Dr. Andy Galpin

If you were to break that down, let's say you were focusing, again, on your hamstrings muscles.

If you did three sets on day one,

Three sets on day two and three sets on day three.

That would give you a total of nine working sets per week.

That's probably a little bit too low.

But if you did two hamstring exercises each day, three sets each, that'd be six sets day one, six sets day two, six sets day three.

And now you're up to close to 18 working sets per week.

That's a pretty good spot to be in.

Lots of things we could talk about there in terms of advanced athletes and elite, but structurally and roughly, that's going to put you in the ballpark.

That's going to be enough stimulus for most people to grow most of the time.

Last consideration here is frequency.

As I sort of alluded to here, somewhere between two to three days per week per muscle group is a great way to go about it.

More is fine as well if you can handle the recovery.

Less than two days a week is also theoretically possible.

There's excellent research showing one day a week per muscle group is sufficient to grow muscle.

It does become practically challenging though, because now you've got to fit all those working sets into a single day.

And that is challenging both in the length of the workout, as well as how sore and how much damage you create.

So what I recommend here is what I call the 72 hour rule, which is every 72 hours or so,

Work each of your muscles to a nice pump or contraction.

Remember, we want to stimulate muscle growth here, but we don't want to annihilate the muscle either.