One set is enough... until it isn’t.

"You can build muscle with just one set per exercise."

I've been hearing this claim for years. Minimalist training advocates swear by it.

But a new study on older adults just dropped some data that challenges everything we think we know about training volume and muscle growth.

The results? Some people literally don't respond to low volume training — but explode with growth when volume increases.

Study: Recent research on 27 older adults (69+ years) comparing 1-set vs 4-sets per exercise over 10 weeks.

The Setup: Each participant had one leg do 1-set training, the other leg do 4-sets. Same person, same genetics, different volumes.

The Results: Researchers found three distinct groups:

Low-responders: No growth regardless of volume (rare)

Medium-responders: Only grew with higher volume (4-sets)

High-responders: Grew with both volumes, but more with 4-sets

Key Finding: Higher volume didn't just add a little extra growth — for many people, it was the difference between growing and not growing at all.

The Molecular Data: High-responders showed increased protein turnover pathways. Medium-responders showed reduced muscle breakdown markers. Low-responders showed no molecular changes regardless of volume.

Let me break this down like you're five years old:

Think of muscle growth like starting a campfire.

Some people (high-responders) can get a fire going with just a few twigs. Others (medium-responders) need more kindling to get the same flame. A rare few (low-responders) have wet wood that won't catch fire no matter what.

For most lifters, volume is like adding more kindling.

One set might not be enough stimulus to trigger growth. But 3-4 sets? Now you're cooking.

But here's where it gets interesting:

This study was on 69-year-old adults. Older muscles need more stimulus to grow because their protein synthesis machinery is rusty.

My take? Young lifters probably don't need as much volume to respond. But we've been overselling the "minimal effective dose" idea.

If you've been doing 1-2 sets per exercise and wondering why you're not growing — you might be a medium-responder who needs more stimulus.

Volume has diminishing returns, but there's a threshold. Going from 1 set to 3 sets can be huge. Going from 10 sets to 12 sets? Probably not worth it.

What I'd Tell Someone Stuck:

Start with your current volume. Add one set per week to each exercise. Keep intensity high (0-2 RIR). Track your response over 4-6 weeks.

Some people recover better on moderate volume anyway. The goal isn't maximum volume — it's finding YOUR optimal stimulus.

True non-responders exist, but they're super rare. More often, "hardgainers" just haven't found their volume threshold yet.

The Bottom Line: If minimal volume isn't working, don't assume you're doomed. You might just need more kindling to get your fire started.

Next week: I'm analyzing new data on rest periods between sets. The results might change how you time your workouts — especially if you're pressed for time.