This study examined the effects of the use of contact lenses on static and kinetic visual acuity, ocular pain, and blurred vision during a water polo match. Eleven male water polo players participated in this study, and were assigned to one of two groups: contact lens users (CL, n=5） and non-users (NCL, n=5）. Both groups participated in a typical water polo match with four 7-min periods and 2-min resting intervals between the four periods. Static and kinetic visual acuity, subjective ocular pain, and blurred vision were measured before the match (pre-test）, during the match (after each of four 7-min periods）, and during the recovery phase at 5, 15, and 30 min after the completion of the match. Results showed that kinetic visual acuity was significantly lower for the NCL group than for CL in the 4 th period of the match. In addition, for the NCL group, kinetic visual acuity was significantly lower in the 3 rd and the 4 th periods than at the pre-test time. On the other hand, static visual acuity did not significantly differ between the two groups; but, for NCL, static visual acuity was significantly lower in the 4 th period than at the pre-test time. According to self-evaluation scores, ocular pain significantly increased in NCL compared to CL in the 3 rd and 4 th periods. Ocular pain in NCL was significantly higher between the 2 nd period and recovery phase at 5 min than at the pre-test time. Blurred vision was significantly higher in NCL than CL between the 2 nd period and recovery phase at 5 min. Blurred vision in NCL was significantly higher at the same duration than at the pre-test time. These findings indicate that the use of contact lenses may prevent ocular pain and blurred vision, maintaining both the static and kinetic visual acuity at a normal level during a water polo match. Further, the results of this study suggest that the use of contact lenses is effective for water polo players.(Jpn. J. Phys. Fitness Sports Med. 2011, 60：113-120）

This study aimed to clarify the influence of a smaller goal used for children's water polo games in 2010 on total shot, score and shot success rate. Data obtained from three games using standard (spring 2009) and smaller goals (summer 2010 and spring 2011) were analyzed. Results were as follows; 1) The total score for the spring 2009 game was significantly higher than the summer 2010 game (p<0.05). 2) The total shot success rate for the spring 2009 game was significantly higher than the summer 2010 (p<0.05) and spring 2011 (p<0.05) games. 3) Middle shots occurred significantly more frequently in the spring 2011 game than the summer 2010 game (p<0.05) because direct shots from outside the 5 m line were permitted by the 2011 rules. 4) Counter attack shots and goals occurred significantly more frequently in the spring 2009 game than the summer 2010 game (p<0.05). These results indicate that shooters should adapt to the smaller goal early.