This increase could be explained by an improvement in the kinetic chain of movement, but also perhaps by an improvement in technique due to core training, another performance factor involved in throwing. As throwing technique was not analyzed, further studies should be carried out to determine the factors influencing this improvement. These results are consistent with those reported in other studies (Barata, 1999; Ettema, 2008; Gorostiaga, 1999) in which strength was improved using the traditional approach of strength training programs (3 x 6RM, 8-12 RM and pyramid training) over a period of 9 weeks, and in which improvements ranging between 1.4 and 6.9% were obtained.