Paulo Roberto Pereira Santiago holds a Bachelor's Degree in Physical Education (2002), Master's (2005) and Doctor's (2009) in Motricity Sciences, from the São Paulo State University (UNESP - Rio Claro). Associete Professor in Biomechanics at the University of São Paulo (USP - Ribeirão Preto in 2016). Bachelor's Degree in Computer Engineering from the Virtual University of São Paulo-UNIVESP (2023). For six years, he was a columnist for Radio USP on the topic of "Science and Sport" (2017 - 2022). He is currently an Associate Professor (MS5 level 3 in RDIDP) at EEFERP-USP. He teaches undergraduate classes in the courses at EEFERP-USP and Biomedical Informatics at the Faculty of Medicine of Ribeirão Preto (IBm-FMRP-USP). He is a permanent advisor of the Graduate Program in Rehabilitation and Functional Performance at FMRP-USP. He works mainly in the areas of biomechanics and computer engineering applied to sport and physical exercise. Address: University of São Paulo School of Physical Education and Sport of Ribeirão Preto Biomechanics and Motor Control Laboratory
Anais do Encontro Nacional de Inteligência Artificial e Computacional (ENIAC 2020)
Conseguir classificar padrões de corrida, principalmente aqueles associados à fadiga, pode auxili... more Conseguir classificar padrões de corrida, principalmente aqueles associados à fadiga, pode auxiliar na elaboração de treinos mais eficientes e na prevenção de lesões em esportes de alto rendimento. Todavia, essa tarefa não é trivial devido à complexidade dos padrões. Uma alternativa interessante é utilizar métodos de Aprendizado de Máquina, como Redes Neurais Artificiais (RNAs), para classificar padrões de corrida. Nesta pesquisa, sinais de força são obtidos por sensores de carga acoplados à base de uma esteira ergométrica open source de baixo custo. O objetivo é indicar ao usuário a ocorrência de fadiga durante o treinamento com base nos padrões de corrida. Diferentes atributos são extraídos dos sinais temporais gerados durante sessões de treino. Os exemplos obtidos são então classificados por uma RNA. Os resultados experimentais indicam que a RNA é capaz de classificar com boa acurácia os padrões de corrida. Experimentos considerando-se diferentes cenários indicam que a eficiência...
Journal of strength and conditioning research, Jan 4, 2018
Aquino, R, Carling, C, Palucci Vieira, LH, Martins, G, Jabor, G, Machado, J, Santiago, P, Gargant... more Aquino, R, Carling, C, Palucci Vieira, LH, Martins, G, Jabor, G, Machado, J, Santiago, P, Garganta, J, and Puggina, E. Influence of situational variables, team formation, and playing position on match running performance and social network analysis of brazilian professional soccer players. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to investigate the independent and interactive effects of situational variables, opposition team formation, and playing position on running performance and network analysis in Brazilian professional soccer players (n = 22). Global positioning system technology was used to determine total distance covered, mean speed, maximum running speed, and distance covered in 6 speed ranges. Social network analysis was used to assess interpersonal coordination (team interactions characterized as successful passes [n = 3,033] between teammates). Observations of match running performance (n = 129) and network analysis (n = 108) were obtained....
This study investigated the effect of adding haptic information to the control of posture, as wel... more This study investigated the effect of adding haptic information to the control of posture, as well as comparing the effect of both the "light touch" (LT) and "anchor system" (AS) paradigms on postural sway. Additionally, it compared the effect of location and number of points of contact to the control of posture in young adults. The location consisted of using the anchors tied to the finger and held by the hands, and, for LT, the fingertip. For the number of points of contact, participants used two hands, and then separately the dominant hand, and the non-dominant hand, for both anchor and LT paradigms. Participants stood upright with feet-together and in tandem position while performing tasks that combined the use of anchors and LT, points of contact (hand grip and finger), and number of points of contact (two hands and one hand). In this study, the anchors consist of holding in each hand a flexible cable with the other end attached to the ground. The LT consist...
