001 -respectively for pretest and post-test). Strength in tethered swimming A significant improvement find protocol of tethered swimming force for the experimental group (9.64%, p<0.02) was found, whereas the increase was not statistically significant from pretest to post-test conditions (2.86%, p>0.05) in the control group. In addition, tethered swimming force was similar in the control and experimental groups at pretest and post-test evaluations (p>0.05). Moreover, the experimental group presented higher values of TS compared with the control group (35.50%, p<0.001) after six weeks of power training. However, the experimental group presented higher values of TS compared with the control group (27.10%, p<0.002) from the start of the research.

Discussion This study aimed to investigate the effects of a six week combined dry-land strength and aerobic swimming training on upper body strength, tethered swimming force and swimming performance in youth competitive swimmers. It is considered that traditional dry-land strength training or combined swimming and strength training do not appear to enhance swimming performance in untrained individuals or competitive swimmers (Tanaka and Swensen, 1998). It was previously observed that although combined training increases upper body strength, it does not result in faster sprint times compared with swimming-only training (Tanaka et al., 1993). Additionally, Bulgakova et al. (1990) reported that water strength training was more effective than dry-land strength exercises. Additionally, Bulgakova et al.

(1990) reported that strength training in water is more effective than dry-land strength training. Many authors indicate that in youth swimmers technical training is more important than strength training (Kjendlie et al., 2004, Aspenes et al. 2009; Barbosa et al., 2010; Garrido et al., 2010). According to our data, it is not clear that strength training allowed the improvement in swimming performance in youth swimmers although a tendency to improve performance due to both types of training was noticed. It is uncertain whether dry-land strength training leads to improved sprint performance while swimming. Tanaka et al. (1993) explained lack of significant transfer between dry-land strength training and swim performance by the ambiguity of swimming and dry-land training condition.

Different factors determine to what extent training progress in one situation leads to improved performance in the other. Previous studies showed that training effects are angle and velocity-specific. This suggests that effects of dry-land strength training are transferred to the swimming if during strength training people move just as fast or even faster than during swimming in water (Toussaint et al., 1988). Moreover, not only the movement velocity during strength training should Brefeldin_A correspond to that during swimming, but also the relationship between joint angle and strength must be similar to that in water condition.