Practice of an ukemi drill game with young judo athletes: Effectiveness of video shown on a tablet - Ozawa, Y.; Mishima, E.; Kiyota, K.; Mitsuda, R.; Nakamura, I.; Hamada, H.; Ishibashi, G.; Ohkawa, Y.; Sakamoto, M.; Nakahara, H. (Association for the Scientific Studies on Judo, Kodokan, 2021)