The delay of the sensory-motor feedback loop is a destabilizing factor within the neural control mechanism of quiet standing. The purposes of this study were 1) to experimentally identify the neuro-musculo-skeletal torque generation process during standing, and 2) to investigate the effect of the delay induced by this system on the control mechanism of balance. Ten healthy adults participated. The ankle torque, angle, and electromyograms from the right lower leg muscles were measured. A ground-fixed device was used to support the subject at knees, without changing the natural ankle angle during standing. Each subject was asked to mimic the ankle torque fluctuation by exerting voluntary ankle extension while keeping the supported standing posture. Utilizing the rectified soleus electromyogram as the input and the ankle torque as the output, a critically damped, second-order system successfully described the dynamics of the torque generation process. The phase delay induced by this process in the frequency region of spontaneous body sway was considerably large, corresponding to an effective time delay of about 200 to 380 ms. We compared the stability of the balance control system with and without the torque generation process, and demonstrated that a much smaller number of gain combinations can stabilize the model with the torque generation process than without it. We concluded that the phase delay induced by the torque generation process is a more destabilizing factor in the control mechanism of quiet standing than previously assumed, which restricts the control strategies that can stabilize the entire system.