Eccentric vs concentric: what each phase does for strength and size

Eccentric vs concentric is the fancy way of saying lowering vs lifting. Every rep has both. The concentric is the part where the muscle shortens and you move the weight against gravity: standing up from a squat, pressing the bar off your chest. The eccentric is the part where the muscle lengthens under load: sitting down into the squat, lowering the bar to your chest.

The gym-lore version says the eccentric is where the magic happens, so you should lower everything for five seconds. The evidence version is more boring and more useful: both phases build muscle, the eccentric is stronger and makes you sorer, and a controlled tempo gets you nearly all of the benefit. Below is what each phase does, what the research says about concentric vs eccentric hypertrophy and strength, and how to use it without wrecking your legs for Thursday's run. Or let a workout app that actually programs handle the tempo calls for you.

Concentric vs eccentric lifting, defined

There are three types of muscle action:

On most lifts, the concentric is the "lifting" half and the eccentric is the "lowering" half. Running is full of eccentric work too: every landing loads your quads and calves as they lengthen to absorb the impact.

This matters for planning a week, not just a rep. The phase you emphasize changes how sore you get and how your next session feels, which is why the tempo choices in a split built around runs tend to be conservative on leg days.

You're stronger on the way down

You can lower more weight than you can lift. Everyone discovers this the first time they try a pull-up: lowering from the bar is possible weeks before pulling up to it is.

A meta-analysis of eccentric versus concentric training noted that eccentric contractions develop higher loads, and that this likely explains most of their advantage when the two are compared (Roig et al., 2009). In normal lifting, that means the lowering phase of your set is always submaximal. The concentric decides how much weight you can use; the eccentric just has to control it.

That's the logic behind eccentric-emphasis methods: lowering heavier loads than you could lift, or lowering normal loads more slowly, to give the eccentric more work.

Concentric vs eccentric hypertrophy: what the research says

Short answer: both build muscle, and the difference between them is small and uncertain.

• ›A 2017 meta-analysis of 15 studies found eccentric actions produced a slightly larger effect on muscle growth than concentric actions, but the difference wasn't statistically significant. The mean growth across studies was 10.0% for eccentric and 6.8% for concentric training, and the authors concluded a hypertrophy program should include both (Schoenfeld et al., 2017).
• ›A 2025 meta-analysis of 26 studies found no statistical difference between eccentric and concentric training on hypertrophy overall. Some subgroups favored eccentric work, including upper-limb muscles and shorter interventions, but the certainty of the evidence was rated very low (da Silva et al., 2025).

Note what most of these studies compare: eccentric-only training against concentric-only training, often on lab machines. Nobody in a real gym does eccentric-only squats. Every normal rep includes both phases, which is the point the 2017 authors landed on.

So the eccentric hypertrophy vs concentric argument doesn't change much in practice. Train full reps, control the lowering, and count hard sets. The total volume in how many total sets per workout does far more for muscle growth than which half of the rep you obsess over.

What each phase does for strength

Here the eccentric has a clearer edge, with a catch.

The 2009 meta-analysis found that eccentric training at higher intensities increased total strength and eccentric strength more than concentric training, but those gains were more specific to the speed and type of contraction trained (Roig et al., 2009).

A 2025 meta-analysis of 27 isokinetic studies made the specificity point sharper: eccentric-only training improved eccentric strength more than concentric-only training, but the two produced similar gains in concentric and isometric strength (Spudić and Nosaka, 2025).

Translation: you get stronger at the thing you practice. If you want a bigger squat, squatting with full reps (both phases) is still the main event. Eccentric-heavy work is an accessory, not a replacement. The broader trade-offs between training for strength and training for size are in strength vs hypertrophy.

Why lowering makes you sore

Unaccustomed eccentric exercise is well known for causing muscle damage and delayed-onset muscle soreness (DOMS), and the most useful way to avoid that is repeating submaximal eccentric sessions with intensity built up progressively (Hody et al., 2019).

You've felt this. The first time you do Romanian deadlifts or walking lunges after a break, the next two days are stairs-are-the-enemy days. The second time, much less so. Your muscles adapt quickly to the eccentric demand, which is why soreness is a poor measure of whether a session worked.

