scholarly journals O processo de fadiga pode alterar a estratégia motora de velocidade de golpes no karate: um estudo de caso

2016 ◽  
Vol 85 (3) ◽  
Author(s):  
Keith Sato Urbinati ◽  
Matheus Aguiar ◽  
Juarez Trancoso ◽  
Caluê Papcke ◽  
Percy Nohama ◽  
...  
Keyword(s):  
Biomechanical Model ◽  
Left Knee ◽  
Black Belt ◽  
South American ◽  
Camera Motion ◽  
Vo2 Max ◽  
Motor Strategy ◽  
Analysis System ◽  
Camera Motion Analysis ◽  
Motor Strategies

Introdução: Devido às novas exigências nas regras competitivas com maiores pontuações, o karate vem se tornando um esporte com altas demandas da variável velocidade. Dentre diversos fatores que podem afetar a velocidade de golpes, o processo de fadiga exaustão é uma importante variável interveniente. Logo, como ocorre o controle motor para a manutenção de velocidade de golpes em situação de fatigabilidade?Objetivo: Identificar as estratégias motoras na manutenção de velocidade do gyako zuki no processo de fadiga.Métodos: Foi avaliado o atual campeão sul-americano da categoria -78 kg, sub 21 do sistema World Karate Federation (WKF). O atleta prática karate por 7 anos, é faixa preta, nível internacional, com 78 kg, 1,82m, 14,4% de gordura, VO2 máx = 55 kg.ml-1.min-1. O atleta realizou um protocolo de carga progressiva denominado Karate Specific Aerobic Test (KSAT) até a exaustão. Para o modelo biomecânico foi utilizado um sistema de análise de movimento de seis câmeras (Sistema Vicon).Resultados: As diferentes contribuições de velocidade de segmentos para a manutenção de vP (velocidade de pico) do gyako zuki ocorre uma vez que protocolos de fadiga comumente atribuem adaptações funcionais para superar o efeito da fadiga e continuar executando a ação técnica da ‘melhor’ forma possível.Conclusão: A principal estratégia motora adotada no processo de fadiga é a diminuição do deslocamento de tornozelo e joelho esquerdos à frente, o que diminui a vP do gyako zuki. O deslocamento do segmento de quadril ocorre em situação de homeostase e não necessariamente em situação de fadiga.The process of fatigue can change the motor strategy in velocities of strokes in karate: a case studyIntroduction: Because of the new requirements in the competitive rules with higher scores, karate has become a sport with high demands of speed. Among many factors that can affect the speed of strokes, the process of fatigue exhaustion is an important intervening variable. How the motor control for maintaining speed in strokes fatigability situation?Objective: Identify the motor strategies in maintaining gyako zuki speed in the fatigue process.Methods: We evaluated the current South American champion of the category -78 kg, under 21 years of age, World Karate Federation system (WKF). The karate athlete practice for 7 years, is a black belt, internationally, with 78 kg, 1.82m, 14.4% fat, VO2 max = 55 kg.ml -1 .min -1. The athlete made a progressive load protocol called Karate Specific Aerobic Test (KSAT) until exhaustion. For biomechanical model was used a six camera motion analysis system (Vicon system).Results: Different contributions segments speed to maintain Vp (peak velocity) gyako zuki occurs because fatigue protocols commonly assigned functional adaptations to overcome the effects of fatigue and continue running the technical action as 'better' as possible.Conclusion: The main motor strategy adopted in the fatigue process is the reduction of ankle dislocation and left knee forwarding, which reduces the vP of gyako zuki. The displacement of the hip segment occurs in homeostasis position and not necessarily by fatigue condition.

scholarly journals Impact of Engaging the Nonthrowing Arm on Maximal Ball Velocity From an Overhand Throw With Both the Dominant and Nondominant Arms: A Pilot Study

2021 ◽  
pp. 1-18
Author(s):  
Alanna Weisberg ◽  
Hyun Suk Lee ◽  
Tak Fung ◽  
Larry Katz
Keyword(s):  
The Body ◽  
Whole Body ◽  
Camera Motion ◽  
Ball Speed ◽  
Kinematic Data ◽  
Overhand Throw ◽  
Ball Velocity ◽  
Analysis System ◽  
The Impact ◽  
Camera Motion Analysis

