The aim of the study was to determine the effectiveness of the sensors, determined on the basis of pressure changes in airbags of our own design, placed between the saddle and the horse’s back. This would allow for the assessment of the flexibility and correctness of the rider’s seat, as well as the strength of its influence on individual parts of the horse’s back. The research included 10 Polish warm blood horses aged 7-12 years (5 mares, 5 geldings). Before the test, each horse was examined by a veterinarian who did not find any body asymmetries and they did not show any abnormalities in the musculoskeletal system. All of the horses were clinically healthy. The horse was subjected to regular training 5 times a week, of which 3 days consisted of dressage work, 1 day of pole and cavaletti work, and 1 day of jumping training and was ridden by a woman, aged 28 and weighing 65 kg, who was at the second sports class level according to the Polish Equestrian Association in dressage and show jumping. The task of the rider’s seat control system was to determine its correctness. For this purpose, airbags were placed between the saddle and the horse’s back. There were four airbags placed in the pad, two of which worked independently and two were connected in a pair (both airbags had the same pressure). The pair of airbags was placed under the front of the saddle, which enabled the analysis of changes in the impact of the rider’s seat on the front pommel. Separated airbags were placed under the back of the saddle, which made it possible to test the impact of the rider’s seat on the pommel with additional separation into the left and right sides, which enabled, for example, the detection of balance problems or asymmetries resulting from defects in the horse’s structure. The results of preliminary research have shown that it is possible to control the quality of the rider’s seat and determine its parameters based on measurements carried out using the proposed system. The analysis of the presented sample time series shows that the rider does not sit symmetrically in the saddle, putting more strain on the left side of the body.