Introduction:
Obesity may result in increased instability of posture in the case of external disturbances. The consequences of mastectomy may be a disturbance in statics and body balance. Disturbances in postural coordination may be associated with unevenly distributed postural muscle tension or abnormal body mass.

Aim of the research:
To assess the impact of body mass index on postural stability of post-mastectomy women based on posturographic examination.

Material and methods:
The study involved 40 women after mastectomy belonging to the “Amazonki” (Amazons) Club of the Świętokrzyskie Province at the Świętokrzyskie Oncology Centre in Kielce. The age range of patients was from 52 to 87 years. Patients were divided into three groups according to body mass index (BMI) criteria, i.e. normal body mass, overweight, or obese. To assess equivalent reactions, the Postural Stability Test and the Clinical Test of Sensory Interaction and Balance (CTSIB) were used on the Biodex Balance System platform. The research was carried out at the Posturology Laboratory at Jan Kochanowski University in Kielce.

Results:
In the case of the Postural Stability Test in static mode, obese patients demonstrated better postural stability. Comparing the same test in dynamic mode, women after mastectomy with normal BMI maintained body balance better in comparison to obese women. The CTSIB showed lower values regarding all four criteria in obese women compared to women with normal BMI. Upright position of the subjects was characterised by higher sways in the sagittal plane than the frontal one (A/P > M/L).

Conclusions:
Impairment of the postural control mechanism may result from both the aging process and comorbidities – among others, obesity and medication.