Postural control assessed by limit of stability in obese adults

OBJECTIVES: Maintenance of body equilibrium was tested during voluntary leaning posture with the aim to determine the contribution of body weight to dynamic stability. METHODS: Ten obese subjects (mean BMI 31.4 +/- 1.5 kg. m(-2)) and ten subjects with normal weight (mean BMI 22.2 +/- 0.9 kg. m(-2)) participated in this study. The balance control was assessed by evaluating centre of foot pressure (CoP) amplitude of steady leaning position, variance of CoP leaning amplitude, leaning velocity and magnitude of postural adjustment (PA). Body segments position was also measured to investigate the postural strategies used to achieve the forward stability limit. RESULTS: We find that the ability to incline forward - limit of stability (LOS) of obese subjects was lower than in control subjects as attested by their smaller displacement of CoP. The variance of amplitude oscillations during steady leaning position was significantly higher in obese group compared to control group. Magnitude of postural adjustment had an increasing trend in obese group. The mean and maximal leaning CoP velocity was significantly slower for obese subjects. We observed significant difference between trunk and leg angles in obese group. CONCLUSION: The reduction of limit of stability, increase of CoP oscillation during leaning and limited progression of velocity suggest that an adaptive strategy in maintaining dynamic stability of balance is accepted in obese subjects.