This method is somewhat of a newer thing for me, in regards to my xiaohongquan. Been trying this for the past year. So not that long.
When I was being taught my taiji form. There were always two ways I was taught to do the form. One way is like the old man. Slow, soft, very relaxed, no tension. The other way is through mental visualization. fajing/power, resistance, and endurance emphasized in the later format.
For instance. The opening of the taiji form where you raise your arms.
When practicing with the visualization, you are to move and activate your muscle groups as though you are lifting a bucket of sand with each arm, or perhaps children. simply raising the arms is no good. Promoting the correct activation of the muscle groups, as well as muscular endurance. Doing movements slowly like this while all the while truly getting every muscle in the chain to work to the correct effect is a training procedure to help promote this as muscle memory, as well as promoting stronger muscular endurance, since each muscle group is being activated through motion for a longer period of time. every single movement is like this. often times you use a partner to apply resistance to find the muscles taht can be activated that you may have not been using. harder hits. more power, etc.
this is of course one small aspect of why this is done this way.
When i practice my xiaohongquan (i have not started to do my dahongquan slowly) i practice it this way. As seen in the first video that LFJ posted.
Of course I do this 2 times maybe 3 to warm up. not for cool down.
Xiaohongquan on average takes 30 seconds to perform. If i spend 1-2 hours working my form a couple days a week. what is 2-3 times performing in this manner going to do other than benefit me? More attention can be placed on presice movement structure, alignment...etc.
Im not telling anyone they should do this. this is just something that I do. Mainly I was curious to see if others do this. Apparently some of the monks do. I was unsure if anyone else did this.
I spend far less time doing this slowly than doing this fast. I spend far less time doing the form than working the techniques themselves, i spend even less time doing that then i do working against resistance and on my heavy bag.
I am in no way a form collector. I stopped doing all of my other many forms on a regular basis, and only perform them on scheduled review periods so that i can later offer these to others of they wish. IF i decide to ever teach anyone.
So as these 2 forms are the only ones I maintain and work to improve on a very regular basis. I strip them down and try to squeeze everything out of them taht i can. from every angle i can think of.
this of course, is just me with my personal martial art. and of course ive been practicing these sets for years, so it helps to 'spice it up' a bit. keeps it even more interesting.
For whoso comes amongst many shall one day find that no one man is by so far the mightiest of all.