance training protocols with different repetition duration (RD) performed to muscle failure (MF) on gains in strength and muscle hypertrophy as well as on normalized electromyographic (EMG) amplitude and force-angle relationships. Methods. The left and right legs of ten untrained...

This study aimed to analyze the intersession reliability of global positioning system (GPS-based) distances and accelerometer-based (acceleration) variables in small-sided soccer games (SSG) with and without the offside rule, as well as compare variables between the tasks. Twenty-four high-level U-17 soccer athletes played 3 versus 3 (plus goalkeep...

The manipulation of the muscle action duration (MAD) can influence the instantaneous torque along the range of motion, which can lead to adaptations of regional muscle hypertrophy. The aim of this study was to compare the effects of matched resistance training (RT) on the knee extension machine with different MAD in the cross-sectional area (CSA) r...

This study aimed to compare the physical responses of soccer players with different levels of specific endurance during SSG performed by teams balanced according to athletes' specific endurance. Eighteen U-17 athletes from a team that participated in national competitions took part in this study. The Yo-Yo Intermittent Recovery Test Level 2 (YIRT2)...

Aim: The objective of the present study was to compare the amplitude of the electromyographic (EMG) signal of the quadriceps muscle portions vastus medialis (VM), vastus lateralis (VL) and rectus femoris (RF) and the activation ratio (VM/VL, VM/RF and VL/RF) in protocols with different durations of concentric and eccentric muscular actions. Materia...

Resistance training protocols performed to muscle failure (MF) have been employed in an attempt to maximize activation and neuromuscular fatigue. Therefore, the aim of this study was to compare the surface electromyography amplitude (EMGRMS) and frequency (EMGFREQ) of the pectoralis major between protocols performed to MF and non muscle failure (NM...

Background: Previous studies on soccer small-sided games (SSGs) chose between with and without offside rule conditions without evidence-based criteria. The current study aimed to compare the positional dynamics of 3v3 SSGs with and without the offside rule. Methods: Twenty-four Brazilian U-17 national-level soccer players were recruited. They we...

Objectives Despite advancements in resistance training (RT) methods, the acute physiological responses to time under tension (TUT) and load on acute metabolic and neuromuscular responses remains poorly understood. The aim of the present study was to investigate how TUT or resistance load impact muscular activation and blood lactate during an RT ses...

Acknowledgments: We would like to thank the CAPES Brazil, FAPEMIG and the PRPq from the Federal University of Minas Gerais-Brazil. Abstract This study compared the electromyographic response, the blood lactate concentration (BLC), and the maximum number of repetitions (MNR) between protocols of different concentric/eccentric duration taken to muscl...

Running asymmetry is considered a matter of concern for performance and injury, but the association between asymmetry and performance remain unclear. There are different strategies to address asymmetries and its relationship with performance. Here we investigated the correlation between global symmetry index and mechanical efficiency during 10 km r...

This study investigate the effect of 10-week strenght training on the amplitude of the electromyographic (EMG) signal of vastus medialis, vastus lateralis and rectus Femoris. Twenty three untrained volunteers performed 3-5 sets (3 sets-weeks 1 and 2; 4 series-weeks 3 and 4; 5 series weeks 5 to 10) with 6 repetitions, intensity of 50% of 1 repetitio...

The aim of this study was to investigate the effects of muscle failure (MF) or non-MF (NMF) training on strength and muscle hypertrophy relative gains (average and individual data). Ten men untrained in resistance training participated in the study. Each leg was allocated in 1 of 2 unilateral training protocols (MF or NMF with equal volume) on knee...

This study aimed to verify the acute effects of 3vs.3 soccer small-sided and conditioned games (SSCG) on the tactical behavior of youth soccer athletes within one training session. Twenty-four soccer athletes (U-13 and U-14 categories) from a professional club participated in the study. They played four 4-minute 3vs.3 SSCG with 4 minutes of passive...

