Abstract
Computerized analysis of rat gait is becoming an invaluable technique used by some peripheral nerve investigators for the evaluation of function. In this article we describe the use of a biomechanical model of the foot and ankle that allows a quantitative assessment and description of the ankle angle, reflecting plantarflexion and dorsiflexion during the stance phase of gait. Kinematic data of 144 trial walks from 36 normal rats were recorded with a high-speed digital image camera at 225 images per second. The ankle angular changes associated with the specific temporal events of foot placement on the ground through the stance phase were assessed. The information obtained was used to propose a new subdivision of the stance phase in the rat into three major components. This approach will provide a helpful research tool to analyze gait data that rely on the accurate determination of spatiotemporal foot events. (C) 2002 Wiley Periodicals, Inc.

Abstract
Peripheral nerve researchers frequently use the rat sciatic nerve crush model in order to test different therapeutic approaches. The purpose of this study was to determine the sequence of changes after an axonotmetic injury by means of a biomechanical model of the foot and ankle, and compare them with walking track analysis, over a fixed period of time. A kinematic analysis program was used to acquire ankle motion data for further analysis. Although repeated measures analysis of variance showed significant cumulative changes induced by the crush lesion for both ankle kinematic parameters and sciatic functional index, post-hoc multiple comparisons by the Student-Neuman-Keuls test revealed significant differences between week 0 and week 8 only for ankle kinematics. These results are of importance in showing the superiority of ankle kinematics in detecting small biomechanical deficits related to hyperexcitability of the plantarflexor muscles, in contrast with walking track analysis, which showed full motor functional recovery 8 weeks after the crush lesion.

Abstract
In experimental peripheral nerve studies, the rat sciatic nerve model is widely used to examine functional outcome following nerve injury and repair. A variety of evaluation methods exist in the literature, but an adequate selection continues to be a critical point for the researcher. Rats with sciatic nerve injury typically ambulate with an external rotation of the foot. A new functional assessment instrument, the toe out angle (TOA) is quantified using computerized gait analysis. We compared Sciatic Functional Index (SFI) with TOA parameter after peripheral nerve transection and entubulation repair. We found a good correlation between SFI and TOA measurements in terms of predicting functional recovery. Moreover, the TOA provides information on the biomechanical consequences of the external rotation of the foot in the stance phase of walking.

Abstract
The influence of reduced feedback from the cutaneous receptors in the hindpaw in rat locomotion is still unclear. To evaluate this question., we conducted a detailed hindlimb kinematic analysis in animals, which suffered complete loss of thermal sensation. Two-dimensional hindlimb kinematics, temporal and spatial measurements. and walking track analysis were performed in rats before and during hypothermic anesthesia. The walking velocity. duration of the step cycle and stance phase, and stride length between the two testing conditions were statistically indistinguishable. Swing phase duration was significantly decreased during sensory loss. Analysis of angular motion revealed an increased hip and knee extension and an ankle joint with increased flexion during the step cycle under plantar anesthesia. Also after plantar cooling, the hip and knee angular velocity was significantly affected along the step cycle. The remarkably geometric similarity of the angle-angle plots obtained in our experiments reflected an interjoint coordination: however. the interpretation of the cyclogram perimeter revealed a larger excursion by the ankle and hip in their respective joint spaces in rats deprived of sensation. Examination of the horizontal position of the ankle with respect to the hip and the extension before toe-off revealed no major changes. whereas, there was a slight decrease in distance of the hip to the ground during sensory loss. Also, the walking tracks revealed a significant functional deficit following reduced cutaneous information of the plantar aspect of the hindpaw. We therefore conclude that sensory feedback from the hindpaw is important in the maintenance of normal rat locomotion.

Abstract
In experimental peripheral nerve studies, the rat sciatic nerve model is widely used to examine functional changes after different surgical repairs or pharmacological treatments, following nerve injury. The number and diversity of tests which have been used to assess functional recovery after experimental interventions often makes it difficult to recommend any particular indicator of nerve regeneration. Functional assessment after sciatic nerve lesion has long been focused on walking track analysis, therefore, this article describes in more detail the method to obtain and measure the walking tracks in order to calculate the sciatic functional index (SFI). However, it is important to note that the validity of the SFI has been questioned by several researchers. In addition, the present review includes other traditional tests described in the experimental peripheral nerve literature regarding the rate of return of motor function and sensation, such as the extensor postural thrust (EPT), nociceptive function, and the gastrocnemius-soleus weight parameters. In the last decade, several authors have designed a series of sensitive quantitative methods to assess the recovery of hind limb locomotor function using computerized rat gait analysis. This study aims to review kinematic measures that can be gathered with this technology, including calculation of sciatic functional index, gait-stance duration, ankle kinematics and toe out angle (TOA). A combination of tests, each examining particular components of recovered sensorimotor function is recommended for an overall assessment of rat sciatic nerve regeneration.

Abstract
The two-dimensional (2D) kinematic approach is by far the most popular technique in rat gait analysis. This is a simple inexpensive procedure, which requires only one camera to record the movement. However, maximal precision and accuracy of the kinematic values are expected when the experimental protocol includes a three-dimensional (3D) motion analysis methodology: Locomotor speed is a basic kinematic parameter that is often neglected in most studies of movement disorders and neurological diseases. Because locomotor speed c:an act as confounder for the interpretation of the obtained results we also focused our attention on the relation between speed and 3D hindlimb kinematics. Our experimental set-up consisted of a motion capture system with four CMOS cameras which allowed a non-invasive estimation of the instantaneous position of color markers in a 3D measurement volume. Data were recorded while rats walked at different treadmill speeds (30 vs 60 cm/s). For the first time we reported detailed kinematic data for the sagittal, coronal and transverse plane during treadmill locomotion in rats. Despite the overall time course patterns of the curves were identical, we found significant differences between values of joint angular motion at 30 and 60 cm/s at selected points of the step cycle. The adaptation to higher treadmill walking included greater joint angular excursions. The present report highlights the importance of walking speed when evaluating rat hindlimb kinematics during gait. Hopefully, this study will be useful in experimental data assessment when multiple gait abnormalities are expected to occur in all planes. of motion.