Experiment

Procedure
- Tibialis anterior muscle: The active 4-bar electrode (1-cm-long bar); distance between each bar was 1 cm.
- Supramaximal stimulation: a pair of stimulation pads (2.5 cm by 2.5 cm) on the motor point area; The period of the stimulation pulse was 1 s.
- Force transducer:
- 70% MVC:
- Visual feedback:
- Three trials:

Signal Conditioning
- Raw surface EMG signals: bandpass filtered, 53 - 1000 Hz: 60 dB.
- Force output and the two single differential EMG signals were sampled at 5 kHz.