Knowledge Base

Problem

Researchers want to compensate or normalize CatWalk XT gait parameters (especially intensity-based parameters) for differences in body weight between animals, but cannot find a built-in feature to do so.

Details

CatWalk XT uses paw print light intensity as an indirect proxy for weight-bearing and limb pressure, but it does not automatically normalize any parameter by the animal's actual body mass. This is a common question in studies comparing groups of animals with substantially different weights (e.g., obese vs. lean, young vs. aged). Affects all CatWalk XT versions.

Solution

CatWalk XT does not include an automatic body-weight compensation or normalization feature. To account for body weight differences in your analysis:
1. **Record body weights** for each animal on each test day and store them alongside your CatWalk data.
2. **Export raw CatWalk data** (File > Export > Run Data or Trial Statistics) to a spreadsheet or statistical software.
3. **Normalize intensity-based parameters post-hoc** in your analysis software (e.g., divide Mean Intensity or Max Intensity values by body weight in grams) for each animal.
4. **Use non-intensity parameters** (e.g., temporal parameters such as Swing Duration, Stance Duration, or spatial parameters such as Stride Length) where body weight has less direct influence, as a complementary approach.
5. **Covariate analysis:** In your statistical model, include body weight as a covariate to control for its effect on intensity-based measures.
6. Document your normalization approach clearly in your methods section, as there is no single community-standard method for CatWalk weight normalization.