International journal of sports physiology and performance, Jan 13, 2018
The present study aimed to investigate whether four weeks of β-alanine supplementation improves t... more The present study aimed to investigate whether four weeks of β-alanine supplementation improves total distance covered, distance covered and time spent in different speed zones, and sprint numbers during a simulated water polo game. The study design was double-blind, parallel and placebo controlled. Eleven male water polo players participated in the study, divided randomly into two homogeneous groups (placebo and β-alanine groups). The participants performed a simulated water polo game before and after the supplementation period (4 weeks). Participants received 4.8g∙day of dextrose or β-alanine on the first ten days and 6.4g∙day on the final 18 days. Only the β-alanine group presented a significant improvement in total sprint numbers compared to the pre-supplementation moment (PRE=7.8±5.2a.u.; POST=20.2±7.8a.u.; p=.002). Furthermore, β-alanine supplementation presented a likely beneficial effect on improving total distance covered (83%) and total time spent (81%) in zone 4 of speed ...
Journal of strength and conditioning research, Jan 26, 2018
Palucci Vieira, LH, Aquino, R, Moura, FA, Barros, RMLd, Arpini, VM, Oliveira, LdP, Bedo, BLdS, an... more Palucci Vieira, LH, Aquino, R, Moura, FA, Barros, RMLd, Arpini, VM, Oliveira, LdP, Bedo, BLdS, and Pereira Santiago, PR. Team dynamics, running, and skill-related performances of Brazilian U11 to professional soccer players during official matches. J Strength Cond Res XX(X): 000-000, 2018-Analyses of movements during soccer competition have been used previously to help develop conditioning programs. However, this has not been extensively studied in youth populations. Therefore, the purposes of this study were to examine (1) dynamics of collective tactical movements, (2) running, and (3) skill-related performances during soccer matches disputed by children to senior players. A total of 120 Brazilian players in the age groups U11, U13, U15, U17, U20, and professional (PRO) were monitored during official competition matches (N = 12). Using semiautomatic video-based tracking (30 Hz), match running variables including total distance traveled, average speed, maximum sprint speed, and high...
Journal of strength and conditioning research, Jan 27, 2017
The aim of the present study was to compare the acute effects of active (AC), ballistic (BA), pas... more The aim of the present study was to compare the acute effects of active (AC), ballistic (BA), passive (PA), proprioceptive neuromuscular facilitation stretching (PNF) methods on performance in vertical jumping, sit and reach, and sprinting in young soccer players. Twelve trained soccer players (17.67 ± 0.87 years) participated in the study. The jump height (H), peak power (PP), and relative power (RP) in the squat jump (SJ) and countermovement jump (CMJ), the range of motion (ROM), the rate of perceived exertion (RPE), and time (s) in 10-20-30 m sprints were evaluated. Significant differences (p <0.05) in H were found in the comparisons between the PA and control condition (CO) for the SJ. For the CMJ, differences in H were observed between the PA and CO, and PNF with CO and BA, and in the PP between the PNF and CO, AC, and BA, as well as in the RP between the PNF and BA. Significant increases in ROM were found in the AC, BA, PA, and PNF, compared to the CO. In relation to RPE, h...
Identifying the trajectory and spin of the ball with speed and accuracy is critical for good perf... more Identifying the trajectory and spin of the ball with speed and accuracy is critical for good performance in table tennis. The aim of this study was to analyze the ability of table tennis players presenting different levels of training/experience to identify the magnitude of the ball spin from the sound produced when the racket hit the ball. Four types of "forehand" contact sounds were collected in the laboratory, defined as: Fast Spin (spinning ball forward at 140 r/s); Medium Spin (105 r/s); Slow Spin (84 r/s); and Flat Hit (less than 60 r/s). Thirty-four table tennis players of both sexes (24 men and 10 women) aged 18-40 years listened to the sounds and tried to identify the magnitude of the ball spin. The results revealed that in 50.9% of the cases the table tennis players were able to identify the ball spin and the observed number of correct answers (10.2) was significantly higher (χ(2) = 270.4, p <0.05) than the number of correct answers that could occur by chance....
