The purpose of this study was to gather knowledge about the functioning of the rein tension meter and test it for future studies of match and mismatch between rider and horse. We looked specifically into the possibilities to use a rein-tension meter to determine the quality of cooperation between horse and rider. We examined whether a rider shows a specific tension pattern and also if certain patterns could be recognised for a specific horse. During the study, a manual with pictures and text was written to support the practical use of the meter. The manual describes in a simple way the first steps in the installation and use of the meter.