Mechanisms underlying center of pressure displacements in obese subjects during quiet stance

Objective: the aim of this study was to assess whether reduced balance capacity in obese subjects is secondary to altered sensory information. Design: cross sectional study. Subjects: 44 obese (BMI = 40.6 +/- 4.6 kg/m(2), age = 34.2 +/- 10.8 years, body weight: 114,0 +/- 16,0 Kg, body height 167,5 +/- 9,8 cm) and 20 healthy controls (10 females, 10 males, BMI: 21.6 +/- 2.2 kg/m(2), age: 30.5 +/- 5.5 years, body weight: 62,9 +/- 9,3 Kg, body height 170,1 +/- 5,8 cm) were enrolled. Measurements: center of pressure (CoP) displacements were evaluated during quiet stance on a force platform with eyes open (EO) and closed (EC). The Romberg quotient (EC/EO) was computed and compared between groups. Results: we found statistically significant differences between obese and controls in CoP displacements (p < 0.01) and no statistically significant differences in Romberg quotients (p > 0.08). Conclusion: the increased CoP displacements in obese subjects do not need an hypothesis about altered sensory information. The integration of different sensory inputs appears similar in controls and obese. In the latter, the increased mass, ankle torque and muscle activity may probably account for the higher CoP displacements.