Browsing by Author "De Villiers, Johanna Elsabe"

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    The effects of being habitually barefoot on foot mechanics and motor performance in children and adolescents aged 6–18 years : study protocol for a multicenter crosssectional study (Barefoot LIFE project)
    (BioMed Central, 2016-09-02) Hollander, Karsten; Van der Zwaard, Babette C.; De Villiers, Johanna Elsabe; Braumann, Klaus-Michael; Venter, Ranel; Zech, Astrid
    Background: Barefoot locomotion has evoked an increasing scientific interest with a controversial debate about benefits and limitations of barefoot and simulated barefoot walking and running. While most current knowledge comes from cross sectional laboratory studies, the evolutionary perspective suggests the importance of investigating the long-term effects. Observing habitually barefoot populations could fill the current gap of missing high quality longitudinal studies. Therefore, the study described in this design paper aims to investigate the effects of being habitually barefoot on foot mechanics and motor performance of children and adolescents. Methods: This study has a cross-sectional, binational design and is part of the “Barefoot Locomotion for Individual Foot- and health Enhancement (Barefoot LIFE)” project. Two large cohorts (n(total) = 520) of healthy children and adolescents between 6 and 18 years of age will be included respectively in Germany and South Africa. A barefoot questionnaire will be used to determine habitually barefoot individuals. The testing will be school-based and include foot mechanical (static arch height index, dynamic arch index, foot pliability) and motor performance (coordination, speed, leg power) outcomes. Gender, BMI and level of physical activity will be considered for confounding. Discussion: The strength of this study is the comparison of two large cohorts with different footwear habits to determine long-term effects of being habitually barefoot on foot mechanics and motor performance
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    Foot strike patterns differ between children and adolescents growing up barefoot vs. shod
    (Georg Thieme Verlag, 2017) Hollander, Karsten; De Villiers, Johanna Elsabe; Venter, Ranel; Sehner, Susanne; Wegscheider, Karl; Braumann, Klaus-Michael; Zech, Astrid
    Effects of early and permanent footwear use are not well understood. The aim of this study was to investigate the effects of habituation to footwear on foot strike patterns of children and adolescents. Healthy habitually barefoot and shod participants (aged 6–18 years) from South Africa (n=288) and Germany (n=390) performed multiple 20-m jogging and running trials with and without shoes. Each foot strike was captured using a high-speed camera to determine a rearfoot or non-rearfoot strike. The probability of a rearfoot strike in both cohorts and each age was analyzed by using a mixed-effects logistic regression adjusted for possible confounders. Habitually barefoot children showed a higher probability of using rearfoot strikes than habitually shod children (p<0.001). The probability was age-dependent and decreased in habitually barefoot children with age (ORbarefoot-jogging=0.82, 95% CI, 0.71 to 0.96, p=0.014; ORbarefoot-running=0.58, 95% CI, 0.50 to 0.67, p<0.001 and ORshod-running=0.68, 95% CI, 0.59 to 0.79, p<0.001). In habitually shod children, the probability increased significantly for shod jogging (OR=1.19, 95% CI, 1.05 to 1.35, p=0.006). To conclude, foot strike patterns of children are influenced by habituation to footwear. Younger habitually barefoot children show higher rates of rearfoot strikes for shod and barefoot running, and it converges in later adolescence.
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    Growing feet : foot metrics and shoe fit in South African school-aged children and adolescents
    (Stellenbosch : Stellenbosch University, 2017-03) De Villiers, Johanna Elsabe; Venter, Ranel; Zech, Astrid; Stellenbosch University. Faculty of Education. Dept. of Sport Science
    ENGLISH ABSTRACT : The foot undergoes numerous developmental changes during the first few years of life. Due to this continued development of the foot during childhood, it leaves the feet of children exposed to external influences. Factors such as age, gender and footwear can have a significant impact on the development of the foot. The primary aim of the study was to investigate whether the foot metrics of South African children and adolescents are influenced by age, gender, race and body mass index (BMI). A secondary aim of this study was to establish if South African children and adolescents wear well-fitting shoes. A total of 568 children and adolescents between the ages of six and eighteen years from schools within the Western Cape, South Africa, participated in the study. Static foot length and width were measured with a self-manufactured calliper and school shoe length and width were measured with a flexible straw and sliding calliper respectively. Shoe fit was determined by the difference between the width of the foot and the width of the shoe as well as the difference between the length of the shoe and the length of the foot. A toe allowance was also considered. Dynamic arch index (AI) was measured by using the Emed c50 pressure plate (Novel GmbH, Munich, Germany). The effect of age, gender, race, and BMI on foot length, width and dynamic AI was evaluated, as well as its effect on the shoe fit. Statistical analyses were done by using the one-way ANOVA and two-way ANOVA with Fisher’s least significant differences as post-hoc test, as well as its effect on the shoe fit. Cohen’s effect size (ES) for each parameter was calculated to determine practical differences. Gender and race significantly (p < 0.05) influenced the foot length and width of children and adolescents. Girls had shorter and narrower feet than boys. The girls showed no significant increase in foot length and width measurements after 12 years of age. White children had significantly (p < 0.05) and medium practically longer and wider feet, and a lower AI (p < 0.05) than the brown children and adolescents. Statistically (p < 0.05) and practically significant differences in foot length, width and AI were found between the different BMI categories. Furthermore, results show that 67 percent of the children and adolescents wore ill-fitting shoes when looking at the length of school shoes compared to the length of the feet, taking toe allowance into account. There was a significant difference in shoe fit for the width between genders, with girls wearing more tight fitting shoes than boys. Significant differences were seen in the shoe fit for length measurements between the different races, where the brown children’s shoes were a tighter fit than the white children’s shoes. The obese South African children have worn shoes that were too narrow for their feet.
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    Growing-up (habitually) barefoot influences the development of foot and arch morphology in children and adolescents
    (Nature Research, 2017) Hollander, Karsten; De Villiers, Johanna Elsabe; Sehner, Susanne; Wegscheider, Karl; Braumann, Klaus-Michael; Venter, Ranel; Zech, Astrid
    The development of the human foot is crucial for motor learning in children and adolescents as it ensures the basic requirements for bipedal locomotion and stable standing. Although there is an ongoing debate of the advantages and disadvantages of early and permanent footwear use, the influence of regular barefootness on foot characteristics in different stages of child development has not been extensively evaluated. A multicenter epidemiological study was conducted to compare the foot morphology between habitually barefoot children and adolescents (N = 810) to age-, sex- and ethnicity-matched counterparts that are used to wearing shoes. While controlling for confounders, we found that habitual footwear use has significant effects on foot-related outcomes in all age groups, such as a reduction in foot arch and hallux angles. The results indicate an impact of habitual footwear use on the development of the feet of children and adolescents. Therefore, growing up barefoot or shod may play an important role for childhood foot development, implying long-term consequences for motor learning and health later in life.