Balance control impairment in obese individuals is caused by larger balance motor commands variability

- A feedback model of the human balance control accounted for the statistical properties of lean and overweight individuals.
- Faster center of pressure speed observed in overweight individuals is caused by larger balance motor commands variability.
- Altered sensory reweighting could also explain the increased in balance motor commands variability.

It is acknowledged that various factors impaired balance control. Among them, heavy body weight is associated with poor balance control because the location of the center of mass is further away from the ankle joint. Thus, a larger active ankle torque is required to counter the greater gravitational torque. Because balance motor commands have signal-dependent noise whose standard deviation increases with the absolute value of the neural control signal, it was hypothesized that faster center of pressure speed observed in obese individuals would be related to larger balance motor commands variability. A feedback-control model and parametric system identification technique was used to estimate the variability in the balance motor commands and neural controller parameters based on previously published experimental data. Results of the neuromechanical model confirmed that the balance motor commands of obese individuals are more variable than that of lean individuals.