When to Increase the Weight and How Much
Progression is the key to both strength increase and muscle growth.
Progression can come in several forms but the most common element in progression is adding weight to the bar. But when should you add weight and how much should you add?
How Much Weight to Add
In general, try adding about 5% on upper body exercises and about 10% on lower body exercises as long as you can maintain strict form.
When to add weight
The answer will depend somewhat on your goal.
If you goal is hypertrophy and you are working on a range of 8-12 reps you want to increase the weight when you can perform all of your working sets at the top of that range (12 reps in this example) for two consecutive workouts while maintaining strict form.
You’ll need to adjust this guideline for heavy compound lifts like squats or deadlifts. You should be thinking of your set of heavy compound lifts in terms of a series of singles. For example, instead of 1 set of 12 reps, think in terms of 12 sets of 1 rep. There should be a short pause and a complete reset after each rep to avoid rushing through the reps, losing form and risking injury. Over the years I’ve found it better to start slightly below your target reps for a workout or two. So, instead of increasing the weight and trying to hit in the 8-12 range, shoot for 6 reps for a couple of workouts. Then move into the normal range.
If your goal is strength and you are working in the 3-6 rep range, I’d prefer to hit the top of the range (6 in this example) for at least three consecutive workouts before adding weight. Much of the gains in strength is due to neural adaptation and your central nervous system (CNS) needs a little more time to adjust and recover.