I’ve got a lot to say about poles. I am primarily a trail runner and XC skier, so I spend a lot of time with poles in hand.
I am a fan of trekking poles for fast-packing and technical trail runs. I will also use them if I have a long run (>2 or 3 hours) that includes a lot of vert. They definitely help me feel more stable coming down steep descents quickly and are like getting a little push for uphill section. In technical areas, such as an exposed ridge, exposed ledge, or a narrow, cambered trail with scree, you can use the outside pole like a third limb to help you stabilize and not take a tumble. I also might use them on sections of trail that have big step ups or drops over roots and rocks or to go up log or rock stairs on a trail. They are handy for river/stream crossing that might feel dicey otherwise.
I mainly trail run, so I am not generally carrying a substantial amount of weight in the form of packs and gear. I use Leki Ultratrail poles. I really like the glove to pole interface, as it allows for very efficient pole use. The poles fold up easily and are very light weight. I use a Salomon ultra trail vest, and they can hook directly to the vest, although I find attaching them to the vest very awkward, and I have to walk or even stop to get it done. I bought a pole quiver from Salomon, and I like this format a lot better. I can stash the poles while running. The Leki poles are carbon fiber, so great for being light weight but know that when they break, there is no repairing them – kind of like a carbon frame mountain bike. I don’t get too emotionally attached to my poles.
I also have a pair of Black Diamond Z Trekking/Running poles. These are a bit heavier and have a strap rather than a glove interface. I use these when I am going to be carrying a pack, if I traveling via snowshoes, or if I am going to be wearing gloves/mittens more substantial than a basic running glove or XC ski glove. I personally do not find the Loki glove interface to be comfortable with substantial gloves/mittens.
Definitely make sure to stay away from XC skiing or downhill skiing poles. XC ski poles are super long and you will end up with an elbow or shoulder injury. Downhill ski poles are going to be too short to use with good form while running, and you will be too slumped forward. There are some good online tutorials for deciding what length poles to use for running. I am 5’6″, and I use 115 cm Leki poles. The Black Diamond ones are adjustable, which can be nice for more technical terrain if you want shorter poles for uphill and longer for downhill or one pole longer due to sideways slope.
There are loads of good youtube videos on using poles. One that I think seems reasonable and spends some good time on technique is:
From my own experiences, I would highly recommend poles. It definitely makes sense to play around with them on easy terrain and short runs/hikes to get a feel for them. It can take some practice to get smooth an pulling them out, unfolding them, and getting them onto your hands without smacking everyone near you! Form wise, the Leki poles will force you to grip the pole correctly because of the glove interface, so that it a plus.
On most terrain, I like to use my poles with a very natural running motion, so I am not substanially changing what my arms do while running without the poles. As your arms swing back during normal running, you are pushing the ground behind you and helping propel yourself forward. The motion comes from your large upper body muscles (back and shoulders) and less work on biceps/triceps, and even less on wrist and hands. Making the motion an arm exercise (elbow extension and flexion) is a coming mistake and will give you wicked tendonitis. Think about the movement being about the shoulder not the arm. Keep a bit of bend in the elbow when your arm is at its farthest point back in the backswing to avoid triceps tendonitis. It is hard to describe this in words and not with a demo! Start small and short with adding poles to your runs and work from there. Downhill use takes some trial and error to decide how to best help yourself. Sometimes, I have the pole tips out in front of me actually slowing me down as a I descend, so the poles become less about efficiency and more about slowing my descent and keeping me from eating dirt.
Bonus for holding my poles on sections of trail where cougar sitings have been reported recently. I’m not sure that the poles would make a difference, but it makes me feel braver to have them.
As far as training to get efficient and build endurance for poling, I definitely recommend googling videos on uphill ski bounding and adding some short bursts of that to you hill work. You can also train on a ski erg to build the muscle endurance. The ski motion is bigger and more explosive, but it can help build the muscle memory and efficiency. You could definitely add poles without doing specific training, but training will help you be more efficient.
Good luck and looking forward to reading other athletes ideas.