The overhand throw is a complex whole-body motor skill that is fundamental to many sports and activities. When throwing properly, the momentum generated to complete the movement begins in the lower body and transfers through the trunk to the throwing arm. This proof-of-concept study’s primary purpose was to evaluate the impact of the nonthrowing arm on the ball speed during an overhand throw with both the dominant and nondominant arms. Eighteen participants (age: 20.20 ± 2.90 years, nine women) were divided into two intervention groups: a pulling group taught to engage the nonthrowing arm through a pull toward the body and a nonpulling group taught the overhand throw using a component-based physical education curriculum. Each participant completed 12 total throws, six for each side (dominant and nondominant arm). Ball speed and kinematic data were collected using an eight-camera motion analysis system and were assessed using a pre–post study design. The two groups showed significant improvements pre–post when throwing with both the dominant and nondominant arms. Based on effect size comparisons, engaging the nonthrowing arm makes a meaningful difference in maximal ball velocity.

scholarly journals ANALYSIS OF TRUNK POWER AND JOINT STRESSES BETWEEN PROFESSIONAL AND COLLEGIATE PITCHERS

2021 ◽  
Vol 57 (2) ◽  
pp. 121-127
Author(s):  
Maxwell L. Albiero ◽  
◽  
Cody Dziuk ◽  
Janelle A. Cross
Keyword(s):  
External Rotation ◽  
Camera Motion ◽  
Joint Stress ◽  
Joint Torques ◽  
Dynamic Motion ◽  
Shoulder External Rotation ◽  
Analysis System ◽  
Set Up ◽  
3D Software ◽  
Camera Motion Analysis

The dynamic motion of a baseball pitch generates high elbow and shoulder torques that can result in injury. Previous research has noted the importance of properly transferring energy from the lower extremities through the throwing arm to decrease joint stress. The goal of this study was to compare segmental powers between two levels of pitchers at various moments throughout the pitching cycle and observe their influence on upper extremity torques. Thirteen professional and thirteen collegiate pitchers participated in this study. Forty-seven reflective markers were attached to the subjects at specific landmarks. An 8-camera motion analysis system was set up surrounding an artificial pitching mound, where participants threw 10 fastballs. Data were exported and processed using Visual 3D software. Welch’s T-tests compared the means between groups with a significance set at p < 0.05. Professional pitchers were found to have significantly greater torso power at foot contact, maximum shoulder external rotation, ball release, and overall peak torso power. They also demonstrated significantly greater pitch velocity. Professional pitchers generated similar elbow varus torque and shoulder internal rotation torque compared to collegiate pitchers. These findings suggest professional pitchers more effectively use torso power to help increase pitch speed without increasing overall joint torques.

Influence of cross-fit footwear on patellofemoral kinetics during running activities

2017 ◽  
Vol 13 (2) ◽  
pp. 105-111 ◽  
Author(s):  
J.K. Sinclair ◽  
P.J. Taylor ◽  
B. Sant
Keyword(s):  
Repeated Measures ◽  
Camera Motion ◽  
Repeated Measures Anova ◽  
Joint Pathology ◽  
Limb Kinematics ◽  
Analysis System ◽  
Camera Motion Analysis ◽  
Lower Limb Kinematics ◽  
Reduced Risk ◽  
Modelling Approach

The aim of this work was to examine the effects of barefoot, cross-fit, minimalist and conventional footwear on patellofemoral loading during running. Twelve cross-fit athletes ran at 4.0 m/s in each of the four footwear conditions. Lower limb kinematics were collected using an 8 camera motion analysis system and patellofemoral loading was estimated using a mathematical modelling approach. Differences between footwear were examined using one-way repeated measures ANOVA. The results showed the peak patellofemoral force and stress were significantly reduced when running barefoot (force = 3.42 BW & stress = 10.71 MPa) and in minimalist footwear (force = 3.73 BW & stress = 11.64 MPa) compared to conventional (force = 4.12 BW & stress = 12.69 MPa) and cross-fit (force = 3.97 BW & stress = 12.30 MPa) footwear. In addition, the findings also showed that patellofemoral impulse was significantly reduced when running barefoot (0.35 BW·s) and in minimalist footwear (0.36 BW·s) compared to conventional (0.42 BW·s) and cross-fit (0.38 BW·s) footwear. Given the proposed association between patellofemoral loading and patellofemoral disorders, the outcomes from the current investigation suggest that cross-fit athletes who select barefoot and minimalist footwear for their running activities may be at reduced risk from patellofemoral joint pathology in comparison to conventional and cross-fit footwear conditions.

