How much should you reduce when you restart?
According to the ACE article, intensity is the main thing to reduce. Duration and frequency should be scaled back as well, perhaps by 10 to 25%. No source we found gives exact load percentages for lifters, so choose a weight you can move with clean form and stop well short of failure.
How long should the comeback phase last?
The NSCA and CSCCa consensus guidelines on safe return to training provide a framework for the first 2 to 4 weeks after a period of inactivity. Plan a gradual build-up over that period, and take longer after a longer break.
Which exercises should you start with?
Start with movements you already know. Familiar lifts let you focus on form, and you can use simpler versions, such as goblet squats instead of heavy back squats, if you are coming back after injury or a very long layoff.
How do you progress?
Add a little weight or one rep only when your reps are clean and the last set feels controlled. If a session feels harder than expected, repeat the same weight the next time rather than pushing on.
What if something hurts?
Normal soreness is expected after a long break. Sharp pain, or pain that gets worse as you warm up, is a reason to stop or modify the exercise and, if it persists, to see a professional.
Can you protect strength during a short break?
The ACE article says that during a break one resistance session per week can help maintain most previous strength gains.
Roarer shows your last performance while you log, so you can see where you left off and rebuild step by step from your own history.