The aims of the current study were to analyze a kick from 10 m in a futsal context and the parame... more The aims of the current study were to analyze a kick from 10 m in a futsal context and the parameters of muscular strength using an isokinetic dynamometer in a laboratory environment, performed with the dominant (DL) and nondominant lower limbs (NDL). Seventeen professional elite players participated. Kicking performance was evaluated from the second penalty mark. Next, athletes completed a strength evaluation with an isokinetic dynamometer at speeds of 60°⋅s–1, 180°⋅s–1, and 300°⋅s–1. Significant differences were observed for hip (15.64 ± 3.44; 13.97 ± 2.62), ankle (63.19 ± 8.90; 52.55 ± 8.72), foot (82.31 ± 7.93; 68.41 ± 7.85), and ball (99.74 ± 8.45; 88.31 ± 7.93) speeds (km⋅h–1), and average power at 180°⋅s–1 (325.59 ± 40.47; 315.79 ± 39.49 W), but not for accuracy (1.33 ± 0.57; 1.66 ± 0.77 m) between the DL and NDL, respectively. Few moderate correlations were observed in the DL (r = .54–.64) or NDL (r = .53–.55) between the kinematic variables of kick and muscular strength par...
Http Dx Doi Org 10 1080 02640414 2014 990490, Jan 2, 2015
The aim of this study was to analyse the characteristics of the asymmetries in the dominant and n... more The aim of this study was to analyse the characteristics of the asymmetries in the dominant and non-dominant limbs when kicking stationary and rolling balls. Ten experienced Brazilian amateur futsal players participated in this study. Each participant performed kicks under two conditions (stationary ball vs. rolling ball) with the dominant and non-dominant limbs (five kicks per condition per limb). We analysed the kicking accuracy, ball and foot velocities, angular joint displacement and velocity. The asymmetry between the dominant and non-dominant limbs was analysed by symmetry index and two-way repeated measures ANOVA. The results did not reveal any interaction between the condition and limb for ball velocity, foot velocity and accuracy. However, kicking with the dominant limb in both kicks showed higher ball velocity (stationary ball: dominant - 24.27 ± 2.21 m · s(-1) and non-dominant - 21.62 ± 2.26 m · s(-1); rolling ball: dominant - 23.88 ± 2.71 m · s(-1) and non-dominant - 21.42 ± 2.25 m · s(-1)), foot velocity (stationary ball: dominant - 17.61 ± 1.87 m · s(-1) and non-dominant - 15.58 ± 2.69 m · s(-1); rolling ball: dominant - 17.25 ± 2.26 m · s(-1) and non-dominant - 14.77 ± 2.35 m · s(-1)) and accuracy (stationary ball: dominant - 1.17 ± 0.84 m and non-dominant - 1.56 ± 1.30 m; rolling ball: dominant - 1.31 ± 0.91 m and non-dominant - 1.97 ± 1.44 m). In addition, the angular joint adjustments were dependent on the limb in both kicks (the kicks with non-dominant limb showed lower hip external rotation than the kicks with the dominant limb), indicating that the hip joint is important in kick performance. In conclusion, the kicks with the non-dominant limb showed different angular adjustments in comparison to kicks with the dominant limb. In addition, kicking a rolling ball with the non-dominant limb showed higher asymmetry for accuracy, indicating that complex kicks are more asymmetric.
The Journal of sports medicine and physical fitness, Jan 14, 2016
The objectives of this study were to describe and compare the displacement patterns and the tacti... more The objectives of this study were to describe and compare the displacement patterns and the tactical performance of the players in the first to the second game time and verify possible associations between indirect markers of muscle damage with displacement patterns in a 30 simulated game played by young soccer players. 18 young soccer players were submitted to a simulated game and two blood collections, one before and another 30 min post-game to analyze the behavior of creatine kinase and lactate dehydrogenase enzymes. The patterns of displacement and tactics variables were obtained through functions developed in Matlab environment (MathWorks, Inc., USA). It is observed a significant increase in average 35 speed (p = 0.05), number of sprints (p < 0.001), the percentage the total distance covered at high intensity (p <0.001) and tactical variables (team surface area - p = 0.002; spreading - p = 0.001) in the second period of the simulated game. In addition, there was significa...
