Do exist differences in kinematics and EMG of the hip and knee between male runners with and without patellofemoral pain in different running speeds?

OBJECTIVE: Patellofemoral pain (PFP) presents a higher prevalence in female runners, while PFP in male is somehow neglected. Moreover, the effects of progressive greater running speed have not been reported. This study investigates the influence of progressive greater running speed on lower limb tridimensional kinematics and muscle activation (EMG) in male runners with PFP while compared with controls. DESIGN: Cross-Sectional Design. METHODS: Thirteen runners with PFP and 18 controls ran in a treadmill under three different speeds: 9, 11, and 13 km/h. Principal component scores from kinematic data and EMG onset and amplitude were used to compare groups through the Mann-Whitney test at each running speed. RESULTS: Male PFP subjects presented increased hip internal rotation at 11 km/h and increased hip and knee internal at 13 km/h, as well as reduced knee adduction at all speeds. PFP subjects also ran with delayed and shorter vastus medialis oblique pre-activation compared with normal subjects. CONCLUSIONS: This study demonstrated that PFP increased knee and hip internal rotation at higher demand running, therefore, it is important to evaluate the transverse plane of the hip and knee biomechanics in male runners with PFP to optimize the rehabilitation and reconditioning method of these subjects.

Association between knee-to-hip flexion ratio during single-leg vertical landings, and strength and range of motion in professional soccer players.

The aim of this study was to test the correlation between knee-to-hip flexion ratio during a single leg landing task and hip and knee strength, and ankle range of motion. Twenty-four male participants from a professional soccer team performed a continuous single leg jump-landing test during 10s, while lower limb kinematics data were collected using a motion analysis system. After biomechanical testing, maximal isometric hip (abduction, extension, external rotation), knee extension and flexion strength were measured. Maximum ankle dorsiflexion range of motion was assessed statically using the weight bearing lunge test. Pearson correlation coefficients were calculated to determine the associations between the predictor variables (knee and hip strength, and ankle ROM) and the main outcome measure (knee-to-hip flexion ratio). Correlation between knee-to-hip flexion ratio and hip abductors strength was significant (r = -0.47; p = 0.019). No other significant correlations were observed among the variables (p > 0.05). These results demonstrated that a lower hip abductors strength in male soccer players was correlated with a high knee-to-hip flexion ratio during landing from a single leg jump, potentially increasing knee overload by decreasing energy absorption at the hip. The results provide a novel proposal for the functioning of hip muscles to control knee overload.

Do hip strength, flexibility and running biomechanics predict dynamic valgus in female recreational runners?

BACKGOUND: Dynamic valgus has been the focus of many studies to identify its association to an increased risk of running-related injuries. However, it is not known which physical and biomechanical variables are associated with this movement dysfunction. RESEARCH QUESTION: This study aimed to test the correlation between strength, flexibility and biomechanical variables and dynamic valgus in female runners. METHODS: Twenty-nine healthy females ran on a treadmill at 2.92 m/s and performed strength, range of motion and endurance tests. Pelvic, hip and ankle kinematics were measured with a 3D motion analysis system. Six multiple linear regression models were used to identify the ability of physical and biomechanical variables to predict excursion and peak of contralateral pelvic drop, hip adduction and internal rotation. RESULTS: Contralateral pelvic drop and hip adduction were positively correlated to ankle eversion and step cadence. Hip internal rotation had a negative correlation with ankle eversion. Despite significance, predictor variables explained less than 30% of dynamic valgus variance during running. No interest variable had significant correlation with the hip strength and hip and ankle passive range of motion. SIGNIFICANCE: The results showed that distal joint kinematics and spatiotemporal variables should be considered during biomechanical running analysis to identify their possible relationship with joint overload caused by dynamic valgus. Caution should be taken when linking hip disorders during running to posterolateral hip strength and stiffness, core endurance, and ankle dorsiflexion range of motion since no correlation occurred amongstthese variables in this sample of female runners.

Prediction of mild anatomical leg length discrepancy based on gait kinematics and linear regression model.

