The Influence Of Thigh Circumference And Waist-to-hip Ratio On Step Width In A Large Sample Of Women

Abstract

Kinematic analyses of obese individuals have found significantly altered gait mechanics. Of the dynamic changes routinely identified, increased step width (SW) appears to be one of the most common and crucial adjustments that occur. The prevailing hypothesis asserts that this increase, resulting from either disproportionate thigh girth or excessive thigh adiposity, provides for greater control of lateral balance while walking. However, little research has been published in this area and, as is typical with gait analyses, the sample sizes are very small. To date, no studies have looked at thigh circumference (TC) and SW across a large spectrum of obese and non-obese women. PURPOSE To examine the influence of TC, waist-to-hip ratio (WH), BMI and percent body fat on SW in a population of middle aged women. METHODS Gait data were collected from a sample of 125 healthy women (mean age 36.9 ± 8.6 years, mean BMI 26.2 ± 5.3) participating in research testing at the Lifespan Health Research Center. Participants walked barefoot at a self-selected velocity across a 13.5 meter walkway in the center's Motion Analysis Laboratory. These trials were recorded by a six camera, three force plate motion capture system (Motion Analysis Corporation). Three walking trials in which each foot contacted separate force plates were subsequently analyzed. Additionally, anthropometrics including stature, weight, and abdomen, hip and thigh circumferences were obtained. Standard descriptive statistics and Pearson's product moment correlations were computed. A multiple regression analysis was used to determine the influence of TC and waist-to-hip ratio on SW. RESULTS Significant correlations were found when comparing TC, WH, BMI and percent body fat to SW (0.40, 0.44, 0.41, and 0.33 respectively, p<0.01). TC alone accounted for just over sixteen percent of the variance (R2 = 0.16, p<0.01), whereas TC and WH combined to account for one quarter of the variance in SW (R2 = 0.25, p<0.01). Models run with TC, WH and BMI or TC, WH and percent body fat did not account for any increase in variance, and in fact, both BMI and percent body fat caused the each model to become statistically insignificant due to multicolinearity. CONCLUSIONS Although thigh girth does affect variation in SW, differences in SW appear to be more strongly tied to body proportionality rather than obesity in adult women. The influence of the distribution of body mass throughout the trunk and lower body suggests that certain body types may be more prone to the typical gait changes, such as increased SW, associated with obesity. Supported by NIH grants HD12252 and HL06995