ABSTRACT Investigation of the physical demands in futsal by means of computational tracking has b... more ABSTRACT Investigation of the physical demands in futsal by means of computational tracking has been a common interest in this sport. An established model for automatic tracking is seen with the software DVideo. This software is based on videogrammetry involving the mathematical morphology for determination of displacements in team sport such as the total distance covered. Its accuracy was determined in previous studies involving kinematic coordination of human motion during functional or sports tasks such as futsal and soccer kick performance. However, the software’s accuracy has not been defined during futsal tracking. The aim of this study was to verify the accuracy in the determination of the distances covered by futsal players using the automatic tracking system in DVideo. One amateur futsal player ran for a known distance (920m) in a futsal court. Displacement was recorded with three cameras. Automatic tracking was then performed (82.36% automation), generating data arrays of two-dimensional coordinates of the displacements. Following, the experimental distance covered was calculated in Matlab®. Results showed that the automatic tracking had an accuracy of 2.37m, precision of 1.50m and bias of 1.83m. These results are similar to the results observed with the same system analyzing athlete’s displacement in soccer. Thus, we conclude that DVideo has high reliability in determining displacement in futsal. Keywords: Futsal, Automatic Tracking, Accuracy, Biomechanics.
Research quarterly for exercise and sport, Jan 7, 2018
The purpose of this study was to compare the kicking performance of young soccer players in the U... more The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (V), foot velocity (V), V/Vratio, last stride length, and distance between the support foot and the ball. Simultaneously, a two-dimensional procedure was also conducted to compute (60 Hz) the mean radial error, bivariate variable error, and accuracy. Possible age-related differences were assessed through one-way analysis of variance and magnitude-based inferences. Ball velocity increased by 103% (p < .001, η = .39) from the U11 age group (48.54 ± 8.31 km/hr) to the U20 age group (98.74 ± 16.35 km/hr). Foot velocity presented a 59% increase (p < .001, η = .32) from the U11 age group (49.08 ± 5.16 km/hr) to U20 (78.24 ± 9.49 km/hr). This finding was due to improvement in the quality of foot-ball impact (V/Vratio) f...
Anais do Encontro Nacional de Inteligência Artificial e Computacional (ENIAC 2020)
Conseguir classificar padrões de corrida, principalmente aqueles associados à fadiga, pode auxili... more Conseguir classificar padrões de corrida, principalmente aqueles associados à fadiga, pode auxiliar na elaboração de treinos mais eficientes e na prevenção de lesões em esportes de alto rendimento. Todavia, essa tarefa não é trivial devido à complexidade dos padrões. Uma alternativa interessante é utilizar métodos de Aprendizado de Máquina, como Redes Neurais Artificiais (RNAs), para classificar padrões de corrida. Nesta pesquisa, sinais de força são obtidos por sensores de carga acoplados à base de uma esteira ergométrica open source de baixo custo. O objetivo é indicar ao usuário a ocorrência de fadiga durante o treinamento com base nos padrões de corrida. Diferentes atributos são extraídos dos sinais temporais gerados durante sessões de treino. Os exemplos obtidos são então classificados por uma RNA. Os resultados experimentais indicam que a RNA é capaz de classificar com boa acurácia os padrões de corrida. Experimentos considerando-se diferentes cenários indicam que a eficiência...