BACKGOUND: Leg length discrepancy (LLD) can be related to different pathologies, due to an inadequate distribution of mechanical loads, as well as gait kinematics asymmetries resulted from LLD. RESEARCH QUESTION: To validate a model to predict anatomical LLD (ALLD) based on gait kinematics. METHODS: Gait of 39 participants with different lower limb pathologies and mild discrepancy were collected. Pelvic, hip, knee and ankle kinematics were measured with a 3D motion analysis system and ALLD, femur discrepancy (FD) and tibia discrepancy (TD) were measured by a computerized digital radiograph. Three multiple linear regression models were used to identify the ability of kinematic variables to predict ALLD (model 1), FD (model 2) and TD (model 3). RESULTS: Difference between peak knee and hip flexion of the long and short lower limb was selected by models 1 (p < 0.001) and 2 (p < 0.001). Hip adduction was selected as a predictor only by model 1 (p = 0.05). Peak pelvic obliquity and ankle dorsiflexion were not selected by any model and model 3 did not retain any dependent variable (p > 0.05). Regression models predicted mild ALLD with moderate accuracy based on hip and knee kinematics during gait, but not ankle strategies. Excessive hip flexion of the longer limb possibly occurs to reduce the limb to equalize the LLD, and discrepancies of the femur and tibia affects gait cycle in a different way. SIGNIFICANCE: This study showed that kinematic variables during gait could be used as a screening tool to identify patients with ALLD, reducing unnecessary x-ray exposure and assisting rehabilitation programs.

Dynamic leg length asymmetry during gait is not a valid method for estimating mild anatomic leg length discrepancy.

The purpose of this study was to test the validity of dynamic leg length discrepancy (DLLD) during gait as a radiation-free screening method for measuring anatomic leg length discrepancy (ALLD). Thirty-three subjects with mild leg length discrepancy walked along a walkway and the dynamic leg length discrepancy (DLLD) was calculated using a motion analysis system. Pearson correlation and paired Student t-tests were applied to calculate the correlation and compare the differences between DLLD and ALLD (α = 0.05). The results of our study showed DLLD is not a valid method to predict ALLD in subjects with mild limb discrepancy.

Influence of age and gender on knee and hip isometric strength of recreational physically active young and middle-aged subjects / Influencia de la edad y el sexo en la fuerza isométrica de la rodilla y la cadera de personas jóvenes y de mediana edad que practican actividades físicas recreativas / Influência da idade e do sexo na força isométrica do joelho e do quadril de indivíduos jovens e de meia idade praticantes recreacionais de atividades físicas

ABSTRACT Muscle strength is an essential part of the functional assessment of health professionals to select and analyze the effects of clinical interventions. This study aimed to determine the influence of gender and age on isometric strength of hip and knee muscle groups. A total of 127 subjects (50.4% men), aged from 20 to 49 years (stratified into three groups: 20-29 years; 30-39 years; and 40-49 years) participated in this study. A hand-held dynamometer was used to measure isometric normalized torque of the hip abductors, hip external rotators, knee extensors, and knee flexors muscles. Regressions and a two-way analysis of variance were used to identify the influence of age and gender on torque of each muscle group. Age and gender were included in the regression model for all groups. Generally, men aged 20-29 and 30-39 were stronger than age-paired women. For participants aged 40-49, torque was similar for men and women for all muscle groups. There was no difference among age groups for women. Generally, young men were stronger than older men. The association between age and gender in hip and knee strength was proved and liable of subgroup stratification after measurements with a hand-held isometric dynamometer.

RESUMEN La fuerza muscular es un componente básico de la evaluación funcional de los profesionales de la salud para seleccionar y analizar los efectos de las intervenciones clínicas. El objetivo de este estudio fue determinar la influencia del sexo y de la edad en las mediciones de fuerza isométrica de los grupos musculares de la cadera y la rodilla. En el estudio participaron 127 sujetos (50,4% hombres), de entre 20 y 49 años de edad (estratificados en grupos: 20 a 29 años; 30 a 39 años; y 40 a 49 años). El torque isométrico normalizado de los abductores y rotadores externos de la cadera y de los extensores y flexores de la rodilla se midió con un dinamómetro manual. Se utilizaron regresiones y el análisis de varianza (Anova) para identificar la influencia de la edad y el sexo en el torque. Tanto la edad como el sexo se incluyeron en el modelo para todos los grupos musculares. En general, los hombres de entre 20 y 29 años y los de 30 a 39 mostraron tener más fuerza que las mujeres del mismo grupo de edad. Para los participantes de 40 a 49 años, el torque fue similar entre hombres y mujeres para todos los grupos musculares. No hubo diferencias entre los grupos de edad en el grupo de mujeres. En general, los hombres más jóvenes demostraron ser más fuertes que los hombres de mediana edad. La relación entre la edad y el sexo en la fuerza muscular de la cadera y la rodilla se probó y demostró ser susceptible a la estratificación después de las mediciones realizadas con el dinamómetro manual.

