Maintaining balance is a factor critical and integral to our effective physical function as it relates to the normal activities of daily living. Of the “hip strategy”, “stepping strategy” and “ankle strategy”, it is known and accepted that the “ankle strategy” is the first activated parameter to assist in the maintenance of balance in motor output. However, few studies actually evaluated or assessed the precise attributes of “ankle strategy” in relation to any therapeutic effort tocorrect and/or rehabilitate from physical imbalance caused by dynamic tilting perturbation. The aim of the study was to identify precise characteristics of the “ankle strategy” as they respond to dynamic tilting perturbations. Seven healthy male (aged 25.5 ± 1.7 years, average height of 173.9 ± 6.4 cm, average body mass of 71.3 ± 6.5 kg) were recruited to participate. The ankle joint motions were subjected to eight dynamic tilting perturbations generated by the customized tilting perturbation simulator, and the responses were measured by 3D motion capture system. Concurrently, foot pressure distribution and the corresponding centers of pressure (COP) trajectory were measured by a pressure measuring system, and the four main muscles’ activations related to the ankle joint motions were measured by wireless electromyogram system.

The purpose of this study was to develop and verify the smart insole based FSR sensor for measurement and improvement of the muscle strength imbalance. We recruited 15 subjects with muscle strength difference over 20% and 15 subjects with muscle strength balance below 10%. We developed the human body load insole and integrated modules using FSR sensor. Subjects walked for 5 minutes at a slope of 0% and a speed of 3 km / h on a treadmill with a smart insole. We measured the real-time muscle activity and foot pressure according to the muscle strength imbalance during gait. FSR data of the developed smart insole showed that the insole had similar accuracy and efficacy as muscle activity and foot pressure. This is the interval in which the muscle imbalance shifts from the stance phase to the load reaction, and the weight support is the largest, and the center of gravity of the human body passes over the whole foot, which is considered to cause the greatest imbalance. This suggests that there is a direct or indirect correlation between muscle strength imbalance of the lower limb and the imbalance of the body weight distribution during gait.