This study aimed to investigate the bio- mechanical response of the hamstring muscles to acute stretching in dancers (D) compared to non-dancers (ND). Maximal range of motion (ROMMax) and stiffness of the hamstrings were assessed in 46 young males, 23 undergraduate students (ND) and 23 professional dancers (D). Ages of the two groups were D 21.5 ±...

To assess the test – retest reliability and sensitivity of an instrument developed to measure the passive mechanical properties of the midfoot joint complex (MFJC), nine female and three male healthy young adults were evaluated in two different days by two experienced examiners. After proper participant positioning on the instrument, the left foref...

It is still unclear what is the optimum local vibration stimulus (LV) configuration to generate a greater range of motion gain (ROM) and how LV affects the mechanical and sensory responses of the skeletal muscles. This study aimed to compare the acute effects of four LV configurations on mechanical and sensorial variables related to the muscle‐tend...

Purpose Small-sided games (SS G) with floaters are frequently adopted during the training process of soccer players. However, no study has previously investigated how the rules imposed to these additional players impact the physical, tactical, and physiological responses of the regular players. This study aimed to analyse the influence of the numbe...

Different small-sided games (SSG) can be used by coaches to induce specific demands on athletes during team sports training. In basketball, defensive and time pressures are common stressors experienced by players during official matches. However, no studies have investigated the effect of changing these variables in SSG during training. We compared...

We present a critical reflection on the mechanical variable Player Load, which is based on acceleration data and commonly used in sports. Our motivation to write this paper came from the difficulties that we encountered in the calculation and interpretation of Player Load using our own data, since we did not use the Catapult Sports equipment, which...

The present study compared neuromuscular activation, measured by surface electromyography (EMG) amplitude [measure by EMG peak (EMGPEAK)] and range of motion (ROM) where EMGPEAK occurred between two training protocols, matched by time under tension, but with a different number and duration of repetitions. Sixteen recreationally trained males perfor...

The first purpose of this study was to compare the lower limb peak force (Fpeak) asymmetry in two different procedures, simultaneous and sequential, measured in countermovement jump (CMJ) of soccer players. Three series of six CMJ were performed on two force platforms. For the sequential procedure, the 18 CMJ were divided into two blocks of nine at...

This study aimed to compare the physical and physiological responses of young football players of different categories during small-sided games (SSGs) played on different pitch sizes. Forty-eight (24 U-13 and 24 U-14) athletes played a 3 vs. 3 + 1 SSG in two experimental conditions: regular (36 × 27 m) and large pitch sizes (40 × 29 m). The total d...

Lacerda, LT, Costa, CG, Lima, FV, Martins-Costa, HC, Diniz, RCR, Andrade, AGP, Peixoto, GHC, Bemben, MG, and Chagas, MH. Longer concentric action increases muscle activation and neuromuscular fatigue responses in protocols equalized by repetition duration. J Strength Cond Res 33(6): 1629-1639, 2019-The aim of this study was to investigate the impac...

Introduction: Fatigue due to endurance exercise results from both peripheral and central changes, and may influence subsequent performance during a strength task. The increase in serotonin concentration is one of the central factors associated with endurance exercise-induced fatigue, particularly in hot environments. A nutritional strategy employed...

Introduction: Muscular strength is an essential capacity for soccer players; however, the profile of this capacity has not yet been clearly established in young players. Objective: To compare muscular strength performance in the countermovement jump (CMJ) task and the presence of lower limb asymmetry among soccer athletes of the under 15 (U15), un...

O estudo teve como objetivo comparar a altura no salto agachado (SA) e no com contramovimento (SCM) de mulheres idosas. Vinte e oito mulheres idosas sedentárias voluntariaram-se para participar neste estudo (idade média de 68,7±5,9 anos). Cada sujeito foi instruído sobre como executar as técnicas de salto e descansaram 5 minutos entre a realização...

A presente invenção propõe um dispositivo para medição da rigidez passiva das articulações do antepé em relação mediopé utilizando um sensor de torque e um potenciômetro. O dispositivo compreende um conjunto de peças para imobilização de parte dos membros inferiores e do tornozelo, contendo um medidor de torque e um medidor de rotação, que são liga...

