To inspire confidence in their students instructors should have a degree of physical prowess. This may be strength, rather than fitness (Ueshiba was apparently very strong, even at an advanced age). Many people take up aikido initially as a self-defence and if the instructor appears incapable of defending themselves, then students will loose confidence in them. Physical ability is a necessary component of self-defence. Although strength, fitness, skill and reaction speed are all beneficial, some people have more of one than another. Physical fitness also shows a real dedication to aikido as a martial art, rather than as an esoteric practise.