Objectives:
Muscle dysmorphia is a disorder in which one incorrectly assesses one’s body as too thin and insufficiently muscular. Data on dysmorphia in the female population are still limited. The aim of the study was to culturally adapt and validate the Muscle Dysmorphic Disorder Inventory (MDDI) by Hildebrandt et al. (2004) in the female population.

Methods:
The study included 204 women aged 18 to 35 years. In addition to the MDDI, the following were used: (1) a personal questionnaire to control secondary variables (e.g. BMI, sexual orientation, self-rated health), (2) the Body Image Questionnaire (BIQ) to check the validity of the validated tool, and (3) a subscale of the KOMPAN questionnaire to operationalise the variable “physical activity”.

Results:
It was noted that there are intergroup differences in the intensity of muscle dysmorphia symptoms in the studied sample between women involved in moderate and high levels of leisure-time physical activity. It was proven that the higher the BMI value and the greater the difference between actual and expected body weight, the greater the intensity of muscle dysmorphia symptoms in the studied women.

Conclusions:
The results of the study confirmed the three-factor structure of the MDDI-PL and demonstrated its satisfactory reliability both as a whole and in its separate subscales. MDDI-PL can be used as a screening tool, especially for examining women who engage in physical activity (including competitively).