RESUMO
BACKGROUND: The clinical measure of forefoot-shank alignment (FSA) predicts the amount of foot pronation during weight-bearing tasks. This may be mediated by a relationship between FSA and the mechanical resistance of the midfoot joint complex (MFJC) to forefoot inversion, which is a component of weight-bearing foot pronation. OBJECTIVE: To investigate if the clinical measure of FSA is associated with MFJC mechanical resistance to inversion. DESIGN: Cross-sectional observational study. METHOD: Forty-six healthy individuals (27 males; 19 females) with mean age of 26.4 years (SD 5.3) participated in this study. FSA was measured with photographs. The resistance torque of the MFJC against inversion was measured with a specially designed device. Mean torque, mean torque normalized by body mass, and joint resting position were calculated as variables related to MFJC mechanical resistance. Correlation analyses were carried out to test the association between each MFJC resistance variable and the FSA (αâ¯=â¯0.05). RESULTS: /findings: There were significant moderate correlations of FSA with mean torque (râ¯=â¯-0.44, pâ¯=â¯0.002), mean normalized torque (râ¯=â¯-0.42, pâ¯=â¯0.004) and resting position (râ¯=â¯0.39, pâ¯=â¯0.007). The clinical measure of FSA is associated to the mechanical resistance of the MFJC: (a) the greater the FSA, the smaller the resistance torques; (b) the greater the FSA, the more inverted the forefoot resting position. CONCLUSIONS: These results showed that the clinical measure of FSA is moderately related to mechanical properties of the MFJC.
Assuntos
Antepé Humano/fisiologia , Adulto , Fenômenos Biomecânicos , Estudos Transversais , Feminino , Voluntários Saudáveis , Humanos , Masculino , Fotografação , Pronação , Torque , Suporte de CargaRESUMO
BACKGROUND: Previous studies discussed the repeatability and variability in plantar pressure measurement, but a few considered different age groups. Here we determine within and between-days repeatability and variability of plantar pressure measurement during gait in participants from different age groups. METHOD: Plantar pressure was recorded in children, young adults and older adults walking at preferred speed in four non-consecutive days within one week. Data from 10 steps from each foot in each day were analyzed considering the different regions of the foot. Mean and peak plantar pressure and data variability were compared between the steps, foot regions and days. RESULTS: To describe mean and peak pressure during gait in children and adults a single measurement can be enough, but elderly will requires more attention especially concerning peak values. Variability in mean pressure did not differ between age groups, but peak pressure variability differed across foot regions and age groups. CONCLUSION: One single observation can be used to describe plantar pressure during gait in children and adults. When the interest concerns older people, it might be pertinent to consider more than one day of assessment, especially when looking at peak pressure.
Assuntos
Pé/fisiologia , Marcha/fisiologia , Pressão , Caminhada/fisiologia , Adulto , Fatores Etários , Idoso , Análise de Variância , Fenômenos Biomecânicos , Criança , Feminino , Antepé Humano/fisiologia , Humanos , Masculino , Manometria/métodos , Reprodutibilidade dos Testes , Fatores de TempoRESUMO
The purpose of this study was to evaluate the midfoot longitudinal arch height and correlate it with active hip external rotation (ER) in dancers during static postures and technical steps of classical ballet (i.e., first position, demi-plié, battement fondu à la seconde, pas jeté à la seconde, and grand jeté à la seconde). A 3D motion analysis system was used for kinematic analysis. The arch height was significantly reduced during the battement fondu à la seconde, pas jeté à la seconde, and grand jeté à la seconde when compared to standing (p = 0.000 for all comparisons), first position (p = 0.000, p = 0.000, and p = 0.001, respectively) and demi-plié (p = 0.015, p = 0.003, and p = 0.006, respectively). No significant correlation was found between arch height and active hip external rotation (p > 0.05). Hence, active hip external rotation does not seem to be related to midfoot pronation in this sample. Other factors, such as intrinsic and extrinsic foot muscle strength, may be related to the midfoot arch height. These findings contribute to a better understanding of ballet steps, but future studies are required to clarify this topic completely.
