Do you need to build more muscle to get stronger?

Strength or size: what’s the difference?

Your strength is often measured by your max, your 1RM: the heaviest weight you can lift just once. Your muscle is its size. Both rise together, but not at the same pace: your max is partly a skill, which improves most when you practice it or lift close to your max (Buckner et al., 2017).

Why does your weight rise faster than your muscle?

In a study of 32 young volunteers, those who did 12 weeks of leg extensions saw their weight rise by about 200%, roughly tripling, while the strength of their thigh, measured with the leg held still, rose only 15 to 20%. For the authors, most of it came from better coordination of the other muscles in the movement, like those holding the body steady (Rutherford and Jones, 1986). That’s their conclusion, not a direct measurement.

Skill weighs most early in training, but muscle also starts growing from the outset (Folland and Williams, 2007).

Do you need to get bigger to raise your max?

In 38 beginners, over 8 weeks of leg extension and chest press, one group did 4 sets to failure, the other just up to 5 attempts at their max per session. The first group gained more muscle at most measured sites, but the max rose the same in both (Mattocks et al., 2017).

In 34 trained men, 1, 3 or 5 sets per exercise for 8 weeks: the same progress on squat and bench press, but more muscle with more sets, for example +5.0% versus +13.7% on the side of the thigh (Schoenfeld et al., 2019). Across 67 studies, more sets also add strength, but that gain levels off much sooner than for muscle (Pelland et al., 2026).

Does muscle matter for strength?

Yes, over the years. 16 men trained for 4 years on average, against 52 untrained men: 60% more quad strength, measured with the knee held still, and 56% more muscle on MRI. For the authors, muscle size is the main explanation for that strength (Maden-Wilkinson et al., 2020). It’s a comparison between two groups, not a trial.

The exact role of growth is still debated: for some, it contributes to strength gains (Taber et al., 2019); for others, no experiment yet shows it to be a mechanism (Loenneke et al., 2019).

Do you have to choose between strength and size?

No. A large analysis, 178 studies for strength and 119 for muscle, ranks several heavy sets first for strength, above 80% of max, three times a week; for muscle, several heavy sets twice a week, while all the formulas tested built muscle comparably (Currier et al., 2023).

And for your max, do your heavy sets on the lift itself: it’s a skill, which improves most when you practice it (Buckner et al., 2017).