This study aimed to compare technical actions of soccer players from different playing position during small-sided games in which teams were composed of players from the same position (e.g., three defenders). In total, 14 U-14 soccer players (14.43 ± 0.16 years), four defenders, four midfielders and four forwards, as well as 2 non-evaluated goalkee...

This study aimed to investigate the influence of numerical superiority and tactical knowledge on players’ physical and physiological demands and RPE during soccer SSGs. Eighteen male soccer players were divided into two groups with 9 athletes (G1 with 3 defenders, 3 forwards and 3 mid-fielders with the highest score in the Procedural Tactical Knowl...

O objetivo deste estudo foi determinar a influência de um exercício de resistência aeróbica no desempenho de força e a relação entre a capacidade aeróbica VO2máx e o desempenho de força. 14 homens com 24.37 ± 3.91 anos de idade e 47.92 ± 32.67 meses de treinamento na musculação participaram de quatro sessões de testes: (i) capacidade aeróbica (VO2m...

Sport climbers frequently use campus board (CB) to improve their upper limb strength under similar conditions of high-difficulty sport climbing routes. The objective of this study was to assess the test-retest reliability of peak force and impulse measured using a CB instrumented with two load cells on starting holds. The same evaluator examined 22...

This study aimed compare individual tactical behavior and network properties of players with higher and lower tactical skills during soccer small-sided games. The sample was composed of 18 U-17 elite soccer players (16.2 years old) from the same national level team. Players were divided into group 1 and group 2, with higher and lower tactical skill...

This study aimed to compare the tactical behavior of young soccer players during small-sided games played with team composition criteria based on procedural tactical knowledge, aerobic power and speed performance. Eighteen male soccer players played 3vs.3 small-sided games with teams balanced according to players’ performance on Sprint Test, Yo-Yo...

Space creation dynamics (SCDs) describe actions players perform to create a scoring opportunity. This study compared SCDs and types of offense during three different three versus three (3vs.3) basketball small-sided games (SSGs) played in half court: 3vs.3 with man-to-man defense in half playing area (3vs.3HALF), 3vs.3 with man-to-man defense in fu...

The aim of this study was to propose a mechanical device that could increase the mechanical load during the entire eccentric (ECC) action on a knee flexor machine and to compare the muscular activity when the device was used during a testing protocol. Fifteen physically active women were recruited, and they performed two protocols: control and ecce...

The aim of this study was to propose a mechanical device that could increase the mechanical load during the entire eccentric (ECC) action on a knee flexor machine and to compare the muscular activity when the device was used during a testing protocol. Fifteen physically active women were recruited, and they performed two protocols: control and ecce...

The aim of this study was to investigate the impact of protocols equalized by the repetition duration but composed of different concentric and eccentric durations on muscle activation and neuromuscular fatigue. Seventeen males with previous experience in resistance training performed 3 training protocols (A - 2s con : 4s ecc; B - 3s con : 3s ecc; a...

Mudança de direção (MDD) pode ser descrita como a habilidade de desacelerar, reverter ou mudar a direção de um movimento e acelerar em uma nova direção (3). Alguns testes utilizados para avaliar esta habilidade possuem grande distância a percorrer em linha reta, não oferecendo uma avaliação específica sobre a MDD e sim, sobre a habilidade de mudar...

Abstract presented in the Brazilian Congress of Biomechanics

Abstract presented in the Brazilian XVII Congress of Biomechanics

Flexibility is an important component of physical fitness, particularly in elderly people whose flexibility tend to deteriorate with the passing of time. The purpose of this longitudinal study was to determine how flexibility of older adults’ change over time. The control group consisted of 54 physically active adults (17 men and 37 women) all of w...

O objetivo deste estudo foi comparar a concentração de lactato sanguíneo em protocolos de treinamento de força com diferentes durações das ações musculares no exercício supino. Dezessete voluntários executaram três protocolos com três séries de seis repetições a 60% de 1RM, pausa de três minutos entre as séries e diferentes durações das ações muscu...