You just can't understand until you've wielded a weapon of 20 lbs or above. And 20lbs is nothing. The folks who specialize in heavy weapons go 80 lbs and up.
For me, 20 to 25 lbs is sufficient, and maybe all the way up to 36 for exercise, to make the 20 pounder "feel light in your hands."
The advantage of a light iron staff is it can be wielded "quickly and lightly." Like in any other real practice of martial arts, haymakers are rare, and only come after the opponent has been properly set up.
"Internal Staff" is generally considered to be useless and crappy by real masters, who understand that it's taught mostly to encourage students, and even most of the teachers know it has no utility againt Shaolin staff or Guandao.
In fact, most of the movements of Internal Staff come from Guandao and Iron Staff. The weight of battlefield weapons in this class requires internal waist technique to execute techniques effectively.
It's hard to even say if it's internal or external with a weapon of this weight.
The muscles such as the biceps must have some tension, just to bear the weight, even when fuly relaxed in meditative posture, standing on one leg.
But the weapon cannot be manipulated efficiently, quickly and with perfect control unless the motion is fundameltally driven by the waist, before the arms and legs direct that motion.
Unless you're as strong as the Rock or Arnold.
Are you as strong as the Rock or Arnold?
Are you as strong as Iron Mike?
I'm not, but to kill a bear with a single shot I only needs one blow to the skull with a 25lb staff, and that's just physics. If you can land the hit, it is dure to be a doozy!
Unlike a hammer, you don't even really have to have perfect aim because you really only have to aim in one dimension, like early space invader videogames.
Go pick up a 25lb iron staff, swing it around, and tell me if you think I'm wrong. Ask anyone who swings a heavy sledge for a living the effect of 20 lbs of force multplied.
Shaolin Abbots have bells on their iron staves to give evildoers a chance to flee, because Shaolin monks are prohibited from killing.
There is no feeling like manipulating a weapon of that weight. You can't understand until you've done it.
After a session, lying in bed, you can feel the movements in your muscles and tendons. You can replay them in your head, and feel the connection in the nervous system. You can feel the weight, even after you've put the weapon down for hours and even days. It's muscle memory you can access without moving your body, because memory of manipulating the weight is still echoing in the new and reinforced neural pathways.
You become hungry to pick it up again. You begin to dream of wielding it.
As meditation there is nothing finer. You can't mess around with a weapon of that weight or you will get injured. If your attention wavers and you do a movement incorrectly, you will get injured.
The primary requirement of the art is learning to wield a weapon of that weight without injuring yourself.
It requires strengthening tendons and prefecting body alignment over a period of years and decades, but if you do it right, you can do it even past the age of 80.
The best part is that when you attain feeling in your weapon, you can put inertia into a light weapons just as well, and get a good portion of the power without the weight, dependent on the structural strength of the weapon.
I'm not as good as Sifu. As many hours as I train, which is more than most in my generation, is not quite as many as she trained.
Of course, I did have an even better teacher than her, because she fulfilled her own teachers' goals by exceeding them, the reason they wanted to teach her in the first place, so hopefully that compensates.
Sifu said you don't need to work with heavy weapons, and everything she taught me has proved correct, especially when it has contradicted with what others teach in internal arts.
But she didn't tell me not to train with heavy weapons, and actually encouraged me training with iron staff, because I was the male with the least body mass. I needed it to be able to hold my own with the big boys, sometimes twice my size. There are no weight classes in real martial arts!
Sifu gave me pointers about wielding polearms of that weight. The footwork should be light, regardless of the weight of the weapon. The hands are closer to the body due to the weight that must be borne. (This is similar to Richard Francis Burton's observation that pulling the arm closer to the body when making the cut with a heavy cavalry saber in a charge helped increased the generally sub-par efficacy of curved blades wielded one handed.
There's more connection to what we call the "root" or "center" with a heavy weapon when the arms are close, unlike with a light weapon, say a sword of under 3 lbs or a staff of under 15 lbs, where keeping the arms extended and the hands away from the body yields maximum effect. The heavy polearm reinforces the root.
When the weapon is wielded close to the body in the correct manner, the wielder never has real openings, even on attack. Any response can be responded to. This is why Wudang sword is wielded close to the body. You want to invite the opponent in so that you can strike from a position of power.
To great effect, if accounts are to be believed.
Trust me, when anyone hits you in the head with an iron skillet, it's non-trivial, and if that woman has bulk or really knows how to swing, she will knock your lights out.
It's not the worst thing in the world if you're a woman to be able to crack a man in the bak of the skull or the side of the head with a blunt object of a few pounds so that they drop like the strings were cut out of their legs, and they don't wake up until the paramedics comes.
Cross-fit introduced a lot of fitness oriented folks to working with some weights in addition to aerobic exercise.
So trust me when I tell you that a staff of even 2, 3, 4 or 10 lbs. is going to make you strong and physically capable.
The movements are beautiful and effective, providing the appeal of dance and self-defense.
Done correctly, it's more about tendons than muscles, so while it will make your body hard and able to withstand impact, you can stay lithe if you want, like me and Jet Li. I'm pretty sure Jet's staff in Whitesnake is not more than 4lbs, which is in a hardwood staff is quite if you have a fraction of Jet's skill. In general, for any striking art, mobility is the most important thing, and Jet specifically with a 4lb staff could take me with a 20. Amituofo!
Shaolin staff is a weapon that, no matter the weight, can defend against any cold weapon devised by man in the hands of a competent practitioner.
Bow Sim Mark swore by it. In some domains she favored it, even over sword.
And if you've ever wielded a pole arm up to eight or nine pounds like she did, you'll understand why.
You don't have to be the Rock or Arnold to wield a hardwood staff heavy enough to knock a sucker out.
Polearms are the easiest weapon in which to gain competency.