RESUMO A força muscular é um componente essencial da avaliação funcional de profissionais da saúde para selecionar e analisar efeitos de intervenções clínicas. O objetivo do estudo foi determinar a influência do sexo e da idade sobre medidas de força isométrica de grupos musculares do quadril e do joelho. Participaram da pesquisa 127 sujeitos (50,4% homens), com idade de 20 a 49 anos (estratificados em grupos: 20 a 29 anos; 30 a 39 anos; e 40 a 49 anos). O torque isométrico normalizado de abdutores e rotadores externos de quadril e extensores e flexores de joelho foi medido com dinamômetro manual. Regressões e uma análise de variância (Anova) foram usados para identificar a influência da idade e do sexo sobre o torque. Tanto idade quanto sexo foram incluídos no modelo para todos os grupos musculares. Em geral, homens de 20 a 29 anos e de 30 a 39 anos demonstraram mais força do que mulheres da mesma faixa etária. Para participantes de 40 a 49 anos, o torque foi similar entre homens e mulheres para todos os grupos musculares. Não houve diferença entre as faixas etárias no grupo de mulheres. Em geral, homens mais jovens se mostraram mais fortes do que homens mais velhos. A relação entre idade e sexo na força muscular do quadril e do joelho foi provada e se mostrou passível de estratificação após as medições feitas com o dinamômetro manual.

USE OF SPATIOTEMPORAL GAIT PARAMETERS TO DETERMINE RETURN TO SPORTS AFTER ACL RECONSTRUCTION.

OBJECTIVE: : To compare gait spatiotemporal parameters of healthy and ACL reconstructed subjects in order to classify the status of gait normality. METHODS: : Fourteen healthy subjects and eight patients submitted to ACL reconstruction walked along a walkway while the lower limbs movement was captured by an infrared camera system. The frames where the initial contact and toe-off took place were determined and the following dependent variables, which were compared between groups through the Mann-Whitney test (a=0.05) were calculated: percentage of time in initial double stance, percentage of time in single stance, percentage of time in terminal double stance, stride length and gait velocity. Initially, all variables were compared between groups using a Mann-Whitney test. A logistic regression was applied, including all dependent variables, to create a model that could differentiate healthy and ACL reconstructed subjects. RESULTS: : ACL reconstructed group showed no differences in any spatiotemporal parameter of gait (p > 0.05) in relation to the control group, although the angular kinematic differences of the knee remained altered, as evidenced in a study with a similar sample. CONCLUSION: : The regression classified all subjects as healthy, including the ACL reconstructed group, suggesting the spatiotemporal variables should not be used as the sole criterion of return to sports activities at the same level as prior to injury. Level of Evidence III, Case Control Study.

Sinergismo entre o vasto lateral e vasto medial oblíquo durante a marcha após a reconstrução do ligamento cruzado anterior / Synergism between vastus lateralis and vastus medialis oblique during gait after anterior cruciate ligament reconstruction

