Elsevier

Clinical Biomechanics

Volume 18, Issue 8, October 2003, Pages 780-782
Clinical Biomechanics

Brief report
Comparison of ground reaction forces between obese and control young adults during quiet standing on a baropodometric platform

https://doi.org/10.1016/S0268-0033(03)00123-2Get rights and content

Abstract

Objective. To determine whether centre of pressure location, plantar surface areas, or plantar pressures differ between obese and control young adults during quiet standing.

Design. Cross-sectional study in university setting.

Background. Given the characteristic distribution of body fat in obesity, it is possible that obesity may systematically alter centre of pressure location, plantar ground contact areas and pressure distributions in males and females.

Methods. Thirty-eight obese subjects (23 women and 15 men) and 34 healthy controls (18 women and 16 men) with a mean age of 23 years were studied. Subjects were asked to stand bipedally on a baropodometric platform while centre of pressure location, plantar ground contact surface areas and pressures were measured over a 5 s interval. Group differences were examined by analyses of variance and Fisher’s PLSD test.

Results. No significant group differences were found in centre of pressure location by weight or gender. Obesity was associated in both sexes with significantly larger plantar contact areas (+12.2%, P<0.0001 for women and +9.9%, P<0.005 for men) and pressures (mean load: +52.6% for women and +44.7% for men, P<0.0001 in both of sexes; peak pressure: +45.5% for women and +40.5% for men, P<0.0001 in both of sexes). There were significant gender differences in plantar contact areas (P<0.0001), while were no significant differences in mean and peak pressures.

Conclusions. Although centre of pressure location was unaffected by obesity, these young obese individuals showed significantly increased plantar contact areas and pressures.
Relevance

The higher plantar pressures associated with obesity may have negative ramifications for foot function over the longer term.

Introduction

The literature reports elevated plantar pressures in obesity (Hills et al., 2001; Vela et al., 1998; Cavanagh et al., 1991). The greatest effects have been found under the longitudinal arch of the foot and under the metatarsal heads (Hills et al., 2001). Moreover, obesity increases the risk for a fall (Richardson, 2002), perhaps because adiposity may move the centre of mass forward and affect postural stability in response to a perturbation (Corbeil et al., 2001). The aim of this study, therefore, was to test the primary hypothesis that centre of pressure (CoP) location is significantly further forward in quietly standing obese individuals than it is in age-matched controls. In addition, we tested the primary hypothesis that this would not be affected by gender. We tested the secondary hypothesis that either obesity or gender would affect plantar surface ground contact areas or pressures in order to corroborate earlier published results.

Section snippets

Methods

Thirty-eight obese subjects (23 women and 15 men) and 34 healthy controls (18 women and 16 men) with a mean age of 23 years were studied. Subjects were asked to stand bipedally on a baropodometric platform while CoP location, plantar ground contact surface areas and pressures were measured over a 5 s time interval. Obesity was defined as body mass index (BMI) of ⩾30.00 kg/m2.

The same researcher recorded the subjects’ body weight, stature, waist and hip circumferences in standing position

Results

The anthropometrical differences between obese and respective control groups were expected for both the sexes (Table 1). BMI and WHR were significantly higher in obese groups, whereas shoe size difference was significantly larger in the obese women, and marginally significant in the obese men, compared with the respective controls.

The total area of both feet was significantly increased in obese compared to control groups (+12.2%, P<0.0001 for women and +9.9%, P<0.005 for men; Table 2). Obese

Discussion

This study confirms that obesity in young subjects significantly modifies the plantar surfaces in both of sexes (Hills et al., 2001), with an increase in the ground mid-foot contact area, whereas the percentage pressure distribution in the plantar areas was not different between the obese and normal weight groups, in either sexes, during static weight bearing (standing). The wider plantar surfaces, including the mid-foot, and the higher plantar pressures for obese young subjects were not

Conclusion

Baropodometric analysis showed that the obese individuals of both sexes had greater total plantar surfaces and higher mean plantar pressure and peak values compared to controls. Obesity does not seem to influence the position of CoP under the foot during quiet standing.

Acknowledgements

This work was supported by a grant from the MURST. Special appreciation is extended to all volunteers who so willingly participated in these studies.

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