練功講究火候
Training is particular about the crucial moment
一日練一日功,一日不練百日空
A day spoil for a day training, a hundred empty days for a day without training
If there is an old method definitively lost in modern times, it is the idea of a crucial moment in training, basically having to do the right effort at the right moment. Indeed, modern training not practised on a 24/7 basis and not focusing on deeply transforming one’s body, such method has become obsolete. The timing issue is very similar to forging a sword, when and how are crucial, hence the use of 煉 instead of 練 in some texts regarding training.