Movement Behavior of High-Heeled Walking: How Does the Nervous System Control the Ankle Joint during an Unstable Walking Condition?

The human locomotor system is flexible and enables humans to move without falling even under less than optimal conditions. Walking with high-heeled shoes constitutes an unstable condition and here we ask how the nervous system controls the ankle joint in this situation? We investigated the movement behavior of high-heeled and barefooted walking in eleven female subjects. The movement variability was quantified by calculation of approximate entropy (ApEn) in the ankle joint angle and the standard deviation (SD) of the stride time intervals. Electromyography (EMG) of the soleus (SO) and tibialis anterior (TA) muscles and the soleus Hoffmann (H-) reflex were measured at 4.0 km/h on a motor driven treadmill to reveal the underlying motor strategies in each walking condition. The ApEn of the ankle joint angle was significantly higher (p<0.01) during high-heeled (0.38±0.08) than during barefooted walking (0.28±0.07). During high-heeled walking, coactivation between the SO and TA muscles increased towards heel strike and the H-reflex was significantly increased in terminal swing by 40% (p<0.01). These observations show that high-heeled walking is characterized by a more complex and less predictable pattern than barefooted walking. Increased coactivation about the ankle joint together with increased excitability of the SO H-reflex in terminal swing phase indicates that the motor strategy was changed during high-heeled walking. Although, the participants were young, healthy and accustomed to high-heeled walking the results demonstrate that that walking on high-heels needs to be controlled differently from barefooted walking. We suggest that the higher variability reflects an adjusted neural strategy of the nervous system to control the ankle joint during high-heeled walking

Análise do arco longitudinal medial em adolescentes usuárias de calçados de salto alto Analysis of the medial longitudinal arch in adolescents users of high heeled shoes

O objetivo do estudo foi analisar a influência do calçado de salto alto no arco longitudinal medial (ALM) do pé de adolescentes. Fizeram parte do estudo 82 adolescentes entre 13 e 20 anos, sendo 54 não usuárias (grupo controle - GC) e 28 usuárias (grupo experimental - GE) de calçado de salto alto. Foram obtidas as impressões plantares de ambos os pés para análise do ALM, antes e depois do uso de um calçado de salto alto padronizado por um período de 30 minutos. As impressões plantares foram avaliadas pelo índice de Chippaux-Smirak (ICS) e pelo arco de Cavanagh & Rodgers (ICR). O teste de Shapiro-Wilks foi utilizado para a verificação da normalidade dos dados. Variáveis paramétricas pareadas foram tratadas com o Teste t de Student pareado e as não-paramétricas com o teste de Wilcoxon. As comparações não-pareadas foram realizadas com o teste t de Student para as variáveis paramétricas e o de Mann-Withney para as não-paramétricas, com nível de significância de 0,05. Houve diferença no ALM entre os lados direito e esquerdo apenas no GC antes do uso do calçado. Na comparação entre antes e depois do uso do sapato, notou-se diferença apenas no pé esquerdo do GC pelo ICS. Já entre GC e GE, não houve diferença. Apesar dos resultados não evidenciarem alterações no ALM, deve-se lembrar que esta é uma medida estática, sendo necessários estudos do componente dinâmico e do uso do calçado de salto crônico para correlacionar com os achados deste trabalho.<br>The aim of this study was to analyze the influence of high heeled shoes in foot´s medial longitudinal arch in adolescents. Eighty two female adolescents between 13 and 20 years old participated, being 54 non-users of high heleed shoes (control group - GC) and 28 usuaries (experimental group - GE). The footprints of both feet were collected to analyse the medial longitudinal arch (ALM), before and after 30 minutes using a shoe with heel high given by the examiner, an then evaluated by Chippaux-Smirak index (ICS) and Cavanagh & Rodgers Arch index (ICR). The Shapiro-Wilks test was performed to evaluate data normality. For paired comparisons, paired Student's t-test was used in case of parametric data, and the Wilcoxon test in non-parametric data. In non-paired comparisons was used the Student's t-test and the Mann-Whitney test with a level of significance of 0.05. There was a difference between right and left only in CG before the use of the shoe given by the examiner. Comparing before and after the use of this shoe, a difference was noticed only on left foot in CG by ICS. There wasn't any significative difference between CG and EG. Although the results haven´t shown changes in ALM, it must be remembered this is only a static measure, being necessary studies of the dinamic component and the chronic use of high heeled shoes to correlate with the findings of this work

The effect of high-heeled shoes on overground gait kinematics in young healthy women

Purpose The purpose of this study was to assess the modifications in body center of mass (CoM), total mechanical work and walking characteristics during low-heeled and high-heeled gait performed in ecological conditions. Methods The 3D coordinates of 19 body landmarks were recorded by an optoelectronic motion analyzer in 13 women while walking overground at self-selected speed with either low-heeled or high-heeled shoes (minimum height, 70 mm). Using mean anthropometric data, the CoM was estimated, and its position evaluated during normalized gait cycles. Shoulders, pelvic and knee orientations were also assessed together with estimates of total mechanical work. Results High-heeled walking was performed with significantly lower horizontal speed (p < 0.05) but with the same cadence than low-heeled walking. During the whole gait cycle, the CoM (calculated from the malleolus landmarks) was 3 % lower during high-heeled walking (p < 0.05), had higher vertical displacements and vertical velocity modifications (p < 0.001), and it was significantly more anterior (p < 0.01). On average, walking with high heels at self-selected speed required a 16 % higher total mechanical work, but the difference was not significant. At heel strike with high heels, the shoulders were more inclined (p < 0.05), the support limb knee was significantly more flexed (p < 0.05), with a 12 % reduced total range of motion (p < 0.001), while the back limb knee was less flexed (p < 0.05). Conclusions Wearing high-heeled shoes significantly alters the normal displacement of human CoM; high-heeled gait exaggerated female walking characteristics with a more anterior CoM position, a wider vertical movement and a slower velocity