Dropsets, rest-pause, continuous tension, flushing a muscle with blood with multiple exercises—you've tried all these intensity techniques, and probably many others. The problem is that your arms seem to have found permanent residency in Plateauville. Growth is no longer a foregone conclusion, it's something you read about only on social media.
Doing the same thing over and over and expecting different results is the definition of insanity. I'm going to help you break free of your training-imposed straitjacket with a nontraditional approach. The results will be nontraditional as well.
The only prerequisite is that you're willing to work hard.
Enter the Cluster Set
For more than a half century, record-setting strength athletes including powerlifters, Olympic lifters, and strongmen have reaped the benefits of training with cluster sets. While these athletes don't train specifically for hypertrophy like bodybuilders, at 350+ pounds of body weight, these men carry a helluva lot of muscle mass.
Now, I get that your goal is probably to get big rather than be a strongman, but you can program cluster sets to meet this objective by achieving more volume in less time. And trust me, you won't be lacking intensity, as the relative intensity of training is greater when using cluster sets compared to traditional straight sets.
So what exactly is a cluster set?
Cluster sets are those in which the main sets are broken into several parts. For example, instead of doing a set of 9 straight reps, you do a set of 3+3+3 reps, which allows for a very short rest period within the set. That intraset rest period allows you to lift more total weight than you'd be able to with straight reps, providing a greater anabolic stimulus. For bodybuilding purposes, the rest period can be very short, but no more than about 20 seconds.
For this workout, you're going to do six total exercises using two different types of cluster sets. The first type of cluster set is what I call hypertrophy-specific cluster set (HPSC). The second type is termed a jailhouse-strong cluster set (JSCS), originally developed for "Jailhouse Strong," which I co-authored with Adam benShea.
Pick a weight you can lift for 10-15 reps. Lift the weight for 5 reps, rest 15 seconds, and repeat the sequence. Do this for five minutes straight. If you can no longer do 5 reps, drop it to 4 reps; if you can no longer do 4 reps, continue with 3 reps. If 3 reps becomes unmanageable, lengthen the rest interval to 20 seconds. When that becomes too much, stop the set and move on to the next exercise. On the last set, if you have any gas left in the tank, take that set for as many reps as possible (AMRAP).
Start with a weight you can do for 15 reps. Lift the weight for 5 reps, rest 20 seconds, and repeat the sequence until you reach failure. Don't reduce the number of reps or increase the rest intervals here. Some individuals may well be able to go beyond five minutes, but this technique isn't timed; you simply go to failure, however long that takes.
Cluster Bomb Your Arms
All of the exercises in this workout will be performed with either an HPSC or a JSCS. You're going to alternate triceps and biceps exercises. Perform this workout once a week as part of a traditional bodybuilding split or twice a week if you're arms are a lagging body part.
Because the intensity is so high for each movement, this technique works less favorably if you try to train the same body part with successive exercises, so stick to the scheme. Don't forget to perform a few warm-up sets (never taken to muscle failure) before starting the cluster sets.