Despite the strong theoretical basis which supports the use of this type of training and the studies cited here that support this theory, inconsistencies still remain in the literature concerning the effect of core training on performance or injury prediction in athletes (Danneels et al., 2001; Koumantakis et al., 2005; McGill, 2003). Poor design of the progression of the selected core exercises may explain why some authors have not observed any effect with regard to improving performance in various sports disciplines (Schibek, 1999; Stanton et al., 2004), although such improvement has been observed in pelvic girdle stability. In our study, subjecting the extremities to increased instability and resistance heightened the difficulty of the exercises, providing sufficient stimulus to core muscles during the training period.