Comparison of Foot Pronation and Lower Extremity Rotation in Persons With and Without Patellofemoral Pain

2002 ◽  
Vol 23 (7) ◽  
pp. 634-640 ◽  
Author(s):  
Christopher M. Powers ◽  
Pon-Yo Chen ◽  
Stephen F. Reischl ◽  
Jaquelin Perry
Keyword(s):  
Lower Extremity ◽  
Internal Rotation ◽  
Three Dimensional ◽  
Patellofemoral Pain ◽  
Group Differences ◽  
Camera Motion ◽  
Foot Pronation ◽  
Analysis System ◽  
Camera Motion Analysis ◽  
Female Subjects

Abnormal foot pronation and subsequent rotation of the lower extremity has been hypothesized as being contributory to patellofemoral pain (PFP). The purpose of this study was to test the hypothesis that subjects with PFP would exhibit larger degrees of foot pronation, tibia internal rotation, and femoral internal rotation compared to individuals without PFP. Twenty-four female subjects with a diagnosis of PFP and 17 female subjects without PFP participated. Three-dimensional kinematics of the foot, tibia, and femur segments were recorded during self-selected free-walking trials using a six-camera motion analysis system (VICON). No group differences were found with respect to the magnitude and timing of peak foot pronation and tibia rotation. However, the PFP group demonstrated significantly less femur internal rotation compared the comparison group. These results do not support the hypothesis that individuals with PFP demonstrate excessive foot pronation or tibial internal rotation compared to nonpainful individuals. The finding of decreased internal rotation in the PFP group suggests that this motion may be a compensatory strategy to reduce the quadriceps angle.

scholarly journals The Test-Retest Reliability of Anatomical Co-Ordinate Axes Definition for the Quantification of Lower Extremity Kinematics During Running

2012 ◽  
Vol 35 (1) ◽  
pp. 15-25 ◽  
Author(s):  
Jonathan Sinclair ◽  
Paul John Taylor ◽  
Andrew Greenhalgh ◽  
Christopher James Edmundson ◽  
Darrell Brooks ◽  
...  
Keyword(s):  
Three Dimensional ◽  
Lower Extremities ◽  
Camera Motion ◽  
Anatomical Landmarks ◽  
Kinematic Parameters ◽  
Paired Samples ◽  
Kinematic Analyses ◽  
Analysis System ◽  
Test Retest Reliability ◽  
Camera Motion Analysis

Three-dimensional (3-D) kinematic analyses are used widely in both sport and clinical examinations. However, this procedure depends on reliable palpation of anatomical landmarks and mal-positioning of markers between sessions may result in improperly defined segment co-ordinate system axes which will produce in-consistent joint rotations. This had led some to question the efficacy of this technique. The aim of the current investigation was to assess the reliability of the anatomical frame definition when quantifying 3-D kinematics of the lower extremities during running. Ten participants completed five successful running trials at 4.0 m·s-1 ± 5%. 3-D angular joint kinematics parameters from the hip, knee and ankle were collected using an eight camera motion analysis system. Two static calibration trials were captured. The first (test) was conducted prior to the running trials following which anatomical landmarks were removed. The second was obtained following completion of the running trials where anatomical landmarks were re-positioned (retest). Paired samples t-tests were used to compare 3-D kinematic parameters quantified using the two static trials, and intraclass correlations were employed to examine the similarities between the sagittal, coronal and transverse plane waveforms. The results indicate that no significant (p>0.05) differences were found between test and retest 3-D kinematic parameters and strong (R2≥0.87) correlations were observed between test and retest waveforms. Based on the results obtained from this investigation, it appears that the anatomical co-ordinate axes of the lower extremities can be defined reliably thus confirming the efficacy of studies using this technique.

