A Quantitative Evaluation of the Greater Toe Agility

We introduce the new method of quantitative assessment of the greater toe agility using the frequency response. In the patient rehabilitation with hallux valgus, therapists need the assessment of muscle strength and greater toe agility. In order to assess the muscle strength, they usually use the manual muscle testing (MMT) in a clinical setting, however, there are few studies on the measurement method of greater toe agility. We developed the new evaluation method to assess the agility of greater toe based on the frequency response. Two kinds of hallux valgus angles (hallux abductus angle and hallux interphalangeal abductus angle) are measured on each subject before the experiment. Two subjects were asked for sitting on the stool and watching the target moving on the monitor screen. They were also asked for pressing the button of load sensor in lateral directions following the target with their right greater toe. A target and the output force were displayed on the monitor and these time series were recorded. Target was moved 15 different frequencies from 0.2 Hz to 3 Hz. Then the frequency responses of the greater toe agility were obtained. The subject with larger hallux valgus angle showed lower cut off frequency than the healthy one. From the result, this method could be useful for detecting functional abnormalities of the greater toe.