Not true from an aikido stand point. Steven Segal is a freak of nature in the aikido world because he is such a large man. The redirection of energy in aikido instead of frontal hard blocks makes it a great art for smaller people. There are certain techniques in aikido that will work better for smaller folks and techs that will work better for taller/larger folks. This is the one time in my life where I can hear the phrase "Size doesn't matter" and actually believe it.Ive always heard that bigger, stockier people are better suited for certain japanese styles like aikido, jui jitsu, judo or wrestling styles. Smaller frames work better for offensive styles like Korean where there are more kicks and speedy moves.
Im a big guy but I prefer chinese styles like wushu and wing chun. Id also like to learn judo and aikido.