For hybrid athletes, this is the practical bit:

• ›New eccentric-heavy work goes in gradually. One or two sets the first week, more later.
• ›Keep it away from key runs. Slow-lowering leg work or a new lunge variation the day before intervals is how intervals get bad.
• ›Expect downhill runs to do the same. Running downhill is heavily eccentric for the quads. If a hilly race is coming, build up to it.

How to use tempo

Most people need one rule: control the lowering, don't drop it.

A meta-analysis of repetition duration found similar muscle growth across rep durations from 0.5 to 8 seconds when sets were taken to failure, and suggested very slow reps, over about 10 seconds, may be worse (Schoenfeld et al., 2015). That's a wide window. Any sensible tempo works.

In practice:

• ›Default: lower in about two to three seconds, lift with intent. Fast up, controlled down.
• ›Technique work: slow the lowering to three or four seconds on a new lift to learn the position.
• ›Beginners: a controlled eccentric is how you learn to feel the bottom position of a squat or a push-up. It's part of beginner strength training whether you call it tempo or not.

Eccentric-emphasis methods

Worth a place, occasionally:

• ›Negatives for pull-ups and dips. Jump or step to the top, lower in three to five seconds. The classic way to build toward your first pull-up.
• ›Slow-lowering accessories. Three-second eccentrics on split squats, Romanian deadlifts or push-ups make lighter loads harder. Useful with limited equipment.
• ›Two up, one down. On machines, lift with two limbs and lower with one, which overloads the eccentric without a spotter.
• ›Supramaximal negatives. Lowering more than you can lift. For advanced lifters with a spotter, sparingly. Not a beginner tool.

Rate the effort the same way you would any set; on the RPE scale, a slow-eccentric set at RPE 8 still leaves about two reps in reserve. Slower lowering means you'll need a lighter weight for the same reps. Choosing that load is the same skill as how to choose the right weight for your sets: hit the target reps with a rep or two left.

Myths about the eccentric

"The eccentric is where all the growth happens." Both phases build muscle. The difference in the research is small and uncertain.

"Eccentrics build a different kind of muscle." There's a related debate about sarcoplasmic hypertrophy vs myofibrillar hypertrophy, and another about bigger fibers versus more fibers, covered in our guide to hypertrophy vs hyperplasia. Neither changes the practical answer: full reps, controlled lowering, enough hard sets.

"Slower is always better." Not past a point. Super-slow reps reduce the load you can use, and the repetition-duration meta-analysis suggested reps over about 10 seconds may grow less muscle (Schoenfeld et al., 2015).

"Soreness proves it worked." Soreness mostly proves the work was new.

Where tempo fits in a running and lifting week

If you run, eccentric volume adds up from both directions. Running provides a lot of it already, especially downhill. So for most hybrid athletes:

• ›Keep leg-day tempo normal (controlled, not slow-motion), and save slow eccentrics for upper body and accessories.
• ›Introduce new eccentric-heavy leg exercises in a base phase, not the weeks before a race.
• ›Put the leg session on an easy-run day, away from intervals and the long run, as in all the sample weeks for beginner workout splits.

How exrsz handles it

exrsz builds a periodized plan from your goal, schedule, level and equipment, balances running and lifting in one plan, and keeps hard leg sessions away from hard runs. It adapts each week to how you actually trained and reshuffles missed sessions.

FAQ

What is the difference between eccentric and concentric?

Concentric is the muscle shortening under load (lifting the weight); eccentric is the muscle lengthening under load (lowering it). Most exercises include both in every rep.

Is eccentric or concentric better for hypertrophy?

Both build muscle. A 2025 meta-analysis of 26 studies found no statistical difference between them overall (da Silva et al., 2025), so full reps with a controlled lowering phase are the practical answer.

Why are eccentric exercises more painful?

Unaccustomed eccentric work is known to cause muscle damage and delayed-onset soreness, which fades as you repeat it and build intensity gradually (Hody et al., 2019).

How slow should the eccentric be?

About two to three seconds is plenty for most lifts. Muscle growth was similar across rep durations from 0.5 to 8 seconds (Schoenfeld et al., 2015).

Do negatives help you get a pull-up?

They're a standard coaching tool for it: jump to the top and lower slowly for a few sets, alongside assisted pull-ups and rows.