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.

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.

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.

The relationship of hip rotation range, hip rotator strength and balance in healthy individuals

2020 ◽  
Vol 33 (5) ◽  
pp. 761-767
Author(s):  
Yongwook Kim ◽  
Seungmook Kang
Keyword(s):  
Motion Analysis ◽  
External Rotation ◽  
Dynamic Balance ◽  
Three Dimensional ◽  
Camera Motion ◽  
3D Motion ◽  
3D Motion Analysis ◽  
Balance Ability ◽  
Analysis System ◽  
The Relationship

BACKGROUND: Few studies have explored the relationship between muscle strength, range of motion (ROM), and balance in the horizontal plane of the hip joint using three-dimensional (3D) motion analysis. OBJECTIVE: We investigate the relationships of hip internal rotation (IR) and external rotation (ER) ROM, measured using a 3D motion capture system, with hip internal and external rotator strength and single-leg standing balance. METHODS: The participants were 40 healthy adults. Kinematic data on hip ROM were collected using an eight-camera motion analysis system. Hip rotational strength measurements were obtained using hand-held isometric dynamometry. A Single-leg standing test and a pendular test were conducted to evaluate static and dynamic balance ability using BioRescue. RESULTS: Significant correlations were found between hip strength and each variable measured during hip ROM assessments (p< 0.05). Significant positive correlations were found between the hip IR/ER strength ratio and the IR/ER ROM ratio (r= 0.72, p< 0.01). The subgroup with a normal IR/ER ratio of hip rotator strength and ROM showed significantly better dynamic balance ability than the subgroup with a hip rotator muscle imbalance (p< 0.05). CONCLUSIONS: There is a significant relationship between hip IR/ER strength and IR/ER ROM with a normal hip IR/ER strength and ROM ratio positively affecting dynamic balance ability.

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 Effect of a 6-Week Weighted Baseball Throwing Program on Pitch Velocity, Pitching Arm Biomechanics, Passive Range of Motion, and Injury Rates

2018 ◽  
Vol 10 (4) ◽  
pp. 327-333 ◽  
Author(s):  
Michael M. Reinold ◽  
Leonard C. Macrina ◽  
Glenn S. Fleisig ◽  
Kyle Aune ◽  
James R. Andrews
Keyword(s):  
Range Of Motion ◽  
Training Program ◽  
Repeated Measures ◽  
External Rotation ◽  
Controlled Trial ◽  
Injury Rate ◽  
Control Group ◽  
Injury Rates ◽  
Shoulder External Rotation ◽  
Experimental Group

Background: Emphasis on enhancing baseball pitch velocity has become popular, especially through weighted-ball throwing. However, little is known about the physical effects or safety of these programs. The purpose of this study was to examine the effects of training with weighted baseballs on pitch velocity, passive range of motion (PROM), muscle strength, elbow torque, and injury rates. Hypothesis: A 6-week weighted ball training program would result in a change in pitching biomechanical and physical characteristics. Study Design: Randomized controlled trial. Level of Evidence: Level 1. Methods: During the baseball offseason, 38 healthy baseball pitchers were randomized into a control group and an experimental group. Pitch velocity, shoulder and elbow PROM, shoulder strength, elbow varus torque, and shoulder internal rotation velocity were measured in both groups. The experimental group then performed a 6-week weighted ball throwing program 3 times per week using balls ranging from 2 to 32 ounces while the control group only used a 5-ounce regulation baseball. Both groups performed a strength training program. Measurements were then repeated after the 6-week period. Injuries were tracked over the 6-week training program and the subsequent baseball season. The effect of training with a weighted ball program was assessed using 2-way repeated-measures analysis of variance at an a priori significance level of P < 0.05. Results: Mean age, height, mass, and pretesting throwing velocity were 15.3 ± 1.2 years (range, 13-18 years), 1.73 ± 0.28 m, 68.3 ± 11 kg, and 30.3 ± 0.7 m/s, respectively. Pitch velocity showed a statistically significant increase (3.3%) in the experimental group ( P < 0.001). There was a statistically significant increase of 4.3° of shoulder external rotation in the experimental group. The overall injury rate was 24% in the experimental group. Four participants in the experimental group suffered elbow injuries, 2 during the training program and 2 in the season after training. No pitchers in the control group were injured at any time during the study. Conclusion: Performing a 6-week weighted ball throwing program increased pitch velocity. However, the program resulted in increased shoulder external rotation PROM and increased injury rate. Clinical Relevance: Although weighted-ball training may increase pitch velocity, caution is warranted because of the notable increase in injuries and physical changes observed in this cohort.

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 Modelling of Muscle Force Distributions During Barefoot and Shod Running

2015 ◽  
Vol 47 (1) ◽  
pp. 9-17 ◽  
Author(s):  
Jonathan Sinclair ◽  
Stephen Atkins ◽  
Jim Richards ◽  
Hayley Vincent
Keyword(s):  
Repeated Measures ◽  
Sagittal Plane ◽  
Vastus Lateralis ◽  
Reaction Force ◽  
Rectus Femoris ◽  
Camera Motion ◽  
Barefoot Running ◽  
Chronic Injuries ◽  
Analysis System ◽  
Hip Flexion

Abstract Research interest in barefoot running has expanded considerably in recent years, based around the notion that running without shoes is associated with a reduced incidence of chronic injuries. The aim of the current investigation was to examine the differences in the forces produced by different skeletal muscles during barefoot and shod running. Fifteen male participants ran at 4.0 m·s-1 (± 5%). Kinematics were measured using an eight camera motion analysis system alongside ground reaction force parameters. Differences in sagittal plane kinematics and muscle forces between footwear conditions were examined using repeated measures or Freidman’s ANOVA. The kinematic analysis showed that the shod condition was associated with significantly more hip flexion, whilst barefoot running was linked with significantly more flexion at the knee and plantarflexion at the ankle. The examination of muscle kinetics indicated that peak forces from Rectus femoris, Vastus medialis, Vastus lateralis, Tibialis anterior were significantly larger in the shod condition whereas Gastrocnemius forces were significantly larger during barefoot running. These observations provide further insight into the mechanical alterations that runners make when running without shoes. Such findings may also deliver important information to runners regarding their susceptibility to chronic injuries in different 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.

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