Sore Isn't Growth: How Hard (and How Much) You Need to Train to Elicit Muscle Growth

Can't walk down the stairs after leg day? That doesn't mean it worked.

I hear it all the time. People training four times a week, chasing that sore feeling, and wondering why their body looks the same as it did six months ago. They're turning up.

They're putting the effort in. It's just not the kind of effort that builds muscle.

In this post I'll cover why soreness is a poor measure of progress, how hard your sets need to be, how much training you need each week, and why doing more past a certain point gets you very little.

Soreness Isn't a Measure of Growth

Muscle soreness, or DOMS (delayed onset muscle soreness), is your body reacting to something it isn't used to. A new exercise, a bigger range of motion, a lot of slow lowering under load. It usually peaks a day or two after the session, then fades.

Here's the bit most people miss. Run the same programme for a few weeks and the soreness drops right off. The muscle growth doesn't. Your body gets used to the work, so it stops complaining about it, but it keeps adapting to it.

So if you've been judging your sessions by how wrecked you feel the next day, you've been measuring the wrong thing. Plenty of productive sessions leave you barely sore at all.

The question isn't "how sore am I?" It's "am I getting stronger?" If the numbers in your notebook are going up over the weeks, you're growing. Sore or not.

What Builds Muscle: Effort

The main driver of muscle growth is tension. Hard sets that take your muscles close to their limit, with a little more weight or a few more reps over time.

The easiest way to judge how hard a set was is reps in reserve, or RIR. At the end of a set, ask yourself how many more reps you could have done with good form.

• 5 or more in reserve: too easy. Not much is happening.

• 1 to 3 in reserve: this is where growth happens.

• 0 in reserve: failure. Useful now and then, not on every set.

Most people stop well short. Ten reps when you had fifteen in the tank doesn't give your body a reason to change.

Here's how I set it up with clients:

• Big lifts like squats, deadlifts and presses: finish 2 to 3 reps short of failure. Your form holds up, and you can keep doing it week after week without getting beaten up.

• Smaller lifts like curls, lateral raises and calf raises: push to 0 to 2 reps short. There's less risk, so you can go closer.

Turning up isn't the same as training hard. Count your hard sets, not your total sets.

How Much: Sets Per Week, Not Per Session

Once your sets are hard enough, the next question is how many.

The research on training volume generally lands on around 10 to 20 hard sets per muscle group per week for building muscle. That's per week, not per session. Split across two sessions, it works out at roughly 5 to 10 hard sets for a muscle each time you train it.

If you're newer to training, or coming back after time off, start at the bottom end. Around 10 hard sets per muscle a week is plenty to grow. Build up from there as your recovery allows.

And don't assume more is automatically better. Which brings me on to the next bit.

Is More Better?

Two hours in the gym doesn't mean twice the results.

Past a point, each extra set adds less and less while the fatigue keeps climbing. A 2025 analysis (Remmert et al.) found the gains from a single session flatten out at around 10 hard sets for one muscle. They don't crash after that, but beyond it you're mostly buying fatigue.

That's what people mean by junk volume. The tenth exercise, done half hearted at the end of a long session, is costing you more than it gives you. The fatigue carries into your next session, your next run and your sleep. And long, draining sessions are harder to keep up week after week, which matters more than anything else on this list.

What I'd do instead:

• 3 to 5 exercises per session

• 2 to 4 hard sets on each

• Stop when the quality drops

• Progress the weight, not the time you spend in the gym

Train harder, not longer.

Putting It Together

Here's what two lower body sessions in a week could look like:

Session A

• Back squat: 3 sets of 6 to 8, 2 to 3 reps in reserve

• Romanian deadlift: 3 sets of 8 to 10, 2 to 3 reps in reserve

• Lying leg curl: 2 sets of 10 to 15, 1 rep in reserve

• Standing calf raise: 3 sets of 10 to 15, 0 to 1 reps in reserve

Session B

• Bulgarian split squat: 3 sets of 8 to 10 each leg, 2 reps in reserve

• Leg press: 3 sets of 10 to 12, 1 to 2 reps in reserve

• Leg extension: 2 sets of 12 to 15, 0 to 1 reps in reserve

• Seated calf raise: 3 sets of 12 to 15, 0 to 1 reps in reserve

That's around 10 to 12 hard sets a week for your quads, 5 direct sets for your hamstrings (add another curl if they're a priority), and 6 for your calves. Each session takes about an hour.

Then write everything down. The weight and the reps, every set. Next week, try to beat one number: a rep more, or a bit more weight. That's progressive overload, and it's the thing that turns hard sessions into results.

The Bottom Line

Soreness isn't the goal. Hard sets taken close to failure, around 10 to 20 a week for each muscle, a handful of exercises done properly, and a little more over time.

Get that right and you'll stop wondering why your body looks the same.

If you want the structure laid out for you, grab my free Training and Nutrition Blueprint from the home page at andrewcainept.com. And if you want a programme built around you and progressed every week, apply for coaching through my website.

Andy.