Assuntos
Dança/fisiologia , Antepé Humano/fisiologia , Músculo Esquelético/fisiologia , Amplitude de Movimento Articular/fisiologia , Articulação do Tornozelo/fisiologia , Fenômenos Biomecânicos , Feminino , Articulação do Quadril/fisiologia , Humanos , Masculino , Contração Muscular/fisiologia , RotaçãoRESUMO
This study aimed to investigate the activation of lower limb muscles during barefoot and shod running with forefoot or rearfoot footfall patterns. Nine habitually shod runners were asked to run straight for 20 m at self-selected speed. Ground reaction forces and thigh and shank muscle surface electromyographic (EMG) were recorded. EMG outcomes (EMG intensity [iEMG], latency between muscle activation and ground reaction force, latency between muscle pairs and co-activation index between muscle pairs) were compared across condition (shod and barefoot), running cycle epochs (pre-strike, strike, propulsion) and footfall (rearfoot and forefoot) by ANOVA. Condition affected iEMG at pre-strike epoch. Forefoot and rearfoot strike patterns induced different EMG activation time patterns affecting co-activation index for pairs of thigh and shank muscles. All these timing changes suggest that wearing shoes or not is less important for muscle activation than the way runners strike the foot on the ground. In conclusion, the guidance for changing external forces applied on lower limbs should be pointed to the question of rearfoot or forefoot footfall patterns.
Assuntos
Antepé Humano/fisiologia , Marcha/fisiologia , Músculo Esquelético/fisiologia , Corrida/fisiologia , Sapatos , Fenômenos Biomecânicos , Eletromiografia , Pé/fisiologia , Humanos , Perna (Membro)/fisiologia , Masculino , Tempo de Reação/fisiologia , Adulto JovemRESUMO
OBJECTIVE: The aim of this study was to evaluate the vertical component of the ground reaction force, plantar pressure, contact area of the feet and double-support time using static and dynamic (gait) baropodometry before and after bariatric surgery. METHODS: Sixteen individuals with a body mass index of between 35 and 55 were evaluated before and after bariatric surgery. Thirteen patients (81.3%) were female and three (18.8%) male and their average age was 46±10 (21-60) years. An FSCAN system (version 3848) was used for baropodometric analyses (1 km/h and 3 km/h). The peak plantar pressure and ground reaction force were measured for the rear foot and forefoot. The double-support time and foot contact area were measured during gait. RESULTS: There were reductions in the ground reaction force in the forefoot and rear foot and in the foot contact area in all evaluations and of the double-support time at 3 km/h, as well as a significant reduction in the body mass index at six months post-surgery. The peak pressure did not vary at 1 km/h and at 3 km/h, reductions in peak pressure were observed in the left and right rear feet and left forefoot. CONCLUSIONS: Weight loss after bariatric surgery resulted in decreases in the ground reaction force and contact area of the foot. Plantar pressure was decreased at 3 km/h, especially in the forefoot. There was an increase in rhythm because of a reduction in the double-support time at 3 km/h.
Assuntos
Cirurgia Bariátrica , Pé/fisiologia , Marcha/fisiologia , Aparelhos Ortopédicos , Pressão , Adulto , Fenômenos Biomecânicos/fisiologia , Índice de Massa Corporal , Feminino , Antepé Humano/fisiologia , Humanos , Masculino , Pessoa de Meia-Idade , Podiatria/métodos , Redução de Peso/fisiologia , Adulto JovemRESUMO
OBJECTIVE: The aim of this study was to evaluate the vertical component of the ground reaction force, plantar pressure, contact area of the feet and double-support time using static and dynamic (gait) baropodometry before and after bariatric surgery. METHODS: Sixteen individuals with a body mass index of between 35 and 55 were evaluated before and after bariatric surgery. Thirteen patients (81.3%) were female and three (18.8%) male and their average age was 46±10 (21-60) years. An FSCAN system (version 3848) was used for baropodometric analyses (1 km/h and 3 km/h). The peak plantar pressure and ground reaction force were measured for the rear foot and forefoot. The double-support time and foot contact area were measured during gait. RESULTS: There were reductions in the ground reaction force in the forefoot and rear foot and in the foot contact area in all evaluations and of the double-support time at 3 km/h, as well as a significant reduction in the body mass index at six months post-surgery. The peak pressure did not vary at 1 km/h and at 3 km/h, reductions in peak pressure were observed in the left and right rear feet and left forefoot. CONCLUSIONS: Weight loss after bariatric surgery resulted in decreases in the ground reaction force and contact area of the foot. Plantar pressure was decreased at 3 km/h, especially in the forefoot. There was an increase in rhythm because of a reduction in the double-support time at 3 km/h.
