For a long time tai chi has been promoted as being an effortless exercise.
Do not be misled by this: if it were truly effortless, there would not be any exercise.
The word 'effortless' should refer to the absence of resistance in your body and the surprising effect of your actions once conflict has been removed.
Tai chi involves physical work, the strengthening of muscles and bones, the stretching of the elastic tissues.
This is not to be confused with gym work, sport or weight training.