Are you maximizing your muscle gain?
When I was in undergrad we learned resting 30-45 seconds between sets maximized muscle growth. Newer research states that in order to maximize growth we need 2-5 minutes of rest between sets and here is why. In order to maximally damage the muscle, thus creating muscular growth sets must be at the highest intensity. That means full stretch and full contraction with tension in the muscle all the way to near failure (not just to 8-12 or when it burns, you need to be 1 rep shy of failure or to failure for the last set). Since the intensity during the set is so high, we require more rest. The 2-5 minutes is used for recovery so that the next set can be just as intense and we are ready to push to near failure again, doing that with 45 seconds of rest would not allow us to push as hard and damage the muscle. Therefore we would have less gains ): and gains = happiness. Happiness = Good Such intense sets may be taxing to the overall nervous system so hitting 2-3 really solid sets close to failure is where you will maximize your growth. Still warm up but the working sets should not really be past 3 sets if you are doing this type of approach. Can you still rest 30s? Are HIIT classes useless cuz there's no rest? Why do powerlifters rest that long and have different goals? You can rest 30s and still see gains, not as optimal but sometimes you got no time. HIIT Classes are different styles, you're not lifting as heavy as you can and they're not isolated muscle movements, they're overall movement patterns in the body. Still a good workout option. Powerlifters are also at super high intensities and they'er trying to maximize their strength. Similar in their intent, but different rep range to get a different adaptation. TLDR: Warm up. Do working sets, 2-3 sets to 1 shy of failure, 1 shy of failure, to failure. Reps should still be between 8-12 (if you're going past the range go up in weight). Rest 2-5 min between sets to maximize intensity. 2-3 minutes of rest for upper, 2-5 for lower as needed on really tiring sets.