Assuntos
Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Adulto Jovem , Cirurgia Bariátrica , Pé/fisiologia , Marcha/fisiologia , Aparelhos Ortopédicos , Pressão , Índice de Massa Corporal , Fenômenos Biomecânicos/fisiologia , Antepé Humano/fisiologia , Podiatria/métodos , Redução de Peso/fisiologiaRESUMO
Lack of alignment between the lowerlimb structures, such as the hips, knees, and longitudinal arches of the feet, has been described as an important predisposing factor in musculoskeletal injury among classical ballet dancers. However, no studies were found that analyzed basic ballet movements with quantification of objective criteria of the movements. The purposes of this study were: 1. to establish a methodology to quantify, using kinematic evaluation, the technical criteria that guide the correct execution of all phases of the plié (simultaneous flexion of the hips, knees, and ankle joints); and 2. to explore whether experienced ballet dancers respect those criteria when performing the plié. The technical criteria considered were the following: 1. midfoot stability; 2. pelvic positioning in a neutral alignment; 3. pelvic stability, represented by pelvic angle variation; and 4. vertical alignment of the knee joint with the second toe of the ipsilateral foot. Twenty dancers from Porto Alegre, Brazil, with 18 years of uninterrupted ballet training, were filmed while performing plié using four synchronized cameras. The descriptive statistical analysis involved calculating the median, minimum, and maximum of each of the technical criteria. Results showed that for criterion 1, the 20 dancers showed great stabilization of the midfoot; for criteria 2 and 3, 18 dancers displayed pelvic instability tending toward retroversion throughout execution of the plié; and for criterion 4, 13 dancers presented with medial misalignment of the knees at all phases of the plié. Using these criteria, it was possible to characterize the plié from a kinematic point of view.
Assuntos
Dança/fisiologia , Calcanhar/fisiologia , Equilíbrio Postural/fisiologia , Dedos do Pé/fisiologia , Articulação do Tornozelo/fisiologia , Brasil , Feminino , Antepé Humano/fisiologia , Articulação do Quadril/fisiologia , Humanos , Extremidade Inferior/fisiologia , Masculino , Contração Muscular/fisiologiaRESUMO
OBJECTIVES: To investigate the relationships between the perception of comfort and biomechanical parameters (plantar pressure and ground reaction force) during running with four different types of cushioning technology in running shoes. DESIGN: Randomized repeated measures. METHODS: Twenty-two men, recreational runners (18-45 years) ran 12km/h with running shoes with four different cushioning systems. Outcome measures included nine items related to perception of comfort and 12 biomechanical measures related to the ground reaction forces and plantar pressures. Repeated measure ANOVAs, Pearson correlation coefficients, and step-wise multiple regression analyses were employed (p≤0.05). RESULTS: No significant correlations were found between the perception of comfort and the biomechanical parameters for the four types of investigated shoes. Regression analysis revealed that 56% of the perceived general comfort can be explained by the variables push-off rate and pressure integral over the forefoot (p=0.015) and that 33% of the perception of comfort over the forefoot can be explained by second peak force and push-off rate (p=0.016). CONCLUSIONS: The results did not demonstrate significant relationships between the perception of comfort and the biomechanical parameters for the three types of shoes investigated (Gel, Air, and ethylene-vinyl acetate). Only the shoe with Adiprene+ technology had its general comfort and cushioning perception predicted by the loads over the forefoot. Thus, in general, one cannot predict the perception of comfort of a running shoe through impact and plantar pressure received.
