摘要:Introduction. Obesity is a serious health and social problem. Various sources indicate that it affects approx. 20% of the world’s population. It is also counted among the diseases of affluence. Excessive body weight adversely affects a number of systems in the human body, including the locomotor system. Studies have shown that there is a close relationship between obesity and either a dysfunction or osteoarthritis of knee joints. Aim. To evaluate the impact of weight reduction on the basic parameters of the overall capacity of obese women and their well-being. Material and methods. 7 extremely obese women aged 28-51 looking to reduce their body weight participated in the study. The weight reduction program lasted for 12 months and consisted of reported intervention. The validated survey by Johanson was used to assess the performance of the lower limbs. Each tested person filled in 3 surveys of the same kind – the first at the beginning of the research project, the second after losing 20 kg of body weight, and the third after 12 months of weight reduction. Results. There has been a statistically significant decrease in body weight (p=0.002) and BMI (p=0.002) of women surveyed between the specific periods of observation. The pain from the knee joints decreased or was resolved through weight reduction (p=0.004) in the respondents. The participants also started to take less painkillers for knee discomfort (p=0.005). Authors also noted an increase of the walking distance without rest (p=0.01) and less problems while walking upstairs (p=0.004). There was a statistically significant improvement in their self-care for the feet (p=0.003), as well as in the ability to use public transport (p=0.05) or to do shopping (p=0.05). There were no significant differences in the performance of household chores, getting out of bed, using the bath or shower or in need of orthopaedic equipment. Conclusions. Significant weight reduction in obese women proportionally reduces or relieves knee pain and improves their performance. It reduces the need for using analgesics. Weight reduction in obese people has a significant impact on improving the performance of lower limbs.