Physiotherapy programs, physical education classes as well as sport activities are commonly aimed at increasing flexibility of the pelvic-hip complex muscles [14–22]. Stretching exercises might be used as a warm-up or as a primary aim of the physiotherapy session [14,17,21]. These exercises are usually applied on the basis of the results of tests assessing muscle and trunk flexibility [14–17,19,20,22]. The most common tests used for this are straight leg raise test, modified Thomas test, fingertip-to-floor distance test and lateral trunk flexion test [23–26].