Journal of strength and conditioning research, Jan 4, 2018
Aquino, R, Carling, C, Palucci Vieira, LH, Martins, G, Jabor, G, Machado, J, Santiago, P, Gargant... more Aquino, R, Carling, C, Palucci Vieira, LH, Martins, G, Jabor, G, Machado, J, Santiago, P, Garganta, J, and Puggina, E. Influence of situational variables, team formation, and playing position on match running performance and social network analysis of brazilian professional soccer players. J Strength Cond Res XX(X): 000-000, 2018-The purpose of this study was to investigate the independent and interactive effects of situational variables, opposition team formation, and playing position on running performance and network analysis in Brazilian professional soccer players (n = 22). Global positioning system technology was used to determine total distance covered, mean speed, maximum running speed, and distance covered in 6 speed ranges. Social network analysis was used to assess interpersonal coordination (team interactions characterized as successful passes [n = 3,033] between teammates). Observations of match running performance (n = 129) and network analysis (n = 108) were obtained....
This study investigated the effect of adding haptic information to the control of posture, as wel... more This study investigated the effect of adding haptic information to the control of posture, as well as comparing the effect of both the "light touch" (LT) and "anchor system" (AS) paradigms on postural sway. Additionally, it compared the effect of location and number of points of contact to the control of posture in young adults. The location consisted of using the anchors tied to the finger and held by the hands, and, for LT, the fingertip. For the number of points of contact, participants used two hands, and then separately the dominant hand, and the non-dominant hand, for both anchor and LT paradigms. Participants stood upright with feet-together and in tandem position while performing tasks that combined the use of anchors and LT, points of contact (hand grip and finger), and number of points of contact (two hands and one hand). In this study, the anchors consist of holding in each hand a flexible cable with the other end attached to the ground. The LT consist...
International journal of sports physiology and performance, Jan 13, 2018
The present study aimed to investigate whether four weeks of β-alanine supplementation improves t... more The present study aimed to investigate whether four weeks of β-alanine supplementation improves total distance covered, distance covered and time spent in different speed zones, and sprint numbers during a simulated water polo game. The study design was double-blind, parallel and placebo controlled. Eleven male water polo players participated in the study, divided randomly into two homogeneous groups (placebo and β-alanine groups). The participants performed a simulated water polo game before and after the supplementation period (4 weeks). Participants received 4.8g∙day of dextrose or β-alanine on the first ten days and 6.4g∙day on the final 18 days. Only the β-alanine group presented a significant improvement in total sprint numbers compared to the pre-supplementation moment (PRE=7.8±5.2a.u.; POST=20.2±7.8a.u.; p=.002). Furthermore, β-alanine supplementation presented a likely beneficial effect on improving total distance covered (83%) and total time spent (81%) in zone 4 of speed ...
Journal of strength and conditioning research, Jan 26, 2018
Palucci Vieira, LH, Aquino, R, Moura, FA, Barros, RMLd, Arpini, VM, Oliveira, LdP, Bedo, BLdS, an... more Palucci Vieira, LH, Aquino, R, Moura, FA, Barros, RMLd, Arpini, VM, Oliveira, LdP, Bedo, BLdS, and Pereira Santiago, PR. Team dynamics, running, and skill-related performances of Brazilian U11 to professional soccer players during official matches. J Strength Cond Res XX(X): 000-000, 2018-Analyses of movements during soccer competition have been used previously to help develop conditioning programs. However, this has not been extensively studied in youth populations. Therefore, the purposes of this study were to examine (1) dynamics of collective tactical movements, (2) running, and (3) skill-related performances during soccer matches disputed by children to senior players. A total of 120 Brazilian players in the age groups U11, U13, U15, U17, U20, and professional (PRO) were monitored during official competition matches (N = 12). Using semiautomatic video-based tracking (30 Hz), match running variables including total distance traveled, average speed, maximum sprint speed, and high...