Objetivo: O objetivo deste estudo foi comparar a co-contração muscular (CCM) e ativação dos músculos vasto lateral (VL) vasto medial oblíquo (VMB) durante a marcha e uma amostra saudável ­ grupo controle (GC) e pacientes submetidos a reconstrução do ligamento cruzado anterior (RLCA). Métodos: Vinte e três indivíduos participaram neste estudo, 14 GC e 9 RLCA. A atividade mioelétrica do VL e VMO foram captados para cálculo da CCM. A razão VL/VMO foi obtida dividindo o sinal normalizado desses dois músculos em cada ponto da curva. O valor da CCM e a relação de ativação na fase de apoio duplo, fase de apoio simples, fase de apoio terminal e fase de balanço foram obtidas pelo cálculo da média aritmética dos valores de intensidade da curva comum em cada intervalo. Resultado: CCM foi significativamente menor no grupo RLCA durante a fase de apoio dupla (p=0.001), efeito máximo (1.72). Não foram encontradas diferenças entre as outras comparações. Conclusão: O resultado desse estudo mostrou que a contração dos músculos VL e o VMO na fase inicial de apoio duplo da marcha foi diferente entre indivíduos saudáveis e submetidos a RLCA. Este achado pode estar relacionado a diminuição da estabilidade patelofemoral durante a resposta a carga, aumentando o potencial risco de desenvolver lesões nesta articulação.

Objective: The aim of this study was to compare vastus lateralis and vastus medialis oblique (VL/VMO) muscle co-contraction (MCC) and activation ratio during gait between healthy subjects- control group (CG), and those with anterior cruciate ligament reconstruction (ACLR). Methods: Twenty-three subjects participated in this study, 14 CG and 9 ACLR. The myoelectric activities of the VL and VMO were captured to calculate the MCC. The VL/VMO ratio was obtained by dividing the normalized signals of these two muscles at each point of the curve. The MCC values and the activation ratio in the initial double limb stance, single limb stance, terminal double limb stance and swing were obtained by calculating the arithmetic mean of the intensity values ​​of the common curve in each interval. Results: MCC was significantly lower in the ACLR group during the initial double limb stance phase (p=0.001), with a high effect size (1.72). No significant differences were found for the other comparisons. Conclusions: The results of this study showed that the VL and VMO muscles co-contraction in the initial double limb stance phase of gait was different between the healthy and ACLR individuals. This finding may be related to lower patellofemoral stability during the loading response, increasing the potential risk for the development of injuries in this joint.

Classification of gait kinematics of anterior cruciate ligament reconstructed subjects using principal component analysis and regressions modelling.

The aim of this study was to compare the knee kinematics of anterior cruciate ligament reconstructed (ACL-R) and healthy subjects (CG) during gait and classify the status of normality. Ten healthy and six ACL-R subjects had their gait analyzed at 60 fps. 3D knee angles were calculated and inserted into three separate matrices used to perform the principal component (PC) analysis. The scores of PCs retained in each analysis were used to calculate the standard distances (SD) of each participant in relation to the center of the CG. The PC scores of the three planes were used in a logistic regression to define normality. In the sagittal plane there was no difference between groups. In the frontal and transverse planes ACL-R subjects showed higher SD values than CG. PCs identified that ACL-R subjects showed increased adduction, internal and external rotation. All these subjects had their gait classified as abnormal by logistic regression. Therefore, in the studied ACL-R subjects the gait pattern did not return to normal levels after surgery. This may lead to degenerative injuries, as osteoarthritis, in the future.

Uso de medidas espaço-temporais da marcha para determinar o retorno ao esporte pós-reconstrução do LCA / Use of spatiotemporal gait parameters to determine return to sports after ACL reconstruction

Objetivo: Comparar os parâmetros espaço temporais da marcha de sujeitos hígidos e pacientes submetidos à reconstrução do LCA, classificando o status de normalidade. Método: Quatorze sujeitos hígidos e oito com reconstrução do LCA há aproximadamente um ano caminharam enquanto o movimento era capturado por um sistema de câmeras infravermelhas. Os instantes de contato inicial e retirada do pé do solo foram determinados e as seguintes variáveis dependentes, as quais foram comparadas entre os grupos por meio do teste Mann-Whitney(α=0,05), foram calculadas: percentual de tempo no apoio duplo inicial, percentual de tempo no apoio simples, percentual de tempo no apoio duplo terminal, comprimento da passada e velocidade da marcha. Inicialmente, foi aplicada uma regressão logística a todas as variáveis dependentes para determinar os sujeitos hígidos e aqueles com reconstrução do LCA. Resultados: Os dois grupos não apresentaram diferenças em nenhum parâmetro espaço temporal da marcha(p > 0,05), apesar da cinemática angular do joelho permanecer alterada,como evidenciado por um estudo anterior com a amostra similar.Conclusão: A regressão classificou todos os sujeitos como hígidos,inclusive aqueles do grupo com reconstrução do LCA, sugerindo que as variáveis espaço temporais aplicadas nesse estudo não devem ser usadas como critério isolado de retorno incondicional às atividades esportivas. Nível de Evidência III, Estudo de Caso Controle.

