Role of Toe - Flexors in Ankle Plantar Flexion during Normal and Rapid Walking - 3 Dimensional Kinetic Study

Chung, Chin Youb; Jung, Hong Geun; Ahn, Jong Hwa

Abstract

It is known that the toe-flexors exert some power generation in ankle plantar flexion. However, there has been no paper published in which the power generation was quantified. The purpose of this paper, therefore, is to quantify the amount of contribution of the toe-flexors to the ankle plantar-flexion in normal and rapid walking using the kinetic data of three dimensional gait analysis system. In order to restrict the action of the toe-flexors, we designed special braces which can be applied to the forefeet of the examinee during walking. We performed the gait analysis in ten normal adult volunteers with and without braces, and evaluated the moment and power of toe-flexors during terminal stance and pre-swing phase of gait cycle. Gait analysis was done with the VICON 3-dimensional motion analysis system (VICON, Oxford Metrics, Oxford, England) and 2 force plates (AMTI, Advanced Mechanical Technoiogy, Newton, MA, U.S.A,). The kinetic results are as follows: l. Average speeds of normal and rapid walking were 1.12m/sec and 1.41m/sec respectiveIy. 2. In normal walking, peak ankle plantar-tlexion moment decreased 5.5% with braces, and sum of ankle plantar-flexion moment decreased 12.3% with braces. Both of the results were not significant statistically (p>0.05). Peak ankle power generation decreased 11.0% with braces, and sum of ankle power generation decreased 10.4% with braces. These decreases were also insignificant statistically (p>0.05). 3. In rapid walking, peak ankle plantarflexion moment decreased 26.7% with braces. The decrease was horderline significant statistically (p=0.062). The sum of ankle plantar-tlexion moment decreased 26.6% with braces, but the decrease was not significant statistically (p>0.05). Peak ankle power generation decreased 40.2% with braces, and sum of ankle power generation decreased 37.9% with braces. These decreases showed borderline significance statistically (p=0.062). In conclusion, toe-flexors may contribute about 10% of the total ankle plantar-flexion power generation, and the contribution will be increased with increase of walking velocity. We must be very careful to sacrifice the toe-flexors in cases with weak triceps power.