Journal of strength and conditioning research, Jan 27, 2017
The aim of the present study was to compare the acute effects of active (AC), ballistic (BA), pas... more The aim of the present study was to compare the acute effects of active (AC), ballistic (BA), passive (PA), proprioceptive neuromuscular facilitation stretching (PNF) methods on performance in vertical jumping, sit and reach, and sprinting in young soccer players. Twelve trained soccer players (17.67 ± 0.87 years) participated in the study. The jump height (H), peak power (PP), and relative power (RP) in the squat jump (SJ) and countermovement jump (CMJ), the range of motion (ROM), the rate of perceived exertion (RPE), and time (s) in 10-20-30 m sprints were evaluated. Significant differences (p <0.05) in H were found in the comparisons between the PA and control condition (CO) for the SJ. For the CMJ, differences in H were observed between the PA and CO, and PNF with CO and BA, and in the PP between the PNF and CO, AC, and BA, as well as in the RP between the PNF and BA. Significant increases in ROM were found in the AC, BA, PA, and PNF, compared to the CO. In relation to RPE, h...
Identifying the trajectory and spin of the ball with speed and accuracy is critical for good perf... more Identifying the trajectory and spin of the ball with speed and accuracy is critical for good performance in table tennis. The aim of this study was to analyze the ability of table tennis players presenting different levels of training/experience to identify the magnitude of the ball spin from the sound produced when the racket hit the ball. Four types of "forehand" contact sounds were collected in the laboratory, defined as: Fast Spin (spinning ball forward at 140 r/s); Medium Spin (105 r/s); Slow Spin (84 r/s); and Flat Hit (less than 60 r/s). Thirty-four table tennis players of both sexes (24 men and 10 women) aged 18-40 years listened to the sounds and tried to identify the magnitude of the ball spin. The results revealed that in 50.9% of the cases the table tennis players were able to identify the ball spin and the observed number of correct answers (10.2) was significantly higher (χ(2) = 270.4, p <0.05) than the number of correct answers that could occur by chance....
The aims of the current study were to analyze a kick from 10 m in a futsal context and the parame... more The aims of the current study were to analyze a kick from 10 m in a futsal context and the parameters of muscular strength using an isokinetic dynamometer in a laboratory environment, performed with the dominant (DL) and nondominant lower limbs (NDL). Seventeen professional elite players participated. Kicking performance was evaluated from the second penalty mark. Next, athletes completed a strength evaluation with an isokinetic dynamometer at speeds of 60°⋅s–1, 180°⋅s–1, and 300°⋅s–1. Significant differences were observed for hip (15.64 ± 3.44; 13.97 ± 2.62), ankle (63.19 ± 8.90; 52.55 ± 8.72), foot (82.31 ± 7.93; 68.41 ± 7.85), and ball (99.74 ± 8.45; 88.31 ± 7.93) speeds (km⋅h–1), and average power at 180°⋅s–1 (325.59 ± 40.47; 315.79 ± 39.49 W), but not for accuracy (1.33 ± 0.57; 1.66 ± 0.77 m) between the DL and NDL, respectively. Few moderate correlations were observed in the DL (r = .54–.64) or NDL (r = .53–.55) between the kinematic variables of kick and muscular strength par...
Http Dx Doi Org 10 1080 02640414 2014 990490, Jan 2, 2015
The aim of this study was to analyse the characteristics of the asymmetries in the dominant and n... more The aim of this study was to analyse the characteristics of the asymmetries in the dominant and non-dominant limbs when kicking stationary and rolling balls. Ten experienced Brazilian amateur futsal players participated in this study. Each participant performed kicks under two conditions (stationary ball vs. rolling ball) with the dominant and non-dominant limbs (five kicks per condition per limb). We analysed the kicking accuracy, ball and foot velocities, angular joint displacement and velocity. The asymmetry between the dominant and non-dominant limbs was analysed by symmetry index and two-way repeated measures ANOVA. The results did not reveal any interaction between the condition and limb for ball velocity, foot velocity and accuracy. However, kicking with the dominant limb in both kicks showed higher ball velocity (stationary ball: dominant - 24.27 ± 2.21 m · s(-1) and non-dominant - 21.62 ± 2.26 m · s(-1); rolling ball: dominant - 23.88 ± 2.71 m · s(-1) and non-dominant - 21.42 ± 2.25 m · s(-1)), foot velocity (stationary ball: dominant - 17.61 ± 1.87 m · s(-1) and non-dominant - 15.58 ± 2.69 m · s(-1); rolling ball: dominant - 17.25 ± 2.26 m · s(-1) and non-dominant - 14.77 ± 2.35 m · s(-1)) and accuracy (stationary ball: dominant - 1.17 ± 0.84 m and non-dominant - 1.56 ± 1.30 m; rolling ball: dominant - 1.31 ± 0.91 m and non-dominant - 1.97 ± 1.44 m). In addition, the angular joint adjustments were dependent on the limb in both kicks (the kicks with non-dominant limb showed lower hip external rotation than the kicks with the dominant limb), indicating that the hip joint is important in kick performance. In conclusion, the kicks with the non-dominant limb showed different angular adjustments in comparison to kicks with the dominant limb. In addition, kicking a rolling ball with the non-dominant limb showed higher asymmetry for accuracy, indicating that complex kicks are more asymmetric.