Objective: To compare gait spatiotemporal parameters of healthyand ACL reconstructed subjects in order to classify the status of gaitnormality. Methods: Fourteen healthy subjects and eight patientssubmitted to ACL reconstruction walked along a walkway while thelower limbs movement was captured by an infrared camera system.The frames where the initial contact and toe-off took place were determinedand the following dependent variables, which were comparedbetween groups through the Mann-Whitney test (α=0.05) were calculated:percentage of time in initial double stance, percentage of timein single stance, percentage of time in terminal double stance, stridelength and gait velocity. Initially, all variables were compared betweengroups using a Mann-Whitney test. A logistic regression was applied,including all dependent variables, to create a model that could differentiatehealthy and ACL reconstructed subjects. Results: ACLreconstructed group showed no differences in any spatiotemporalparameter of gait (p > 0.05) in relation to the control group, althoughthe angular kinematic differences of the knee remained altered, asevidenced in a study with a similar sample. Conclusion: The regressionclassified all subjects as healthy, including the ACL reconstructedgroup, suggesting the spatiotemporal variables should not be usedas the sole criterion of return to sports activities at the same level asprior to injury. Level of Evidence III, Case Control Study.

Subpeitoral ou subglandular: qual é a melhor localização do implante para pacientes com hipomastia? / The best plane for breast implantation in patients with hypomastia: submuscular or subglandular?

INTRODUÇÃO: A mamoplastia de aumento é um dos procedimentos mais realizados em cirurgia plástica no Brasil e no mundo. Existem duas localizações principais para o implante: o plano subpeitoral ou submuscular e o plano subglandular. O objetivo deste trabalho é defender o uso do plano subpeitoral em casos de hipomastia. MÉTODO: Dezesseis pacientes foram submetidas a aumento da mama entre 2008 e 2011. Utilizou-se o plano submuscular em 9 pacientes e o plano subglandular em 7. Miotomia do músculo grande peitoral foi realizada em todos os casos de localização submuscular. RESULTADOS: Foram selecionados 5 casos de pré e pós-operatório de pacientes submetidas a mamoplastia de aumento. Verificaram-se melhores resultados utilizando-se o plano submuscular para as pacientes com hipomastia acentuada. A miotomia do músculo peitoral provou ser fundamental para o sucesso da cirurgia, pois conferiu à loja submuscular o espaço necessário para abrigar o implante mamário, sem submetê-lo à pressão causada pela contração do músculo. CONCLUSÕES: O uso adequado do plano submuscular em pacientes com hipomastia é seguro, facilita o rastreamento de câncer de mama, não altera a função muscular, protege o parênquima mamário e garante resultados mais naturais e duradouros.

BACKGROUND: Breast augmentation is one of the most common plastic surgery procedures in Brazil and worldwide. There are 2 main locations for the implant: the subpectoral or submuscular plane and subglandular plane. The objective of the current study was to indicate the efficacy of the use of the subpectoral plane in cases of hypomastia. METHODS: Sixteen patients underwent breast augmentation between 2008 and 2011; the submuscular and subglandular planes were used in 9 and 7 patients, respectively. Myotomy of the pectoralis major muscle was performed in all cases where the submuscular plane was used. RESULTS: The pre- and postoperative aspects of 5 cases of patients undergoing breast augmentation are presented. Better results were obtained using the submuscular plane for patients with severe hypomastia. Myotomy of the pectoralis proved critical to the success of the surgery, because it provided the submuscular pocket required to house the breast implant without subjecting it to the pressure caused by muscle contraction. CONCLUSIONS: The proper use of the submuscular plane in patients with hypomastia is safe, facilitates cancer screening, does not alter muscle function, protects the breast parenchyma, and ensures more natural and long-term results.