This study aimed to investigate the impact of gym exercises for riders on their posture and the subsequent effect on reducing discomfort for their horses during training, using electronic pressure sensors. The study involved 20 warmblood horses aged 5–10 years, regularly ridden under saddle, and four riders of similar height and body weight. The study group was divided into a control group (10 horses) and an experimental group (10 horses). The horses were trained 5 days a week for 60 days in total. Riders trained three times a week for approximately 60 minutes. The exercises were designed to improve the riders’ flexibility, mobility, and fitness. A pad with electronic pressure sensors was placed beneath the saddle to detect pressure force and changes in the rider’s position. The results clearly indicate that exercise has a positive impact on riders’ balance maintenance. In each analysed case, the experimental group observed a reduction in amplitude non-uniformity in the measurement performed upon completion of riders’ training. This method may help more easily assess seat irregularities and correct them through appropriately selected exercises. Improving the rider’s balance should significantly improve the horse’s comfort while riding.