Using Strength in Martial Arts?

Techniques done correctly need no additional strength. Using strength will usually cause the person doing the technique to do it wrong. If the martial arts were about strength, only young strong people would be good at it. In the orient the old guys are the ones to watch out for. What they do is not flashy or fancy. But it works and works extremely well.

here are example of some masters who are really good at what they do and yet they have small physic but they're skills are known.

Gichin Funakoshi doing grappling application 

from a kata "Bunkai"

These are Japanese martial arts masters and are know for there small stature.

Some Filipino Martial Arts Masters Anciong Bacon and Tatang Ilustrisimo small stature yet feared by many.

Taika Seiyu Oyata "RyuTe RenMei" 

Seiyu Oyata who is know to combine joint manipulation techniques (tuite jutsu) with effective strikes to the body's weak points (kyusho jutsu). And one of the pioneer in spreading the practical bunkai (application) of a traditional kata.

If Martial arts Techniques is all about strength then IMHO these people won't exist in the Martial Arts cause of their Age and Physic. Yet they are known to be legends.