The Journal of sports medicine and physical fitness, Jan 14, 2016
The objectives of this study were to describe and compare the displacement patterns and the tacti... more The objectives of this study were to describe and compare the displacement patterns and the tactical performance of the players in the first to the second game time and verify possible associations between indirect markers of muscle damage with displacement patterns in a 30 simulated game played by young soccer players. 18 young soccer players were submitted to a simulated game and two blood collections, one before and another 30 min post-game to analyze the behavior of creatine kinase and lactate dehydrogenase enzymes. The patterns of displacement and tactics variables were obtained through functions developed in Matlab environment (MathWorks, Inc., USA). It is observed a significant increase in average 35 speed (p = 0.05), number of sprints (p < 0.001), the percentage the total distance covered at high intensity (p <0.001) and tactical variables (team surface area - p = 0.002; spreading - p = 0.001) in the second period of the simulated game. In addition, there was significa...
ABSTRACT Investigation of the physical demands in futsal by means of computational tracking has b... more ABSTRACT Investigation of the physical demands in futsal by means of computational tracking has been a common interest in this sport. An established model for automatic tracking is seen with the software DVideo. This software is based on videogrammetry involving the mathematical morphology for determination of displacements in team sport such as the total distance covered. Its accuracy was determined in previous studies involving kinematic coordination of human motion during functional or sports tasks such as futsal and soccer kick performance. However, the software’s accuracy has not been defined during futsal tracking. The aim of this study was to verify the accuracy in the determination of the distances covered by futsal players using the automatic tracking system in DVideo. One amateur futsal player ran for a known distance (920m) in a futsal court. Displacement was recorded with three cameras. Automatic tracking was then performed (82.36% automation), generating data arrays of two-dimensional coordinates of the displacements. Following, the experimental distance covered was calculated in Matlab®. Results showed that the automatic tracking had an accuracy of 2.37m, precision of 1.50m and bias of 1.83m. These results are similar to the results observed with the same system analyzing athlete’s displacement in soccer. Thus, we conclude that DVideo has high reliability in determining displacement in futsal. Keywords: Futsal, Automatic Tracking, Accuracy, Biomechanics.
Research quarterly for exercise and sport, Jan 7, 2018
The purpose of this study was to compare the kicking performance of young soccer players in the U... more The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (V), foot velocity (V), V/Vratio, last stride length, and distance between the support foot and the ball. Simultaneously, a two-dimensional procedure was also conducted to compute (60 Hz) the mean radial error, bivariate variable error, and accuracy. Possible age-related differences were assessed through one-way analysis of variance and magnitude-based inferences. Ball velocity increased by 103% (p < .001, η = .39) from the U11 age group (48.54 ± 8.31 km/hr) to the U20 age group (98.74 ± 16.35 km/hr). Foot velocity presented a 59% increase (p < .001, η = .32) from the U11 age group (49.08 ± 5.16 km/hr) to U20 (78.24 ± 9.49 km/hr). This finding was due to improvement in the quality of foot-ball impact (V/Vratio) f...
Uploads