Dancers’ Joint Strategies for Achieving Turnout in Low and High Friction Conditions

2020 ◽  
Vol 35 (2) ◽  
pp. 96-102
Author(s):  
Rebekha Duncan ◽  
Catherine Wild ◽  
Leo Ng ◽  
Danica Hendry ◽  
Sarah Carter ◽  
...  
Keyword(s):  
Repeated Measures ◽  
External Rotation ◽  
Injury Rate ◽  
Camera Motion ◽  
Joint Angles ◽  
Low Friction ◽  
Training Tool ◽  
Analysis System ◽  
Lumbar Extension ◽  
Camera Motion Analysis

BACKGROUND: Dancing with legs externally rotated (turnout) is a fundamental element of ballet technique. A reliance on floor friction to achieve turnout may contribute toward the high injury rate in dancers. Joint strategies used by dancers in high and low friction turnout conditions are not well understood. OBJECTIVES: To quantify the lower limb and lumbar spine joint strategies used by female pre-professional dancers to achieve turnout in low-friction (rotation discs) and high-friction (functional and forced) conditions. METHODS: Twenty-three pre-professional female dancers participated in the study. A 12-camera motion analysis system collected hip and knee external rotation (ER), ankle abduction, and lumbar extension angles in three turnout conditions and passive hip ER range of motion angles. Repeated measures ANOVA analysed the differences between joint angles, maximum turnout angle (foot relative to pelvis), and available hip ER. RESULTS: Dancers demonstrated lower knee ER (18.5±4.8°) and ankle abduction (6.0±7.7°) angles during low-friction turnout compared to higher friction conditions (p<0.05). Dancers utilised between 70–83% of available hip ER within all conditions. Low-friction turnout demonstrated greater hip ER contribution within maximum turnout (43%) compared to higher friction conditions. Dancers demonstrated greater lumbar extension angles in low-friction turnout compared to higher friction conditions (p<0.05). CONCLUSIONS: Further hip ER strength training is required to promote greater hip ER range within the position. Rotation discs may be a valuable training tool as dancers demonstrated greater hip ER utilisation with less knee ER and ankle abduction; however, this position did promote undesirable lumbar extension.

The Stance Phase of Walking During Late Pregnancy

2005 ◽  
Vol 95 (3) ◽  
pp. 247-253 ◽  
Author(s):  
Janelle K. Lymbery ◽  
Wendy Gilleard
Keyword(s):  
Ground Reaction Force ◽  
Stance Phase ◽  
Center Of Pressure ◽  
Reaction Force ◽  
Late Pregnancy ◽  
Camera Motion ◽  
Motion Analysis System ◽  
Step Width ◽  
Analysis System ◽  
Camera Motion Analysis

The purpose of this study was to investigate temporospatial and ground reaction force variables in the stance phase of walking during late pregnancy. An eight-camera motion-analysis system was used to record 13 pregnant women at 38 weeks’ gestation and again 8 weeks after birth. In late pregnancy, there was a wider step width, and mediolateral ground reaction force tended to be increased in a medial direction. The center of pressure moved more medially initially and less anteriorly at 100% of stance in late pregnancy. The differences suggest that women may adapt their gait to maximize stability in the stance phase of walking and to control mediolateral motion. (J Am Podiatr Med Assoc 95(3): 247–253, 2005)

scholarly journals Stride Pattern of the Lower Extremities Among Stride Types in Baseball Pitching

2021 ◽  
Vol 3 ◽  
Author(s):  
Shu-Wei Chen ◽  
Wen-Tzu Tang ◽  
Jung-Tang Kung ◽  
Tsung-Ying Hung ◽  
Yu-Lin Chen ◽  
...  
Keyword(s):  
Motion Analysis ◽  
Sampling Rate ◽  
Force Plate ◽  
Lower Extremities ◽  
Knee Extension ◽  
Camera Motion ◽  
Motion Data ◽  
Baseball Pitchers ◽  
Analysis System ◽  
Camera Motion Analysis

