CatWalk XT - Gait Analysis White Paper
Last updated: Jul 31, 2026
Gait Analysis with CatWalk XT
Gait is an important behavioral endpoint in research on any disorder or disease affecting the movement or gait of animals. Traditionally, gait analysis was done by inking the animal's paw and letting it run across a piece of paper. This way only a limited number of gait characteristics could be measured. Nowadays, more sophisticated and automated systems are available for detailed analysis of a large number of gait parameters. The CatWalk XT system is one of them.
How Does CatWalk XT Work?
CatWalk XT is a semi-automated gait analysis system for rodents. The heart of the CatWalk XT system is a walkway with a corridor on a glass plate through which a rat or mouse walks from one side of the walkway to the other. Green light sent into this glass plate is able to escape only at those areas where the animal's paws make contact with the glass plate; as a result, the light is scattered and paw prints are visible. These are captured by a high speed video camera that is positioned underneath the walkway. Each pixel recorded has a certain brightness, allowing CatWalk XT to detect intensity differences between an animal's paws. CatWalk XT also measures many other parameters related to paws, and related to the spatial and temporal relationship between paws.
The CatWalk XT illuminated ceiling contains red light. This allows you to see the animal's body contour in the recordings, which facilitates correct classification of the paws (e.g., left front/hind, right front/hind). The goal box on the right side can hold, for example, the animal's home cage. This makes it more attractive for the animal to cross the walkway and facilitates the acquisition of high-quality runs.
Experiment Settings
In the Experiment Settings you can predefine Time Points (e.g., Day 0, Day 7) and Treatment Groups (e.g., Control, Experimental, Sham). You can also set Run Criteria (minimum and maximum duration, maximum allowed variation in running speed) to check the quality of your runs during acquisition of data. A run is an animal's crossing of the walkway from one side to the other. In the Experiment Settings, you can also define how many runs per animal you want to acquire in one trial that meet the Run Criteria. In Data Acquisition, CatWalk XT will then automatically keep acquiring runs until the minimum number of compliant runs have been recorded.
Trial List
In the Trial List you can define Trials that you want to acquire. A Trial corresponds to an animal from one of the Treatment Groups at a particular Time Point. A Trial consists of one or more runs.
Training Animals
Before you start acquiring runs, you can train the animals to cross the walkway without interruptions or hitches and to enter the goal box, so all animals start from a similar baseline. This is important in order to be able, during an experiment, to compare different runs and pick up gait abnormalities that are the result of effects of treatment rather than differences in quality of runs. Training of the animals can be started before treatment.
Detection Settings
Configuring the Detection Settings is an important step in a CatWalk XT experiment, because light conditions and the type of animals you use may vary between labs and between experiments. The Detection Settings allows the software to adapt so that the program can distinguish between paw prints and background noise in any situation. CatWalk XT can automatically set the optimal values for Camera Gain and Intensity Threshold based on your lab conditions and your animals. After automatic configuration of the Detection Settings you have the option to manually fine-tune the settings to get even better paw prints. This is especially important if you also want to detect the animal's toes.
Preparing the Walkway
A clean glass plate will make sure your prints are clean. The spring-operated corridor opens up easily, so you can clean the glass plate using some proprietary glass-cleaning fluid. The width of the corridor can also be adjusted to the size of the animal; if the corridor is too wide, the animal might meander too much, and if the corridor is too narrow, a normal gait of the animal might be hampered.
Carrying Out Data Acquisition
You manually start acquisition, put the animal on the walkway on the left side, and then CatWalk XT automatically keeps acquiring runs until the required number of runs (as set in the Run Criteria) has been recorded.
Paw Print Classification
Classification of runs means assigning the correct label (left front/hind, right front/hind) to paw prints. Optionally, before classification, you have the possibility to slightly adjust the Detection Settings to improve the quality of your paw prints.
With the Automatic Footprint Classification module, CatWalk XT automatically labels paws. Optionally, you can manually label paws that have not been labeled automatically, or you can label other prints than paw prints (for example, nose, tail, or abdomen).
You can install the CatWalk XT software on any computer and classify runs without the hardware key. The hardware key is only required for data acquisition.
Toe Classification
Classification of toes is done with the Interactive Footprints Measurements Module and comes after classification of paw prints. Toe classification of the hind paws (by measuring the Toe Spread, Intermediate Toe Spread, and Print Length) can be used to calculate the Sciatic Functional Index, Peroneal Functional Index, and Tibial Functional Index. These indexes are commonly used as a tool for the evaluation of the recovery of the sciatic nerve and its branches.
Additionally, CatWalk XT automatically calculates the Paw Angle, which is the angle at which the paw is placed relative to the body.
Run Visualizations
After you have finished classifying prints, you can visually inspect your runs by displaying 2D and 3D pictures of the paw prints. These visualizations can be exported as pictures or video so you can use them in presentations.
Run Statistics
Once a run and its prints have been classified, all CatWalk XT parameters are automatically calculated and can be viewed in the Run Statistics window. The Run Statistics provide a large number of gait parameters that fall into three main categories:
Individual Paw Prints
Print Intensity — CatWalk XT provides a number of intensity parameters that are related to how much weight the animal put on each paw. You get the minimum, maximum, and mean intensity of a paw print, but also information about the weight bearing when the largest area of the paw was in contact with the glass plate. This gives you detailed information about whether the animal avoids putting weight on one or more paws as a result of, for example, pain.
Print Area — This is the surface area of the complete print (including the toes), as if it were an inked print. The Contact Area is the surface area of the paw at the moment of maximum contact with the glass plate. Furthermore, CatWalk XT provides information about at which time point during the whole contact of a paw with the glass plate the maximum contact is reached.
Spatial Relationships Between Paw Prints
Stride Length is the distance between successive placements of the same paw and therefore measures the step size of a paw.
Regularity Index is an indicator of how normal an animal walks. CatWalk XT recognizes a number of walking or footfall patterns. If an irregular placement of a paw breaks a pattern, this paw cannot be assigned to one of the footfall patterns. As a result, the Regularity Index decreases.
Base of Support is a measure of how wide either the front paws or the hind paws are placed apart during walking. Base of Support is an important parameter in spinal cord injury research; because injured animals have problems keeping their balance, they put their hind paws further apart, which is reflected in an increased Base of Support in CatWalk XT.
Temporal Relationships Between Paw Prints
Stand and Swing are parameters that reflect the temporal aspects of an animal's gait. Stand is the duration of contact with the glass plate of a paw, whereas Swing is the time the paw is in the air in between steps. By looking at the Stand and Swing of all four paws you can get a good idea of how a decrease in Stand of one paw is compensated by an increase in Stand of another paw.
Phase Dispersions is an interesting parameter that is an indicator of inter-paw coordination. It describes the temporal relationship between the placement of a target paw relative to an anchor paw.
Parameter Charts
In the Run Statistics, all parameters and their values are shown in tables. To visually inspect your data or to easily create graphs, CatWalk XT comes with the Parameter Charts module. In this module, bar charts are created for all paw parameters for all classified trials in each combination of Treatment Group and Time Point. This way you can very quickly visually inspect possible differences between Treatment Groups and/or Time Points for paw statistics. You can format the charts to your own needs and export them individually or all at once.
Data Export
CatWalk XT offers the possibility to export a variety of different data types. You can export the Run Statistics, either as raw data or at run/trial level, to Excel. You can also export the recorded run or the Run Visualizations to a video file for playback in a presentation.
Source: White paper Gait CatWalk, Noldus Information Technology