Assuntos
Antepé Humano/fisiologia , Corrida/fisiologia , Sapatos , Equipamentos Esportivos , Adulto , Fenômenos Biomecânicos , Humanos , Masculino , Pessoa de Meia-Idade , Percepção , Pressão , Distribuição Aleatória , Método Simples-CegoRESUMO
BACKGROUND: The forefoot midsole stiffness of the shoe may affect the kinematics of the foot segments. We evaluated the effects of two different levels of forefoot midsole stiffness on the angular displacement of the forefoot and rearfoot in the three planes of motion during the stance phase of gait. METHODS: Thirty-six participants walked on a 10-m walkway at their self-selected speed wearing shoes having either low or high forefoot midsole stiffness. Three-dimensional kinematic data of the foot segments were obtained during the stance phase of gait using an eight-camera motion analysis system synchronized with a force platform. The dependent variables were forefoot and rearfoot total range of motion and maximum and minimum angle values in the sagittal, frontal, and transverse planes of motion. RESULTS: Reduced forefoot midsole stiffness produced significantly greater forefoot total range of motion in the sagittal plane (1.59°). The low-stiffness condition also increased the magnitude of the forefoot dorsiflexion angles (4.14°). Furthermore, the low-stiffness condition increased the magnitude of the rearfoot inversion (1.21°) and adduction (11.38°) angles and reduced the rearfoot abduction angle (12.1°). CONCLUSIONS: It is likely that reduced stiffness of the forefoot midsole stretched the plantar fascia, increasing rearfoot stability during the stance phase of gait. Increased muscular contraction may also explain increases in rearfoot stability. Therefore, the integrity of the plantar fascia and ankle muscles' force and resistance should be considered when choosing a shoe with reduced or increased forefoot midsole stiffness for walking.
Assuntos
Órtoses do Pé , Antepé Humano/fisiologia , Marcha/fisiologia , Adulto , Feminino , Humanos , Masculino , Amplitude de Movimento Articular , Sapatos , Suporte de Carga/fisiologia , Adulto JovemRESUMO
BACKGROUND: The intention of this investigation was to longitudinally describe and compare the plantar pressure distribution in orthostatic posture and gait throughout pregnancy. METHODS: A prospective longitudinal observational study was conducted with six pregnant women (mean ± SD age, 32 ± 3 years) with a mean ± SD weight gain of 10.0 ± 1.4 kg. Peak pressure, contact time, contact area, and maximum force in five plantar areas were evaluated using capacitive insoles during gait and orthostatic posture. For 1 year, the plantar pressures of pregnant women were evaluated the last month of each trimester. Comparisons among plantar areas and trimesters were made by analysis of variance. RESULTS: For orthostatic posture, no differences in contact time, contact area, peak pressure, and maximum force throughout the trimesters were found. During gait, peak pressure and maximum force of the medial rearfoot were reduced from the first to third and second to third trimesters. Maximum force increased at the medial forefoot from the first to second trimester. Contact area increased at the lateral rearfoot from the second to third trimester and at the midfoot from the first to third trimester. Contact time increased at the midfoot and medial and lateral forefoot from the first to third trimester. CONCLUSIONS: Pregnant women do not alter plantar pressure during orthostatic posture, but, during gait, the plantar loads were redistributed from the rearfoot (decrease) to the midfoot and forefoot (increase) throughout pregnancy. These adjustments help maintain the dynamic stability of the pregnant woman during locomotion.
Assuntos
Pé/fisiologia , Marcha/fisiologia , Postura/fisiologia , Feminino , Antepé Humano/fisiologia , Humanos , Gravidez , Trimestres da Gravidez/fisiologia , Pressão , Estudos ProspectivosRESUMO
BACKGROUND: The influence of distal mechanical factors that change the interaction between the forefoot and the support surface on lower-limb kinematics is not well established. This study investigated the effects of the use of lateral wedges under the forefoot on the kinematics of the lower extremity during the stance phase of walking. METHODS: Sixteen healthy young adults participated in this repeated-measures study. They walked wearing flat sandals and laterally wedged sandals, which were medially inclined only in the forefoot. One wedged sandal had a forefoot lateral wedge of 5 degrees and the other wedged sandal had a forefoot lateral wedge of 10 degrees. Kinematic variables of the lower extremity, theoretically considered clinically relevant for injury development, were measured with a three-dimensional motion analysis system. The variables were evaluated for three subphases of stance: loading response, midstance, and late stance. RESULTS: The 5 degrees laterally wedged sandal increased rearfoot eversion during midstance and the 10 degrees laterally wedged sandal increased rearfoot eversion during mid- and late stances, in comparison to the use of flat sandals. The 10 degrees laterally wedged sandal produced greater internal rotation of the shank relative to the pelvis and of the hip joint, during the midstance, also compared to the use of flat sandals. CONCLUSIONS: Lateral wedges under the forefoot increase rearfoot eversion during mid-and late stances and may cause proximal kinematic changes throughout the lower-extremity kinetic chain. Distal mechanical factors should be clinically addressed when a patient presents late excessive rearfoot eversion during walking.