The present study investigated the differences in the stride pattern of the lower extremities among different stride types in baseball pitchers with the aim of evaluating stride movement and skills to improve training effectiveness. Thirty elite male college baseball pitchers volunteered to pitch on an indoor-mound-like force plate, where motion data of their fastest strike trials were collected using an eight-camera motion analysis system at a 200–250 Hz sampling rate. Pelvis center trajectories of each participant were calculated and further categorized into three groups: tall-and-fall (TF), dip-and-drive (DD), and mixed (MX) pitchers. Motion analysis revealed that DD pitchers initiated pivot–knee extension and pivot–hip adduction earlier than TF pitchers and accelerated their bodies sooner than TF pitchers. In addition, TF pitchers accelerated their bodies forward by pivoting their legs until the middle of the arm-cocking and acceleration phases. The movement patterns of MX pitchers were similar to those of DD pitchers in terms of pivot leg, although this occurred a little later in the stride. Our findings are useful in developing training strategies for coaches, players, and trainers to better meet the demands of different pitching styles.

The Influence of Different Force and Pressure Measuring Transducers on Lower Extremity Kinematics Measured During Running

2014 ◽  
Vol 30 (1) ◽  
pp. 166-172 ◽  
Author(s):  
Jonathan Sinclair ◽  
Sarah J. Hobbs ◽  
Paul J. Taylor ◽  
Graham Currigan ◽  
Andrew Greenhalgh
Keyword(s):  
Repeated Measures ◽  
Force Plate ◽  
Three Dimensional ◽  
Measuring Transducer ◽  
Camera Motion ◽  
Gait Patterns ◽  
3 Dimensional ◽  
Measuring Devices ◽  
Analysis System ◽  
Camera Motion Analysis

In running analyses where both kinetic and kinematic information is recorded, participants are required to make foot contact with a force and/or pressure measuring transducer. Problems arise if participants modify their gait patterns to ensure contact with the device. There is currently a paucity of research investigating the influence of different underfoot kinetic measuring devices on 3-dimensional kinematics of running. Fifteen participants ran at 4.0 m/s in four different conditions: over a floor embedded force plate, Footscan, Matscan, and with no device. Three-dimensional angular kinematic parameters were collected using an eight camera motion analysis system. Hip, knee, and ankle joint kinematics were contrasted using repeated-measures ANOVAs. Participants also rated their subjective comfort in striking each of the three force measuring devices. Significant differences from the uninhibited condition were observed using the Footscan and Matscan in all three planes of rotation, whereas participants subjectively rated the force plate significantly more comfortable than either the Footscan/Matscan devices. The findings of the current investigation therefore suggest that the disguised floor embedded force plate offers the most natural running condition. It is recommended that analyses using devices such as the Footscan/Matscan mats overlying the laboratory surface during running should be interpreted with caution.

A comparison of several barefoot inspired footwear models in relation to barefoot and conventional running footwear

2013 ◽  
Vol 9 (1) ◽  
pp. 13-21 ◽  
Author(s):  
J. Sinclair ◽  
S.J. Hobbs ◽  
G. Currigan ◽  
P.J. Taylor
Keyword(s):  
Lower Extremity ◽  
Repeated Measures ◽  
Reaction Force ◽  
Camera Motion ◽  
Motion Analysis System ◽  
Increased Risk ◽  
Impact Parameters ◽  
Analysis System ◽  
Rearfoot Eversion ◽  
Camera Motion Analysis

This study examined differences in kinetics and kinematics between barefoot and shod running, as well as between several barefoot inspired footwear models. Fifteen participants ran at 4.0 m/s ±5% in each footwear condition. Lower extremity kinematics in the sagittal, coronal and transverse planes were measured using an eight camera motion analysis system alongside ground reaction force parameters. Impact parameters and joint kinematics were subsequently compared using repeated measures ANOVAs. The kinetic analysis revealed that, compared to the conventional footwear, impact parameters were significantly greater in the barefoot and more minimal in barefoot inspired footwear. Running barefoot and in the minimal barefoot inspired footwear was associated with increases in flexion parameters of the knee and ankle at footstrike in relation to the conventional footwear. Finally, the results indicated that the barefoot and minimal barefoot inspired footwear were associated with greater peak eversion magnitude when compared to the conventional footwear. This study suggests that in barefoot and more minimalist barefoot inspired footwear running is associated with impact kinetics and rearfoot eversion parameters, previously linked to an increased risk of overuse injury, when compared to conventional shod running.

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