Something is experienced as a change that takes place during these, and indeed, any exercises. It can be called movement of qi if you like.
Current consensus around these parts might be that qi is a cultural construct that cannot really be defined because it refers to many ideas over the centuries.
These exercises work if they appear to increase your strength, concentration, self awareness or range of movement. They can be said to increase qi. Whether qi exists as a substance or not is another question.
Yik kan king may be said to open pathways within the body for improved health. Sam chin may be for another purpose entirely--do develop the ability "to issue power" suddenly.
Lots of old threads on the subject here. Dig around.
"Look, I'm only doing me job. I have to show you how to defend yourself against fresh fruit."
For it breeds great perfection, if the practise be harder then the use. Sir Francis Bacon
the world has a surplus of self centered sh1twh0res, so anyone who extends compassion to a stranger with sincerity is alright in my book. also people who fondle road kill. those guys is ok too. GunnedDownAtrocity