My elbows hated me. I got to a single rep with a 3+ inch bar and 150 lbs. Not much weight for most people but for me it was brutally hard. I also did some 2 inch thick DB tossing and catching with up 50s and that was HARD. I prefer Dinosaur Training and H.I.T. to any other style but have to be careful.
About 14 years ago I would take work breaks and throw a 3+ inch thick piece of brass we had laying around the shop (about 10 inches in length) about 8 or so feet in the air and alternate catching and throwing it until I couldn't do it any more. FUN! I highly recommend this movement for grip and bicep power. I need to find my Dinosaur Training book and get inspired... I got out my Mike Mentzer book and it is helping to fuel the passion too.
Interesting to hear, since I've never heard of someone who performs plyometric training for arms. This kind of training is highly effective for explosive strength/functional strength training, but -with all respect- since you're already at a certain age, I would not recommend this type of training and the same goes for HIT. In fact, I wouldn't recommend HIT to anyone, since it's too taxing on your joints & CNS, it's a guaranteed road to problems.
However, I have to give credits to Mike, since he was the first one who encouraged me to THINK about, and to apply LOGIC to training. However, practice combined with logic is your best teacher.