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.

Kinematics and muscle forces in women with patellofemoral pain during the propulsion phase of the single leg triple hop test.

BACKGROUND: Approximately 25% of orthopedic knee conditions are related to patellofemoral pain (PFP), with young women being the most affected. It is thought that this condition is associated with modifications in the kinematics and muscle control patterns of the lower limb during weight-bearing support activities, which increases femur movement under the patella. OBJECTIVES: To compare kinematics and muscle induced acceleration patterns between PFP subjects and healthy controls during the preparation phase of the single leg triple hop test. STUDY DESIGN: Biomechanical analysis was performed using OpenSim. Ten physically active women (23.2 ±â€¯4 years, 59.3 ±â€¯5.8 kg, and 1.63 ±â€¯0.06 m) with no history of lower limb injury (CG) and 11 volunteers (23.5 ±â€¯2 years, 55.4 ±â€¯4.9 kg, and 1.66 ±â€¯0.04 m) with PFP (PFPG) were recruited. The participants performed a series of single leg triple hop tests while the ground reaction forces and kinematic data were recorded. RESULTS: Vector field statistical analysis indicated increased lumbar extension, anterior pelvic tilt, contralateral pelvic drop, and lower induced accelerations from the core and hip muscles in PFPG. CONCLUSION: PFP volunteers presented with alterations in lumbar muscle control associated with a possible compensatory pelvic strategy to minimize knee extensor moment.

Biomechanical alterations of gait on overweight subjects

Abstract Introduction Obesity is a major global public health issue and approximately half of the population is classified as overweight. Many studies have investigated gait modification in obese people; however, no research has been carried out in overweight subject´s gait influence. Methods The goal of this study was to identify biomechanical changes on gait in overweight subjects by the application of principal component analysis (PCA). Two groups of adults participated of this study: overweight (n = 9; 25.0 < Body Mass Index < 29.9 kg/m2), and normal-weight (n = 15; 20.0 < Body Mass Index < 24.9 kg/m2. Three-dimensional kinematics of the lower limb and ground reaction forces (GRF) were recorded during gait. PCA was performed on data. Results PCA evidenced statistical differences at the first principal component (PC) of the sagittal ankle movement, anteroposterior and mediolateral GRF, as well as at the third PC of the sagittal hip movement and mediolateral GRF. Overweight subjects walked with reduced ankle plantarflexion at toe-off and reduced hip flexion at the heel strike and at mid swing, as well as a reduced hip extension during push off. Additionally, increased anteroposterior and mediolateral GRF on overweight subjects were observed. Conclusion overweight individuals might adjust their gait characteristics in response to their increased weight to reduce overload lower limbs joints. These gait modifications pointed to a possible increase in the risk of musculoskeletal pathology in this population.

Análise do impacto do tênis e coturno fornecidos pelo exército brasileiro durante a marcha / Analysis of shock absortion during gait wearing tennis shoes and military boots from Brazilian Army

O objetivo do presente estudo foi comparar a absorção de impacto durante a marcha descalço e com tênis e coturno fornecidos pelo Exército Brasileiro. A amostra foi composta por 20 soldados saudáveis recém-incorporados sem sintomas ou lesões musculoesqueléticas ou neurológicas que interferissem na marcha. Os sujeitos foram instruídos a caminhar em uma plataforma de madeira de 10 metros de comprimento por um metro de largura, com duas plataformas de força (Bertec, EUA) embutidas no centro. O componente vertical da força de reação do solo foi avaliado durante a marcha nas situações tênis, coturno e descalço. O sistema de cinemetria (Qualysis, Suécia) foi utilizado para medir a velocidade da marcha em cada situação de teste. O primeiro pico de força (PPF), o tempo para atingir o PPF (T_PPF), pico transiente de impacto (IPF) e a taxa de aceitação do peso (TAP) entre 10% e 30%, 30% e 50%, 50% e 70%, 70% e 90% e 10% e 90% do PPF foram avaliadas. O T_PPF foi em média 1s menor (p < 0,0001), o IPF e a TAP entre 10% e 30% do PPF foram maiores (p < 0,0001, ambos) descalço comparados a marcha com tênis e coturno. Não foi observado diferença estatística nas outras variáveis estudadas nas três condições de teste, bem como em nenhuma variável na comparação entre tênis e coturno. Os calçados avaliados são eficientes em reduzir o impacto durante a marcha por atrasar em média 1 s o tempo em que o PPF foi atingido, reduzir o IPF e a TAP nos primeiros 30% do PPF

This study aimed at comparing shock absorption during gait while walking barefoot, tennis shoes and military boots. Twenty healthy soldiers without neurologic or musculoskeletal disorders were evaluated. Subjects walked 10 meters along a straight and level walkway at a comfortable speed in barefoot condition and using tennis shoes and military boots. Two force platforms (Bertec, EUA) were placed in serial at the middle of the walkway used to measure the ground reaction forces (GRF). The kinematic system (Qualysis, Sweden) was used to measure gait speed in each test condition. The first peak of force (FPF) of the vertical component of the GRF, time to reach to FPF (T_FPF), transient impact peak force (IPF) were evaluated and the weight acceptance rate at 10% to 30%, 30% to 50%, 50% to 70%, 70% to 90% and 10% to 90% of FPF. T_FPF was 1 s shorter (p < 0.0001), as well as IPF and weight acceptance rate at 10% to 30% in barefoot was higher (p < 0.0001, both) than tennis shoes and military boots gait patterns. None statistical difference was found in the others analyzed variables, even as in the tennis shoes and military boots comparisons. The analyzed footwear delayed the FPF impact during gait, reduce the IPF and the weight acceptance phase during 10% to 30% of FPF, being efficient in reduce impact forces during gait

Avaliação biomecânica das fraturas intra-articulares do calcâneo e sua correlação clínica radiográfica / Biomechanical evaluation of intra articular calcaneal fracture and clinical radiographic correlation

O presente estudo teve o objetivo de oferecer uma avaliação clínica, radiográfica e biomecânica de pacientes com fratura intraarticular de calcâneo, submetidos à redução aberta e fixação interna. A amostra consistiu em 22 pacientes, 20 do sexo masculino e dois do sexo feminino, com idade média de 40,95 (± 11,63) anos. Os autores realizaram avaliações radiográficas do ângulo de Bõhler e Gissane, no pré e no pós-operatório, além de utilizarem a tomografia computadorizada para avaliação da classificação de Sanders. A avaliação da Distribuição da Pressão Plantar foi realizada pelo sistema F-scan. Os resultados clínicos encontrados foram satisfatórios apresentando, pontuação média de 75,5 no critério da AOFAS.. A redução cirúrgica resultou em uma melhora dos ângulos de Bõhler e Gissane. O estudo mostrou diferenças estatisticamente significantes entre o antepé o retropé fraturados no que tange sobre a área de contato, pressão e força de reação do solo. Os valores encontrados para estes parâmetros foram maiores no retropé que no antepé fraturados. A trajetória de Pressão (COP) foi menor no pé fraturado que no pé normal. Encontrou-se correlação entre o Angulo de Gissane após a redução e o Segundo Pico de Força, indicando que quanto melhor a redução deste ângulo , melhor a impulsão. Também encontrou-se a correlação entre a pontuação AOFAS e o Primeiro Pico de Força, mostrando que quanto melhor o resultado clínico melhor o apoio do retropé.